Birete Dam Project - Diversion Structure Design Summary

Ministry of Mines, Energy and Water Resources Land and Water Studies Agency
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birete dam project SPECIFICATIONS AND BILL OF QUANTITIES
X
ADDIS ABABA May 1981
9Ministry of Mines, Energy and Winter Resources Land and Vater Studios Agency
SIRETE DAM PROJECT SPECIFICATIONS AND BILL OF QUANTITIES
ADDIS ABABA
MAY 1?81
Tr ■ABSTRACT
The report contains spaelficatlons for the construction of Birete Da» Project* It includes payment clauses. The spacifieations and the payment clauses have been tied with the items of the Dill of Quantities, Thu specifications
and tho Bill of Quantities have been cooipilot! in a way that this doctiQont can fora a part of the contract if tho work11
ACKNOWLEDGEMENT
Specifications hevfr been based on the standards of ^ater and
Pow&r Development Authority end National Engineering Sorvicos , Pakistan  incorporating modifications and changes to suit the
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local site conditions* Bill of Quantities have boon yorkod
out by Ato Eanteyehun Hallo, engineer L.WSA and Mr* Simon do Hann, Ahsoelate Export, UNDP*
NAFIS AHMAD
UN ENGINEERING ADVTSERTABLE OF CONTENTS
Item
ABSTRACT........... .. .................. ................................... *.....................................*       1
ACKNOWLEDGEMENT, « . . . . ....... *.......................... ........................... • * ' ■ 11
TABLE OF CONTENTS. . ... ................................... *................................................ ..ill specifications
SECTION — Environiwntal Protoetion
■* B  Nobi li zRtion for Project Construction
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-   C  Diversion and Care of Water
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during Construction,
-    D  Excavation
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-    E  Construction of Earth and Rock fill
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- F, ConerotO* Plain and Reinforced
-   G  Miscellaneous
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BILL OF QUANTITIES31 RETS DAM PROJECT SPECIFICATIONS
SECTION A
E NV IRQ iiKEICTj. L P,S CT .lC TI ON LANDSCAPE. PRES EH- - .TT ON
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The Contractor shall take du® precautions to preserve the fiat oral a ur row-rid Ings and jhr-.ll carry out his construction activities in such a manner as to avoid damage to or ^polling
nf the nut ura 1 Land a on pn around t He ftroa of tho pro Joe t r Clasping of trues, bushes, vegetation, grft«ihS land, crops or property shall ba Limited to the arms of pormcnent uorks, approved construction road a and th-o arc an uf o.’ioavation opomtionj. On eoraplation of the project construction, all
work areas rirowid the permanent structures ehall hu cleared and graded so ae to blond with thn natural landscape,. Ttie comp
area shall be loft in a clean condition and the obondoned
borrow pits and cjuarry nitss shell bp drossod to stable slopes.
5 PREVENTION QF_tfAT5R POLL UTTON
Tho Cotitractor >bkl;l carry out his construction activities in a manner that would prevent entrance oi- accidental spillage of solid natter, contaminants  objectionable pol1uttmta, wmstBS,
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i'ufu.o, garbage, eaeago affluent, oil jr other potroleum products into stream,
i DUST ABATEMENT
during the construction of the project the contractor shall carry out proper and *fitciant measures wherever and whenever neceaiary to reduce the dust nuisantt,
*              5UREVENTS                   PAYMENTS
The oust of all work required by thia eoctidrt shall bo included in th* price bld In th* schedulo fur other items
of workgSECTION 3
MOBILIZATION FCa PSCJgQT CONSTRUCTION ; OftK INCLUliED
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The work under thi* section consists of furnishing ell
plant, labour, oquipraant, PtUricls uk! superintendence., and other services and facilities required to corapleto th* Birete Dnm
Project *
]fE^SjJggM-ZKTS AND P^YfrENTS
B*2(1) General
The Contractor shall submit n. breakdown of th® lump 1811171 price bid for J train 1 0 1 Mo^ni I i zfiL _o.ri l ot Project Construction, to the Engineer within thirty days
of the date of award of Contract. Ths breakdown shall
r®fleet in ropsonail* detail aa detsrainod by tho Engineer, th® cost of each of the principal itoras of
work included for payment under th® contract lump sum price and, subject to such revision as the Engineer
may require., shall bo used as a basis for partial and. final payment ss th® work under Item 101  Mobilization,
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for Project Construction, is performed and completed* B-2 ( 2 } Meo s ur eraojs t
Measurement will bo made of th® mobilization. of facilities for project construction and work related thereto, oil as mentioned in clause 8—2(3) below, ns specified hereunder us a cotaplot® unit*
0-2(3) Payment
Payment will be muds for the unit measured as provided above at tho Contract lump sun price for Hob ill nation for Project Construction, and shall constitute full compensation for providing all facilities including camps  raalntonunce and services roquirud in
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connection therewith as indicated,, specified or otherwise required for the proper operation of the facilities and not included for payment under any other Contract ltora  Payment under this Item will
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include but is not necesaarily limited to, all costa incurred Ln connootion with providing quarters for tho Contractor’a personnel} Workshops  Varohoueas^
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sheds and yardsj and the Contractor’s adrainiatrttive and field offloos.3
SECTION 0
DIVERSION j-.ND_.GARE CF JATEN DURING_CONSTRUCTIQN
SCOPE
C- 1 (1) General
This section covers the- construction! ac-in tenent*, and the performince of all work necessary to care for river wator  ground water, and local drainages in
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connection with the entire Contract  so that meh water
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does not intorfare with the progress or affect the quality of the construction a
C-l(2) Wark included
The work includes but ia not liciitcd to the
following?
(i)        Diversion and care of river during constructions
(ii)       Unwatering and tending of wstor behind Coffer dams! in conduit and all other parts of the work*
(ill) Such dosijjn as nay be necessary to supplement that shown on the Drawings and carry out the intent of this section*
c-K3) Structures
The structures Include but are not limited tot are Upstream and Downstream Cofferdams! and the Diversion R*C*C* Structure including inlet  conduit and
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outlet. Work in connection with each of those
structures not covered in this section shall be
performed in accordance with the applicable requirements of the various Sections of the Specifications for tho particular work involved*
2 DIVERSION SJHEME
C*2(1) General
The Construction of dam will require a diversion to poreiit preparation of foundation and placing of
fill raateriale in dry* River diversion will bo occompllshod by constructing the Upstream and Downstream Cofferdams, and diverting the river flows through the Diversion Structure* Tho Diversion la
to bo accomplished in two stages*- if -
a)       Stage I*
In th® firat dry season, it is intended to construct, i)          the Diversion structure,
ii)         the spillway, and
til) the Intake Structure.
lv) It is also intended to simultaneously construct the dam
from both sides to the full height leaving a gap in the
embankment a* shown in the Drawing to enable the high flows during the rainy season after the first dry season to
a ft a
b)         Stago II
In the next dry ucason, it is intended to construct.
4)       th<» Upstream Cofferdam,
±i)        ths Downstream Cofferdam,
Ui)       the diversion of tho river through the Diversion Structuro, and
lv)        closing of tho gap in the Main Dam continuing constructor upto the full height.
CLEARING AND STRIPPING _0r -FOUNDATIONS
All ar^ao under the Cofferdams, Diversion Structure, Spillway, Intake Structure and the main Data shall be cleared of trees, vegetation and any other objectionable materials.
Cleared material shall be disposed of by the Contractor from
the site of work in a waste area designated by the Engineer.
EXCAVATION FOR FOUNDATIONS
Excavation for foundations of Cofferdam, Diversion Structure, Spillway, Intake Structure and the Main Dam shall
bo carriod out in accordance with the Drawings and as specified in Section D-EXCAVAT1ON.
COFFERDAMS
C-S(l) Materials
Materials for cofferdam fill shall be obtained from required excavations or from borrow as selected by the Contractor and approved by the Engineer• The different zones of cofferdams shall be constructed with the material gradation as shown on tho Drawing.- 5 -
The shells of the cofferdams vi.ll be constructed with
random rockfili obtained from the excavation vith maxitaura size particl&e not exceeding 25cmF
0-5(2) Pl a. ecnwnt arid Compact i&n
Th a random rockfill in the shells of the cofferdams shall be placed in 35 cm loose-dypth lifts and epnipactqd with at least four posses (complete coverage) of a. 10
short ton vibratory roller. The impervious zone and
the transition material fill In the Upstream Cofferdam
shall b& pljicfld and compacted In accordance with relevant Clauses of Soctl&n E for th® M-iin D^m impervious and transition fills,
C-5(j) Domolishintf Downstream Cofferdam
After the construetion of the Main Dan has been completfid  th® Downstream Cofferdam or such portions of
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this Caffcrdam as directed by the Engineer shall be demolished and the material so demolished, shall bp dis posed of in the designated spoil areas as directed by
th® Engineer,
5 APPROVAL _QF CONTRACTOR "S PLAN OF OPERATIONS Within thirty days after receipt of notice to pracg&d with
the Contract, the Contractor shall submit his proposed plan of operations for ail ft-tago I and Stage II works under this Section for approval of th® Engineer, including:
a) Description of method including layout of unwatering system for cofferdam*  exemtion areas, and other parts of the
f
at
work *
b} Stalls including capacity of uimtarlng equipatent, for unwatering coffordens, ojecnvatlon ureas , end other r  Tpte of the work,
f PROTECTION Of PEAKANENT li'QftK
The Contractor shell provide such nenns ns arc necessary to Buppl H  nt the approved achenes for diversion, care of
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river, and unwatering during construction far the protection of the porEon&nt work,~ 6 -
UNVATESING AND CA^e. Or V.VEqlL-
Thc Contractor shell provide, install, operate and maintain
approved unwatering ayatona (including: sufficient standby
equipment) to unvtt&r and keep dry all areas of construction
that are bc-low the stream or ground water elevation during
construction operations and as required to keep oxcavnted
foundation and underground areas and aide slopes stable* ^11
fill material shall be placed in the dry.
. l.syrarm£ h"T^ v k_l- fa YK--: h'T5
C-9( 1) Item No, 102. Riv*r Diversion and Cara of Mater.
a)       Measurement,
Measurumont       will       be       nade       of       all       work       acceptably performed       under       this       ituti,       which       is       not       included       for payment under another itnzi, as a complete unit.
b)       Payment,
Payment will bo aade for the unit □ensured abovta at the Contract lump sun price for River Diversion and Care of Vctor and shall constitute
full compensation for all costs related to diversion and care of water and other water for which payicent is not made under other items including repair or
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replacement of damaged work due to flood and other wutor»| expense incidental to overtopping of cofferdams, dewatering, ro-exeavation and all
other work Tainted to the item,
0—9(2) Items No, 103-a* 10^—a  and 201 Clearing and
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Stripping of Foundations.
a)       Moasuremuntr
Meesurefflont will be made for the number of square metres projected vertically to a horizontal
piano of the foundations area acceptably cleared, stripped and graded,
b)       Payment,
l*aycient will bo made ftjr tho numb or of square metres as Measured above for clearing* stripping
and grading and shall constitute full compensation far clearing  stripping and grading of all material
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pointed to this item i-ncludlng dispose! of stripped material in tho approved spoil ar#?.
0-9(3) XfcalM *<>- 1O>C? 103-^ :0>e’
P=nde,ffl
F.oc!cl'lll,         Tt-MielUon         Material         I1U,         oo4         Ipporvloua         <±11 in Upstream anti Downs troan C^fferdaas,
a)       Maa a ur ernent v
FoaouroDont under those Items mH be
actual measur errant method far the number of cubic metres of each tiitcricl in place and acceptably
in the coffer dan fill to the lines* grades and troaMGctiqna shoran an the Drairiug ar established by the 2nginoer*
b)       Pnyraqnt,
Payment will be made for th* number Of cubic nctrtrS uraasurfld as provided above for the Contract unit price per cuble Metre for the-so itensi payment shall cenatitute full coapensation for constructing
the cofferdam fills from required excavation  stock
by
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piles and borrow nreai includings-c^tio^^ulingt rehandling   processing, moi $ tuning  placing and
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eorapacting the materials as specified Ud all otbr-r work related to the it-eo,
C-9(4) iltem tIo  105- Demolishing of Downstrena Cofferdam.
B
ci J WMwonont*
Measurement will be made for the number of cubic motors of fill acceptably demolished end
removed. fro in the Downstroaia Coff orders as spe-cifiod in clause C-j(j}+
b) PfiyniBnt,
Payment will be made for the nuribor of cubic metres of fill domolished from the Downstroara Cofferdam as Mdsured abov^ and shall constitute full compensation. for excavation, demolishing, and disposal of oscfivftted material in the approved
areas and grading, leveling and clearing the Downstream Cofferdam site in tm approved manner*C-9(5) J tom 106 « Punpinfl; of water from Foundations,
a)      Measurement.
Maasuromant will be made for the number of 3 litres per second per hour of wfiter removed {excluding water supplied Tor construction purposes) froa all work areas whenever required by pumping regard leas of Jirfad against which it is pumped, acceptably performed, and as a complete unit* Measurement will be made by acceptable devices provided by the Contractor and acceptable to the Engineer*
b)      Ptyn*nt.
Fayoent will be made for the number of 5 litres per sacoiid per hour measured ax ahove at the CanEraci unit price per 5 litres per second per hour for
pumping of Water from foundations and shall constitute full compensation for the work related
to pumping of water as described in clauses C-7
and C-B*
SECTION D
EXCAVATION
SCOFF
This section covers excavation for Cofferdams, Diversion Structure, Spillway, Intake Structure and th* Main Dam;
borrow areas; dental excavation? oth&r excavation not
specified in other sections? and disposal of all excavated
materials except ns the placement of materiel is covered in
other sections,
CLASSIFICATION OF EXCAVATION MATERIALS
D-2(l) General
The tone* Rock, Fandom Rock, Format Ion and Earth are hereby defined when used far the purpose of
classifying excavated materials for payment undor
th e vari ous Items
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D-2(2) Rock
Rock shall zncan all in place bods or lodges of solid mineral matter sound and intact and as So classified by tho Engineer. Processing and utilization o± rock shall be required in the construction of the9
D—2(3) Rand om—Ro ck
Random Reek shall mean in placfl solid mineral material withered to a reasonable degree having
pieces of rock sound and intact* and as so classified
by tho Engineer,
D_2(J») Transition Material (leathered Basalt), Formation, Formation of igneous material generally called
rock but not raeeting the classiflcation requirements for Rock or Random Rock as in clauses D-2<2) and D-2<3) respectively, and being in such a weathered condition that it can be effectively loosened or broken by
rippint!?i and ae so clnsfli f 1 t*d by the Lnginnor.
D^2(5) Earth
Earth ehall meats all oa to rials uxcepl Rock, Random Rock and Formation na defined above in clause* D-2(2)  0-2(3), and o-2(^)* Earth shall include,
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but not necessarily Vo limited to  all fjenlogically
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recent materials overlying rock such as alluvium and talue| all layers of earth which arc cenienttd ho that the garth becomes conglomera te, «hall be considered as Earth*
EXCAVATION, OPEN CUT-—GENERAL
D-3(1) Exea va t i on Me thods
The Contractor ohall perform all open cut excavation and grading to the final elevation linos
and grades shown on th* Drawings or approved by the Engingtr* Excavation shall bo performed by approved methods* The Contractor shall make such trial excavations as are necessary to indicate the
adequacy of the oxcavatlon m&thodH. The rock excavation in the foundation area of structures shall bo done by such careful methods ua Lino Drilling Pre Splitting or Cushion Blasting* The Contractor shall plan hici excavation operations in the rock area in Such a manner that the bulk of material produced is of (-) 30cm size. The responsibility for th*
aucom of the excavation method shall rest with the Contractor regardless of approval by the Engineer*IO -
In general for the earth -nd quarried rock materials
the Engineer will use his best endeavours to advise
the Contractor at the loading uroas regarding the suitability of excavated materials for use in
L-mbnnkrnent based on the Engineer's examination prior to transportation to points of placflHont and 'Stock piling will not bo paid for. Rock excavation from
the dam and other structures’ foundation area shall be stockpiled as per instructions of th* Engineer, Tho quality roquirementa of tho materials arc specified
In clause E — D-J(2) Excav.ition Extent
t  Materials*
Excess excavation performed by the Contractor fox'
•my purpose or rc&sgnp except that ordered in writing by tho Engineer, shall ba at the expense of the Contractor, All excavation for structures shall be carried to foundation material satisfactory to tho Engineer regardless of who the-r the elevation thereof is higher or lower than the elevation shown on the Drawings, All necessary precautions shall be taken
to preserve th* matorial below and beyond the linos of all excavation in sound undisturbed conditions.
All over excavations required by the Engineer to be backfilled shall be backfilled by the Contractor in accordanco with the instructions of the Engineer|
over-excavation In rack below or against concrete structures and impervious fill shall be backfilled
with concrete or as directed by the Engineerj if over- oxcavation is unauthorised it shall be backfilled at tho Contractor's expense, Except where the use of other materials is specifically approved by the Engineer, unauthorised excessive excavation along
the sides of structures in rock and in earth whore
aide forms arc not used shall be backfilled with concrete at the Contractor’s expense. Materials for use in ths work shall be carefully oxcavatad to product) the material in form suitable for the work;
additional Kicasuras such as secondary blasting and mixing shall be used, if necessary, to make theH
excavatod material suitable for the retired use.
Excavation* through cvorburden into rock shall b* performed In a manner to r-atiJt in oopersllon of the
rock from th* overburden so that the maximum practicable amount of suitable embankment and fill material will
be produced. Stripping of bpahes. shrubs, topsoil shall
b« done prior to start of excavation* In th* area,
in accordance with clauflfi C-3 hereof *
D-3(j) Excavation Tol&rances
Excavation shall be performed within th* tolerances for excavation limits indicated on the Dryings. Where
no tolerances Fire indicated, otcavatinn shall he performed to tolerances established by the Engineer
as acceptable for the design and type of work Involved.
In case where the structure or other governing criterion permits f the Engineer may relax the tolerance to facilitate:- construction#
D-3(i<) Excavation Line to Suit Field Conditions
The character and desired dimensions of the proposed excavations are in general indicated on the Drawings* The Engineer, however, shall have the right
to:
a)       Vary the depth* width, and the length of the excavations and to increase or docroast,- the slopes including berms of the excavations; and
b)       Require the use of berms of dimension as instructed in permanent slopes whore none are shown on the
□rowings, if Conditions require or permit such modifications for the purpose of obtaining mor® stable or economical slopes and/or foundations, Tho Engineer shall have the right to vary the excavation lines after excavation has been
a 
Commenced .
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□~3(4) Contact Excavation for Cora
ail tnrt^1
Boneath the impopvloua core of th# Main dam embankment within limits as shown on th# Drawings
shall be excavated, rock surface?
shall be prepared and itnpsrvioua material shall bo- 12
placed qb required for the- control of undor-seopiiKe * Excavation shall ba carried to reasonably sound rock .
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suitable to receive the impervious core material. Contact longth between the impervious core and reck
at the Main Embankment Dam shall be as shown on the Drawings, Th# suitable material oxcavnirtd will be allowed to be placed in the shells of the main dam as directed by the Engineeri and the Contractor may stockpile such suitabU material for further uae. The payment for placement of suitable material will be made separately according to other shell material in tha dam. The unsuitable nmUrlftl will bo disposed of
in the designated spoil area b and no additional payment will bo made for stockpiling and disposal work,
D- 3 ( J ) DENTAL EXCAVATION
Zones cl" unsatisfactory material below tho foundation levels shown on the Drawing: which will require Q3d?XLv&tion^ wiy be ancourtttrad. All such material, regardless of character  shall be removed
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and disposed uf as directed by th# Engineer, Dental excavation shall consist of the removal of earth such as talus or alluvium or unsound rock ^uch as soft, friable or highly weathered rock from below the foundation or other base excavation line^ indicated on the Drawings or directed by the Engineer for Structures and for impervious earth-rock: contact  and
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from locations such b.# Joints , fl w h urn a j, pn r=W ft t. *c jind between rock bed±  where th® use of power excavation
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equipment la not practicable. Dental excavation shall
not include rumovnl of njaterial# by pressure washing and shall net include excavation which is classified by
th® Engineer and paid for under another Contract Item, Excavated aroaa covered in this clauan shall be
cloaned as specified and provided with dental trontment as specified in clause D-S(l)l.13
0-3(6) Clearing and Stripping for QutrHea
The areas from which Rock  Random—Hock  Transition
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Material, and Enrth is to bo excavatod for fill in the
Dam, shall bo cleared and stripped of all bushes,
trRGSj shrubs, top unsuitable soil or material aa
directed by th® Engineer* Blasting and Excavation work in the quarries shall start only after tlu stripping
and clearing bos boon. complGtod to the satisfaction of
tho Engineer and the stripped surface has been
approved by tho Engineer, The stripped materiel shall
be dispoaod of in the. waste area* as directed by the Engineer*
D-3(7) Measurement find Payment
The measurement nnd Payment for excavation shall be made according to the type* of excavation that is Rock or Random-Hock or Transition Matoriel(Weathered Hosolc) or Earth, as classified in the field by the
Engineer* Tho i tom rate for payment of Excavation shall include the disposition of" material in the specified mantaer*
ROCK QUARRIES
D-4(l) General
The material for rock^fill will be obtained from thu approved Rock Quarries as indicated on the Drawing or as selected by ttao Contractor end approved by the Engineer* The Contractor shall exploit, develop and maintain the approved quarries and pits in a suitable condition for the oxtraction and removal of the ■ required materials in a manner satisfactory to tho Engineer,. so as to obtain at all times tho greatest practicable yield of suitable materials in the
deposit* The fact that the Employer has approved the site and location from which material for rock—fill may be obtained shall not be construed as constituting tho approval for use of all material extracted from the quarries and the Contractor shall bo responsible lor the specified quality and grading of such produced material* For quality and gradation of rock-fill material tho clause E - 4 materials shall be
applicable *14 -
D-l4 (2 ) Blasting and Excavations
a)       The Contractor shell plan his quorryintf and blasting operations in such a manner that bulk of
material produced is of {-) 30cm s1ae* lhe (-) 30cm
reek material from tho approved area and quarried ±n approved m&nnor shall be uaod in the rockfill shells
of the QEr.hankmont.
b)       For riprap mate ria-I to b° used on the upstream fecit, separate quarrying and salvaging shall be
required. The gradation of riprap is specified in
clausa, E-M )
04(3) Kommwnt nnd Piyroeht for quarried matorinl.
The processed mudtoriftl from the rock quarries
shall bv placed and compacted in the dam as per clausesE— 5f E-6  E-7 and E-8 which items shall include the entire
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cost of proecssingf aOpera ting, grading, handHng, placDinont end compaction of this material* No separate payment shall be made for the* excavation of the mcLturial under thia clause.
TRANSITION MATERIAL QUAPRY
D«-5 ( 1) Excavation
The transition material will bo obtained frota the approved weathered. Basalt areas as indicated on the Drawing or as selected by the Contractor and approved by the Engineer, The Contractor shall plan his ripping^ excavation and quarrying opgrations in such h. manner that the Historic. 1 produced is of (-) 0cm size, and
shall be responsible for the specified quality and grading of transition materiul produced. For quality and gradation of transition materiel the clause
E4(4) Materials shall be applicable* The (-) 8cn
site material from the approved ares and quarried in approved manner shall tan used in the transition zones of the Embankment.
IIJ*5( 2 ) Hoa r,urcrnent and payraon t
The tranailion material from the quarry shall be placed and compacted In the da® as ptf ClOU<Gi B*-5 to £—6 which items shall Include the entire cost of
processing   3eperating  grading,, handling, plac^sent
p
t
and compaction of this notorial* No sopercte payaent shall be made for the excavation of the oaterial
under this clause.
EAgTIi BQrtKOiC AflbAS
D-6(l) General
Borrow arcs- for earth material in the porcunonx work shall be the borrow area shown on the ^rawing, other borrow aroc designated by the Engineer and other borrow area selected by tho Contractor subject to approval by the Engineer. The outline of the borrow area shown on Srswifti; i> general and. schematic  the
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actual borrow excavation nay bu entirely within the area or partially outside of and beyond the indicated outline or borrow .nror,, If the Contractor proposed to uso borrow area other than that shown on the drawing, ho shall make such investigations at his axpunso and furnish such evidence for approval of rho Engineer  as
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will indicata that the borrow aroa can be used as a source of malarial suitable for tho embankment.
D-6(2) Operation &f Borrow Areas
In the earth borrow areas the Contractor shall perforin fiolectivA excavation to nocosaary depth and extent in the dry, draining of borrow areas, prowetting of niDtsrial in the borrow areas, dressing of borrow area during and after campktion and disposition of materials to obtain and make the materials suitable for uso in the work.
Ji3POSITION OF MATERIALS
The Contractor shall be permitted to use all suitable materials fro* roquirod mLvation in th«i work ihovn «  the
n
drawings, Suitable materials l'rom burrow arras and quarries shall bo usoci in the work shown on the Drawing. j materialsfrom borrow and quarries that are designated by the EnglTier-r ns unsuitable shall be- neatly disposed of in approved locations
at no expense to the Employer. The Contractor shall be
responsible for miking and maintaining all haul roads
required for transport of the materials from the Borrow Areas, Excavation and Quarries to their required destinations« tfo
Superate payment will be cue to tho Contractor for the haul
roads and all costs related to this shall bo included in the
unit prices of the materials ns provided in the Bill of
Quantities*
FOUNDATION PREPARATION
D-B(l) Preparation of Contact Surface between Rock and Impervious Core-Dental Treatment,
Exposed rock surface within the rock-core contact areas shall be cleaned by brooming and compressed air to permit inspection. Surface treatment shall be performed if necessary, to ensure that no open or loosely filled fissures, joints or bedding plants nre present which might permit seepage concentrations along tht rock-core contact areas. Unsatisfactory material in pockets, seams and rissures shall bo removed, if so ordered by the Engineor* Fissures,
seams and shear zones exposed in thu cleaning process shall bo immediately filled with eooerste, as directed
by the Enginner,
D-8(2} Structured-Foundation Surface between Rock and Concrete* Exposed rock surface within thu foundation
against which concrete 1* to bo placed shall be
cleaned and broomed and tbo surface *nd undulations shall be covered and filled with a layer of blinding concrete as directed by the Engineer. The Blinding Concruto shall bo provided according to Specifications in Section F for Concrete *17 -
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AND PAYMENTS
D-9( l) Execvatlon from Earth Eori ow Areas,
b
Nd 9c-poratfl payment will bfl made to the Contractor Tor clearing, stripping, vntering and oxcuvation from
the earth borrow areas# All excavation works from
eurth borrow nrc&o .3 ha 11 bo included Tor pnyniont under’ the item which Covm the placement of this material#
H-9(2) Items No, 103-b, 202* Earth Excavation in foundations.
a)       Moa « uromont
Naasuroment for Earth Exccvatinn of foundations will bo made in cubic metro- measure of unsuitable material in original positions acceptably removed
to thn- satisfaction of the Engineer*
b)       Payment
Payment will b*j made for the number of cubic metros measured ca provided above at tho contract unit price par cubic metro and shall constitute
full cottiponsatiQn for removing all unsuitable material including disposal in the waste areas*
D "9(3) Item Mo, 203+ Random-Rock Excavation in foundations +
a)       Hvanuropient
Measurement tor Random-Rock Excavation in foundations a» defined in Clause M(j) shall be
mads in cubic metre neaauro of Random-Rock in original position acceptably or.cavatod*
b)       Payment
Payment will bo made for the number of cubic metre* measured as provided above at the contract unit price per cubic raetrn and shall constitute
full compensation Tor removing all unsuitable material to the waste areas and suitable material for stockpiling*1B
Item No* 20*4  Rock Excavation tn foundations
1
a)       Measurement
Measuromoat of Rock Excavation In foundations as defined in Clause D-2(2) shall bo made in cubic
metre measure of Rock in original position
accc-ptably excavaltd by means of Lino drilling,
prq-splitting, cushion blasting or by other
approved methods p within the lines and grades provided by the Engineer and stockpiled, as
specified and directed by the Engineer*
b)       Payment
Payment will be made for the number of cubic metres measured as above at the contract unit price for txcaiion of Eock from th* foundation area, including full co^pansatlon for stockpiling of this [FEi tori al ns specified.
Rehandling of Rock from the Approved Stockpiles
No separate payment will be made for rehandling of rock from the approved stockpiles and this work will be included for payment of it on which covora the placement of material*
□-9(6) hock from Quarrying
No separate payment for quarrying, stockpiling,
•sorting and mixing of rook material will bo made to the Contractor* The measurement and payment for
j
Rockfill and Riprap material from the quarry will be
made in the fill under the items which cQvtr the placement of rockfill and riprap material*
D -9(?) Item 20J* Surface Dental Treatment of Foundation for
Core-Rock Contact-Dental Concrete*
a) Measurement
Measurement will bo made for the* number of cubic metros of Dental Concrete acceptably placed
in the foundation for treatment of fissurow, seams and shear sones ns specified in clause D-8{ 3),.
No separata moasurtimont will bo madia for cleaning work required in connection with dental
treatment *b) Payment«
Pcryirt^nt for Jontol eoncrFjta lfill &e mad* far the nujnt.*!- of cubic mat*** M aeftsurfrd <bCVfl ■* the Contract unit price per cubic metre of Dental Concrete and shall constitute full compunction Tor
fill Ing up the cleaned fissu«B, shear zones with concrete sild nil vork related to this itcffl*
SECTION E
CONSTRUCTION GF EAL?TH ANU-ROCK FILL
SCOPE
The work covored by this section consists of construction of the Main Dam, tho torfcrdans  and other scellanwus fills,
p
DEFINITION
The tflFGi Till ae used in Suction E of th^so Specifications
Is defined a» thti earth and rock fill portions of the m&in
dn.ro and cofferdams structure* and all
other fill|
riprap.
filter find transition materials far those dams and as used in
connection with other structures.
GENERAL   PROVISIONS
E-3(l)         Equipment and Methods
Before proceeding with any of the work specified In thia section, thu Contractor shall furnish the tonstruetien sequence and material utilization schomo
he proposes to use in fill tgn.itrijction to the
Engineer as further information for approval.^
E-5(2)         Lines and Grades
Fill shall be constructed to tho lines , grades
and cross-sections indicated an the Drawings, unless otherwise directed by the Engineer, Mater1ala
Cqnfor^i-ng to the requirements specified in clause
E-4          Materials! shall b* placed and compacted within the ±ndltp.t<jd ion? limits, Thu Engineer reserves
the right to increase Or decrease the foundation widths, the embankment slopes or “the zone limits or
to make such other changes in the embankment sections as may tag doomed necessary to produce safe structures,- 20
or for efficient utilization of mztoriels from
required excavation* Settlement of embankmont for the pest construction period will bo provided for
by incr&islrigj the height of the section** Required height increases will be de-terrr.inea ana specified by the Engine&r from settlement observation made as the work progresses!
L-3(3) Conduct of Work
a) Maintenance  Protection and Testa.
p
The Contractor shall maintain tnd protect the Kain Dam in a satisfactory condition at all times
until final completion of all work under the
Contract. Tho Engineer will establish & proETamoe
of testing of in-placo fill to injure th&t the
work is being performed in conformance to the requirements of these specifications* The Engineer
will also perform tests of materials at their
source and during their prosseesing and handling
as necessary for quality control and the Contractor shall adjust his methods as required for ths improvement of the product to meet Specification requirements. Tests of raat&riula and mbanknent tonstructidn will be made at regular intervals and
the Engineer will notify \he Contractor of any deficiencies in materials and/or construction whan the results of tests are known* Doficienclas shall
be remedied by such nieasux-os as the Engineer may direct* The Contractor may be required to removef at his own uxpwo, any fill placed outside of the prostribod slop* lines whore each placement is
not authorised by the Engineer*
b) Haul deads
Haul road5 shall bo located and. constructed as approved by tho Engineer* They shall be designed to maintain the intended traffic aafolyt without undangoring ombankraent stability drulng th* embankment cona truetian period and shall be constructed in 0. mannor to preclude contamination or alteration of materials forming tho embankmant
V r Tiuiuf21
section. All roads located on •obanknwit slop^ *ha11
be romovad at the completion of <ob»nk»«Ht construction. Haul or construction roads shall bo provided and will
not bo measured for payment*
MATERIALS
E-4(i) General
Fill materials shall ba chtnined from required excavations, from the borrow areas «nd from rock quarries as Indicated on the Drawings and At specified in Section D* All materials shall conform to the requirements of the Spoc-ificutionsj and their disposition in the dam shall be at shown on the Drawings except as Qihervi>c directed by the Engineer •
E—U(2) Riprap
Material for riprap slope protection on the upstream of the dum shall be ^njularj sound, durable blocky Rock, free from cracks, scans or other defects which would tend to increase unduly its deterioration from natural causes* Material for riprap shall conform to tho following gvnural gradation of rock sizes*
Gradation         RcrfjuirecDon t  for RiprSp M*terljLl
Ma tori a.1
Si
Percent Finer Than,
By   Weight
JO dm                                                  100
60 ■'
15 *
a -
E-t|(3) Sock-fill ahull?
80 to 90
ID to 20
Not
EjcrnnA’i n         10
Average Weight
175 ks 110 "
10 - 1 ”
Material for upstream and downstrocni rock-fill
ohoIls aha11 ba angular  sound, durable blocky rock
t
t
well graded within the following gradation limits.
Gradation Apquircmonta for Rock-fl11 Material
Matori al
Slzo
30 cm
No* ** sIoyo
Percent Finer Than
By Voight
100
.75old)               Not Exceeding 25
N0» 200 sieve
( 0 * O7 J* tnm )         in
h
j- 22
Oversize rocks produced in the required excavations or brought front the qunrry shall bo pushed towards
the outor slopes of the rock—fill sholls»
8-MM Transition Material
Material for compacted transition upstream and downstrtnm of clay core shall he weathered Basalt + angular^ sound and durable as specified in clause
D-2(*i) and quarried by means of ripping and scraping to a gradation within the following Units*
Gradation Ttcquircraents for Transition Material
Mate
rial
Percent Finer Than
Si
ze
By Weight
0 cm
IGO
2 m
50-60
No* sieve
 (^*75    )
£Ufl
25 - 50
No. 200 
Sieve (0.07tnnn>
5-15
£-^(5} Inporvlous Core
Mattrial for compacted impervious core shall be
the natural deposits of clay designated as borrow
area 3*. on Drawing No* DE 101*
PLACEMENT
£-5(1) General
No fill shall be placed on any part of the dam
or other structure foundations until such area has
bfir^n inspntted and approved. Materiala of the several types and qualities required shall be deposited and distributed within the zone Limits shown on the
Drawings and to the slopes indioatnd within the Ukmcfj? specified ba Low* The gradation and distribution of materials in the zones of the dam shall bo such
as to produce in each zone a reasonably wall gradnd oiaaBi Fill materiol shall bo handled and placed by such methods as will miniraize segregation  In lifts
t
of depths as specified* and in general the omaller sizes of material within wn^s of rockfill are placed towards the clay core, and the larger sizes towards
ths outer- 23
faces, ifhorc roekfill
riprep alapo protection
arc pl at a ci on pornucLiiontly exposctl tmb-.nkniL-n t slopes, the placing of fill shell be such as to obtain sirftces
within a tolerance of" plus 15cm ?md minus 0cd except that the gxtreat minus tolerance nhall not be continuous over an area greater than 20 square Deeres. For all other zones not specified abov*  or elsevher^.
f
*
material shall be placed as close as practicable to
ths      lints      shown      on      the      drawings      as      approved      by      the Enginc-or-a           Bridging       ih       tho       fill*       and       all       slabs       or slabby rock shall bo broken down,
E- 5 ( 2 ) Rate of plac orient.
Unless otherwise indicated or dir<rctod  tht top
T
of caoh fimbankirwnt zone, including the riprap, shall
be □aintained at approximately tho same level throughout ouch cpibankmen t cons true tion s tage rejgB.r-d.lesB of the numbo-r of typos of matcirials b:iing placed, except as
may be required to prevent mixture of embankment materials, Material shall be delivered in proper
sequence and distributed over the surfaces of the
fills st such rate ao will ensure the completion of
each embankraunt zone and stage thereof within the
sp&clfiud timo.
E-5(3) Slope protection placement
Riprap material shall be placed by dumping on the embankment within the limits indicated in such a
manner as to produce a well graded mass of rack with the minimum practicable pcrcontago of voids, and shall be constructod within the specified tal»rance
to the lines and grades shown on the Drawings or stoked in tho field. Th* larger stones shall be well distributed and tho finished riprap alkali be free
from objectionable pockets of small scones and clutters of larger 3tonoa   Tho desired distribution of the
fr
various Sizes of Ji tones throughout the mass shal l bo obtained by selective loading of the material nt
its source and by controlled dumping of successive loads during final placing. Rearranging of individual- 2*4
status by mochuaical aquipr-ont or by hcnd will ba roqulrod to th' oxtont niceasary to obtzjirt a rc-asoricbly wall gradod distribution*
Impervious Fill Placrjnsc-nt
The Tmporvious fill for elay tore shi.ll ba placed in the Embankments within th£ limit* indicated for impervious core. If in the opinion of thi Ln^incer
th& rolled surface of any L&yer at i^pjrvicus fill Is
too dry or smooth to bond properly with th® layer of material to be placed thereoni it shall bs moistmed
and work&d with a * ecrow or scarifier in ar. approved manner to sufficient dopth to provide " saris;-torory bonding surface bc-foro the sucCtoaine lsyor of impervious material is placed. If in th«r opinion of Engineer the rolled surface ol" any lxyar of in—place impervious fill is too wot for proper plucjsent of tht
l^yor to be placed thorconii it shall roiaovcd ar scarified or bar* awed to reducts thi water eonttnx to the required amount before thu succeeding layer is placed ihcroan. So impervious fill shall be placed below water.
The Impervious fill for clay blanket upstream of the dam to cow exposed rock shall be placed in the same manner as specified aboveh
E-5(5) Rock-fill Placement
the upstream end downstream roekrill sones materiel shall bo placed in the embankment within the limit* indicated on the Drawings. Ratrrftjitfiitmt of individual stonoa by mechanical equipment or by hand methods will be required co the extent necessary to produce a lovol, smooth and wen finish at the Borm.
E-j(6) Transition Material l  Inc omen c
:
Thu transition material shall be placed immediately upstream and downstream of the impervious eoro within the limits shewn on the drawing?* Care shall be taken that transition material dace not ^ot oiixtil with the impervious fill.- 25
The loading and handling of the transition material shall ba* dong in such a manner that astrogation will be minimizod. If considered necessary by the Engineer, some mixing by scarifying or watting of material
bfii-crt? hauling shall be ^ont ±n order to cr&aU a homogeneous layer* 
■’/'ip Jj,    1 " *'■' "
ft "        /
\
material after spreading in uniform Inyer shall be scarified
hy harrows to brssk any lumps of material and to tnsuro proper
and uniform compaction* Except as otherwise qir«ted by tht?
Engineer aa a rcsu.lt of tht- tests condiicU'd during construction,
the thickness of each compacted layer of imporviouo core
material shall not exceed iScra, thu compacted thickness of
transition material shall not exceed 25cm and the compacted
thickness of rockfill material shall not ffxcocd JOctbs* The
Contractor shall determine by making tust sections, the loose
lift thickness required in order to attain ths compacted
thickness opacified herein •<«
Aa soon as practicable after commoneeiaent of construction of impervious zone, the fill surface shall be
sloped with a tranavona slops of not lass than 3 percent
throughout construction* During dumping and spreading the
Contractor shall provide at ell times adequate facilities for
removal of all unsuitable and/or oversize material* Unsuitable
materials* shall be removed from the embankment and disposed of
in an approved manner* The entire surface of any section of
embankment under construction shall bo maintained in such
condition that construction equipment can travel on arty -rqjz t
of the section, huta in the surfaces of any layer l^T
filled satisfactorily before compacting* 
MOISTURE CONTROL
E-7(l) Impervious Material (clay core)
Control of moisture tontant will b< placing and compacting umterial in the 1
S' X 2
So far as practicable, the material shall be delivered and spread in moisture range of 2-0 percent bolowstandard optimum to standard optimum moiaturc content
by irrigating or drying within th© borrow areas* On
the basis or tests conducted during construction th*
* Engineer roserves the ri -_{ht to mako modiflea cion in
the required rango of moisture for thia ttUrinl. Only
.«ueh moisture control n® needed for minor adjustment
of ntoiaturc changes canard by evaporation during
handling an; placemont or irom rainfall shall be
nccoinpli ®hud on the- fill* Tho moisture shall he
distributed uniformly throughout naeh layer prior to compaction* Optimum moisture content shall bo
r|!-jtorminod in the laboratory by the iwiginoer by making standard compaction tost. Tho optimum moi a Lura^ con tents for the materials in the borrow area will bo furnished
by tho Engineer to the Contractor at daily intervals
or nt significant changes of material being placed*
E-7(2) Other “ion a a
No partlcukr moisture control will be required for compaction of material^ in other zonea of the dam, Some addition of moi aturo in tho transition zone# material may be required to reduce segregation
tondc-ncios* The addition of water for this purpose shall be accompliahod prior to handling.
COMPACTION
E-fl(l) Equipment
Compaction equipment shall conform to the following roquirc-nicnte and shall be used aa proscribed in subaequant clau.ios and as determined and ordered by the Engineer aa a result of tho tMts conducted during eons true tion*
a)           Vibratory Roller*
Vibratory rollers shall havfr a total static wight of approximately ton short tone, with at least ninety percent of the weight transmitted
to the ground through a single smooth drum when the roller is standing in a level position hitched
to the towing vehicle* The dlamotor of the drum shall be approximately five feet end width27
approximately six feet. The roller shall produce
a dynspclc impact of approximately sixty thousand pounds at rated vibration frequency. The roller
shall be towed at speeds not to exceed 4 Km per
hour* The equipment manufacturer shell furnish sufficient data* drawings and computations for verification of the above specifications* and the character and efficiency of this equipment shalL
be subject to the approval of the Engineer*
b)     Temping Rollers
Tamping Hollers shall be usod for compacting Impervious fill. Each drum of the roller shall
have an outside diamotor of not less chan 5 feet and shall not bo loss than 4 feet or more than 6
r
feet in length. The apace botwoen the two drums when on a level surfaco shall not be loss than 12 inches or mono than 15 inches. Ono tanping foot shall be provided on the drum for at least 100 square inch of drum surface. The length of each tamping foot from th* outside surface of drua shall be not Loss than 9 inches, The cross-section area
of each ta-mplng foot shall he not more than 10 square inches at a place normal to the axis of the shaft six inches from the drum surface and shall bo not loss than 7 square inches at eight inches from th* drum surface. The weight of roller when, fully Loaded shall not tn loss than 4 OOO pounds pur
t
foot length of drum. The loading used shall be as ruquirad to obtain ths desired compaction, During the operation of rolling, the Contractor shall
keep the space between the tamping foot clear of materials which would impair the effectiveness of the tramping rollors.
c)      Special Compactors
Compaction of materials in areas whore it iv Impracticable to use a roller or a tractor, as provided above, shall be performed by tha uso of compactors of the heavy-duty power-driven type.E-8(2)
They shall be capable of producing densities at
least equal to those produced by the equipment specified in aub-clauids (a) and (b) hereof* All
such equipment will be subject to approval by the engineer* Compactors which do not obtain the required density with reasonable amount of coverage of each Layer and at a production rate consistent with the adjacent embankment, shall not be used in the work. Compacted layer thicknesses by this
■eq ui ptu-e nt shill not ojecq^cI W ems*
d)      Sprinkling Equipment
Sprinkling equipment shall consist or tank trucks, pressurc-distrlbutorsj or other equipment designed to apply water uniformly and in controlled quflntltiDs tn variable widths of surfnep. Tr_nk trucks shall be equiped with positive shut off
vrIvgs 80 that no lockage will result from tha nozzles when oqulptnant Is not operating. Leaks shall bn rQpiilrijd immediately and any material rcnderedi too wg t b&eauso of faulty equipment shall bo removed or reconditioned and no additional pay* mo nt will bo made thereof.
Compaqt i on Gena ra1
After a layor of fill natural has boon deposited, it shall be scarifiedj bladed or orhorvise treated as necessary to produce a uniform material with reapoet to moUturti content and grain  ±»e distribution, in
3
accordance with clause (E-7), Moisture Control, Mixing
shall be performed t  the Tull depth of the layor if
o
so required, When the Buisturo content and condition
of the layer is sstisfac tory the lift shall be compacted, Portions of the fill which ore not
*
accessible to the roller shall be placed in lift*
consistent with the material sice and compacted with
power tampers to a degree equal to that obtained on
tho other portions of the compacted fill by rolling
as specified, Dumping, spreading, sprinkling, and
compacting may be performed at the acme time at
Idifferent points along a section of embankment when
there is sufficient area to permit these operations to
proceed siinultanoously•
E-80) Compaction of fill material
Except os otherwise determined and ordered by the
Engineer fill materials shall be deposited in successive
layers of thickness as specified, end compacted as
follows:
a)             Each       layer       of       material       in       the       impervious       (clay) core      zono      shall      be      compacted      with      not      Loss      than ten passes of the specifiod tapping roller,
b)       In ell other zones, each layer of tea tori al, except riprap slopu protection shall be compacted with not U53 than four passes of the specified vibratory
roller•
c)       Ono pass of the vibratory roller is defined as eno complete coverage of the surface of the area being compacted, in which the drum of the roller comes in contact with tho entire surface of the area,
For the tamping roller, the satno definition shall apply, no consideration being given to the spaces between the drums, the entire width betwoon the outside walls of the. outside drums being considered as a continuous drum,
8(U)E-a(4) Additional Rolling
If it is so determined by tho Engineer, that tho desired compaction of any portion of tho embankment is not secured by the minimum number of passes specified, additional coraploto passes to the extend directed by the Engineer shall be made over the surface area of such designated portion,
9 miscellaneous fills an:? backfills
E-9(l) General
In addition to the embankment fill for the dam certain miscellaneous fills and backfills will be required for spillway and other structures, Material requirements for those backfills shall be specifiod on- JO
the Drawings and the type of material for these fills will bo as specified in Clause E-U.. Haterials or as directed by the Engineer.
£-9(2} Operations Adjacent to rx’-sting Structures
In £tfnersl, no fill, backfill dr other load shell be placed on or against the surface of any concrete structure earlier than is permissible with regard to the protection of the structure. At locations where the safety of the structures night be endangered  such
t
operations shall not proceed until the construction
has been crmplGtad tc such estc-nt and the concrete has attained sufficient stronjtli to withstand any stresses
that ffl-lfaht develop incidental to the operations required. If so required the Contractor shall submit details of
tho Ei&thnds of placement, spreading and compaction ha proposes to use for the protection of structures at
such locations for th* approval of the Engineer. Vi thin areas where rollt-rs cannot bo used. the material shall be compacted by ro&ans of power tampers.
10 MEASU^MZWT AttD PAYMENT
E-10(1) Items No. 301 through J06  Main Dam Fills.
t
a)      Measuraraont
Moasurernent under these items will be computed by actual measurements methods and will be r?ade of the number of cubic metres of each material zone
in place and accepted in the embankment fill to the linos  grades and cross-sections shown on the
t
drawings or established by the Engineer*
b)      Payment
Payment shall constitute full compenaation for constructing the embankment from required borrow areas, quarries and stockpiles including excavating, loading, rehandling, hauling, processing* moistening, placing and Compacting the matqricla and all other work related to the
Item.
iI tore No. 301, Riprap Slope Protection
Payment will be made for the number of cubic meters measured as provided above at the Contract unit prico per cubic metre for Riprap.
Item No. 302, Rockfill Zone
Payment will be made Tor the number of cubic raotroa measured as provided above at the Contract unit price per cubic metre for Rock
fill Zone.
Item No. 303, Transition Material Zone.
Payment will b«o made for the number of cubic metres measured as provided above at the Contract unit price per cubic metre for Transition Material Zone.
Item No. 30t», Impervious Fill Zone (Clay core) Ps,y.-3«nt will be made for the number of
cubic meters measured as provided above at the Contract unit price per cubic ootro for Impervious Fill Zone (Clay core).
Item No. 30J, Impervious Fill for clay Blanket Payment will bo made for the number of
cubic metres measured as provided above at the Contract unit price per cubic metre for Impervious Fill placed as Clay Blanket.
Item No. 306* Miscelleous Backfill
Payment will be made for the number of cubic metres measured ns provided above nt Contract unit price per cubic metro for Hiscelleoua Backfill behind retaining walls
and other structures and shall constitute full compensation for constructing the backfill with the materials obtained from the specified stockpiles- including hauling, placing and compacting the material and all other works related to the itntp.- 32 -
SECTTON P
CONCRETE, PLAIN .'■JO R';:T?;?C?CES
F-1 SCOPE
This section covers the manufacture, Qj.rming, tran sport rug, placing, stripping of forms, finishing, and 
curing of concrete in the structures included in the
specifications.
F-2 COMPOSITION
Concrete shall be composed of Portland cement, water, fine and coarse aggregate,
F-3 QUALITY
The concrete mixture will be designed by the Engineer who will determine the required quality of the concrete for
the structures covered by these specifications.
F-4 CEMENT
Cement shall be furnished packaged as approved by the Engineer, It shall be Portland Cement and shall conform tn British Standard 12;1958, Portland Cement (ordinary) or to ASTM Designation C 150-64, Standard Specification fqr Port land Cement, for Type I cement.
F-4(2) Test Requirements
Cement shall be aampled  at storage site and  tested  at the expense of the contractor,  in  accordance with  the ASTM requirements. Additional teats will be made by, or under- 33
-the supervision of the Engineer, and at the expend** of the Employer. Wo comont ahull be used until notice has been given by the Engineer that the teat results are satia-
factcry, Tf testa prove that a cement which has been delivered is flnaatlsfactory, it shall be promptly removed from the site of work* Cement which has been in storage
at the project site longer than four months shall not be
used until reteat p roves it to be satisfactory,
P-4 (3) TrEinaportation of Cement
Transportation of cement to the storage or to the sita of work shall be accomplished ir. Such a manner that cement
is completely protected 
exposure^ moisture, Cement
which has been adversely affected by moisture as determined by the Engineer, shall be rejected*
F-4(4) Storage
Immediately upon receipt at the site of the work  cement
t
shall be stored in a dry we a th e r-ti glkt and properly ventilat ed structure* All storage facilities shall be subject to 
approval and ahall bo such an to permit easy accega for inspection and identification. Sufficient cement shall be in storage at the work site to complete any lift of concrete
started* 'The Contractor shall use Cement in the approximate chronological order delivered at the site in order that
cement may not become widely aged,
F-5 AGGREGATES
f-5(1} Composition
Fine aggregate shall generally consist cf natural pond,, however, uaa of manufactured Band or a combination of natural and manufactured a and will bo permitted on the approval of the Engineer, Co&rac aggregate shall consist of natural- 34 *♦
gravel, or crushed gravel or a combination thereof.
F-5(2) Source
The Contractor shall bring concrete aggregate from approved natural deposits or shall produce crushed aggregate from approved loostions, The Contractor shall he responsible for ascertaining the extent of work, including type of equipment required and amount of waste involved in producing a sufficient quotity required of acceptable aggregate from
the sources finally selected by him and approved by the Engineer,
F-5(3) Sampling and Testing
during construction, aggregates will be sampled as delivered to the mixer to determine compliance with specification provisions. The Contractor shall provide facilities as may be necessary for the ready collection of representative test samples. The Engineer will obtain and test such samples, at the expense of the Enployer, using appropriate standard test methods selected by the Engineer, Tests and analysis of aggregates at various stages in the processing and handling op orations will be made at the discretion of the Engineer, Testing of concrete aggregates by the Engineer shall not relieve the contractor of hie responsibility to maintain control, to ensure the production, atock piling and handling of both fine and coarse aggregates in accordance with these Bpeoificatdona.
F-5(4) Processed Aggregate
Aggregates, aa delivered to the mixers, shall consist Of clean, and uncoated particles, Where directed by the35
Engineer dust shall be removed from the coarse aggregate by adequate washing. The aggregates shall conform to the following specific requirements.
a) Fino aggregate
The grading and uniformity of fine aggregate as delivered to the mixers shall conform to the following requirements.
Sieve Designation U.S, Standard Square Lie eh
3/8”
No. 4
Percent Passing
100
95 to 100
No. 8
80 to 100
No. 16
50 to 85
No. 30
25 to 60
No, 50 No. 100
10 to 30 2 to 10
In addition to the grading limits the fine aggregate
aa delivered to the mixer, shall have a fineness modulus
of not leas than 2,30 hot more than 3.10*
b) Coarse aggregate
The grading of the coarse aggregate shall conform to the following requirements as delivered to the mixer.
U.S, Standard
Percentage by Weight
Sieve Sise
1 in
X in 
% in 
?&a_3ing Individual Sieve
100
90 - 100
20 - 40 
' No, 4
0-5c) Particle Shape
The shape of the particles in the fine aggregate
and in the coarse aggregate shall he generally spherical
or cubical, The quantity of flat and elongated particles
in the coarao aggregate, as defined and determined by 
standard tests approved by the Engineer shall not exceed
25 percent. A flat particle is one having a ratio of width 
to thickness greater than three. An elongated particle is
one having a ratio of length to width greater than three, 
P-5(5) Storage
Aggregates shall be stored at the site of work in 
such n manner as to prevent the inclusion of foreign 
materials in concrete. Sufficient aggregate shall be
maintained at the site at all tines to permit coatinnous placement and completion of any lift of concrete started. 
F-5(6) Moisture Control
All fine aggregates and coarse aggregate shall renm.ir
in f re draining storage at the site for all east 72 hours immediately prior to us&, Under no conditions shall the aggregates be delivered to the mixers dripping wet,
P-6 WATER
Water for washing aggregates and for mixing and curing concrete shall be fresh water free from injurious amounts of oil,acid, salt, alkali, organic matter, or other deleterious Substances as determined by standard tests solected by the Engineer,F_7 PROPORTIONING cf concrete
y-7(1) Control
Trial mixes and teste will be made by the Engineer during tho course of the work for the purposes of designing the mixes and for quality control. The proportions of all material entering into the concrete shall be as directed by 
tho Engineer, The proportions will be changed whenever
such change is determined necessary to maintain the standard of quality required for the structures covered by these specifications and to the varying conditions encountered during construction. The Contractor will be entitled to no compensation additional to that included in the prices for
the applicable tender items in the Bill of qualities because
of such changes.
F-7(2) Cement Content
The cement content of concrete for various parts of tho structure will range from £O0kg pur cubic motre to 365kg per cubic metre depending on the structural requirements.
F-7(3} Water Content
a) Water Cement Ratio,
In general) the Engineer's design of mix will provide for water cement ratio by weight (exclusive of water absorbed by the aggregates) which will be determined on the basis of producing concrete having suitable workability, density, impermeability, durability and the required strength without the use of excessive amount of cement. It is expected that water cement ratios will vary from 0,45 to 0<6j flopendlne
on the strength of concrete and the type of atructure.- J8 -
b) Coniatoney
The amount of water used in the concrete shall ba regulated aa required to secure concrete of proper con- Biatency* Addition of water to compensate for stiffening 
of the concrete bofor placing will not be permitted.
Uniformity in concrete consistency from batch to tntoh 
will be required♦
p^7(4) Strength of Concrete
Concrete for the several structures and parte therof
shall have compressive or flexural strengths at least
equal to the mininum allowable strengths shown on the Drawings, except ns otherwise directed by the Engineer,
P-7C5) Slump
The slump of the concrete after concrete has been deposited but before it has been consolidated shall not
exceed 3 inches (0 oma). The Engineer reserves the right
ta require a leaser slump 'whenever such slump is practicable. Slump will be determined in accordance with ASTJT Designat ion C - 143-5 G, standard method of test for elUmp of
Protland Cement Concrete*
E-8 TEST OF CONCRETE
Strength teats of the concrete placed during the course of the work will be made by the Engineer. The Contractor shall provide such facilities as may be necessary for procuring and handling representative test atunples. Cylinders will be tested by the Engineer in accordance with the applicable requirements of ASTH39 -
Designation 639-64, standard Method of Test for compressive strength of Molded concrete cylinders, or cubes will be
tested in accordance with the applicable British Standard Specifications, The teat results will be baaed on the
average of the strength of the teat specimens. The
standard age of teat will be 28 days, but 7 days teal may 
be used at the discretion of the Engineer, based on the
relation between the 7 days end 28 days strengths of concrete
as established by tests for the materials and proportions used. The frequency of tests will be determined by the Engineer on the basis of pH cement rate and the structure to assure
himself that the concrete being placed conforms to the speci fications and design requirements.
F-9 Mrxiws
F-9(1) Capacity
The Contractor shall provide concrete mixing arrangement having aufficlent capacity to produce concrete at such e rate
as will enable the completion of monolith poura and will assure the completion of concrete structures in accordance with the requirements of the construction schedule,
F-9(2) Location
The concrete mixers shall be installed at the site of work at 1coations selected by the Contractor and approved by the Engineer,P-9 (3) Arranganient
Seperate bins or compartments shall be provided for
each classification of aggregate. The compartments snail be
O f ample filse and bo constructed that the materials *ill be
maintained sepcruted under nil working conditions* All
materials shall be preferably batched by weight. Batching 
by vol1ltrifl may be allawed by the Engineer,
F-9(4) Water Batches
A suitable water measuring device shell be provided by 
the Canrrector which will be capable of measuring mixing 
water within the specified requirements for Each batch to 
control water cement ratio. The water shall be delivered to
the mixer ensuring that so leakage occurs. 
P- 9(5) Mixers
Suitable mixers ahull be provided by the Contractor, Each mixer shall be capable of combining the materials into 
a uniform mixture and of discharging this mixture without segregation. Mixers shall not be charged in excess of the capacity recommended by the manufacturer on the name plate. Excessive ove mixing requiring additions of water will not
be permitted. The mixers shall be operated at a drum speed designated by the manufacturers on the neune plate. The mixera ahull be maintained in satisfactory operating condition, and mixer drums shall be kept free of hardened concrete. Mixer blades shall ba replaced when worn down more than to percent of their depth.
■p-10 CQJTV EYING
Concrete shall be conveyed, from mixer to forma as rapidly as practicable, by methode which will prevent segregation or lose of ingredients. Any hopper through 
which the concrete passes shall be conical in shape. There
shall be no vertical drop greater then 1.5 metre except
where suitable equipaer-t is provided to prevent segregation and where specifically authorized, Chutes or other similar equipment will not be permitted for conveying concrete except where the use of such equipment is approved in writing by the Engineer in advance of any use,
F-11 PLACING
P-11(1} General
No concrete ahull be placed in the structure until the metho da of placement have been approved by the Engineer, Approval of the method of placement proposed will not relieve the Contractor of responsibility for its adequacy* Concrete shall be worked into the corners and angles of the forms and. around all reinforcement end embedded items without per mitting the material to segregate. Concrete shall be deposited as close as possible to its final position in the forms* 
The depositing of concrete shall bo
regulated so that the concrete may be effectively compacted with a minimum of lateral movement into horizontal layers, approximately JO to 45 eras in 
thickness* Not more than two cubic metres may be deposited in one pile for compaction. The surfaces of construction- U2 -
joints shall be kept continuously wet for at least
eighteen hours during the twenty four hour period prior to . placing concrete except es otherwise directed by the Engineer. All free water shall be removed and the construction join-
shall be dry of surface water prior to placement of concrete. Concrete placement will not be permitted, when, in the
opinion of the Engineer weather conditions prevent proper placement «md consolidation.
P-11{2) Tine interval Between Mixing and Placing
Concrete shall be placed within thirty minutes, after
it has been mixed, unless otherwise approved by the Engineer. 
F-11<3) Lifts in Concrete
The depth of concrete placed in each lift will be as shown on the Drawings or as directed by the Engineer, The placement shall be carried out at such a rate that formation 
of cold Joints will be prevented, Slabs shall be placed in 
one lift unless otherwise authorised or directed. In walls, 
slabs and other structures lift shall terminate at such 
levels as will conform to structural detailB.
P-11(4) Vibration af Concrete
Concrete shall be compacted with mechanical vibrating equipment supplemented by handspading and tamping, in no case shall vibrators be used to transport concrete inside
the forms. The vibrating equipment shall be of the intern.nl> type and shall at all times be adequate in number of units and power of each unit to properly consolidate all concrete. Borm or surface vibrations shall not ba used unlean spool.fically approved* Internal vibrators shall maintain ?, 
frequency when submerged in the concrete of not less then 7 P000 impulses per minute* The intensity (amplitude) of vibration shall be sufficient to produce satisfactory 
consolidation. The duration of vibration shall be United 
to that necessary to produce satisfactory consolidation* Excessive surface working will not be permitted.
P-11 (5} Placing Concrete Through Reinfprcesent and in Spillway a)     In placing concrete through roinforcemer.o care shall
be taken that no segregation of the coarse aggregate occurs, b)     The unformed portions of ogee crest at spillways, 
chute slab placed on siope the flip bucket at the spillway 
(
end which are to be finished, shall ba placed according to the grade and finished by accurate scraeding. In general, chute slab of spillway shall be divided into strips consisting of square blocks with construction control joints except some poura which will be odd sizes* Each atrip of the chute slab shall be placed in a single continuous pour and in the direction from down elope upwards and in a sequence atrip by strip. If, for any reason, placing any of the strips is interupptsdbefore completing its full length, a construction-control joint ahull be provided at the temporary end of the atrip. Unless other wise shown on the Drawings or directed by the Engineer, ths maximum differential in height between adjacent maa concrete bonolithe shall be 3 mettoo.P-11(6) Placing Concrete on Rock
Rock surface upon which concrete 1b to he pieced shell be clean free from oil, standing or running water, ciuii, drur-ty
rock, coatings* debris, loose or semi detached or unsound fragments, Faults and seams shall be cleaned to sati&l&ctory depth and to the firm rock on the sides. Lnaedia'.el y before concrete in placed, all rock surface shall be throughly cleaned 
by use of air water jets or other approved methods. All rock surfaces shall be kept" continuously wet far at least 24 hours immediately prior to placing concrete thereon.
F-12 CONSTRUCTION JOINT TREATMENT
F-12(1) General
As u lift is completed, the top surface shell be t i-mpdi at a)
□.nd carefully protected from any condition that will adversely affect the hardening of concrete.
^-12(2} Cleaning
Horizontal construction joints on lifts shall bo prepared for receiving the next lift by cleaning with air-water cutting* The surface shall be cut with a high pressure air-water jet
to remove all laitance and to expose clean, sound aggregate, but not so as to undercut the edges of the larger particles
of the aggregate. The air pressure used in the jot shall be
100 Pai plus or minus 10 Psi and the water pressure shall be just sufficient to bring the water into effective Influence
of the air pressure. After cutting, the surface shall be
■washed and rinsed as long ns there is any trace of cloudiness of the wash water* The surface shall again be washed with an air-water jot just prior to planing the succeeding lift.
cr- 45 -
JL.-I 3 EXFANSIOW^XMIRACTlOa ABD C0N3TRIKTIQN JOINTS F-13(1) General
Joints shall be provided dt the location indicated _ 
an the Drawing? or nfl otherwise approved or directed by the Engineer, In no case any filed metal embedfed la concrete ne oontinucua through an expansion-contract ion joints
F-O(z) E*p ana ion-Contract ion Joint Miler
Miere indie tied on the drawings exp «isi on-con tract ion Joint filler shall be installed using cauterisl of type and 
quality indicated, Expireion-eontraction joint filler will
consist of sponge rubber or self expending cork or cr.y other material and type ns directed by the Engineer meeting the requirementa of AS TN Designation Di 752, 
7-13(3) Water Stope
Water a tope gf copper and polyvinylchloride (7 VC) shall be installed in joints us shown oti the Brewings or otherwise directed. All joints of the metal water stop shall he bmded 
or w&idod* All water stops shall be installed so as to form
a continuous water tight diaphre® in oach joint. Adequate prevision should be made to support and completely protect the water steps during the progress of work. The Contractor shall replace or repair, at his expense, any water stop punctured or otherwise damaged befor riual acceptance of the work,
nJ Capper
Copper water stops shall canfonn to the requiranentn of ASTM Designation BJ7O-66, otundard specification for Copper Sheato and strip far Building Conetruction.- 46 -
b) Polyvinylchloride Water Stope
Polyvinylchloride wetter stops shall be extruded from
an elustomericpleatic compound the basic resin of which sell be polyvinylchloride (PVC),
p_14 CURINE AND PROTECTION
a)      All concrete shall be cured for a period of not lesH than fourteen (14) consecutive days by an approved method or combination of methods. The contractor shall have all equipment needed for adequate curing and protection of the concrete available at site before actual concrete plucetncnt begins. The curing methods ehall be approved by the Engineer* Unhardened concrete ehall be protected from rain and flowing water. All concrete shall be adequately protected from damage.
b)     Concrete ahall be moiat-cured by maintaining all surfaces continuously (not periodically) wet for the duration of the entire curing period. Water for curing shall be clean and. free from any elements which will cause staining or discolouration of the concrete. The quality of curing water shall be the same as given in clause F-6, Where forms of wood lagging are used and left in place during curing, the lagging ahall be kept wot at all times. Horizontal construct ion joints and finished horizontal surfaces cured with sand shall be covered with a minimum uniform thickness of 5 cma of sand which shall bo kept continuous saturated during the entire curing period.
■ ■b) polyvinylchloride Water Stop®
Polyvinylchloride water stops shall he extruded from
an  laotomericpl<wtlc compound the basic resin of which sail
e
be polyvinylchloride {PVC)+
y_14 CURIWG AflD PROTECTION
a )      All concrete shell be cured for ex period of not less than fourteen (14) consecutive days by an approved method ar combination of methods. The contractor ahull have all equipment needed for adequate curing and protection of the concrete available at site before actual concrete placement begins. The curing methode ehall be approved by the Ifrigineer, Unburdened concrete shall be protected from rain and flowing water* All concrete ahull be adequately protected from damage.
b)     Concrete ahull be moiat-cured by maintaining all eurfuces continuouely (not periodically) wet for the durst ion of the entire curing period* Water for curing shall be clean and free Trom any elements which will cause staining or discolouration of the concrete* The quality of curing water shall bo the game as given in deuce P-6, Where forma of wood lagging are used and left in place during curing, the lagging ahull be kept wet at all times* Horizontal construct- ion joints and finished horizontal surfaces cured with sand shall be covered with a minimum uniform thioknesa of 5 cm® of sand which shall be kept continuous saturated during the entire curing period#- <*7
p-15 FORMS
F-15(1) General
Forms shall to true to line and grade within allowable tolerances for concrete surfaces, mortartight and sufficiently rigid or prevent objectionable deformation under load* Where forms for continuous surfaces are placed in successive units, cure shall be taken to fit the forms over the completed sur
face so uh to obtain accurate alignment of the surface and 
to prevent leakage of motor. Responsibility for their ade quacy shall rest with the Contractorj however, the type, 
shape, sije, quality, and strength af all suite rials of which 
the forms arc made ahull be subject to specific approval of
the Engineer* All forms shall be so constructed that they 
can be removed without damaging the concrete, All exposed joints, edges, and external corners shall be chamfered to provide a neat and uniform appearance unless otherwise directed by the Engineer.
P-15(2) Coating
Poms for exposed surfaces shall be canted with an approved nonstaining form oil which shall be applied shortly before the concrete is placed, After oiling, surplus oil
on the form surfaaeo and any oil on the reinforcing steel
or other surfaces requiring bond with the concrete shall be removed, Forms for unexpoaed surfaces may be thoroughly wetted in lieu of oiling immediately befor placing of Concrete,- ttd -
F-l 5 C3 ) ReTHOWli of ?Qr3lH
Portns Shall not be rerooved without prior approval of Engineer and ell removals ahull be accomplished in a manner which will prevent damage to concrete. Forms shall not he removed before the expiration of the n±n±MUHi time indicated below  except aa othcrrwisc directed or specifically
(
autharized.
Slabs and conduit a 7 days
Walin o 2 days
F-16 TOLERAJQE JOfi CONCRETE GQTBTRUCT.Ipjj Variation in alignment, gnide and di mens lor. 3 of the
structures from the eatublichod alignments, grade and dimensions shewn on the Drawings shell be within the tolerances specified in the following table,
1)     Variation from the plumb
a) Ln the lines and surfaces of walls and in arrises
b} For exposed comers, joint groves and oth&ra
2)   Variation from the level
or from the grades indicated on the drawings <
3} Footing3
a) Toriatiop of dimenaiona in plan.
Tn 3 metres,,0.5am
In 6 metres.... 1.Oom
Ini2 metres.,,.2.Ocm
In   6   metres,   .   .   #0,5oni Xh12 TfietreB,.,,1.0cm
In 3 metres,,..0.5cm
Minus.« ■ , , , , , , 1 , Ociq 
Fl as
5,0c jhb Reduction in thickness at any point.
Minus......... 2^
of Specified thickness
4) Conduit
a)   Departure from established grade and level.
b)   Variation in thickness at any point.
o) Variation from inside dimension.
Total length..* 1.Ocm
Minus....       ..... 0 era
Maximum...............
F-17 FINISHING
Immediately after removal of forms, all unsightly ridges or lips shall be removed and undesirable local buldging on the surfaces to be permanently exposed, shell bo remedied. Excessive rubbing of formed surfaces will
not be permitted. Voids and hales left by the removal of tierods in all permanently exposed surfaces and surfaces
ta be exposed to wcter shall be reamed and completely filled with dry patching mixed in the proportions directed. Defective concrete shall be repaired, by cutting out the unsatisfactory material and placing new concrete which shall be secured with keys, dovetails or anchors. Concrete for patching shall be drier than the usual mixture and shall be thoroughly tamped into place. All finishing shall be per formed immediately after the forms are removed. All un- formed surfaces of concrete that are not to be covered by additional concrete or backfill, shall have a wood float
finish unless a steel trowel finish is specified, without additional mortar and shall be true to elevation as shown 
on the Drawings, Core shall be taken to see that all free
water which has accumulated at the surface is removed before making any finish. Every precaution shall qc taken by the Contractor to protect finished surfaces from stains or abrasions. Surfaces or edges likely to be damaged during 
the construction period shall be properly protected. The length of the tomplate will be 1.5 m for testing cf formed surfaces and 3.0 in for tc3ting of unformed surfaces.
F-18 REPAIR OF CONCRETE
Concrete that is damaged from any cause; concrete that is honeycombed, fractured or otherwise defective; and concrete which, because of excessive surface depressions, must be excavated and build up to bring the surface to the prescribed lines; shall be removed end replaced with drypack, mortar, 
or concrete. Repair of concrete shall be performed only 
by skilled workmen and within 24 hours of removal of forms. All fillings shall be bonded properly to the surfaces and 
shall be sound and free from shrinkage cracks and druitmy aretg after the fillings have been cured and have dried, Repairs shall be made in accordance with procedures approved by the Engineer, All materials used in the repair of concrete shall conform to the applicable requirements ol  this section of ths specifications. Concrete, mortar
and drypack filling shall each be mixed in proportions approved by the Engineer to produce a repair atleast- 51 -
equivalent in strength and durability to the concrete in 
the repair ia required.
J PORIJISHING and placing steel reinforcement P-19(1) General
The Contractor shall furnish, cut, bend, and place all steel reinforcement including rods, bars and structural
shapes as indicated on the Drawings or otherwise required. All reinforcement ehe.il he, when surrounding concrete is placed, free from loose, flaky ruat, and scale, and free form oil, grease or other coating which might destroy or reduce
its bond with concrete. All placing shall be in accordance with Drawings furnished or as approved by the Engineer,
P-1 9(2) Cutting and Bending
Steel reinforcement may be cut and bent in the field. All bending shall bo in accordance with standard approved practice and methode.
p- 19(3) Quality
The steel reinforcement shall conform to the following Acquirements *
c) Reinforcement bars (rods) shall be deformed bars -f intermediate grade billet steel in accordance with the A37f< Designation A-15-65, or equivalent.
Yield point ■ 40,000"lbH/3q.inch Tensile strength » 70,000 lbs/sq.inGh- 52
b) Deformation of bars shall be in accordance with ASTM Designation A.-3O5-65,
P-19(4) Splicing
All splicing in reinforeament shall be in accordance
with AC I standard "Building Code Requirements for Reinforced Concrete,"
P-19(5) Supports
All reinforcement shall be secured in place by use of metal or concrete supports, spacers or ties, as approved. Such supports ahull be of sufficient strength to maintain 
the reinforcement in place throughout the concreting operation, 'rhe supports shall be used in such a manner that they will not be exposed or contribute in any way to the diacolouration or deterioration of the concreta.
P-20 E13 EDDE D ITZMS
deforce placing concrete, care shall be taken to determine that all embedded items are firmly and securely lastenened in place as indicated on the Drawings, Einbedded material shall be free from oil and other foreign matter such as loose coatings of rust, paint or reales. The embedding of wood and other foreign material in concrete shall not be allowed.« 53 -
p-z1 BLINDING LAYER (CONCRETE)
Foundations of spillway shall be provided a concrete blinding layer as directed by the Engineer to achieve an approximately smooth surfaoe before laying and binding of
steel reinforcement. The estimated range of cement in this concrete shall be 200kg per cubic metre.
F-22 DENTAL CONCRETE
Dental concrete shall be placed in dente.1 excavation such as joints, fractures, cracks, fissures, pockets and 
between rock beds. It shall also be 'rovided in other below
grade excavations,
F-23 measurement and payment
a) Item No.401, Furnish Portland Cement (ordinary)
i) Mea butement.
IZeasurement for bagged cement will be made of the number of tons of bagged cement acceptably used in the per-
’’mneriv works for which items for measurement and payment are included in the Bill of Quantities. The quantity to be paid 
°r
be based on the number of bags end standard weight
P®r bag as detemined by the Engineer of cement acceptably 'ified at the mixer.
ii) Payment.&-
cement    used    in    concrete    that    is    wasted;    cement    used    in    the replacement     of     damaged     or     defective     concrete-     cement     that is     otherwise     wastedj     cement     used     in     extra     concrete     placed qU tBidc     the     concrete     paylines,     unless     such     extra     concrete la    required    as    a    result    of    written    order    of    the    Engineer; and    cement    used    in    concrete    placed    by    the    Contractor    in excavation      intentionally      performed      by      the      Contractor      to facilitate his o ^erations.
b) Item Wo,402, Furnish and Install Reinforcing Steel i) Iteaeurementa.
Measurement will be made of the number of killo-grairj of reinforcing steel acceptably placed on the basis of the lengthy of bars installed in accordance with approved Drawings or bar schedules or as directed, converted to 
weights for the ei2e of bars listed by the use of unit
’eights per linear metre.
Steel in laps indicated on the Drawings or required by the Engineer will be paid for at the Contract Unit Price, N ° measurement for payment will be made for the additional
i  i
n   apa wtlicil flre
 authorized for the convenience of
tiw  Contractor.
Payment
*synient will be made for the number of Icilio-grsGiB ^sur^d aa provided above at the applicable Contract unit
w °rk related to the Items-c)      Item Ko. 403, Furnish and Install Water Stop,
1) Measurement
Measurement will be made of the number of linear metres
of water stope acceptably placed in the work bQflt?d ofi
applicable unit linear metre for material. In computing lengths no allowance will be made for laps,
ii) Payment
Payment will be made for the number of linear metrea tneesured an provided above at the Contract unit price to famish and install water stops, and shall include full compensation for splicing material and all other work 
related to the Item.
d)     Measurement and Payment of Concrete.
General
Except as otherwise specified herewunder, measurement °* concrete will be made on the basis of actual volume of concrete in place within the neat lines of the structures us
indicated on the Drawings or aS others Engineer. Measurement for payment wil nor any ingredients including cemen 
Placed outside of the lines show
of concrete placed against the 3ilM 0
^h^rwise establia^4 the
u eaeurement
rsfl tiW
eXCGVation *i
B
thout
■
the pBy
the use cf intervening forms wii
lines of the structure. Unless °the
f or concrete will be made at thG r p
_  -rill be
eddied payment
. ct Unit ^pctive Coatt®01 v
% “Wtl
en> whlDh prlce ahnll
,h
. „.  Of oil labour,
tF
tarlalSr and ’the use
and tools required
t0  comp 19-1:0 *he batching, mixing, transporting, placing, protecting, curing and other concrete work- except the cement, 
inf or cement, and embedded parts which are specif led to be "aid for g&perutely, The Contract unit pride per cubic metre for concrete will include the cost af formwork, form oils, Bggregotwe* wulot, j*r4paration of joints, joint fillers, specified Gleaning, preparation of surface to receive concrete, finishing and all other v.'ork required to Complete the concrete structures. No [iieaeurement or payment for patching or repair ing fnultj concrete by any method will be made. The Items
for the Concrete work are specified hereinafter,
e} Item No, 206, 404, Dental Concrete,
Dental concrete includes concrete required to be placed in the dam foundation, spillway, diversion structure, ur.d intake structure as directed by the Engineer in accurdence
*ith the requirements of Clause F-22 Dental Concrete,
i) Measurement
^Busuretnent will be made of the number of cubic metres concrete acceptably plabed as directed by the Engineer in 
excavation os specified above,
*1) Payment
p HJf»«ni will te tuade for the number of cubic metres '’aaure^ an provided above at the Contract Unit Price per
Ublc
eL
^ - 3utiQu 
for Dental Concrete* and shell cpnwtit’Jte
flll work related to the Item,- 5? -
f) rtam No,                         Blinding Concrete,
KLindins concrete includes concrete within llndta Bfl
directed by tbs Engineer, except Dental Concrete* 
Paymem't
Payment will be made for the number of cubic metrea
measured an provided in Cleuse »-2J(d) at the Contract
Unit Fries per cubic metre for Blinding concreU and shall
constitute full compensation for all work related to the
Item in accordance with Clause J-21,
gj Item No, 406, Plain Concrete,
Thia Item incl udon concrete in Approach channel of
Diversion Structure and Approach channel of intake Structure
us shown on the Drawings.
Paymen t.
Payment will be made for the numb at pf cubic -
rtetrea measured us provided in Clause 7-23td) at the Contract
Unit Frioe per cubic metre for concrete laid in position and 
Qhsll constitute full payment for ell Work related to the Item
h} Item No, 407^ Reinforced Concrete
Item includes concrete in Spillway, Diversion, and
" Intake Structures as ahovn on the Drawings,
^fiyment,
Payment    will    be    made    for    the    number    of    cubic   meter?
^ eflaurQd Qb ?ZTOvl[ied in clauao p_^3 (d) at the Contract
Price peP cubic meter for concrete laid is the ^turea and shall constitute full payment for all Tari„ - SCOF.E
5A
SECTION G
hlgCgLLAtfSQUS
rn iri section cpvera furnishing and installing of
fltrl3
Fp
ct:iiral drains  Gates  Steel pipe for Intake Structure, 
nnd Other miscGllanot)^ works connected with the
atructurca,.
5-?  STXUCTUhE DRAINS
G-2(1 ) General
Under drainage will be provided for the Spillway Structure downsrmm of the toe of
zone of the dam along ths side walls of the chute as
shown on the Drawing* It will also bo provided under
ths downs treasi toe of the dara as shown on the relevant Drawings•
0-2(2) Materials
a)     Pipes.
Concrete pipes of the internal dlawUr sizes as specified on the Drawings shall be used,. Each 
piece shall be JO cms long with straight ends and shall ba laid dry  Pieces of pipe shall be laid 
rock-fill
r
looping J to 4 mm tpaca between the ends..
b)    Wateriej around the pipes»
The material around the pipes Ahall con-si st °f gravol clean and well graded from h'o, Ui-S. standard sieve size to three qimrt-tr inch sl2e  e>
p
approved by the Engine or-
2
<)
3   lnstaliatlon
a ) Trenching
Width* and tt^pihi of th* trenches tw Grains ahull be ns indicated on the Drawings and where not
indicated 
be Qf minirnmn width necessary for
Pr«p,r laying of pipe, ElcmMw f<Jr
be  Performed b  barring end wedging or
* ho11
y
approved method which will not damage rhe rock in  th* foundations.59 -
b) PiP  Installation
e
Each pipe shall be carefully Inflated beroM
it is laid. Any defective or damaged pipe shall be rejected. The laying of pipe shall proceed upgrade beginning at the lower end of the pipe iiRej. 
no circumstances the pipe shall be laid ±b water
and pipes shall not bp laid when the trench conditions arc unsuitable for sueh work. Full responsibility for dewatering of tranches during construction shall be born by the Contractor, 
pipes shall be laid to the lines and graded as
shown on the Drawings, Whan pipe layinr- is inter rupted the contrantor shall seal the ends of the
pipe line to prevent the entry of foreign matter. 
No backfill shall be placed over or around the
pipe untill the installation is approved by the Engineer,
c) Backfilling
Before pipes art laid, graded gravel material as specified above shall be Placed tc the depth as shown on the Drawings or as directed by the Engineer Care shall be taken to ensure thorough compaction of the fill under the pipe. Material shall be
placed along the side of the pipe id layers not exceeding 10cm in the depth and shall be compacted by hand tamping.
g£TES AND TRASH RACK
C eneral
The Contractor shall furnish, assemble, install
and
the foil owing:-
Two bulkhead gates  one for Diversion Struc.ure
f
and tha other for Intake Structure; hoists; anchorage'assembly, hoist stems nr chains, crack bap 3t seals, sill and other embeded itaras show
■  the drawings and required for sati--
n
^ration of gate.g-X3)
- 6o -
b) Trash rack including anchorage and arrangements required for satisfactory installation.
Material Specifications
All material used shall be of highest grade, free from defects and imp er feet ions, all material shall
be of recent manufacture and unused and of classfficBtto.- and grade designated an the Drawings, phtr rubber
seals for gates shall be moulded only.
Workmanship.
a) General
Workman:hip and finish shall be first class and equal to the best practice in modern fabrication and machine shops. Before laying out, cutting 
or fabricating the woi-k in any way, the material shall be thoroughly straightened by methods that will not result in damage, except that sharp 
kirks or bends in members to be straightened will be cause for rejection. Finished members shall be free from kinks, bends, or winds. Shearing 
shall be accurately done, and all portions of the work neatly finished. Bends, except for minor details, shall be made by approved dies or bending rolls. Where heating is required, precautions
shall be taken to avoid overheating the metal and 
it shall be allowed to cool in such s manner as
hot to destroy the original properties of the
metal. Holes for drainage shall be provided in 
such horizontal or inclined members as raay be subject to retention of entrapped water.
b ) Dimensional Tolerances for Structural Works. i) Structural work fabricated under this
Contract and delivered to the work site in sub-assemblies will have been fabricated to, and shall be assembled in accordance with the dimensional tolerances herein sped- 6i
ii)       unless       otherwise       specifically       authorized       the major     dimensions     of     any     structure     fabricate
of structural steel shall be within 5 
of the dimensions shown on the Drawing Dimensions shall be measured by means of
an approved calibrated steel tape *he
same temperature as the structure at the time of measurement. Unfairness of platework shall ba held to a practicable minimus:.
c) Welding
i) All welding and work related thereto shall
comply with the requirement a of the American Welding Society or the ASME Code as applicable to the equipment being welded. All welds shall be continuous unless otherwise approved by the Engineer and shall be made in such a manner thet residual shrinkage stresses will be reduced 
to a minimum.
ii) Members to be joined by welding shall be cut accurately to size. The edges of the members shall be sheared, flame cut er machined to suit the type of welding. The cut surfaces shall expose sound metal free from defects. The surfaces of plates to be welded shall be free from rust, grease and other foreign catter
for a distance of at least 2 cos back Iron the edge of the weld.
All welding shall be performed by the ®lec ^
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a rc method. After being deposited, welds
be cleaned of slag and shall show uniform sections, smooth ones a of weld metal, fe edges without .overlap and freedom fro® P° ^
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and clinkers. All pinholes, cracks end 0 defects shall be repaired by chipP '^ grinding the defects to sound ®*tai d rewelding.f
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Summery

Project Overview

Project: Birete Dam Project - Design of Diversion Structure

Author: Nafis Ahmad, UN Engineering Adviser

Date: August 1980

Location: Ethiopia (UNDP Project ETH-75/005)

Abstract: The report covers the diversion scheme proposed for the Birete Dam project, including hydraulic and structural design of the conduit and details of inlet and outlet structures.

Design Considerations

The diversion structure is designed to:

Facilitate dam construction within stipulated time
Keep diversion costs low
Incorporate a gap in the embankment for flood passage during construction

Construction Sequence:

First dry season: Complete diversion structure
Second dry season: Construct dam from both sides, leaving a gap
Third dry season: Divert river through conduit and close gap

Gap Design Parameters:

Capacity to pass 25-year return period flood (64 m³/sec)
Bottom width suitable for machine construction
Side slopes of 1:4 (H:V) for stability
Quick closure capability

Hydraulic Design

Gap Calculations:

For 25-year flood (64 m³/sec):

Depth: 1.5 m
Area: 24.0 m²
Velocity: 2.96 m/sec
Discharge capacity: 71.7 m³/sec

Conduit Design:

For 5-year flood (40 m³/sec):

Circular conduit diameter: 2.00 m
Velocity: 12.73 m/sec
Total head required: 9.32 m
Length: 85.9 m

Structural Design

Conduit Structure:

Two sections analyzed:

Lighter loaded portions (fill level 120.00)
Heavier loaded central portion

Loading Cases:

Case	Vertical Load	Horizontal Load
i	1.5γH_h	0.5γH
ii	γH_h	γH

Reinforcement Requirements:

Crown: 14.1 cm² tension inside
Springing: 4.7 cm² tension outside
Invert: 13.0 cm² tension inside

Intake and Outlet Structures

Intake Structure:

Stop log slot provided
Bell mouth entrance with elliptical curve
Ellipse equation: x²/1 + y²/(0.30)² = 1

Outlet Structure:

Diverging channel (1 in 2 slope)
6m length increasing bed width to 6m
Side walls flared to 1:1 slope

References

Design of Small Dams - USBR
Design of Concrete Structures - Winter et al.
US Army Corps of Engineers EM 1110-2-2902
USBR Engineering Monograph No. 14