// Acc-JSJ ? *1 h .11L. I I I I I [ r r r r r r r r r r r rMinistry of Water and Energy - Section - I, Volume - II Federal Democratic Republic of Ethiopia_____________________________ Design of Weir & Head Regulator LIST OF VOLUMES SECTION I - DESIGN REPORTS VOLUME I EXECUTIVE SUMMARY VOLUME II DESIGN OF WEIR'AND HEAD REGULATOR VOLUME III DESIGN OF IRRIGATION AND DRAINAGE SYSTEM VOLUME IV DESIGN OF STRUCTURES ON CANAL AND DRAINAGE SYSTEM VOLUME V DESIGN OF HYDROMECHANICAL GATES VOLUME VI INFRASTRUCTURE DESIGN VOLUME VII OPERATION AND MAINTENANCE MANUAL SECTION II - DRAWING ALBUM PART I DIVERSION WEIR AND HEAD REGULATOR PART II IRRIGATION AND DRAINAGE SYSTEM PART III CANAL AND DRAINAGE STRUCTURES PART IV HYDROMECHANICAL GATES PART V ' INFRASTRUCTURE DESIGNS SECTION III - TENDER DOCUMENTS VOLUME VIII BID DOCUMENTS VOLUME IX TECHNICAL SPECIFICATIONS VOLUME X BILL OF QUANTITIES WVVDSE, Addis Ababa in Association with -i-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October. 2011! I ? I I I r r r r F F F F F F f F F FMinistry of Water and Energy - Federal Democratic Republic of Ethiopia TABLE OF CONTENTS Section-I, Volume -1! Design of Weir & Head Regulator LIST OF VOLUMES..................................................................................................................................... I TABLE OF CONTENTS.............................................................................................................................. •• ACRONYMS AND ABBREVIATIONS........................................................................................................ IV 1 INTRODUCTION........................................................................................................ 1 1.1 Scope and Objective of the Detail design Report...............................................................................................1 1.2 Location of Project.......................................................................................................................................... 1 1.3 Altitude............................................................................................................................................................................... 1 2 HYDROLOGY & WATER RESOURCES.................................................................... 2 2.1 The Design Discharge......................................................................................................................................... 2 2.2 Selection of the Recurrence Interval................................................................................................................ 2 2.3 The Design Discharge......................................................................................................................................... 2 3. GEOLOGICAL FEATURES OF THE PROJECT AREA........................................................................ 3 3.1 Weir Site Geology.............................................................................................................................................. 3 3.3 Seismicity of the Area.........................................................................................................................................4 4. DESIGN CRITERIA AND ESTABLISHING DESIGN PARMETERS..................................................... 5 4.1 Components of the Headwork............................................................................................................................ 5 4.2 Headwork Layout................................................................................................... „...........................................5 4.3 Design.Discharge.................................................................................................J............................................. 5 4.4 Weir Site Topography..........................................................................................‘..............................................5 4.5 River Cross Section and Weir Crest Length......................................................................................................6 5. DESIGN CRITERIA AND BASIC CONCEPTS...................................................................................... 8 5.1 Selection of Type of Head Works...................................................................................................................... 8 5.2 Fixing of Crest Level of Weir.............................................................................................................................8 5.3 Shape and Length of Weir................................................................................................................................... 8 5.4 Discharge Carrying Capacfty of Weir............................................................................................................... 9 5.4.1 Discharge through Under Sluice............................................................................................................9 5.4.2 Discharge to be Passed Over the Weir....................................................................................................10 5.5 Leveland Length of Downstream Floor.......................................................................................................... 10 5.6 Cutoffs............................................................................................................................................................ 11 5.7 Total Floor Length and Exit Gradient............................................................................................................ 14 5.8 Design of Downstream Floor Thickness......................................................................................................... 15 5.9 Energy Dissipation...........................................................................................................................................15 5.10 Upstream and Downstream Bed Protections....................................................................................... 16 5.11 Height of Protection Embankment....................................................................................................... 16 5.12 Fixation of Levels of Components of weir........................................................................................... 16 5.13 Control Gates and Operating Platform Level of under Sluice........................................................... 17 5.14 Top Levels of Wing Walls and Return Walls.......................................................................................17 6. HEAD REGULATOR............................................................................................................................ 18 6.1 Setting of Crest..............................................................................................................................................18 6.2 Length of Crest.............................................................................................................................................. 18 6.3 Shape of Crest................................................................................................................................................ 19 6.4 Crest Width.....................................................................................................................................................19 6.5 Level ano Length of Downstream Floor..................................................................................................... 19 6.7 Cutoffs........................................................................................................................................................... 19 6.8 Total Floor Length and Exit Gradient............................................................................................................ 19 6.9 Floor Thickness............................................................................................................................................ 20 WWDSE, Addis Ababa in Association with -ii-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. andABCE PLC October, 2011I I I I I [ I I f r r r i r r r r i rMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator 6.11 Transitions........................................................................................................................................... 20 6.12 Freeboard.............................................................................................................................................20 7. FINAL HYDRAULIC DESIGN PARAMETERS.................................................................................... 21 8. GROOVES FOR EMBEDMENT OF GATES AND THE SUPERSTRUCTURE................................... 22 9. WATER STOPS / PVC SEALS............................................................................................................ 23 10. WATER LEVEL RECORDER..............................................................................................24 11. STRUCTURAL DESIGN......................................................................................................25 11.1 Permissible Stresses in Concrete........................................................................................................25 11.2 Allowable Stresses in Steel................................................................................................................ 26 11.3 Stablity Analysis of Weir and Selection of Material.......................................................................... 26 12. CONSTRUCTION OF FLOOR............................................................................................ 27 13. STABLITY ANALYSIS OF WING WALLS AND DIVIDE WALL........................................ 28 14. DESIGN OF BREST WALL FOR HEAD REGULATOR AND UNDER SLUICE................. 30 15. DESIGN OF BRIDGE SLAB FOR HEAD REGULATOR AND UNDER SLUICE............... 31 16. GUIDE BUNDS AND EMBANKMENTS............................................................................. 32 WWDSE, Addis Ababa in Association with -Hi-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October. 2011IL ILMinistry of Water and Energy - Federal Democratic Republic of Ethiopia ACRONYMS AND ABBREVIATIONS Section - I, Volume - II Design of Weir & Head Regulator ABCE PLC: Amare& Families Consulting Engineers (ABCE) PLC BAGIDP Bale-Gadula Irrigation & Drainage Project CWR Crop Water Requirement CCA Cultivable Commanded Area El Elevation FAO Food and Agricultural Organization FSL Full Supply Level Fig Figure GCA Gross Commanded Area ha Hectare IWR Irrigation Water Requirement Km Kilometer masl Meters above sea level mm Millimeters Mm3 Million cubic meters NIR • Net Irrigation Requirement MC Main Canal WSP Water Surface Profile Z Side Slopes of canal WWDSE, Addis Ababa in Association with -iv-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. andABCE PLC October, 20111 f\ j 5 ■ ■7 I I IMinistry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia______________________________ Design of Weir & Head Regulator 1 INTRODUCTION 1.1 Scope and Objective of the Detail Design Report This report covers the planning and design of Bale GadulaDiversion Weir and appurtenant works. It should be read in conjunction with the drawing album in Draft Detailed Design Report Volume III. The hydraulic design of Weir and Under-sluice is attached as Annexure-I and design of Head Regulator as Annexure-ll, The stability analysis of Divide wall in Annexure-lll, Pier in Annexure-IV, wing walls in Annexure V Design of Brest walls etc. in Annexure VI. and bridges in Annexure-VII. 1.2 Location of Project BAGID project is administratively located in Bale administrative zone of the Oromia National Regional State (ONRS). Goro is the project woreda and the Goro town, the capital of the woreda is located 82km East of Robe town which is currently identified as the capital of Bale zone. Robe is located 380km from Addis Ababa in a general South-Eastern direction via Asela (a town located 175km from Addis Ababa & capital of Arsi Administrative zone). Goro town is located 494km from Addis Ababa, the capital of the nation. The proposed weir site is located 9km from Goro town in its general North direction. The command ^rea is located on the left bank of the Weyb River. Geographically the project command area is located extending from 7°36’N to 7°9'N and 34°28'E to 40°37'E. As per the detail weir site topographical map of the weir site, the river center at the weir site is located at 647319.500 E, 788385.380 N UTM readings. The weir is located across the river Weyb so as to raise the normal water level to divert the required supply into the canals. The Head Regulatoris integrated with the Diversion weir and their purpose is to control supplies of water and prevent sediment into the offtaking canal. The weir bed has a slope of about 8 ml Km (0.008) at this site. The afflux can be accommodated as a low weir is provided. The under-sluices is provided for excluding the silt from the river bed The crest levelsof regulator is provided 1.0 m above the general floor level. 1.3 Altitude The altitude of the river bed at the proposed weir site is approximated at 2073.50masl. The command area starts at an altitude of 2060 OOmasI and extends to an altitude of 1580masl in its downstream tail. The narrow elongated low-lying valley, where the entire command area is located in, has a total length of about 35 km. WWDSE, Addis Abaoa in Association with -1-Detail Design of Bale Gadu/a Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011I i I i » 1 * 1 f r r r r rMinistry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia_____________________________ Design of Weir & Head Regulator 2 HYDROLOGY & WATER RESOURCES Weyb, river is the only available river that can serve as water sources in the project area. Weybriver is circumscribing the command area in the general from the south. The hydrograph at Weyb watershed is gauged at the Goro-Ginir main road bridge located d/s of the proposed abstraction point. Recording has been made since 1986 and mean daily hydrograph data from 1986 to 2005 was made available for the study of the BAGID project. 2.1 The Design Discharge As per the feasibility report of the Meteorological and Hydrological Study of the project component (Vol-3 Annex-1 of the feasibility report) flood frequency analysis technique wasused to fix the design discharge of the Weybriver at the proposed weir site. 2.2 Selection of the Recurrence Interval Basedon the discussions made with the engineering hydrologist and as per design criteria the design discharge for hydraulic design of headworks having 100 years recurrence interval is considered. 500 year interval is considered for the flood protection^works. . 2.3 The Design Discharge The Design Flood (Q ): The occurrence of a certain peak flood of given return d period during the life time of a project is a probability of a given flood that we aspire to safely discharge through hydraulic structures. The design flood is one important design parameter for fixing weir dimensions. Its magnitude has significant role in determining the type and the various components of the weir. The watershed hydrology defines the size of the design flood applying flood frequency analysis techniques. The design discharge at 100 years recurrence interval is estimated to be255 cumec and for 500 year interval as 315 cumec. A design flood discharges with different recurrence intervals and probability of occurrence as simulated by the hydrologist is presented in Table 2.1 below Table 0.1:Flood Discharges at the Proposed Weir Site (Weyb River) Return Period 2 5 10 25 50 100 200 500 1000 10000 Annual daily extreme Flood 86 137 167 203 229 255 281 315 340 426 Source: Vol-3: Annex-1 .Meteorological^ Hydrological Studies Report for BAGID Project (Nov, 2009) WWDSE, Addis Ababa in Association with -2-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011r ft fJLMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume-II Design of Weir & Head Regulator 3. GEOLOGICAL FEATURES OF THE PROJECT AREA According to the seismic risk map of Ethiopia 100 years return period, 0.99 probabilities by Laike Mariam Asfaw, (1986) the country is divided into zones of approximately equal seismic risks based on the known distribution of the past earthquakes. According to this mapping the Bale Gadula weir site and it is command area is located within intensity Zone 5 with ground acceleration of 0.02g. Hence, the project area lies in low seismic risk hazard zone thus the probability of occurrence of earth quake in this area is least. 3.1 Weir Site Geology To investigate the thickness and engineering character of the overburden soil and rock units and to investigate the existing subsurface geological structures at diversion weir site, a shallow depth borehole namely BHBG-1 having a depth of 16.65 m was drilled in the left bank of the river course. Moreover,the geophysical investigation was also conducted to reinforce the sub surface investigation details. Furthermore, 1 test pit namely TPBG-1, was dug along Bale Gadula weir axis. Based on these data geological map and log profile of the geological cross section at the weir site were produced According to this geological investigation the weir site geology consists of: (i) alluvial/ terrace deposit and silty clay soil underlain by (ii) volcanic rock units. The project area lies in low seismic risk hazard zone of Ethiopia thus the probability of occurrence of earth quake in the area is least. The weir site is characterized by residual soil and alluvial overburden material underlain by volcanic rock units. As far as the weir site geological condition is concerned the selected area is suitable since strong and sound bed rock is at a required foundation depth. WWDSE, Addis Ababa in Association with -3-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 20111 I rMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator Figured.1: Geological Map of the Weir Site 3.3 Seismicity of the Area It is indicated that the Bale Gadula weir site and the command area is located within intensity zone of 5, a low seismic hazard zone. According to Johnson (1988), these seismic intensity zones are related to the ground acceleration as follows. Table 3.1: Ground accelerations and Zones Intensity <5 5 6 7 8 Ground Acceleration o.01g 0.02g 0.05g 0.1g 0.2g The seismic zoning of Ethiopia is given in Figure 3.2 Figure 0.2:Seismic Zoning of Ethiopia . V«,S» XX'/ n?l froU'ri E3 uvaear • s ------ UVittiFS ■ »--- tf m ic>»u r "7 L*V5CAri WWDSE, Addis Ababa in Association with -4-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011r r r r r r r i — nMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator 4. 4.1 DESIGN CRITERIA AND ESTABLISHING DESIGN PARMETERS Components of the Headwork The headworks for Bale-Gadula has two major components, the weir proper and the head regulator.The design criteria is already submitted in the Interim ReportVol VAnnexure V Part II. 4.2 Headwork Layout The headwork of Bale-Gadula is aligned perpendicular to the river flow direction having a straight weir proper layout. 4.3 Design Discharge As already discussed, design discharge for the 100 year recurrence interval is taken as 255 cumec and 500 year interval as 315 cumec and selection of recurrence interval 4.4 Weir Site Topography The two major ridges located on the left and right sides of the Weybriver are characterized with long narrow strip running along the course of the river. The altitude of these two ridges is at about 2200masl. In between these two ridges a valley having an altitude of 1800masl is formed. The long and low-lying flat land strip is located in the left bank of the river. The Weybriver bounds the command area in its general south direction. The river course runs close to the foot of the right side ridge. At the foot of this hill the Weyb river forms relatively deeply incised gorge with the depth of the gorge increases in its downstream reach. In some reaches the river bank is as deep as more than 20m and forms a relatively U-shaped river channel. At the proposed weir site the gorge becomes shallow (less than 5m high) and relatively flat in topography. The left bank is as steep as more than 10% and the right bank is less than 5% slope. Altitude ranges from 2073.5 at the river bed of the weir axis to 2080masl at both banks of the river. The right side rises up to 2200masl. The left bank extends at a gentle slope at an altitude of less than 2100m for about 500m and lifted to the ridge as high as more than 2200masl. WWDSE, Addis Ababa in Association with -5-Detait Design ot Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October. 20111^-1Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator Figure 0.1: Weir Site Photo as Taken During Field Investigations on 03 Oct, 2009. 4.5 River Cross Section and Weir Crest Length r During the surveying process 12 river cross sections (four in the d/s reach) were established at the weir site to enable formulating stage-discharge relations for the weir site and also to simulate water surface profiles at the weir site. The stage discharge relation curves for three reaches (one 20m u/s of the weir axis, one at the weir axis and the third 20m d/s of the weir axis) are used to characterize approach velocities and tail water depths of the river inflow at various discharges. The approach velocity is used to compute energy levels u/s of the weir bay and the tail water depth is used to fix the level of the stilling basin floor. Table 0.1: Stage-Discharge Relationship for BAGID Weir Site U/S section At the Weir U/S Section of the Weir Axis Stage (masl) A(m ) 2 P(m) R(m) R (2/3) A N V(m/s) Q(cumecs) 2073.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2074.00 3.6959 14.82 0.249 0.396 0.03 1.14 4.23 2075.00 26.4355 30.86 0.857 0.902 0.033 2.37 62.58 2076.00 64.9003 46.53 1.395 1.248 0.035 3.09 200.46 2076.50 87.60 52.96 1.654 1.399 0.0365 3.32 290.73 2076.55 92.25 53.60 1.721 1.436 0.0365 3.41 314.34 2077.00 117.4831 59.39 1.978 1.576 0.038 3.59 421.93 WWDSE, Addis Ababa in Association with -6-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011J ■- r r r r r r r r f r r nnMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section - /, Volume - II Design of Weir & Head Regulator Figure 0.2: Stage-Discharge Rating Curve at the Axis for BAGID Weir Site WWDSE, Addis Ababa in Association with -7-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011r r r r r r r r Rp* ■** -? n n nMinistry of Water and Energy - Federal Democratic Republic of Ethiopia 5. DESIGN CRITERIA AND BASIC CONCEPTS Section -1, Volume - II Design of Weir & Head Regulator The Weir has been designed to pass a discharge of 255Cumecs; which is the flood discharge for 100 years return period. The free board has been provided considering the HFL for 500 year return floods i.e. 315Cumecs approximately. The hydraulic design calculations of Weir and Under-sluice are shown in Annexure-1. 5.1 Selection of Type of Head Works Various alternatives; envisaged in the design criteria were evaluated. The one that was ultimately considered most appropriate is “Weir without crest gates and with one gated under sluice with a breast wall". The discharging capacity of the under sluice is kept in the range 20% to 25% of the flood discharge. 5.2 Fixing of Crest Level of Weir At the location of selected weir site the river bed level is 2073.5 m and fixation of weir crest elevation and other elevations are arrived accordingly. For fixing crest elevation of minimum height of weir is required to be fixed first. The height of weir is fixed with reference to river bed elevation. The height of weir is fixed from consideration' of silt exclusion, bed level and full supply level of canal, driving head, and allowance for storage. Crest elevation and in turn the height of weir has been fixed from following consideration and boundary conditions; (■) River bed elevation at site of weir 2073.5 masl (ii) Floor level of the Weir/Undersluices Head Regulator -2073.5masl iii) Canal full supply level -2074.1masl iv) Crest level about 1m above the floor level -2074.5 masl (v) Pond level required including - 2076masl minimum driving head vi) Crest level of the weir - 2076.0 masl vii) Height of weir -2.50 m It will not be appropriate to have lower weir than this on account of practical considerations. 5.3 Shape and Length of Weir The weir provided is broad crested trapezoidal shape having upstream slope 1.0H;1V and downstream slope 2H:1V. The top corners of weir rounded by 0.25m radius to provide smooth hydraulic conditions. The shape is considered most appropriate as dictated by the river cross section, requirements of waterway, afflux and approach for inspection and maintenance activities. Constriction of waterway on a lower side is considered appropriate to avoid unwarranted loading of the energy dissipation WWDSE. Addis Ababa in Association with -8-Detail Design of Bale Gadula Irrigation i Drainage Project ICT Pvt. Ltd. and ABCE PLC October. 2011f f F F F F FMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section - I, Volume - II Design of Weir & Head Regulator arrangements. Accordingly the length of the overflow portion of the weir provided is 40.5 m. The under sluice has been provided width as 3.0mfor above considerations . The divide wall in between the overflow portion and the under sluice is 2.0 m wide. This will take care of the separation of flows required as well as the stability requirements. As per Lacey's formula the regime width shall be arrived as: pw = This is works out to 77.3 m Where Pw = Lacey’s minimum waterway Q = Total maximum flood discharge The actual waterway of the weir is decided by trial and error on the basis that around 15 to 20% of the maximum flood discharge should be able to pass through the under sluice, and the balance from over the weir. Provision is also to be made for only one undersluice on left bank for supplying water to the left bank canal. The waterway of 50.00 m is provided which will cater for space for weir, undersluices, Divide Walls and pier of undersluice. The Looseness factor is evaluated as 0.725 and is appropriate and is dictated by the topography. 5.4 . Discharge Carrying Capacity of Weir *” The disch arge carryin g capacit y ha s been calculated F for discharge intensity and head loss under d ifferent flow conditio ns. The wa terw ay is des igned on the basis of high flood discharge for 100 year return period. The energy dissipation device and floor has been designed as per 100 year discharge with 20% concentration and 0.50 m retrogression. The levels of components of weir have been decided on the basis of high flood discharge for 500 year return period. 5.4.1 Discharge through Under Sluice The Under sluice is provided on the left flank - the end from which the canal takes off. As per design criteria, the discharge of under sluice should not be less than two time discharge of canal when water level is at crest elevation. It should also be in the range of 15% to 20% of the Flood Discharge. The size and crest level has been arrived at from these considerations. The under sluice is aligned in line with axis of weir. The discharge through under sluice for various conditions of the upstream water and downstream has been computed details of which are explained in Annexure-1. The under sluice is provided as 3.0 m wide and 2.65 m high orifice having crest level by 0.20 m above upstream river bed level i.e. 2073.5 m. Discharge through under sluice is calculated for two conditions; (i) Maximum Flood (100 Year Return Period) When the water elevation is at high flood level of 2079.1 m in upstream, downstream water level is also at highest flood level of 2076.2 m. The under sluices shall work as drowned orifices. WWDSE, Addis Ababa in Association with -9-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section - I, Volume - II Design of Weir & Head Regulator Discharge through drowned orifice shall be obtained by formula Q = Cd x L(eff) x d x [ Hj + Va] Where, Cd = Coefficient of discharge, 0.65 L(eff) = Effective length d = Orifice height H, = Upstream Head H2 = Downstream Head Va = Velocity of approach Discharge passing through under sluice is 59.53 cumec out of maximum flood discharge of 100 year return period 255cumec which is 23% and fulfill the design criteria. (ii) Flow at Pool Level (with full gate opened) Discharge through under sluice for the condition when the upstream water level is at pool level of 2076.00 m and no water in downstream has been calculated. Under this condition the openings of under sluices shall work as free orifice. Discharge through free orifice shall be obtained by formula Q = Cd x L(eff) x d x J2gh Where, Cd = Coefficient of discharge, 0.60 L(eff) = Effective length d = Orifice height and h = Head over centre of opening Discharge passing through under sluice is calculated 59.53cumec at pond level. 5.4.2 Discharge to be Passed Over the Weir The crest width of the weir shall be kept 2.00 m. The head over the crest is 2.2 m which is less than 1.5 times the width of crest. Thus the weir will behave as broad crested weir. Discharge passing over broad crested weir Q = 1.705 xCx Lx Where, L = Length of crest of weir and H = Head over crest. C is the coefficient based on degree of submergence. Hence, Discharge passing over weir is 225.32cumec 5.5 Level and Length of Downstream Floor The downstream floor is designed for different section for varying uplift pressure for the worse of the followings. WWDSE, Addis Ababa in Association with-10-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011[■"- 1 r- i1 - -------- ’--------- . ‘ mhj * ;v '3i *'Ministry of Water and Energy - Section - I, Volume — II Federal Democratic Republic of Ethiopia__________________________ Design of Weir & Head Regulator (i) Maximum flood passing over crest and hydraulic jump is formed (ii) Water level upstream at pond level and no water downstream For these conditions of flow, the discharge intensity ‘q’ and head loss 'HL' is worked out. q =£ and H = upstream TEL - downstream TEL L Knowing q and H[_ corresponding value of Ef2 is read from Blench Curves (Figure 1.6). Then, Downstream floor level = downstream TEL - Ef2 Length of downstream floor Ef1 = Ef2 + H|_(worked out E^) Knowing the values of 'q', E^ and Ef2 for different flow conditions, the values of D and D2 (Depths of streams entering and leaving the standing wave are 1 read from Montague specific energy of flow curves given below. Cistern elevation = Downstream tail water elevation - D2 (depth of hydraulic jump) The length of downstream floor i.e Cistern length = 5to6(D2~D1) * r 5.6 Cutoffs RC cut offs are provided on upstream and downstream as per scour depth requirements keeping the practical considerations in view. The cut offs shall be provided at the end of upstream and downstream floors for safety against scour, undermining ano exit gradient. The depth of cutoffs provided should be such that the length of floor is practical Table 5.1: Minimum Depth of Cutoff S.No Discharge (cumec) Minimum Depth of u/s Cutoff below u/s bed level Minimum Depth of d/s Cutoff below d/s bed level 1 Up to 3 1.00 m 1.20 m 2 3 to 30 1.20 m 1.50 m 3 30 to 150 1.50 m 1.80 m 4 Above 150 1.80 m 2.00 m However, 3 m depth of cutoff has been provided. WWDSE, Addis Ababa in Association with -11-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia_____________________________ Design of Weir & Head Regulator Figure 5.1 : Blench Curves i Hl metre ■> -a « WWDSE, Addis Ababa in Association with -12-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd and ABCE PLC October, 2011r r r rMinistry of Water and Energy - Section - I, Volume - II Federal Democratic Republic of Ethiopia______________________________ Design of Weir & Head Regulator ;|r- I ’ll . *r i Figure 5.2 zMontague Curves WWDSE, Addis Ababa in Association with -13-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011fj rJ r>Ministry of Water and Energy - Section I, Volume II Federal Democratic Republic of Ethiopia_______________________________Design of Weir & Head Regulator The depth of downstream cutoff shall be provided from safe exit gradient considerations as per given in table below. Tables.2 Safe Exit Gradient for Various Soils S.No Type of Material Safe Exit Gradient 1 Shingle 1/4 to 1/5 2 Coarse Sand 1/5 to 1/6 3 Fine Sand 1/6 to 1/7 In case of BaleGadulaExit Gradient is taken as 1/4 5.7 Total Floor Length and Exit Gradient The weir floor is subjected to the maximum static head when the river is closed and the full supply level is maintained in the upstream at pool level. Thus maximum static head (H) = Pond Level - Downstream bed level Keeping maximum static head (H) and the downstream cutoff depth (d), work out the value of Lj~x-g ^L and for this value read a from khosla’s curve /r x EH given below The total floor length will be a x d. The crest level and the downstream floor level are joined with a sloping glacis of minimum slope 2:1. The balance of the floor length is provided in the upstream. If the total floor length works out excessive as mentioned above, the depth of downstream cutoff should be increased and floor length reduced keeping safe exit gradient. As a matter of fact the most suitable combination of total ^loor length and depth of downstream cutoff should be decided on the basis of economic considerations after meeting the minimum hydraulic requirements. Figure 5.3:Khosla Curves 2s 2O o 1O o v~» 5 WWDSE, Addis Ababa in Association with -14-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October. 2011Ministry of Water and Energy - Section - I, Volume - II Federal Democratic Republic of Ethiopia_____________________________ Design of Weir & Head Regulator 5.8 Design of Downstream Floor Thickness The maximum uplift pressure shall act on downstream floor when there is water up to pond level elevation on upstream and no water on downstream. The pressure calculations have been carried out according to the standard international practices. (i) Downstream floor thickness Floor thickness can be evaluated by work out the pressure variation at various points by Khosla’s analysis. Floor Thickness = (Px/7)/(5p.Gr.-l)xl00 Where H = Maximum static head = Upstream pool level - Downstream bed level P = Uplift pressure at that point (ii) Upstream floor thickness Since there is no pressure of water or uplift pressure, 1.00 m thick floor is provided and it is minimum arrived by design calculations. The top 300 mm is wearing coat in M-25 where the rest part is in Concrete M-20. The reinforcement provided jn the wearing coat is nominal, which will take of the temperature variation and static load variation. The floor level is kept equal-to river bed elevation. The floor will be thickened under the crest by the amount equal to height of crest. Generally gravity floors in Cement Concrete (1:2:4) M-20 grade concrete are provided and made safe against uplift pressure for the following conditions unless the thickness of floor works out to be excessive. In such cases raft floor is provided. For calculating the weight of the concrete specific gravity of the concrete shall be taken equal to 2.24 (submerged 1.24). 5.9 Energy Dissipation For energy dissipation hydraulic jump stilling basin with horizontal apron has been provided. The Cistern elevation and length are worked out on the basis of total energy lines. Standard energy dissipation devices have been provided. The detailed computations are given in Annexure 1, the design of Weir and Under-sluice. For horizontal apron there are two types of apron, a selection of which is dependent on Froude number. Froude number is given as; Froude number, F = -^= Where V = Velocity at jump point d = Depth of water at jump point For calculating V1 and D1; total energy line elevation above downstream riverbed and upstream of weir and at hydraulic jump shall remain same. So WWDSE. Addis Ababa in Association with -15-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd and ABCE PLC October. 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section-I, Volume-II Design of Weir & Head Regulator equating the total energy lines at two section, values of V1, and D1; shall be worked out. Basin type shall be chosen on the basis of the calculations and basin-1 is provided when Froude number is up to 4.50 and basin-ll in case it is higher than 4.50. Standard energy dissipation devices have been provided. 5.10 Upstream and Downstream Bed Protections Scour depth (R) for looseness factor less than 1.0 is given by formula; Where f = silt factor considered as 1.0 depend upon grain size q = Discharge intensity The anticipated scour depth has been considered 1.5 R for upstream protection works and 2 R for downstream protection works. Downstream of impervious floor, properly designed filter loaded by cement blocks should be provided. The length of inverted filter may be kept as 2 D where D is the Scour depth below downstream bed The overall size of block and minimum thickness of the filter shall be as given in table as under. The width of gap between the blocks is kept 50 mm. The gap shall be packed with large size pebbles/aggregates. Beyond inverted filter launching apron is provided equal to 2.25 D cubic m/m length. A toe wall is provided between Invert filter and launching apron to intact the invert filter blocks. Similarly block protection in the upstream is provided in a length equal to D cubic m/m length. The cubic content of material in launching apron should be equal to 2.25 D cubic m/m length. 5.11 Height of Protection Embankment The top elevation of protection embankment has been fixed taking into consideration the requirement of the “minimum free board over maximum flood level". For free board computation the high flood discharge for 500 years return period is considered and a freeboard of 1.50 m has been provided. Top elevation of protection embankment shall be fixed taking into consideration of the following: • Upstream River Bed Level • Upstream High Flood Level (500 years) - 2073.50 masl - 2078.50masl • Top level of protection embankment (Free board 1 50m) - 2080.00masl Thus, total height of protection embankment is provided as 6.5 above upstream floor 5.12 Fixation of Levels of Components of Weir Fixation of elevation for components from free board consideration is computed for 500 years period flood and free board of 1.50 m is considered WWDSE, Addis Ababa in Association with -16-Detail Design o/ Bale Gadula Inigation & Drainage Project ICT Pvt Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Section - I, Volume - II Federal Democratic Republic of Ethiopia_____________________________ Design of Weir & Head Regulator for top level of divide wall, operating platform and protection embankments, whereas the top level of wing walls has been kept 0.50 m higher than protection bunds to check the entry of soil and debris in the river and standard railing is provided along wing walls at river side as well as along divide wall at both side for safety point of view. 5.13 Control Gates and Operating Platform Level of under Sluice The under sluice is provided with fixed wheel vertical lift gate. The clearance between the top level of the opening and the operating platform is 4.25 m which is more than the gate height. This will not only facilitate the operations of vertical lift gate in all conditions including the high floods but will ensure uninterrupted access. An emergency gate is provided to facilitate maintenance and repairs to the service gate The service gate is up stream skin plate - up stream sealing type were as the emergency gate is also upstream skin plate - upstream sealing. 5.14 Top Levels of Wing Walls and Return Walls Wing walls are provided to define and protect the River channel on upstream and downstream of the weir structure. HFL computed (2078.5 m) for 500- years period flood is considered for fixing the top levels of wing walls and the dived wall. The free board provided is 1.50 m for the divide wall and the wing walls. The top elevation of the operating platforms of under sluice and the head regulator is 1.50 m above the HFL. The role of the divide wall is separation of flows over the overflow section and through the under sluice. WWDSE, Addis Ababa in Association with -17-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia 6. HEAD REGULATOR Section - I, Volume - II Design of Weir & Head Regulator One Head Regulator is provided at the head of the main canal MC-1 on the left bank to control the supplies entering the canal and is designed so as to prevent entry of silt. The measuring staff gauge will be painted upstream of the gates on wing wall. This can read the upstream water level and the discharge can be calculated by using the standard design formula by reading the gate opening. The levels will be noted in the gauge register kept at site. The hydraulic design calculations in detail are shown in Annexure-2. For the Left Bank head regulator. 6.1 Setting of Crest The crest level of Head Regulator is kept 1.00 m higher than the upstream canal bed level or downstream canal bed level whichever is higher. The crest level is provided at 2074.50.The crest level of under sluice is kept 2073.50 m, thus the crest level of Head Regulator is higher than the crest level of under sluice by about 1.00 m which is sufficient to prevent sediment entry in the canal. 6.2 Length of Crest The length of crest i.e. waterway (L) of head regulator should be such so as to pass the designed discharge into the off taking canal. The Drowned Weir Formula is normally used to calculate the Waterway Q = Q1 + Q2 = free weir discharge +drowned part discharge £?, = + -h/2] O = Cd Lh\y]2g(h + h ) 22 a (Free weir equation) (Drowned weir equation) Hence, Q = Lcd^lgUh + h,)y/l - />/] + Cd Lhj2g(h + h,) } Where, Q = Discharge passing through Regulator h = Difference in Upstream FSL & Downstream FSL of canal ha = Head due to velocity of approach hi = Depth of Downstream FSL above Crest Level Cd! = 0.577 and Cd = 0.800 2 Calculate the Crest Length and provide it on higher side to assure the full supply discharge to meet fluctuation in upstream full supply level in parent canal or pool level. However use of these formulae will depend on the degree of submergence. WWDSE. Addis Ababa in Association with -18’Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of EthiopiaDesign of Weir& Head Regulator 6.3 Shape of Crest Section — I, Volume II Upstream face of the crest shall be vertical. The down-stream sloping glacis should not be steeper than 3H:1V and the comers at the crest should be rounded for better efficiency. 6.4 Crest Width Width of the crest shall be kept equal to 2.00 m. However with the provision of the emergency gate, the crest is widened. 6.5 Level and Length of Downstream Floor This is worked out for the following conditions: (i) Design discharge passing through Head Regulator and hydraulic jump is formed (ii) Water level upstream at high flood level and no water downstream of canal Downstream floor level = Downstream TEL - Ej2 Cistern elevation = Downstream tail water elevation - D2 (depth of hydraulic jump) The length of downstream floor i.e. Cistern length = 5 or 6 (D2 - D^ The values of E(2 D-j and D2 will.be works out similarly as in design of weir. 6.7 Cutoffs The cut offs shall be provided at the end of upstream and downstream floors for safety against scour, undermining and exit gradient. The upstream cutoff shall be carried out to Lacey’s scour depth to provide for safety of the structure, even when the lining in the parent canal gets damaged. However in small structures, like these, the depth of cutoff should be more than the depth of the foundation of the wing wall or pier. Depth of cut off less than the depth of foundation dees not mean anything. 6.8 Total Floor Length and Exit Gradient The regulator floor is subjected to the maximum static head when the canal is closed and the full supply level is maintained in the upstream for the feeding the off-take canal. Thus maximum static head (H) = Upstream HFL - Downstream bed level Keeping maximum static head (H) and the downstream cutoff depth (d), work out the value of = C x d_ and for this value read a from khosla’s /r £' H curve(Figure 1.8). The total floor length will be a x d WWDSF, Addis Ababa in Association with -19-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section - I, Volume - II Design of Weir & Head Regulator The crest level and the downstream floor level are joined with a sloping glacis of minimum slope 2:1. The balance of the floor length is provided in the upstream. If the total floor length works out excessive as mentioned above, the depth of downstream cutoff should be increased and floor length reduced keeping safe exit gradient. As a matter of fact the most suitable combination of total floor length and depth of downstream cutoff should be decided on the basis of economic considerations after meeting the minimum hydraulic requirements. 6.9 Floor Thickness (i) Downstream floor thickness Floor thickness can be evaluated by work out the pressure variation at various points by Khosla’s analysis. Floor Thickness = (Px/f)/(Sp.(7r.-l)xl00 Where H = Maximum static head = Upstream HFL - Downstream bed level P = Uplift pressure at that point (ii) Upstream floor thickness The net uplift pressure on the upstream floor will be nil as all the uplift pressure shall be counter balanced by the weight of standing water. Theoretically, no floor thickness is required however minimum equal to near the downstream end shall be provided. The floor shall be thickened under the crest by the amount equal to height of crest. Generally gravity floors in Cement Concrete (1:2:4) M-20 grade concrete are provided and made safe against uplift pressure for the following conditions unless the thickness of floor works out to be excessive. In such cases raft floor is provided. For calculating the weight of the concrete specific gravity of the concrete shall be taken equal to 2.24 (submerged 1.24). 6.11 Transitions The downstream wing wall shall be splayed from downstream end of cistern to end of downstream slope length and vertical section of canal widen from crest length (Waterway) to downstream bed width. The downstream profile wall shall be embedded by 1.00 m into the bank beyond top of bank line for head regulator. 6.12 Free Board The free board shall be adopted as provided in design of feeder canal and it is 0.70m. The hydraulic design calculations of the Head Regulator are given in Annexure-2. WWDSE, Addis Ababa in Association with -20-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy • Section - I, Volume - II Federal Democratic Republic of Ethiopia_________________________ Design of Weir & Head Regulator 7. FINAL HYDRAULIC DESIGN PARAMETERS The final hydraulic design parameters shall be presented in table below for easiness of reference and use in other designs and report as well as for future operation and maintenance. Table7.1 : Final Hydraulic Design Parameters S.No Description Unit Weir Under sluice Head Regulator 1 River bed level Masi 2073.5 2073.5 2073.5 2 H.F.L (For 100 year) Masi 2078.1 2078.0 2078.0 3 H.F.L. (For 500 year) Masi 2078.55 2078.5 2078.5 4 Afflux M 1.9 1.8 2.075 5 Crest level Masi 20760 2076.0 2076.0 6 Height of weir M 2.5 0.00 - 7 Height of Clear Opening M - 2.5 1.50 8 Pond Level Masi 2076.0 2076.0 2076 0 9 Lacey's waterway M 77.13 10 Waterway M 40.50 7.5 2.0 .41 Thickness of Divide Wall M 2.Op - ‘"12 Overall waterway M 50.00 - 13 Looseness factor - 0.725 - 14 Discharge cumec 225 32 59.53 3.5 15 Total Discharge cumec 284 3.5 16 Cistern Level Masi 2072.50 2071.50 2072.4 17 Cistern length M 17 17 9 18 Total Floor Length M 33 33 WWDSE, Addis Ababa in Association with -21-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd and ABCE PLC October. 2011Ministry of Wafer and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia______________________________ Design of Weir & Head Regulator 8. GROOVES FOR EMBEDMENT OF GATES AND THE SUPERSTRUCTURE Grooves for Embedment of anchors have been provided in the left side wing wall and the divide wall for under sluice service and emergency gates. Hoisting arrangements/ hoisting platform have been provided for operation of gates. Appropriate structure to support crane for lifting has also been provided as shown in detail in the design of gates. The details of the exact sizes of grooves shown are tentative and shall be finalised in consultation with the supplier. Grooves for embedment will have to be provided in the under-sluices and Head Regulator at the crest i.e. seat of gate in closed position and on sides of abutment/divide wall etc. Similarly the embedment will have to be provided for the Stop-log gates at the crest and divide wall and left abutment. Hoisting arrangements/Hoisting platform for operation of gates will be required to be provided. Also structure to support crane for lifting the stop log gates of under-sluices will have to be provided. For these, grooves shall be left for supporting the bolts of foundation of superstructure on top of abutment and divide wall. WWDSE Addis Ababa in Association with -22-Detail Design of Bale Gadula Irrigation i Drainage Project ICT Pvt. Ltd. and ABCE PLC * October. 20n[ L JI rJl r> r» r1 r1Ministry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia_______________________________ Design of Weir & Head Regulator 9. WATER STOPS / PVC SEALS The weir should be constructed in blocks to prevent the formation of cracks due to shrinkage. Water seal or water stops of about 300mm wide and 10mm thick shall be provided at every construction joint. The weir shall be constructed of Cement Concrete M-20 with boulders embedded in concrete with cement concrete C-25 wearing coat 0.30 m thick. Since continuous construction of weir for such long length is not done, it is proposed to construct weir in 4 blocks of 10 m length. Thus, there shall be a construction joint at every 10 m to stop water leakage from joints. The PVC seals shall be provided at the following locations • Junction of right wing wall and the weir body, • Junction of divide wall and the weir body, • Between the weir monoliths and • Weir floor concrete and raft foundation of under-sluices, VVWDSE, Addis Ababa in Association with -23-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia______________________________ Design of Weir <& Head Regulator 10. WATER LEVEL RECORDER Three gaugewellsare provided; one in the pond - upstream of weir, one on the downstream of weir in the river channel and the third downstream of the head regulator. Two of the wells will be within the divide wall where as the third will be on the canal bank. All the locations will ensure still water for the measurement gauges. Self (automatic) water level recorders are proposed to be installed suitably to record the water levels round the clock. The gauges shall be calibrated and a standard discharge rating curve prepared for discharge measurement and monitoring. WWDSE, Addis Ababa in Association with -24-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC * Ocfc^err r r rMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section - /, Volume - // Design of Weir & Head Regulator 11. STRUCTURAL DESIGN L 1 I 11.1 Permissible Stresses in Concrete Allowable stresses depend on the grade of concrete used. All RC structures are designed with C20 concrete. The RCC designs are based on the provisions Indian Standard 456. For C20 concrete, following stresses have been allowed [i 1 Characteristic strength of C20 concrete Compressive stress in bending Direct Compression Permissible stress in bond Modular Ration m Shear stress checking for values of 200kg/sq cm i.e. 20N/mm2 70 Kg /sq cm i.e. 7 N/mm2 50 Kg/sq cm i.e. 5 N/mm2 8 kg/sq cm i.e.0.8 N/mm2 13 100/15 as given in table below. bd Table11.1 : Permissible Stresses in Concrete Grade of Concrete Permissible stress in compression (N/mm2) Bending (ocbc) Direct (occ) Permissible stress in Bond (Average) for plain bars in tension (N/mm2) Tbd M15 5.0 4.0 0.6 M20 7.0 5.0 0.8 M25 8.5 6.0 0.9 I ■ M30 10.0 8.0 1.0 Table'll.2 : Permissible Shear Stresses in Concrete 100.45 bd Permissible shear stress in concrete Tc, N/mm2 for grades of concrete C15 C20 C25 C30 S0.15 0.18 0.18 0.19 0.20 0.25 0.22 0.22 0.23 0.23 0.50 0.29 0.30 0.31 0.31 0.75 0.34 0.35 0.36 0.37 1.00 0.37 0.39 0.40 0.41 1.25 0.40 0.42 0.44 0.45 1.50 0.42 0.45 0.46 0.48 1.75 0.44 0.47 0.49 0.50 2.00 0.44 0.49 0.51 0.53 2.25 0.44 0.51 0.53 0.55 2.50 0.44 0.51 0.55 0.57 WWDSE. Addis Ababa in Association with -25-Detail Design cf Bale Gadula litigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October. 2011 1Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator IO(Ms bd Permissible shear stress in concrete Tcr N/mm2 for grades of concrete C15 C20 C25 C30 2.75 0.44 0.51 0.56 0.58 2* 3.00 0.44 0.51 0.57 0.60 2 11.2 Allowable Stresses in Steel Steel reinforcement used is High Yield Strength Deformed (HYSD) bars conforming to Ethiopian Building Code Standard Fe 430 (equivalent Indian Code 1786-1979 Grade 415). All structures except the bridge slabs are in constant touch with water and hence reduced strengths shall be considered as for Liquid retaining structures. Tensile stress in bending 1500 Kg/sq cm i.e. 150 N/mm is considered. 11.3 Stablity Analysis of Weir and Selection of Material The height of weir above the River Bed Level is only 2.5 m. and the top width is 2.00 m. The up stream and down stream slopes of trapezoidal shaped weir are 0.5H:1V and 2H:1V respectively. This geometry preempts necessity of any kind of stability analysis exercise. Concrete is considered as the most suitable material for construction/ The entire weir can be constructed in one working season subject to resource availability and advance planning of diversion. In that case there is no point in going for a concrete and masonry combination for the weir body. As such concrete weir is proposed. The exposed surface is in M25 Concrete. This concrete is provided with nominal reinforcement to take of temperature variation and erosion. Asconcludedinthediscussionsinparagraphongeologyabovethesafebearingavail ableatthislevelwillbeinexcessof40t/m2anditwillsafetohavethefoundation at this level. In case, at the construction stage, it is found that the scour depth and bearing capacity considerations allow raising of foundation levels, so may be done. The grade proposed for core concrete is M20. The grade of foundation concrete is M15; a 0.300 m thick leveling course is proposed to be laid below the foundation concrete. The actual thickness shall be in consonance with the excavation profile. WWDSE, Addis Ababa in Association with -26-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011r r r r r r rMinistry of Water and Energy - Federal Democratic Republic of Ethiopia 12. CONSTRUCTION OF FLOOR Section - I, Volume - II Design of Weir & Head Regulator The thickness of floor varies from 1.400 mm down to 2.4 m. The top 300 mm is wearing coat in M-25 where the rest of the portions are in Cement Concrete M-20. The reinforcement provided in the wearing coat is nominal, which will take of the temperature variation and attrition. The floor invert is varying being determined by the hydraulic considerations described in Annexure 1. r WWDSE, Addis Ababa in Association with -27-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011J t ■ iMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section - I, Volume - II Design of Weir & Head Regulator 13. STABLITY ANALYSIS OF WING WALLS AND DIVIDE WALL Detailed Stability Analysis has been carried out for sections in different reaches of wing walls and the divide wall. Horizontal forces on account of water pressure and the soil pressures; both active and passive have been considered. It is ensured that the factor of safety against sliding and overturning, specified below, are attained. Factor of safety in Sliding > 1.50 Factor of safety in overturning >2.0 These factors will be reduced while checking in earthquake conditions. The sliding and overturning phenomenon are considered at the foundation level. Since for the levels in between, for which the stability is checked, it is sufficient to ensure that the Pmax and Pmin are within the permissible limits. The permissible stresses referred to here in are In Compression In Tension Masonry Concrete 0.70 KN/ M2 r 70 KN/ M2 0.1 KN/ M2 3.0 KN/ M2 The stresses computed are within these limits as can be seen from the analysis given in Annexure-3. The permissible stresses in seismic condition are increased by 33% as specified in the code. In absence of conclusive exploration data it is assumed that the safe bearing capacity available all the component of the head works is 40 tons/ m2.which is quite safe as hard rock is expected at foundation level. This is very reasonable. However this needs to be reassessed at the time of construction. The bearing pressures are within this. The sections are so designed that there is no tension what so ever for any of the loading conditions and no pressure redistribution is resorted to. The retaining walls are proposed to be constructed in masonry (CM 1:3). This is proposed in view of the availability of local material, skills as well as the economy. They are gravity structures and option of masonry is considered appropriate. The wing walls are extended as dog legged returns on upstream and downstream ends. The flaring provided is of 30% and the walls dip with a slope of 2H:1V. The returns have a minimum height of 1.00 m and are continued inside the bank for two meter. The coping provided is in M-20 concrete and the footing is in M-15, details of which are shown in related drawings. The divide wall is proposed to be constructed in M-20. The stability analysis carried out is on the lines of that of the wing walls. Two Inspection decks one on upstream and the other on the downstream, are provided for facilitating WWDSE, Addis Ababa in Association with -28-Do(ail Design of Bale Gadula Irrigation £ Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section - I, Volume - II Design of Weir & Head Regulator inspection. The stilling wells are accommodated within the deck area. The design of divide wall as well as inspection deck attached as Annexure III. The wing walls are provided with M.S. Railing on water side for safety of inspection. The divide wall is provided with M.S. Railing on both sides. The top of all these walls is to be provided with non skid surface. Steps are provided to negotiate the level difference between the upstream and downstream reaches of the walls. The design of railing is also given. H/WDSE, Addis Ababa in Association with -29-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section - I, Volume - II Design of Weir & Head Regulator 14. DESIGN OF BREST WALL FOR HEAD REGULATOR AND UNDER SLUICE (1) Brest wall for under sluice: The RC breast wall 0.75 m thick has been designed for hydraulic head one meter above the HFL. The lower 1.25 m depth of the breast is also designed to functions as the breast beam. The bell mouth and platform projecting from the breast wall are provided with nominal reinforcement since they have no structural function or loads The Design calculations are given in Annexure-VII B. (2) Brest wall for Head Regulator: The RC breast wall 0.50 m thick has been designed for hydraulic head one meter above the HFL. The lower 0.90 m depth of the breast is also designed to functions as the breast beam. The bell mouth and platform projecting from the breast wall are provided with nominal reinforcement since they have no structural function or loads. The Design calculations of Brest Wall are given in Annexure-VI. I/VWDSE, Addis Ababa in Association with -30-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. andABCE PLC October. 2011F' »: n j Hi ItMinistry of Water and Energy - Federal Democratic Republic of Ethiopia Section-I, Volume - II Design of Weir & Head Regulator 15. DESIGN OF BRIDGE SLAB FOR HEAD REGULATOR AND UNDER SLUICE The road bridge is provided for head regulator having clear span 2.00 m and carriage way width 4.50 m whereas the clear span of under sluice is 3.00 m. The road bridge over under sluice is designed for 3.50 m width for making approach to divide wall for inspection and for installation of gate equipments. The design calculations of bridge slab for Undersluices and Head Regulator are attached as Annexure VII. WWDSE, Addis Ababa in Association with -31-Detail Design of Bale Gadula Irrigation & Drainage Project ICT Pvt. Ltd. and ABCE PLC October, 2011Ministry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia________________________ Design of Weir & Head Regulator 16. GUIDE BUNDS AND EMBANKMENTS There is no need of any Guide bunds in Bale GadulaDiversion Weir as the river section is narrow and length of structure is almost equal to the width of river. However,the banks shall be provided with freeboard of 1.50 m, above the highest flood level (HFL) for 1 in 500 years return period, has been provided. WWDSE, Addis Ababa in Association with -32-Detail Design of Bale Gadula Irrigation A Drainage Project ICT Pvt. Ltd and ABCE PLC October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator Annexure-I Design of Bale Gadula Weir and Undersluice 1. DESIGN DATA i) Average bed slope of river ii) Pond Level iii) Lacey's silt factor iv) Safe exit gradient v) Concentration of discharge vi) Bed retrogression vii) Manning's n for flood conditions 0.008 2076.00 5 1 in 4 20% 0.5 m 0.065 viii) Design flood discharge for 100 yr frequency 255 cumec ix) HFL corresponding to Design High Flood 2076.2 m 2. STAGE DISCHARGE CURVE Table 2.1 : Stage-Discharge Relationship for BAGID Weir Site U/S section At the Weir U/S Section of the Weir Axis Stage * r (masl) I A(m ) 2 P(m) R(m) R (2/3) A N V(m/s) Q(cumcs) 2073.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2074.00 3.6959 14.82 0.249 0.396 0.03 1.14 4.23 2075.00 26.4355 30.86 0.857 0.902 0.033 2.37 62.58 2076.00 64.9003 46.53 1.395 1.248 0.035 3.09 200.46 207650 87.60 52.96 1.654 1.399 0.0365 3.32 290.73 2076.55 92.25 53.60 1.721 1.436 0.0365 3.41 314.34 2077.00 117.4831 59 39 1.978 1.576 0.038 3.59 421.93 WWDSE, Addis Ababa in Association with ICr Pvt. Ltd. andAOCE PLC 1- Delail Design of Bale Gadula Irrigation A Drainage Project October, 20111 r1 r1 r1 —Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Regulator Annexure-I Stage Discharge curve WWDSE, Addis Ababa in Association with ICT Pvt. Ltd and ABCE PLC -2- Detoil Design of Bale Godula Irrigation & Drainage Project October, 2011IMinistry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia______________________________________________ Design of Weir & Head Reg ulotor Annexure-I 3?0 FIXATION OF CREST LEVEL AND WATERWAYS The deepest river channel is approximately 2073.50 and hence the upstream floor of under sluice is kept as 2073.50 In case of weir portion, it is recommended that a weir with raised crest withCrest level of 2076.00 should be provided for achieving maximum head for commanding the irrigated area. Pond level required for feeding the canal system is thus provided at 2076.00. The Wetted perimeter for a Design Flood of 255 cumec shall be as follows. Pw=4.83xQA0.5 Pw=4.83x255A0.5 Pw=77.13m Such a width is not available at site and hence the structure will be adjusted as per topography. The following is tried for discharge calculations 4.0 COMPONENTS OF HEAD WORKS 4.1 UNDER SLUICE BAY *. • i) 2 Bays of 3.0 m each ii) 1 pier of 1.5 m overall waterway=6.5m 4.2 WEIR BAY 40.5 m bay is proposed. 4.3 OTHER RELATED STRUCTURES Provide a divide wall of 2 m width Total width of head work between abutment =40.5+2+3.0+1.5+3.0=50.0 m 5.0 Discharge Caopacity of Structure 5.1 Discharge passing through the Weir Assume u/s HFL=2078.1 Velocity= 255/40.5/(2078.1-2073.5) =255/(40.5x4.6) =1.368 m/s WWDSE, Addis ADabo in Association with ICT Pvt. Ltd. and ABCE PLC Detoil Design of Bale Gadulo Irrigation & Drainage Project October, 2011Il It If If If If r r r f ir r r r r r r r r r rMinistry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia Design of Weir & Head Regulator Annexure-I Velocity head =1.368 /2*g=0.0954 say 0.1 m 2 A A u/s TEL = 2078.1+0.1= 2078.2m So, Head over crest=2078.2-2076.0 =2 2m Q=1.705x40.5x2.23/2 =225.327 cumec 5.2 Discharge passing through the Under sluices Let us provide orifices of 3.0mx2.65 m Discharge through the orifices shall be =2x0.65x3.0x2.50x(2g(h1-h2)) 0.5 =2x0.60x3.0x2.50x{2x9.81x(2078.2-2076.3)} 0.5 =67.88 cumec Total Discharge= 225.29+67.78=293.07 cumec>255 cumec OK Under sluice 3x2+1.5 =7.5 m with height of opening as 2.5 m Weir at crest level of 2076.00 and length of 40.5 m Divide wall of 2.0 m Total length of head works =40.5+2+3+1.5+3=50 m 5.3 HYDRAULIC DESIGN OF UNDER SLUICE PORTION a) Without concentration and retrogression Discharge through the undersluice =59 cumec q=61/7.5= 8.33 cumec d/s HFL = 2076.2 d/s TEL = 2076.2+velocity head=2076.2+0.1=2076.3 u/s TEL =2078.1+0.1=2078.1 u/s HFL=2078.1 Head loss H = u/s TEL - d/s TEL L Hl=2078.2-2076.3=1 9 m b) With 10% concentration and 0.5 m retrogression Discharge =61x1.1 cumec=67.1 cumec WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and ABCS PLC -4- Detatl Design of Bale Gadula Irrigation & Drainage Project October, 2011IL S’Ministry of Water and Energy - Section-1, Volume-II Federal Democratic Republic of Ethiopia Design of Weir & Head Regulator Annexure-I A A A q=67.117.5=8.94 m3/m/sec h1-h2=2.15 67.1=2x0.65x3.0x2.65x{2g(h1-h2)} 0.5 2g(h1-h2)={67.1/2/0 65/3 0/2.65} 2 Upstream TEL=2076.2+2.15=2078.35 Velocity head=(67.1/7.5/4.6) 2/2/9.81 =0.192 U/s HFL=2078 35-0.19=2078 16 D/s TEL=2076.2-0.5+0.19=2075.89 Head Loss=2078.35-2075.89=2.46 m Velocity head=(67.1/7.5/4.6) 2/2/9.81 =0.192 U/s HFL=2078.35-0.19=2078.16 D/s TEL=2076.2-0.5+0.19=2075.89 Head Loss=2073.35-2075.89=2.46 m 5.4 HYDRAULIC JUMP CALCU LATION FOR UNDE RSLUICES PORTION A Item Without cone, and Retro. With conc.& retro Unit Discharge intensity 3.33 8.94 M3/sec/m d/s water level 2076.2 2075.7 M u/s water level 2078.1 2078.16 M d/s TEL 2076.3 2075.89 M u/s TEL 2078.2 2078.35 M Head loss HL 1.9 2.46 M D/s Specific Energy Ef2 3.91 4.24 M u/s Specific energy Ef 1 5.81 6.70 M Level at which jump will form 2072.39 2071.65 M Pre jump depth 0.80 0.9 M Post jump depth 3.6 3.9 M Length of still basin 16.8 18.0 M Froude no. 3.72 3.34 The downstream stilling basin shall be provided at El 2071.5 which will take care of any Concentration and retrogression. 5.5 Type of Basin to be provided: WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and A9CE PLC -5- Detail Design of Bale Godulo Irrigation & Orainage Project October, 2011} — iMinistry of Woter and Energy - Section — 1, Volume — II Federal Democratic Republic of Ethiopia Design of Weir & Head Regulator Annexure-I As the froude No is less than 4.5, the stilling basin will be of USBR Type I 5.6 Depth of Cutoff and Length of Floor Depth of scour R=1.35(q/f)'/J R=1.35x(8.94x8.94),/3 = 3.40 m On upstream provide cutoff coresponding to 1.1 R and on d/s side 1.5 R Scour level=2076.1-1.5x3.40=2071.0 These values are very small and hence proiovide cutoffs on the basis of Requirement of weir portion Let us provide 3.0 m deep cut off below the d/s floor ie upto 2071.5-3=2068.5 Ge=H/d/n7>/A ('/A)=H/(G xdxTr) e 25 H=2076-2071.5= 5.5 m (^A)=5.5 x4x7/22/3 =2.33 A=5.44 Alpha=b/d={ (2x5.44-1 ) -1}° =9.83 Length of floor 3x9 83=29.49 m Hence provide floor on the basis of weir requirements for slopes, stilling basin and gates operation, total floor length provided is 33 m 5.6PRESSURE CALCULATION FOR UNDER SLUICE For d =3 m and b 33m, 1/a = d/b = 0.09 ,a = 11 A= 6 02 0E=1 /pi cos-1 (A-2)/ A=.0.267 or 26.7% 0d=Cos-1{(A-1O/ A)}=19% 0d-0c=26.7-18=8.7% 0c correction for depth= 8.7/3=2.9% (positive) 0c corrected = 100-26.7+2.9= 76.2 % For Downstream end 0c=26.7% Pressure on the upstream side=76.2% WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. cndABCE PLC -6’ Detail Design of Bole Gadula Irrigation & Drainage Project October. 2011r* r1Ministry of Water and Energy - Section -1, Volume - II Federal Democratic Republic of Ethiopia Design of Weir & Head Regulator Annexure-I Pressure on downstream side = 26.7-2.9= 23.8 m Pressure variation=76.2-23.8=52.4/33=1.59% Pressure at 12.5 m from upstream end=23.8+(33.12.5)x1.59=56.325% Thickness required=.0.563X5.5/1 4=2.2 m The structure of undersluices is small and hence combined foundation of Divide walls, pier and the wingwall shall be required. Hence provide 2.0 m thick foundation throught with reinforcement 6.0 Design of Weir 6.1 The following section of the weir is proposd- 2071.5 • i “ r 6.2 COMPONENTS OF THE WEIR The structure will have following components as part of the body. The top width shall be 2.0 m. u/s slope shall be 1:1 And d/s slope will be kept as 3:1. The weir shall have cyclopean concrete ie boulders/rock pieces in concrete. The top surface of the weir shall have 1m concrete M25 grade with reinforcement And this 1m thick concrete shall be jointed with masonry with renforcement bars . Upstream and downstream shall be protected with concrete Blocks of 1.5mx1.5x0.9 m size. The u/s level will be 2073.5, the d/s block protection shall be at 2073.5. Discharge intensity per m shall be 225/40.5=5.555 cumec in HFL condition Downstream HFL will be 2076.2 m ’s HFL = 2076.2 ’s TEL = 2076.2+velocity head=2076.1+0.1 =2076.3 ’s TEL =2078 1+0.1=2078.2 ’s HFL=2078.1 ead loss H = u/s TEL - d/s TEL L L =2078.2-2076.3=1.9m WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and ABCE PLC -7- Detail Design of Bole Gadulo Irrigation & Drainage Project October, 2011r1 r1Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Seaion -1, Volume - II Design of Weir & Head Regulator Annexure-I r WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and ABCE PLC Detail Design of Bole Gadula Irrigation & Droinoge Project October, 2011sMinistry of Water ond Energy - Federal Democratic Republic of Ethiopia 6.3 HYDRAULIC JUMP CALCULATION FOR WEIR PORTION Section -1, Volume - II Design of Weir & Heod Regulator Annexure-I Item Without cone, and Retro. Unit Discharge intensity 5.55 M3/sec/m d/s water level 2076 2 M u/s water level 2078.1 M d/s TEL 2076.3 M u/s TEL 2078.2 M Head loss HL 1.9 M D/s Specific Energy Ef2 3.2 M u/s Specific energy Ef 1 5.1 M Level at which jump will form 2073.1 M Pre jump depth 0.65 M Post jump depth 3.0 M Length of still basin 16 M Froude no 3.38 The downstream bed level shall be provided at El 2072.5 which will take care of any Concentration The weir will have flexible downstream jump basin constructed of the concrete blocks. 6.4 Depth of Cutoff and Length of floor The scour depth is little, however cutoff shall be provided on the upstream and downstream and will be 3.0 m deep. Let us provide 3.0 m deep cut off below the d/s floor Ge=H/d/n/VA (A/A)=H/(GeXdxrr) H=Pond Level- d/s Bed Level=2076.0-2072.5 = 3.5 m (>/A)=1.4848 A= 2.20 WWDSE, Addis Ababo in Association with ICT Pvt. Ltd. and ABCE PLC Detail Oesign of Bale Gadula Irrigation & Drainage Project October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopio Alpha=3.24 length b = 3.24x3=9.72 m Section — 1, Volume - II Design of Weir & Head Regulator Annexure-I Total Length required= 16.0+(2076.0-2072.5)x3+minimum 6 m for gates etc = 16+10.5 +2+2.5 = 31 m say 33m as for undersluices. Pressure Calculation Length of Floor provded=33m U/s of axis=6.0 m and 27m d/s of axis Dis of axis=27m Total=33 m 6.5 Depth of Cutoff and Length of Floor Depth of scour R=1.35(q/f)1G R=1.35x(5.55x5.55)1'3 = 2.46 m On upstream provide cutoff coresponding to 1.1 R and on d/s side 1.5 R Scour level=2076.1-1.5x2.46=2072.41 These values are very small and hence provide cutoffs on the basts of Floor r Let us provide 3.0 m deep cut off below the d/s floor ie upto 2072.5-3=2069.5 Ge=H/d/Tr/^A (^A)=H/(GeXdXTT) H=2076-2072.5= 4.5 m (>/A)=4.5 x4x7/22/3 =1.909 A=3.64 Alpha=b/d={ (2x3.64-1 ) -1}° =6.2 Length of floor 3x6.2=18.6 m 25 Hence provide floor on the basis of weir requirements for slopes, stilling basin and gates operation, total floor length provided is 33 m 6.6 PRESSURE CALCULATION FOR UNDER SLUICE For d =3 m and b 33m, 1/a = d/b = 0.09 ,o = 11 A= 6.02 WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and A8CE PLC Detail Design of Bole Gadulo Irrigation & Drainage Project October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Seaion -1, Volume - II Design of Weir & Head Regulator Annexure-I 0E=1/pi cos-1 (A-2)/ A=.0.267 or 26.7% 0d=Cos-1{(A-1/A)}=19% Od-0c=26.7-18=8.7% 0c correction for depth= 8.7/3=2.9% (positive) 0c corrected = 100-26.7+2.9= 76.2 % For Downstream end 0c=26.7% Pressure on the upstream side=76.2% Pressure on downstream side = 26.7-2.9= 23.8 m Pressure variation=76.2-23.8=52.4/33=1.59% Pressure at 12.5 m from upstream end=23.8+(33.12.5)x1.59=56.325% Thickness required=.0.563X4.5/1.4= 1.8 m At this point provide thickness as 2.2 m on thre basis of unbalanced head due To Hydraulic jump At 20.0 m distance Pressure =23.8+(33-20)x1.59=44.47% • • Thickness required= 4447x4.5/1.4=1.43 say 1.5 m At 27m from upstream end Pressure=23 8+(33-27)x1.59=33.34% Thickness req=.3334x4.5/1.4=1,07m say 1.2m. 7. ENERGY DISSIPATION DEVICES 7.1 IN UNDERSLUICES PORTION The energy Dissipation devices will be provided as recommended in Engineering Monograph No 25, Design of Stilling Basins and Energy Dissipators. Chute blocks shall be of hight equal to prejump depth of 0.0.9 m at a spacing of 0.90m and will be o.90 m wide. The endsill shall be of 0.2D2 height i.e , 0.2x3.9=0.78m and will be at a gap of 0.15D2 and of width equal to 0.15 D2 or 0.60m. The details are given in the Drawings. 7.2 IN WEIR PORTION The energy Dissipation devices will be provided as recommended in Engineering Monograph No 25, Design of Stilling Basins and Energy Dissipators. WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. andABCE PIC Detail Design of Bale Godula Irrigation & Drainage Project October, 2011Ministry of Water and Energy - Section I, Volume II Federal Democratic Republic of Ethiopia ____________________________________ Design of Weir & Head Regulator ' Annexure-I No Bed blocks shall be provided as the high velocities will be there in the major structure of Headworks. Chute blocks shall be of hight equal to prejump depth of 0.65 m at a spacing of 0.65m and will be 0.65 m wide. The endsill shall be of 0.2D2 height i.e , 0.2x3.03=0.60m and will be at agap of 0.15D2 and of width equal to 0.15 D2 or 0.45 m. The details are given in the Drawings. 8.0Protection works for Weir and Under sluice The length of the CC Block protection & Inverted Filter a) Upstream q = 8.94cumec/m f=5, Depth of scour-1.35x(q2/f)A( 1 / 3 ) R=3.40 Anticipated scour=1.1 R= 1.1 *3.4 =3.74 Upstream scour level =2078.1-3.74=2074.26 hugher than the floor level of 2073.5 Provide a minimum of 4 Blocks at Upstream of size 1.5x1.5x0.9 b) Downstream As we are not providing any concrete floor, CC block protection shall be provided in upto downstream end of undersluices floor Suitable toe walls shall also be provided. Provide a minimum of 6 rows of 1.5x1.5x0.9 CC Blocks with 10 cm gap in between over 40cm thick graded filter over a length of 10m at Downstream end of Undersluice. c) The length of the Launching Apron: Let the launching apron thickness = 2m Provide 5.0 m launching Apron 2m thick on u/s and d/s of Undersluice and Weir. Suitable toe walls shall also be provided. 9.0 Divide walls One divide wall of 2m shall be provided for separating the flow of undersluices and the weir portion. The length of the Divide Wall will be 33.0 on floor and about 10 m on upstream i.e 43 m The portion of divide wall beyond the floor portion will have WWDSE, Addis Ababa in Association with ICT Pvt Ltd. and ABCE PLC -12- Detail Design of Bole Gadula Irrigation & Drainage Project October, 2011F r rMinistry of Water and Energy - Federal Democratic Republic of Ethiopia____________________________ Design of Weir & Head Reg ulator Section I, Volume — II Annexure-I open foundations. The divide wall shall be designed for a water level difference of 1 m so that it gives the worst condition of stability. Reinforcement will be calculated accordingly. WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and ABCE PLC -13- Detail Design of Bale Gadulo Irrigation & Drainage Project October, 2011- ,TW'Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section - /, Volume - II Design of Weir & Head Regulator Annexure- II Design of Head Regulator Design of Head Regulator: 1. Head regulator: a) u/sHFL 2078.1 m b) Pond level 2076.0 m c) d/s Canal FSL 2074.12 m d) Design Discharge 3.5 cumec e) Bed level of canal 2072.80 m f) Safe exit Gradient HydraulicDesignConsidering HFL condition 1. Fixation of Crest level and waterway : 1.1 High Flood Condition It is recommended crest level of head regulator is kept 1 m higher than the crest level of the Under sluices. So, Crest level of head regulator=2073.5+1 = 2074.5m Q=Cd I d <(2gh) c d =0 65 I = Length of water way h=Difference in u/s and d/s water levels=2078.1-2074.12=3.98 m A 3.5= 0.65x1x1.5x(2xgx3.98) 0.5) L required=0.406m 1.2 Pond Level Considerations Crest level of head regulator=2073.5+1 = 2074.5m h=2076.0-2074.5=1.5m Q=Cd I d >/(2gh) c d =0.65 I = Length of waterway h=Difference in u/s and d/s water levels=2078.0-2074.12=3.88 m d= Depth of d/s water level above the crest of regulator 2075.925-2074.5=1.425 m 3.5= 0.65x1x1.50x\'(2gx1.5) WWDSE, Addis Ababa in Association with -1- ICT Pvt. Ltd. and ABCE PLC Detail Design of Bole Godulo Irrigation & Drainage Proiect ’ October. 2011IMinistry of Water and Energy - Section -1, Volume - II Federol Democratic Republic of Ethiopia__________________________________________________ Design of Weir & Head Regulator Annexure - II L required=0.66 m Provide Length of water way = 1.5 m 2. Hydraulic calculations : u/s water level =2078.1 m d/s water level in canal for full supply discharge = 2074.12 Bed Level of canal=2072.80 Crest Level of HR=2073.00 Head dfference causing Flow = 2078.1-2074 12 =3.98m Let the gate opening be y m, the discharge can then be calculated with the help of submerged orifice formula: Q = C A V(2gh) A A d 3.5= 0.65x2xyx'/(2x9.81x3.98) Y= 0.30m~ .5 m POND LEVEL CONDITION Pond Level is =2076.00 D/s water level in canal=2074.12 Difference of head=2076-2074.12=1.88 m Q=CdxAx(2gx1.88) 0.5 A=BxY where B =width and Y is the height of orifice Y=3.5/0.65/2.0/(2x9.81 x1,88) 0.5 Y= 0.443 m If Pond level reduces by say 1.0 m, the canal should runas such difference of head=0.88 m Y=3.50/0.65/2.0/(2x9.81x0.88) 0.5 Y=1.095m provide orifice of 2.0 m x 1.5 m Discharge intensity = 3.5/2 = 1.75 cumec/m Velocity in the d/s side= 3.5/(2x1.32)= 1.326m/s Velocity head= 1.326 /2g= 0 09 m d/s TEL = 2074.12+0.09 = 2074.21 m u/s TEL = 2078+0.1= 2078.1 m h L =2078.10-2074.21= 3.89 m A 2 WWDSE, Addis Ababo in Association with ICT Pvt. Ltd. and ABCE PLC -2- Detail Design of Bole Godulo Irrigation & Drainage Project October, 2011Ministry of Water and Energy - Federal Democratic Republic of Ethiopio Section -1, Volume - II Design of Weir & Head Regulator Annexure - II 3. Hydraulic jump calculation for Head regulator : Item Without cone, and Retro. Unit Discharge intensity 1.75 M3/sec/m d/s water level 2074.12 M u/s water level 2078.00 M d/s TEL 2074.21 M u/s TEL 2078.10 M Head loss HL 3.89 M D/s Specific Energy Ef2 1.8 M u/s Specific energy Ef 1 5.69 M Level at which jump will form 2072.41 M Pre jump depth 0.3 M Post jump depth 1.7 M Length of still basin 8.4 M Froude no. 3.4 i he Downstream floor has been provided ar R.L. 2072.40m .with a horizontal length of 9 m. 4. Depth of Cut-off: a) u/scut- off: Provide u/s cut- off of 3m depth same as under sluice portion. b) d/s cut- off: discharge intensity = q= 1.75 cumec/m Scour depth = 1.35x(q2/f)’ forf=5, scour depth =1.15 Anticipated scour = 1.5R = 1.72 Provide 3 m length of d/s cut- off below the d/s floor level. 5. Length of floor: Exit gradient = Ge= H/(r|xdx>/A) H=2078.1-2072.8 = 5.3 m WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and ABCEPLC -3- Detoil Design of Bale Gadulo Imgotion & Drainage Project October, 2011Ministry of Woter and Energy - Federal Democratic Republic of Ethiopia = 5.3/(0.25x3x11) A= 5.06 a = 9.06m Length of floor required = axd= 9.06x3 = 27.19m 6 PRESSURE CALCULATION FOR UNDER SLUICE For Upstream end b=15 m d =4 m 1/a = d/b = 0.27 ,a = 3.75 Oc=55%(From Khosla Pressure curves) 4>d=100-32=68% 0>d-Oc=13 <t>c correction for depth= 13/3=4.33% (positive) Section-I, Volume-II Design of Weir & Head Regulator Annexure - II 0>c corrected = 55+4.33= 59.33 % For Downstream end Oc=32%(From Khosla Pressure curves) t Pressure on the upstream side=60%= 0.6*4=2.40 m Pressure on downstream side = 32% = 0.32*4=1.28 rn At 16m from upstream end Pressure=32%+(60%-32%)x9/27=32%+9.33=41.33% Thickness required=0.4133x(2078.1-2072.8)/1.4=1.6 m Provoide 1.8m minimum 7 . The length of the CC Block protection & Inverted Filter a) Upstream :lt shall be same as provided in u/s on undersluices. b) Downstream : discharge intensity = q= 1.75 cumec/m Scour depth = 1,35x(q2/f)1/3 = 0.98 Anticipated scour = 1.5R = 1.47 m downstream scour level =2075.965-1.47 WVVDSE, Addis Ababo in Association with ICT Pvt. Ltd. ondABCE PLC Detail Design of Bole Godula Irrigation & Drainage Project October. 2011If T r r r [- r ■Ministry of Water and Energy - Federal Democratic Republic of Ethiopia Section -1, Volume - II Design of Weir & Head Reg ulator Annexure - II =2074.495 >2074 (bed level) Provide a minimum of 2 Blocks at 0.6 4.4 The length of the Launching Apron: Let the launching apron thickness = 2m Quantity of Launching apron required = 2.25 d cu.m./m ( d=scour depth) Length Required= 2.25x0.98/2=1.1m. Provide 2 m length of launching apron. WWDSE, Addis Ababa in Association with ICT Pvt. Ltd. and ABCE PLC -5- Detoil Design of Bole Gadulo Irrigation & Drainage Project October. 20111[ l[ rAnnexure - /// Downstream Divide Wail 2m 6m TESTING AT 2070.6 item Calculation Verttical horizontal LA M- W1 2x7.9x2.4 37.92 1.00 37.92 Pl 0.5x6.1x6.1 18.61 2.03 P2 0.5X5.1x5.1 37 83 -13.0S 1.70 . -22 24 VI Hl Ml(+) . Ml(-) 37.92 5.52 37.92 15.59 1 M1(+) Without EQ 2 M1(-) ----------------- 37.92 t-m 3 Net moment 15.59 t-m 4 vi " ’ ------------ 22.33 t-m 5 H1 37.92 tons 6 b 5.52 tons 2.00 m 7 e=b/2-(M1-M2)/V1 0 41 m 8 Pr at Toe=V1/b-(1+6*e/b) 42.35 9 Pr at heel=V1/b(1-6e/b) <70 t/mm2 -4.43 < 10 t/mm2 -1-Annexure - /// Downstream Divide Wait EARTHQUAKE FORCES item [Calculation Verttical horizontal LA M+ M- VERTICAL 1.422 1 1.422 Hl 37.92 0.075 2.84 3.95 11.23 H2 18.61 0.075 1.40 2.03 2.84 V2 H2 M2(+) M2(-) 1.42 4.24 1.42 14.07 STABILITY CHECKING AT 1942.8CONSIDERING EARTHQUAKE FOR ICES . 1 M3=M1(+)+M2(+) 2 M4=M1(-) +M2(-) 3 Net moment 4 V3=V1+V2 5 H3=H1+H2 6b 7 e=b/2-(M3-M4)/V3 8 Pr at Toe=V3/b*(1+6*e/b) 9 Pr at heel=V3/b(1-6*e/b) 39.34 29.66 9.68 39.34 9.76 2.00 0.75 64.17 -24 82 t-m t-m t-m tons tons m m <70 t/mm2 >10t/m2 Reinforcement design of divide'wall Let Neutral axis be say 9oo mm. Grade of concrete = M20, Grade of Steel = Fe415 modular ratio(m)=(280/3*7)=13.3 Area of steel = (TT/4)“20’20’(1000/250)=(n*400) = 1256 mm 2 Equating moment about Tensile reinforcement C'x1000x(900-75)x0.5x(2000-900+2x900/3) + 1256xc'x(1.5m-l)x(2000-75-75)x(1850/1925)= Pe C'x825000x0.5xl700 + (1256xc'xl8.85x1850x0.96) =44xl0 x (7904-1000-75) 4 (70.125xl0 + 4.2xl0 ) c' = 44xl715xl0 =75.46xl0 77 4 7 74.2 c' = 75.46 c' = l,02< 7 safe -2--■- —Annexure - /// Downstream Divide kVa// c'x(9O0-75)xl000x0.5+(1.5xl3-l)xl256xc'x(900-75)/900-txl256=4400OO 412500c‘+21817c’-1256t=440000 4430003.34-440000=1256t t=2.39 N/mm2 N.A.= (mc/mc+t)*d = 13.3*1.02/13.3*1.02+2.39)*2000=1700mm»>900mm Let Neutral axis be say 1000 mm. Grade of concrete = M20, Grade of Steel = Fe415 modular ratio(m)=(280/3*7)=13.3 Area of steel = (n/4)*20*20*(1000/250)=(h*400) = 1256 mm 2 Equating moment about Tensile reinforcement Cx1000x(1000-75)x0.5x(2000-1000+2x1000/3) + 1256xc'x(1.5m-l)x(2000-75-75)x(1850/1925)= Pe Cx925000x0.5xl666.67 + (1256xc'xl8.85xl850x0.96) =44xl0 x (790+1000-75) (77.083xl0 + 4.2xl0 ) c' = 44xl715xl0 =75.46xl0’ 81.283 c' = 75.46 c' = 0.93< 7 safe Equating compression and Tension Forces c'x(1000-75)xlOOOx0.5+(1.5xl3-l)xl256xc'x(1000-75)/1000-txl256=440000 462500c'+22016c'-1256t=440000 450599.88-440000=1256t t=8.44 N/mm2 N.A.= (mc/mc+t)*d = 13.3*0.93/13.3*0.93+8.44)*2000=1188mm Provide 4 bars of 20 mm @ 250 c/c per meter on both faces of divide wall and Tie bars of 12 mm @ 300 c/c. 4 77 4Annexure - /// Downstream Divide Wall TESTING AT 2068.6( level) item Calculation Verttical horizontal LA M+ M- W1 2x7.9x2.4 37.92 3.00 113.76 W2 3xO.5x2.4 3.60 3.00 10.80 W3 4x0.5x2.4 4.80 3.00 14.40 W4 5x0.5x2.4 6.00 3.00 18.00 W5 6x0.5x2.4 7.20 3.00 21.60 W6 2x6. lxl 12.20 5.00 61.00 W7 1.5x0.5xxl 0.75 5.25 3.94 W8 lx0.5xl 0.50 5.50 2.75 W9 05x0.5x1 0.25 5.75 1.44 W10 2x5.lxl 10.20 1.00 10.20 Wil 1.5x0.5xxl 0.75 0.75 0.56 W12 lx0.5xl 0.50 0.50 0.25 W13 O.5xO.5xl 0.25 0.25 0.06 Pl 0.5X®. 1x8.1 32.81 2.70 88.57 P2 0,5X7.1x7.1 -25.21 2.37 -59.65 Uplift U1 7.1x6 -42.60 3.00 -127.80 Uplift U2 0.5xlx6 -3.00 4.00 -12.00 VI Hl Ml(+) Ml(-) 39.32 7.60 118.96 28.92 Without EQ 1 M1(+) 118.96 t-m 2 M1(-) 28.92 t-m 3 Net moment 90.04 t-m 4 V1 39.32 tons 5 H1 7.60 tons 6 b 600 m 7 e=b/2-(M1-M2)/V1 0.71 m 8 Pr at Toe=V1/b‘(1+6*e/b) 11.21 <40 t/m2 9 Pr at heel=Vl/b(1-6e/b) 1.90 <40 t/m2 10 Factor of safety in sliding Fs=VTtanphi/H1 2.99 >1.54 11 Factor of Safety in Overturning Fo=M1(+)/M(-) 4.11 >1.2Annexure - III Downstream Divide Wall EARTHQUAKE FORCES item Calculation Verttical horizontal LA M+ M- VERTICAL 1.475 3.025 4.461 Hl 37.92 0.075 2.844 5.95 16.9218 H2 3.60 0.075 0.270 1.75 0.473 H3 4.80 0.075 0.360 1.25 0.45 H4 6.00 0.075 0.450 075 0.338 H5 7.20 0.075 0.540 0.25 0.135 H6 12.20 0.075 0.915 5.05 4.62075 H7 0.75 0.075 0.056 1.75 0.098 H8 0.50 0.075 0.038 1.25 0.047 H9 0.25 0.075 0.019 0.75 0.014 H10 10.20 0.075 0.765 4.55 3.481 Hll 0.75 0.075 0.056 1.75 0.098 H12 0.50 0075 0.038 1.25 0.047 H13 0.25 0.075 0.019 0.75 0.014 H14 32.81 0.075 2.460 2.70 6.643 V2 H2 M2(+) M2{) 1.475 8.829 4.461 33.380 STABILITY CHECKING AT 2068.1 CONSIDERING EARTHQUAKE FORCES . 1 M3=M1(+)+M2(+) 123.42 t-m 2 M4=M1(-) +M2(-) 62.30 t-m 3 Net moment 61.12 t-m 4 V3=V1+V2 40.79 tons 5 H3=H1+H2 16.43 tons 6 b 6.00 m 7 e=b/2-(M3-M4)/V3 1.50 m 8 Pr at Toe=V3/b*(1+6*e/b) 17.01 <40 t/m2 9 Pr at heel=V3/b(1-6e?b) -3.41 <10t/m2 10 Factor of safety in sliding Fs=V3*tanphi/H3 1.43 >1.18 11 Factor of Safety in Overturning Fo=M3/M4 1.98 >1.1 Provide 20 mm bar @300mm c/c at bottom of foundation -5-IAnnexure - III Upstream Divide IV«a// TESTING AT 2072.6 item Calculation Verttical horizontal LA M+ M- W1 2x7.4x2.4 35.52 1.00 35.52 Pl 0.5x5.4x5.4 14.58 1.80 26.24 P2 0.5X4.4x44 -9.68 1.47 -14.20 VI Hl Ml(+) Ml(-) 35.52 4.90 35.52 12.05 -1-L L if ( [ ( r [ r F F F F F F F F F F F ------ - • 11 FAnnexure - /// Upstream Divide Wall Without EQ 1 M1(+) 35.52 t-m 2 M1(-) 12.05 t-m 3 Net moment 23.47 t-m 4 V1 35.52 tons 5 H1 4 90 tons 6 b 2.00 m 7 e=b/2-(M1-M2)A/1 0.34 m 8 Pr at Toe=V1/b*(1+6*e/b) 35.83 <70 t/mm2 9 Prat heel=V1/b(1-6e/b) -0.31 < 10 t/mm2 hence steel will have to be provided EARTHQUAKE FORCES item Calculation Verttical horizontal LA M+ M- VERTICAL 1.332 1 1.332 Hl 35.52 0.075 2.66 3.70 9.86 H2 14.58 0.075 1.09 1.80 1.97 V2 H2 M2(+) M2(-J 1.33 3.76 1.33 11.83 STABILITY CHECKING AT 1942.8CONSIDERING EARTHQUAKE FORCES . 1 M3=M1(+)+M2(+) 36.85 t-m 2 M4=M1(-) +M2(-) 23.87 t-m Net moment 12.98 t-m 4 V3=V1+V2 36.85 tons 5 H3=H1+H2 8.66 tons 6 b 2.00 m 7 e=b/2-(M3-M4)/V3 0.65 m 8 Pr at Toe=V3/b*(1+6*e/b) 54.23 <70 t/mm2 9 Pr at heel=V3/b(1-6*e/b) -17.38 >10t/m2Annexure - III Upstream Divide kVa// 4 4 Reinforcement design of divide wall Let Neutral axis be say 9oo mm. Grade of concrete = M20, Grade of Steel = Fe415 modular ratio(m)=(280/3*7)=13.3 Area of steel = (TT/4)*20,20,(1000/250)=(n*400) = 1256 mm 2 Equating moment about Tensile reinforcement C'x1000x(900-75)x0.5x(2000-900+2x900/3) + 1256xc'x(1.5m-l)x(2000-75-75)x(1850/1925)= Pe C'x82SOOOxO.5x1700 + (1256xc'xl8.85xl850x0.96) =44xl0 x (790+1000-75) (70.125x10’ + 4.2x10’) c' = 44xl715xl0 =75.46xl0’ 74.2 c'= 75.46 e = 1.02< 7 safe c’x(900-75)xlOOOx0.5+(1.5xl3-l)xl256xc’x(900-75)/900-txl256=440000 412500c’+21817c'-1256t=440000 4430003.34-440000=1256t t=2.39 N/mm2 N.A.= (mc/mc+t)*d = 13.3*1.02/13.3*1.02+2.39)*2000=1700mm»>900mm Let Neutral axis be say 1000 mm. Grade of concrete = M20, Grade of Steel = Fe415 modular ratio(m)=(280/^*7)=13.3 Area of steel = (FF/4)*20*20’(1000/250)=([J ’400) = 1256 Aim 2 Equating moment about Tensile reinforcement C'x1000x(1000-75)x0.5x(2000-1000+2x1000/3) + 1256xc'x(1.5m-l)x(2000-75-75)x(1850/1925)= Pe 0x925000x0.5x1666.67 + (1256xc'xl8.85x1850x0.96) =44x10 x (790+1000-75) 4 (77.083xl0 + 4.2xl0 ) c' = 44x1715x10 =75.46x10 77 4 ? 81.283 c* = 75.46 c = 0.93< 7 safe z Equating compression and Tension Forces c'x(1000-75)xl000x0.5+(1.5xl3-l)xl256xc‘x(1000-75j/1000-txl256=440000 462500c’+22016c'-1256t=440000 450599.88-440000=1256t t=8.44 N/mm2 N.A.= (mc/mc+t)*d = 13.3*0.93/13.3*0.93+8.44)*2000=1188mm Provide 4 bars of 20 mm @ 250 c/c per meter on both faces of divide wall and Tie bars of 12 mm @ 300 c/c. -3-Annexure - III Upstream Divide Wall TESTING AT 2070.6(Foundation level) item Calculation Verttical horizontal LA M+ M- W1 2x7.4x2.4 35.52 3.00 106.56 W2 3x0.5x24 3.60 3.00 10.80 W3 4x0.5x2.4 4.80 3.00 14.40 W4 5x0.5x2.4 6.00 3.00 18.00 W5 6x0.5x2.4 7.20 3.00 21.60 W6 2x5.4x1 10.80 5.00 54.00 W7 1.5x0.5xxl 0.75 5.25 3.94 W8 1x0.5x1 0.50 5.50 2.75 W9 05x0.5x1 0.25 5.75 1.44 W10 2x4.4xl 8.80 1.00 8.80 wii 1.5x0.5xxl 0.75 0.75 0.56 W12 IxO.Sxl 0.50 0.50 0.25 W13 0.5x0.5x1 0.25 0.25 0.06 Pl 0.5X7 4x7 4 27.38 2.47 67.54 P2 0.5X6.4x6.4 -20.48 2.13 -43.69 Uplift U1 6.4x6 -38.40 3.00 -115.20 Uplift U2 0.5xlx6 -3.00 4.00 -12.00 VI Hl Ml(+) Ml(-) 38.32 6.90 115.96 23.85 Without EQ 1 M1(+) 115.96 t-m 2 M1(-) 23.85 t-m 3 Net moment 92.11 t-m 4 V1 38.32 tons 5 H1 6.90 tons 6 b 6.00 m 7 e=b/2-(M1-M2)/V1 0.60 m 8 Pr at Toe=V1/b*(1+6*e/b) 10.19 <40 t/m2 9 Pr at heel=V1/b(1-6e/b) 2.58 <10t/m2 10 Factor of safety in sliding Fs=V1*tanphi/H1 3.21 >1.54 11 Factor of Safety in Overturning Fo=M1(+)/M(-) 4.86 >1.2■W-g-Annexure - /// Upstream Divide Wa// item [Calculation | EARTHQUAKE FORCES horizontal Verttical LA M+ M- VERTICAL 1.437 3.026 4.349 Hl 35.52 0.075 2.664 5.7 15.1848 H2 3.60 0.075 0.270 1.75 0.473 H3 4.80 0.075 0.360 1.25 0.45 H4 6.00 0.075 0.450 0.75 0.338 H5 7.20 0.075 0.540 0.25 0.135 H6 10.80 0.075 0.810 4.7 3.807 H7 0.75 0.075 0.056 1.75 0.098 H8 0.50 0.075 0.038 1.25 0.047 H9 0.25 0.075 0.019 0.75 0.014 H10 8.80 0.075 0.660 4.2 2.772 Hll 0.75 0.075 0.056 1.75 0.098 H12 0.50 0.075 0.038 1.25 0.047 H13 0.25 0.075 0.019 0.75 0.014 H14 27.38 0.075 2.054 2.47 5.065 V2 H2 M2(+) M2(-) 1.437 8.033 4.349 28.543 STABILITY CHECKING AT 2070.6 CONSIDERING EARTHQUAKE FORCES . 1 M3=M1(+)+M2(+) 120.31 t-m 2 M4=M1(-) +M2(-) 52.39 t-m 3 Net moment 67.92 t-m 4 |V3=V1+V2 39.76 tons 5 H3=H1+H2 14.93 tons 6 b 6.00 m 7 e=b/2-(M3-M4)/V3 1.29 m 8 Pr at Toe=V3/b'(1+6*e/b) 15.18 <40 t/m2 9 Pr at heel=V3/b(1-6e?b) -1.93 <10 Vm2 10 Factor of safety in sliding Fs=V3*tanphi/H3 1.54 >1.18 11 Factor of Safety in Overturning Fo=M3/M4 2.30 >1.1 Provide 20 mm bar @300mm c/c at bottom of foundationAnnexure - IV Design of Undersluices Pier TESTING AT 2073.2 item Calculation | Verttical horizontal LA M- W1 1.5x7.8x24 28.08 0.75 21.06 Pl 05x5.4x5.4 14.58 1.80 26.24 p2 0.5X4.4x4.4 -9.68 147 -14.20 VI Hl Ml(+) Ml(-) 28.08 4.90 21.06 12.05 Without EQ 1 M1(+) 21.06 t-m 2 M1(-) 1205 t-m 3 Net moment 9.01 t-m 4 V1 28.08 tons 5 H1 4.90 tons 6 b 1.50 m 7 e=b/2-(M1-M2)/V1 0.43 m 8 Pr at Toe=V1/b’(1+6’e/b) 50.84 <70 t/mm2 9 Pr at heei=V1/b(1 -6e/b) -13.40 > 10 t/mm2 hence steel will have to be providedi r i rAnnexure - iV Design of Undersluices Pier EARTHQUAKE FORCES item Calculation Verttical horizontal LA M+ M- VERTICAL 1.053 0.75 0.78975 Hl 28.08 0.075 2.11 3.70 7.79 H2 14.58 0.075 1.09 1.80 1.97 V2 H2 M2(+) M2(-) 1.05 3.20 0.79 9.76 STABILITY CHECKING AT 1942.8CONSIDERING EARTHQUAKE FORCES . 1 M3=M1(+)+M2(+) 21.85 t-m 2 M4=M1(-) +M2(-) 21.81 t-m 3 Net moment 0.04 t-m 4 V3=V1+V2 29.13 tons 5 H3=H1+H2 8.10 tons 6 b 1.50 m 7 e=b/2-(M3-M4)/V3 0.75 m 8 Prat Toe=V3/b*(1+6*e/b) 77.57 >70 t/mm2 9 Prat heel=V3/b(1-6’e/b) -38.73 >10t/m2 Reinforcement design of Pier .Let Neutral axis be say 800 mm. r Grade of concrete = M20, Grade of Steel = Fe415 modular ratio(m)=(280/3*7)=13.3 Area of steel = (fT/4)*20*20*(1OOO/25O)=(TT *400) = 1256 mm 2 Equating moment about Tensile reinforcement C'xlOOOx(800-75)x0.5x(2000-800+2x800/3) + 1256xc'x(1.5m-l)x(2000-75-75)x(1850/1925)= Pe C'x725000x0.5x1733 + (1256xc'xl8.85xl85OxO.96) =33xl0 x (950+1000-75) 4 (62.82xl0 + 4.2xl0 ) c' = 33xl875xl0 =61.875xl0 77 4 7 67 c' =61.875 c' = 0.93< 7 safe Equating compression and Tension Forces c'x(800-75)xlOOOx0.5+(1.5xl3-l)xl256xcx(800-75)/800-txl256=330000 362500c'+21057c'-1256t=330000 356708.01-330000=1256t t=21.26 N/mm2 N.A.= (mc/mc+t)*d = 13.3*0.93/13.3*0.93+21.26)*2000=735mm Provide 4 bars of 20 mm @ 250 c/c per meter on both faces of Pier and Tie bars of 12 mm @ 300 c/c.r1Annexure - V Downstream Wing Wall 10 m Testing at Foundation Level item Calculation Jerttical horizontal LA M+ M- W1 1x7.9x2.4 18.96 2.50 47.40 W2 5x7.9x0.5x2.4 47.40 4.67 221.20 W3 7x0.5x2.4 8.40 5.00 42.00 W4 8x0.5x24 9.60 5.00 48.00 W5 9x0.5x2.4 10.80 5 00 54.00 W6 10x0.5x2.4 12.00 5.00 60.00 W7 15x0.5x2 1.50 9.25 13.88 W8 1xO.5x2 1.00 9.50 9.50 W9 0.5x0.5x2 0.50 9.75 4.88 W10 5x7.9x0.5x2 39.50 6.33 250.17 Wil 2x7.9x2 31.60 9.00 284.40 Pl 0.5x0.26x1.9x1.8x1.8 0.80 8.70 6.96 P2 0.26x1.9x1.8x7,9 7.02 4.05 28.45 P3 0.5x0.26x2x7.9x7.9 16.23 2.70 43.81 P4 0.5x0.26x1x7,9x7.9 8.11 2.70 21.91 Uplift U1 7.9x0.5x10 -39.50 6.67 •263.33 VI Hl Ml(+) Ml(-) 141.76 32.16 772.08 101.13 1-3 a ! a E [ [ [ [ a X x:Annexure - V Downstream Wing Wa// Without EQ 1 M1(+) 772.08 t-m 2 M1(-) 101.13 t-m 3 Net moment 670.95 t-m 4 V1 141.76 tons 5 H1 32.16 tons 6 b 10.00 m 7 e=b/2-(M1-M2)/V1 0.27 m 8 Prat Toe=V1/b*(1+6*e/b) 16.45 <40 t/mm2 9 Pr at heel=V1/b(1-6e/b) 11.91 <40 t/m2 10 Factor of safety in sliding Fs=V1*tanphi/H1 2.54 >1.54 11 Factor of Safety in Overturning Fo=M1(+)/M(-) 7.63 >1.2 EARTHQUAKE FORCES item Calculation Verttical horizontal LA M+ M- VERTICAL 5.32 5.45 28.95 Hl 18.96 0.075 1.42 5.95 8.46 H2 47.40 0.075 3.56 4.63 16.47 H3 8.40 0.075 0.63 1.75 1.10 H4 9.60 0.075 0.72 1.25 0.90 H5 10.80 0.075 0.81 0.75 0.61 H6 12.00 0.075 0.90 0.25 0.23 H7 1.50 0.075 0.11 1.75 0.20 H8 1.00 0.075 0.08 1.25 0.09 H9 0.50 0.G75 0.04 0.75 0.03 H10 39.50 0.075 2.96 7.27 21.53 Hll 31.60 0.075 2.37 5.95 14.10 H12 0.80 0.075 0.06 8.57 0.51 H13 7.02 0.075 0.53 3.95 2.08 H14 16.23 0.075 1.22 2.63 3.20 H15 8.11 0.075 0.61 2.63 1.60 V2 H2 M2(+) M2(-) 5.32 15.40 28.95 71.12 -2-Annexure - V Downstream Wing Wall STABILITY CHECKING AT 1192.1 CONSIDERING EARTHQUAKE FORCES . 1 M3=M1(+)+M2(+) 801.04 t-m 2 M4=M1(-) +M2(-) 172.25 t-m 3 Net moment 628.79 t-m 4 V3=V1+V2 147.08 tons 5 H3=H1+H2 47.56 tons 6 b 10.00 m 7 e=b/2-(M3-M4)/V3 0.72 m 8 Pr at Toe=V3/b*(1+6*e/b) 21.10 <40 t/m2 9 Pr at heel=V3/b(1-6e/b) 8.31 <40 t/m2 10 Factor of safety in sliding Fs=V3*tanphi/H3 1.79 >1.18 11 Factor of Safety in Overturning Fo=M3/M4 4.65 >1.1 -3-I [ r L [ [ [ [ r r c c r r r r r r r r rAnnexure - V Upstream Wing Wall 2m 10 m Testing at Foundation Level item Calculation Verttical horizontal LA M- W1 1x7.4x2.4 17.76 2.50 44.40 W2 5x7.4x05x2.4 44.40 4.67 207.20 W3 7x0.5x24 8.40 5.00 42.00 W4 8x0.5x2.4 9.60 5.00 48.00 W5 9x0.5x24 10.80 5.00 54.00 W6 10x0.5x2.4 12.00 5.00 60.00 W7 1.5xO.5x2 1.50 9.25 13.88 W8 1x05x2 1.00 9.50 9.50 W9 0.5x0.5x2 0.50 9.75 4.88 W10 5x7.4x0.5x2 37.00 6.33 234.33 Wil 2x7.4x2 29.60 9.00 266.40 Pl 0.5x0.26x1.9x2x2 0.99 9.15 9.04 P2 0.26x1.9x2x7,4 7.31 4.20 30.71 P3 0.5x0.26x2x7.4x7.4 14.24 2.80 3987 P4 0.5x0.26x1x7.4x7.4 7.12 2.80 19.93 Uplift U1 7.4x0.5x10 -37.00 6.67 -246.67 VI Hl Ml(+) Ml(.) 135.56 29.66 737.92 99.55[ [ r r r r r r r r r rAnnexure - V Upstream Wing Wa// Without EQ 1 M1(+) 737.92 t-m 2 M1(-) 99.55 t-m 3 Net moment 638.37 t-m 4 V1 135.56 tons 5 H1 29.66 tons 6 b 10.00 m 7 e=b/2-(M1-M2)/V1 0.29 m 8 Prat Toe=V1/b*(1+6‘e/b) 15.92 <40 t/mm2 9 Prat heel=V1/b(1-6e/b) 11.19 <40 t/m2 10 Factor of safety in sliding Fs=V1*tanphi/H1 2.64 >1.54 11 Factor of Safety in Overturning Fo=M1(+)/M(-) 7.41 >1.2 EARTHQUAKE FORCES item Calculation Verttical horizontal LA M+ M- VERTICAL 5.08 5.44 27.67 Hl 20.76 0.075 1.56 5.70 8.87 H2- 51.90 0.075 3.89 - 4.47 17.39 H3 8.40 0.075 0.63 1.75 1.10 H4 9.60 0.075 0.72 1.25 0.90 H5 10.80 0.075 0.81 0.75 0.61 H6 12.00 0.075 0.90 0.25 0.23 H7 1.50 0.075 0.11 1.75 0.20 H8 1.00 0.075 0.08 1.25 0.09 H9 0.50 0.075 0.04 0.75 0.03 H10 43.25 0.075 3.24 6.93 22.49 Hll 34.60 0.075 2.60 5.70 14.79 H12 1.25 0.075 0.09 8.07 0.76 H13 9.34 0.075 0.70 3.70 2.59 H14 18.35 0.075 1.38 2.47 3.39 H15 9.17 0.075 0.69 2.47 1.70 V2 H2 M2(+) M2(-) 5.08 16.74 27.67 75.13ii n .1 ■ J . 1 I Lit,';. • ill PiH. . a. irAnn exure - V Upstream Wing Wall STABILITY CHECKING AT 1192.1 CONSIDERING EARTHQUAKE FORCES . 1 M3=M1(+)+M2(+) 765.59 t-m 2 M4=M1(-) +M2(-) 174.68 t-m 3 Net moment 590.91 t-m 4 V3=V1+V2 140.64 tons 5 H3=H1+H2 46.40 tons 6 b 10.00 m 7 e=b/2-(M3-M4)/V3 0.80 m 8 Prat Toe=V3/b*(1+6*e/b) 20.80 <40 t/m2 9 Prat heel=V3/b(1-6e/b) 7.33 <40 t/m2 10 Factor of safety in sliding Fs=V3*tanphi/H3 1.75 >1.18 11 Factor of Safety in Overturning Fo=M3/M4 4.38 >1.1Annexure- VI Design of Railing and Breast Walls ANNEXURE VI A 1.1 RCC for Inspection Deck on Divide Wall The observation deck is 6 m dia circular slab supported by the divide wall. It is designed as a a cantilever solid slab . The clear span is 2.0 m Loads on a 1 m wide strip Component Curb Slab Floor Live Load CS Area Unit Wt. Lever Arm Wt (MT) B.M.(t-m) 0.10 2.40 2.33 0.24 0.56 0.65 2.40 1.10 1.56 1.72 0.10 2.40 1.20 0.24 0.29 2.00 1.00 1 20 2.00 2.40 Total 4 04 4.98 Design constants For C25 Cone and steel Fe 430 kc = 0.289 Design of section Effective Depth 233 mm jc = 0 904 Rc = 0914 Depth required Hence, Total depth provided With 16 mm main bars and 50 mm cover Effective depth, d = 400 - 50 - 16 Area of steel reiforcement, Ast = 716.5935 Specing of 16 mm dia HYSD bars Provide 16 mm dia HYSD bars @ 250 mm c/c 299 mm = 400 mm 334 mm 280 49 mm2 Min Distribution reinforcement 0.12% 480 mm2 Provide 12 mm dia HYSD bars at 225 mm c/c at top i.e. 502.22 mm2 Hence OK Provide 12mm dia HYSD bars @ 250 mm c c bothways at bottom as temp, reinforcement Minimum embedment = 12 X Dia or effective depth i.e. 192 or 334 mm Since the top reinforcement is through the embedment is 1000mm, hence OK. Check for shear V = 4.04 t M = 4.96 t-m tv = 0 12 for As/bd 0.20 % tc = 0.20 Since tc > tv no shear reinforcement is required. However, provide 8 dia stirrups 300 mm c-c near support and 150 mm at endr F r rAnnexure - VI Design of Railing and Breast Walls ANNEXURE-VI(B) DESIGN OF GLACIS AND FLOOR SLAB The glacis is part of the gravity section. The floor slab on the downstream side is designened to counter uplift pressure and there are no other loads excepting those on account of hydrodynamic forces The floor slab has varying thickness. However top 300 mm layer is provided with nominal reinforcement. Ast = 1000x300 x0.12 7 100 = 360 mm2 Ast = 360 mm . Specing of 12 mm dia HYSD bars works out to 314 mm. Provide specing of 300 mm. 2 The bars shall be provodeded at top, bothways. The clear cover to provided shall be 60 mm. This reinforcement will be temprature and distribution reinforcement. The reinforcement shall be discotinued beyond the panel edges. The upstream slab shall also be reinforced similarly.r1 piAnnexure - VI Design of Railing and Breast Walls ANNEXURE-Vl(C) 1 DESIGN OF RAILING Railing Block- in C25 Cone, size 500 x 750 x500 inclusive of coping. Verticals Horizontals Required z for pipe ISA 75 x 75 x 10 @ 2.5 m c-c lxx= 71.4 Z= 13.5 37.5 mm nominal dia Gl pipes I = 8.68 Z = 3.95 BM 0.05859 t-m Z 3.906 Required z for angle BM 0.1575 t-m Z 12.50 Hence Both the sections are OK Stability of Block Weight 0.494 D 0.960 P 0.494 Since the block supporting the vertical is Btfl 0.158 monolithic with the wall masonry Direct C 1.144 the Pmin realised will be on the safer side Bending 2.279 both C & T Pmax 3.422 Pmin -1.135 OK will be resisted by the anchors FS against Sliding 1.976 Ok Similar railing shall be provided for the divide wall. The anchoring details are shown in the drawing. -3-V 5 * [ t t [ *| r ?Annexure- VI Design of Railing and Breast Walls ANNEXURE-VI(D) 1 DESIGN OF BREST WALL OF UNDER-SLUICE 1.1 Design of Brest Wall Dimentions Levels Length 3.00 m and Height 4.00 m Top 2080.00 m Clear Span Effective Span Load End Conditions Bottom 2076.00 m HFL 2078.10 m 3.00 m 3.75 m Thickness 0.750 m 3.10 t/m2 1 m above HFL BM at Centre Assuming Free Ends BM at Centre 5.45 tm BM at Supports 0 00 tm Max. Shear Force 5.81 t d reqd. d provided Ast required 244 17 mm 680 mm 674.43 mm2 Spacing of 20 dia HYSD bars 465.5783 mm»300mm Provide 20 dia HYSD bars at 225 mm c/c -4-7i /4 r t- ;i. 4 >iAnnexure- VI Design of Railing and Breast Walls 1.2 Breast Beam of Under-sluice Load Weigth of wall + self weight of beam Weight of Hoist Total Load BM SF Depth Required Depth provided Ast Reqd Minimum Ast Provide 20 mm dia 8 bars in two layers 21.60 MT 20.00 MT 41.60 MT 19.5 20.800 533.35 1120 1465.302 1720.482r r r r rAnnexure- VI Design of Railing and Breast Walls ANNEXURE-VI(E) 1 DESIGN OF BREST WALL OF HEAD REGULATOR 1.1 Design of Brest Wall Dimentions Levels Length 2.00 m and Height 4.00 m Top 2080 m Clear Span Effective Span Load End Conditions BM at Centre BM at Supports Max Shear Force d reqd d provided Ast required 1 Bottom 2076 m HFL 2078.1 m 2.00 m 2.50 m Thickness 0.50 m 3.10 Vm2 1 m above HFL BM at Centre Assuming Free Ends 1.94 tm 0.00 tm 3.10 t 145.60 mm • r Specing of 20 dia HYSD bars 370 mm 445.58 mm2 704.70 mm»300mm Provide 20 dia HYSD bars at 250 mm c/c Min main reinforcement 600 mm2 OK No shear reinforcement required, however provide end ties 16 dia at 300 mm c/c. -6-r r t r r1.2 Breast Beam of Head Regulator Weigth of wall + self weight of beam Weight of Hoist Total Load BM SF Depth Required Depth provided Ast Reqd Minimum Ast Provide 16 mm dia 6 bars in two layers Annexure- V/ Design of Railing andtBreast Walls 9.60 MT 10.00 MT 19.60 MT 6.125 9.800 236.61 810 363.6845 460.8434 Provide distribution steel 12 dia 200mm c/c on both sidesAnnexure- VII Design of Bridges ANNEXURE-VII(A) ROAD BRIDGE FOR HEAD REGULATOR OF YADOT Main Canal MC-1 DESIGN OF SLAB The span of bridge in undersluices is 3 m, in Left Bank Head Regulator span is 2.0 m Left Bank Head Regulator DATA (i) Clear span (ii) Clear width of road way 2.00 m 3.50 m (iii) Kerb size 0.225m x 0.225m (iv) Parapet 0.450m x 1.025m (v) Wear coat 0.075m at mid and 0 05m near Kerbs DESIGN OF MAIN SLAB (i) Over all width of bridge (4.50*2x(C > 225 *0.45)1x1000 = 5850 mm (ii) Let the overall thickness o f slab = 250 mm r (iii) Let the de^r cover = 25 mm‘ (iv) Dia of bars = 16 mm (v) Effective depth 300-25-16/2 = 217 mm (VI) Effective span 2000 ♦ 267 = 2267 mm (vii) Slab Length 2000 * 900 2900 mm DEAD LOADS BM (PER METER) CO Dead load of slab 0.250 x 1.00 x 25000 = 6250.00 N/m (ii) Dead load of wearing coat {(0.075*0.05)/2)x1.0x24000 = 1500.00 N/m (iii) Dead load of parapets 2 x 0.45 x 1.025 x 22400 / 5.85 = 3532.31 N/m (iv) Dead load of kerbs 2 x 0.225 x 0.225 x 25000 / 5.85 = 432.69 N/m (v) Total Dead load 7500 ♦ 1500 ♦ 3532.31 ♦ 432.69 = 11715.00 N/m (vi) Dead load 0M (wl / 8) 2 11527 x 2.267 A 2 / 8 = 7045.00 N-mIAnnexure - Vlf Design of Bridges 4 LIVE LOAD BM (PER METER) (i) Width of carriage way and only one vehicle can pass 3 50 m As the loads are dispersed in the direction of span, it is assumed that the maximum BM occurs when the toads are symmetrically placed about centre of span. BM at centre will be taken for design purpose. The position of load is shown in the figure as below and axle load of 114 KN will be place to give maximum BM Value of K for simply supported slab depending on L /1, where L is the width of slab and I is the effictive span of slab.IAnnexure - V7/ Design of Bridges 0.10 0.40 1.10 260 0.20 0.80 1.20 2.64 0.30 1 16 1.30 2.72 0.40 1.48 1.40 2.80 0.50 1.72 1.50 2.84 0.60 1.96 1.60 2.88 0.70 2.12 1.70 2.92 0.80 2.24 1.80 2.96 0.90 2.36 1.90 3.00 1.00 2.48 2 00 Above 3.00 4.85 !1 sB-'-iJWrAn n ex u re - Xfli Design of Bridges (iii) Effective width ’e* Where K for L /1 Value of K for L /1 = 1 81 Kx(1 -x/l) + W 4850/2667 = = 1.81 2 97 Class of loading (Axle load of 114 KN) and W is the width of concentration area of load W g ♦ 2h = 0.50 ♦ 2 x 0.075 = 065 m X 2.267/2-1.20/2 = 0.53 m Hence e 3 00 x 0.53 (1 - 0.53 / 2.267) ♦ 0.65 = 1.86 m > 1.80 m Effective width of wheel will overlap, taking e = 4.00 & full wheel load Modified value of e = 1.075 ♦ 1.80 ♦ 2.24 / 2 = 4.00 m Load intensity 114/400 = 28.5 KN/m Impact factor 4.5/(6*l) = 4.5/(6* 2.667 ) = 0.519 >0 50 Maximum BM at centre 28 50 x 2.267 / 2 - 28.50 x 1.20 / 2 = 15.200 KN-m Max BM due to impact 1 50x20.905 = 22.8700 KN-mAnnexure- Vll Design of Bridges 22870.00 N-m 28.50 KN 28 50 KN *----------------------- 1.20 1.334 m 1.334 m 2.bb/ m Total BM For mix C25 grade crCbc Dead load BM + Live load BM = 30275.0 N-m = 7 N/mm2 m 280 / (3 x scbc) = 280 / 3 x 7 = 13 erst = 200 N/mm2 k macbc / (mocbc + ost) = 0.31 i 1 -K/3 = 0897 R 1 f2 x ocbc x j x k = 0.973 Effective depth required (d) [(302752.5x1000) / (0 .973x1000)] 1/2 A = 176.39 mm Total depth of slab 176.39+ 16/2 + 25 = 209.39 mm Provide total depth = 250 mm Effective depth provided .'250- 16/2-25 = 217 mm ok as assumedAnnexure - VII Design of Bridges MAIN REINFORCEMENT Area of steel required (Ast) MI (ost x j x d) = 986.00 mm2 Provide 16 mm dia HYSD bars at spacing Actual Ast provided = 1000 x 201 06 / 180 180 mm = 1117.01 mm2 Hence OK DISTRIBUTION REINFORCEMENT Distribution steel is provided to resist 0.30 times live load BM A 0.20 times dead load BM. Effectiv ? depth Area of steel required (Ast) M = 0.30 x 31357.5 * 0.20 x 7405 = 10888 N-m 217-8-40 = 169.00 mm M f (ost x j x d) = 359.00 mm2 Provide 10 mm dia HYSD bars at spacing 200 mm Actual Ast provided = 1000 x 78 54 / 200 = 392.70 mm2 Hence OK NOMINAL REINFORCEMENT AT TOP BOTH WAYS Provide nominal reinforcement 0.06% at top both ways minimum spacing Provide 10 mm dia HYSD bars at spacing is thickness SHEAR Actual Ast provided = 1000 x 78.54 / 250 = 130.20 mm2 250 mm = 314.00 mm2 Hence OK (Dispersion at right angle to span = 0.25 ♦ 2 x {(0.05 - 0.075) / 2 ♦ 0.25)} = 0.875 m Maximum shear force occurs when load is near the support. Dispersion width in direction of span ls 0.875m. for maximum shear force wheel load should be at 0.875/2m from mid of the supportAnnexure - VII Design of BridgesI.- *1 JJ-TAnnexure- V7/ Design of Bridges Effective width for 1st wheel, e = 3.00 x 0.571 x (1 - 0.571 1 2 667) ♦ 0 65 2 m > 1.80 m Effective width of wheel will overlap, taking e = 3.88 & full wheel load Modified value of e = 1.075 ♦ 1.80 ♦ 2 / 2 = 3.88 m Load per m width = 114/ 3.88 = 29.38 KN Effective width for 2nd wheel, e = 3.00x1 771 x (1 -1.771 / 2.667) *0.65 = 2.43 m > 1.80 m Effective width of wheel will overlap, taking e = 4.09 & full wheel load Modified value of e = 1.075 * 1.80 ♦ 2.43 / 2 = Load per m width = 114 / 4.09 = Ra 29.38 (2.667 - 0 571) / 2.667 * 27 87 x 0.896 / 2.667 = 4.09 m 27.87 KN 32.45 KN Due to impact effect 1 50 x 32.45 = 486750 KN 48675 N S.F. due to dead load 12965x2.667/2 = 17288.63 N Total Shear Force. V 48675 * 17288.83 • 65963.8 N r 65.96 KN Check for snear stress Shear stress Tv 65963.83 / (1000 x 217) = 0.3 N/mm2 Permissible Shear for 100 x Ast / bd = i00x 1117.01 /(.1000x217) = 0.51 % Corresponding shear stress, Tc = 0.30 N/mm2 Permissible shear stress 33% higher, considenng impact Tc = 0.40 N/mm2 Hence. SAFE Thus. Tv is less than Tc, hence no need to provide shear reinforcementAnnexure - VII Design of Bridges 8 KERBS AND PARAPET WALLS Provide Kerb (Size 0.225 x 0.225 M) in Slone Masonry In Cement Mortar (1:5) Provide Parapet Wall (0.45m Thick & 1.025 m High) in Stone Masonry in Cement Moralar(1:5) Length of Kerb & Parapet Wall = 3 90 m -9-Annexure - V7/ Design of Bridges Right Bank Head Regulator 1 DATA (i) Clear span = 1.50 m («) Clear width of road way = 3.50 m (Hi) Kerb size = 0.225m x 0 225m (iv) Parapet = 0.30m x 1.025m (v) Wear coat = 0.075m at mid and 0.05m near Kerbs 2 DESIGN OF MAIN SLAB (•) Over all width of bridge (3.5+2x(( 1225+ 0.45))x1000 = 4850 mm (») Let the over all thickness of slab = 250 mm (•«) Let the clear cover = 25 mm (iv) Dia of bars = 16 mm (v) Effective depth 250-25- 16/2 = 217 mm (vi) effective span 1500*267 = 1767 mm (vii) Slab Length 1500 + 900 = 2400 mm 3 DEAD LOADS BM (PER METER) or Dead load of slab 0.25 x 1.00 x 25000 = ,-6250.00 N/m (h) Dead load of wearing coat ((0.075*0.05)/2}x1.0x24000 = r 1500.00 N/m (iii) Dead load of parapets 2 x 0 45 x 1.025 x 22400 / 5.85 = 3532.31 N/m (iv) Dead load of kerbs 2 x 0.225 x 0.225 x 25000 / 5.85 = 432.69 N/m (v) Total Dead load 7500 ♦ 1500 * 3532.31 * 432.69 = 11715.00 N/m (VI) Dead load BM (wr 7 8) 11715 x 1 767A 2/8 = 4572 00 N-m I -10- BSBH3Annexure - VII Design of Bridges 4 LIVE LOAD BM (PER METER) (i) Width of carriage way and only one vehicle can pass = 3.50 m As the loads are dispersed in the direction of span, it is assumed that the maximum BM occurs when the loads are symmetrically placed about centre of span. BM at centre will be taken for design purpose The position of load is shown in the figure as below and axle load of 114 KN will be place to give maximum BM. Value of K for simply supported slab depending on L /1, where L is the width of slab and I is the effictive span of slab L/l K L/l K 0.10 0.40 1.10 2.60 0.20 0.80 1.20 2.64 0 30 1.16 1.30 2.72 0.40 1.48 1.40 2.80 0.50 1.72 1.50 2.84 0.60 1.96 1.60 2.88 0.70 2.12 1.70 2.92 0.80 2.24 1.80 2.96 0.90 2 36 1 90 3.00Annexure - VII Design of Bridges 2.48 200 AboveAnnexure - V// Design of Bridges (iii) Effective width *e' Where K for L /1 Value of K for L /1 = 2.19 Kx(1-x/l) + W 5850 / 2267 = 2.58 = 3 00 Class of loading (Axle load of 114 KN) and W is the width of concentration area of load W g + 2h = 0.50 + 2 x 0.075 = 0.65 m X 1.767/2-1.20/2 - 0.28 m Hence e 3.00 x 0.53 (1 - 0.53 / 2.267) + 0.65 = 1.86 m > 1.80 m Effective width of wheel will overlap, taking e = 4.00 & full wheel load Modified v alue of e = 1.075 + 1.80 ♦ 2.24 / 2 4.00 m Load intensity 114/4.00 28.5 KN/rn Impact factor 45/(6 +I) = 4.5/(6 + 2 667) 0.519 >0.50 Maximum BM at centre 28 50 x 1.767 / 2 - 28.50 x 1.20 / 2 8.080 KN- m Max BM due to impact 1 50x20.905 10.0990 KN-m 13-Annexure - V7/ Design of Bridges Total BM For mix C25 grade ocbc Dead load BM ♦ Live load BM 14671.0 N-m =7 N/mm2 m 280 / (3 x scbc) = 280 / 3 x 7 = 13 ast = 200 N/mm2 k mocbc / (mocbc + osl) = 0.31 j 1 -K/3 = 0.897 R 1 /2 x ocbc x j x k = 0.973 Effective depth required (d) A ((14671x1000) / (0.973x1000)) 1/2 = 122.79 mm Total depth of slab 122.79 + 16/2 + 25 = 155.79 mm Provide total depth = 200 mm Effective depth provided 200-16/2-25 167 mmAnnexure - V// Design of Bridges MAIN REINFORCEMENT Area of steel required (Ast) M! (ast x j x d) - Provide 16 mm dia HYSD bars at spacing 489.00 mm 200 mm Actual Ast provided = 1000 x 201.06 / 200 = 1005.3 mm2 Hence OK DISTRIBUTION REINFORCEMENT Distribution steel is provided to resist 0.30 times live load BM & 0.20 times dead load BM. M = 0.30 x 100999 ♦ 0.20 x 4572 = 394"1 N-m Effective depth Area of steel required (Ast) 167-8-25 = 134.00 mm M / (ost x j x d) = 209.60 mm2 Provide 10 mm dta HYSD bars at spacing 200 mm Actual Ast provided - 1000 x 78.54 / 200 - 392.70 Hence OK NOMINAL REINFORCEMENT AT TOP BOTH WAYS mm2 Provide nominal reinforcement 0 06% at top both ways = 100 20 mm2 Provide 10 mm dia HYSD bars at spacing 450 mm Actual Ast provided = 1000 x 78.54 / 200 392.70 mm2 Hence OK SHEAR Dispersion at right angle to span = 0.25 * 2 X {(0.05 * 0.075) / 2 * 0.25)} = 0.575 m Maximum shear force occurs when load is near the support Dispersion widtn in direction of span is 0 875m. for maximum shear force wheel load should be at 0 875/2m from mid of the supportV,- F :r I I feAn a ex u re - VII Design of Bridges Effective width for 1st wheel, e = 2.36 x 0.77 x (1 - 0.77 / 5.365) + 0.65 > 2.21 1.80 m m Effective width of wheel will overlap, taking e = 3.98 & full wheel toad Modified value of e = 1.075 * 1.80 ♦ 2.21 1 2 = 3 98 m Load per m width = 114 / 3 98 2864 KN Effective width for 2nd wheel, e = 2.36 x 1.97 x (1 - 1.97 / 5.365) * 0.65 = 3.59 rr > 1.80 m Effective width of wheel will overlap, taking e = 4.67 & full wheel load Modified value of e = 1.075 ♦ 1.80 ♦ 3.59 / 2 = 4.67 m Load per m width = 114/ 4.67 24.41 KN Ra 28.64 (5.365 - 0.77) / 5 365 ♦ 24.41 x 3.395 / 5.365 = 39.98 KN Due to impact effect 1.396 x 39.98 = 55 8121 KN 55812.1 N S F. due to dead load 16282.53 x 5.365 / 2 = 43677 89 N Total Shear Force. V 55812.1 ♦ 43677 89 = 99490 0 N 7 99 49 KN Chetk for s hear stress • Shear stress. Tv 99489.99 / (1000 x 365) - 0.27 N/mm2 Permissible Shear for 100 x Ast / bd = 100x2094 4/(1000x365) = 0 57 % Corresponding shear stress. Tc = 0.31 N/mm' Permissible shear stress 33% higher, considering impact, Tc = 0.41 N/mm2 Hence. SAFE Thus. Tv is less than Tc. hence no need to provide shear reinforcement 8 KERBS AND PARAPET WALLS Provide Kerb (Size 0.225 x 0.225 M) in Stone Masonry in Cement Mortar (1:5) Provide Parapet Wall (0.45m Thick & 1.025 m High) in Stone Masonry in Cement Moratar (1:5) Length of Kerb & Parapet Wall = 6.50 mr ] J 1 1 1 i M
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