Disclosure to Promote the Right To Information
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इंटरनेट मानक
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“Step Out From the Old to the New”
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“The Right to Information, The Right to Live”
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“Invent a New India Using Knowledge”
है”ह”ह
IS 11155 (1994): Construction of spillways and similaroverflow structures - Code of practice [WRD 9: Dams andSpillways]
IS 11166 : 1994( Reaffirmed 2004 )
\jc~q ff?lT ~+rTrr 3Tfa-STcrT~ ~~:q.,Taif ct»T f;:r11fur ufo ~f~{fT
( q~ ~'lU~1Jf )
Indian Standard
CONSTRUCTION OF SPILLWAYS ANDSIMILAR OVERFLOW STRUCTURES
CODE OF PRACTICE
(First Revision)
UDC 627-831'012-4: 006-76
C BI~ 1994
BUREAU OF INDIAN STANDARDSMANAIC BHAVAN, 9 BAHADUR SHAH ZAFAR MARO
NEW DBLHl110002
A.ugust 1994 Price Gre., ,
Spillways Including Energy Dillipatorl Sectional Committee, RVD 10
FOREWORD
This Indian Standard ( First Revision ) was adopted by the Bureau or Indian Standards, after the draftfinalized by the Spillway. Including Energy Dislipaton Sectional Committee had been approved by theRiver Valley Division Council.
A Dumber of multi-purpose river valley projects including dams with apiJlways and similar overflowstructures are being taken up in the country. As such, standardization of their construction practices halacquired significance so that optimization of cost, material and time can be achieved. It is with this aimthat this standard has been prepared,
For gtneral principles of concrete and concreting, reference may be made to IS 456: 1978 'Code of practicefor plain and rernlorced concrete ( thi,d "vision)' and IS 457 : 1957 'Code of practice for general construetion of plain and reinforced concrete for dams and other massive structures'. For construction of masonry,reference may be made to IS 8605 : 1977 'Code of practice for construction of masonry in dams' Fordesigu ol gravity dams, reference may be made to IS 6512 : 1984 'Criteria for design of solid ~avity dams(firJ" rlVuioli )' and tor drainage sy.tern reference may be made to IS 10135 : 1985 'Code of practice fordrainage .ystem for gravity dams, their foundatioDI and abutments <fir,' ,lfJision )'.
This standard was fint published in 198~. The present revision has been prepared to incorporate thelatest practices prevailing in the field. In this revision recommendations reltarding concrete mix stren~thand aggregate size, and finiahes for formed and unformed surfaces have also been modified.
For the purpose of deciding whether a particular requirement of this standard is complied with the finalvalue. observed or calculated. expressing the result of a test or analysis, shall be rounded off in a~rdancewith IS 2 : 1960 'Rules for rounding off numerical values ( "lJil,d )'. The number of significant placesretained in the rounded off value should be the same as that of the specified value in thiJ standard.
IS 111551 J99f
Indian Standard
CONSTRUCTION OF SPILLWAYS ANDSIMILAR OVERFLOW STRUCTURES
CODE OF PRACTICE( First Revision )
1 SCOPE
This standard deals with procedures for construction of concrete and masonry spillways and similaroverflow structures.
2 REFERENCES
The Indian Standards listed in Annex A arenecessary adjuncts to this standard.
3 GENERAL
Construction of concrete and masonry spillwaysand similar overflow structures may involve allor a number of the following items:
a) Diversion of river;b) Excavation and preparation of foundation;c) De-watering;d) Masonry construction and/or concreting;e) Instrumentation;f) Installation of gates and their hoisting
arrangements; and .g) Provision of bridge superstructure.
4 DIVERSION OP RIVER
When spillway is located in river channel section,the diversion arrangements for constructing spillways form part of overall dam construction andshould mainly depend on the type of dam, for aspillway may be used with both rigid and nonrigid dams. The diversion arrangements to a lesserextent may also be necessary for construction of aspillway adjoining the main dam or separate fromit on a saddle across a minor stream. For detailsof diversion reference may be made to IS 9461 :1980, IS 9795 (Part 1 ) : 1981, IS 10084 (Part 1) :1982, IS 10084 (Part 2) : 1994, IS 10788(Part 1 ) : 1984 and IS 13912 : 1993.
5 EXCAVATION AND PREPARATION OFFOUNDATION
5.1 E:acavatioD
Excavation should be carried out keeping in viewthe provisioDs given at 5.1.1 to 5.t.3.
5.1.1 Generally a considerable length of areaneeds to be excavated to enable the various
I
operations to go on continuously. Congestion inthe work area should be avoided.
5.1.2 For escavation to proceed with machinery,the ground water table should be lowered sufficiently to prevent bogging down of the machinery,For details reference may be made to IS 9759 :1981.
5.1.3 Excavation of foundation for concrete spillway and similar overflow structures should becarried out to the desired depth and concreteshouJd be laid on sound rock. Excavation within500 mm of the foundation grade should be donejust before concrete i. laid on sound rock andshould Dot be allowed to remain exposed for longtime. In case the geological exploration indicatesexistence of faults, shear or weak zones, necessarytreatment of the foundation should be carried outbefore laying the concrete.
5.1.'- Blasting operation should be carried out carefully without affecting the rock mass beyond therequired area of excavation and shall be restrictedto minimum 500 mm above the foundation levelsand at least 30 m away from any exilting structure. However, in special cases the blasting maybe carried out at a distance of less than 30 mfrom any existing structure using controlled blasting. If necessary, field tests may be carried outto decide various parameters of controlled blasting.
5.1.5 It is desirable to keep the foundation slopeupwards in downstream direction.
5.2 Prepa..atioD of FoaadatioD
Provisions given at 5.2.1 to 5.2." should be keptin view while preparing the foundation.
5.2.1 Immediately before placing concrete/masonry. all surface of foundations upon oragainlt which the concrete/masonry is to be placed, should be free from standing water, mud,debris, organic deposits, and other foreign materialwhich may prevent a tight bond between the rockand concretejmasonry, All surfaces of rock upon oragainst which the concrete/mesonry is to be placedshould. in addition to the foregoing requirements,be clean, solid and free from aU objectionablecoatings, sand loose, semidetached or unsound
IS 11155 : IJ9f
2A
CONTRACTIONJOINTS
CONTRACTIONJOINTS
5.2.2 Sitp/ing ill ,It, Foundfllioll
5.2.2.1 SteppiDI in the foundation Ihould beavoided aDd a continuoul foundation profileprovided ( '" Fig. 1 )_ The Ilope in CoundatioDgrade should not, normally, exceed 450
•
fragmtnta and ahould be lufBciendy rough toensure satisfactory bond with the concrete]masonry. The cleaning and roughening of theaurface of rock should be performed by the use ofhigb-velocity air-water jetl, wet sand blaatiDl,stiff brooms, picks or .other effective means satisfactory to the inspection agency. The lurfaces offoundation against which coDcrete/masonry is tobe placed shall be kept continuously wet for atleast twenty-four houri immediately prior to plaeiDg concrete/muonry 10 that moiJture is Dotdrawn from the freshly placed concrete. In caseof foundation. like loft phylites, mica, .chistl, etc,the time of wettinl required may be appropriatelyreduced 10 that the mrrace does Dot become.ticky, loft and coated with a film of argillaceous or micaceous material which would affectproper bonding of concrete/masonry with foundation.
28
FlO. 2 LOOATION OP CoNTRAOTION JOINTS 1MFOUNDATION GRADal WITH SLOP•• Ova. 45-
CON1RACTtONJOINTS
CONTRACTIONJOINTS
FlO. 1 A TYPICAL CoNTINUOUS FOUNDATIONPROPllB
JA
5.2.2.2 10 cases, where foundation grade haa aslope greater than 45°, as in the cue of abutmenta, the arrangement as ShOWD in Fig. 2A or 2Bsbould be adopted. If the alternative shown inFig. 2B is followed, concreting in shaded portionshould be carried out firlt and allowed to cooldown to the temperature of the foundation. Thecontraction joint should then start for the hilherblock from the higher level.
5.2.2.3 Whenever there is a break in slope, thecontraction joints should be located at the pointof break in slope as shown in Fill- SA. In easea,where location or contraction Joints are bed,arrangement aa shOWD in Fig. 3D should beadopted.
CONTRACTIONJOINTS
38
Flo.3 LOCATION 0' CONTRAOTION JOINTlINFOUNDATION GRADS, HAVING BaSAlt IN SLOPS
2
IS 11155 : 1994
'BFlO. 4 TREATMENT OF FOUNDATION GRADEl
HAVING STEPS
7 CONCRETE SPILLWAYS
7.1 MaterialFor proper design of concrete mixes and placingin spillway blocks, general reference may be madeto IS 456 : 1978, IS 457 : 1957 and IS 9103 :1979.
6.1 For ease or construction it becomes essentialthat the work area should be dry. In practice,however, it becomes difficult to obtain a perfectlydry area. Therefore, de-watering sYltem whichensures exclusion of sufficient water to permit theconstruction to proceed smoothly should be aimedat. Reference may be made to IS 9759: 1981 fordewatering.
6.2 Concrete levelling course of a suitable thicknCII may be laid over the excavated surface, ifrequired, for laying the reinforcement in a dryenvironment.
5.2.t In hot climate, it is better to cool foundations before laying concrete.•"or provisions OD thesubject, reference may be made to IS 457 : 1957,IS 7861 ( Part I ) : 1975 and IS 7861 ( Pan 2 ) :1981.
5.3 Groutia.
The principal purpose of grouting is to fill openings in a foundation and render it impervious topercolating water. It is also used to improve thestrength and clastic properties of the foundationmaterial into which it is injected. The method ofgrouting, in large measure, depends upon thenature of treatment to be given to foundationmaterials which, in turn, depends upon the geological features, For details of grouting for foundationtreatment, reference may be made to IS 6066 :1994.
6 DE.WATERING
layers exist in tbe foundation. Deceuary treatmentof the foundation should be carried out in consultation with the geologist and the designer beforelaying the concrete.
FlO. 5 TREATMENT os FOUNDATION GRADalHAVING STEPS IN THR CAIB OP MASONRY SPILLWAY
SHOULD BEEXCAVATED
~GREATER THAN S·Om
CONTRACTIONJOINTS
5.2.2.5 When the spillway is constructed inmasonry and foundation slopes are as shown inFig. 5, concrete of about 0'6 m thickness shouldbe provided at the junction between the rock raceand masonry so as to obtain proper bond betweenmasonry and the sandwiched concrete should befilled up simultaneously with every lift of masonryand properly vibrated. Some stone pins should bekept protruding from the side face of the masonryto have proper keying with the sandwichedconcrete.
5.2.3 Whenever the foundation is sloping steeplyand when shear zones, faults and other weak
5.2.2.f If the excavated foundation rock profileis likely to be as shown in Fig. 4A and it is notf<!Uible to readjust the location of contractionJoints, further excavation should be carried out,as shown, if the level portion of the bottom ofslope i. greater than 5 m. However, if the levelportion is leu than 5 m, arrangement shown inFig. 4B may be adopted. If alternative shown inFig. 4B is adopted, concreting in shaded portionshould be carried out first and allowed to cooldown to the temperature of the foundation beforeraising the block further. The contraction jointshould then start for higher block from the higherlevel.
3
IS 11155 I 199~
7.1.1 Pozzo)anu may be used with advantage incement concrete mix with a view to effectingeconomy in construction and to control alkaliaggregate reaction. The pozzolana cement concrete is considered to have lesl resistance againstabrasive forces and cavitation. The use of suchconcrete should, therefore. be avoided for the toplayer of crest and downstream glacis portions,where ordinary Portland cement concrete isrecommended. For ordinary Portland cement,reference may be made to IS 269: 1989 andIS 8112 : 1989. For use of pozzolanie material,reference may be made to IS 1344: 1981II IS 1489(Parts 1 and 2 ) : 1991, IS 1727 : 1967, IS 2541 :1991 and IS 3812 : 1981.
7.1.2 The concrete mix should be designed onthe requirement of strength (s" IS 6512 : 1984 )in different partl of spillway in dams and otherconsiderations. However, the maximum size ofaggregate and desirable minimum grade of concrete for different structures connected with spillways in dams are given in Table I.
7.1.3 The concrete which comes immediately incontact with trunion girder and takes the thrustin bearing from it should be of non-shrinkagequality for a minimum thickness of 300 mm,
7.1.4 Rli1f!ore,m,'"
The provision of steel reinforcement in concreteshould be governed by IS 456 : 1978.'
7.2 CODerete OperatlO.8 aDd Embedmeat.
Concreting operations should be carried out andembedments made keeping in view the provisionscontained in 7.2.1 to 7.2.5. Maximum height ofconcreting in a lingle pour should not exceed 2 m,each lift in layer. not exceeding 500 mm inthickness, and difference in levels of adjoiningblocks should not generally exceed 10 m Concreteshould be properly and effectively vibrated.
7.2.1 Platin, Cone,,', in SpillwtJ.1
7.2.1.1 Crest and face of the spillway formingpart of the dam should have formed surface. Theformed surface should have accurate alignmentand evenness of surface for prevention of destructive effect of Rowing water. Gradual surfaceirregularities ( SI' Note) should not exceed 6 mm.The chute) bucket and hydraulic jump type stillingbasin ahould have ftoated unformed surface,Floating should be done either by vibro-screedor metal edged screed. The concrete surfaceshould be left undisturbed for 30 to 45 minutesuntil surface water disappears and there ii novisible akin. Joint! and edges . should be finishedwith steel edging tools.
4
NOTE - Offletl aDd fiu caused by dilplaced ormisplaced form IbeathiDl. IiDiDI or form leetioDl, bylOO1e koot. ia forma or by otherwise defective formlumber ar. coruidered a. abrupt lurface irregularitiel.All otben are closed .. If.dual lurface irrelularitiea.Gradual irregularitiel are measured with a templatecOD.ilUn, of a Itra1lbt edle for plane lurfacel or itaequivalent fOf curved surface.. The leDltb of template(or teltiD, formed Iurface. il leoerally 1·5 m.
7:Z.I.2 Precautionary measures should be takento prevent cavitation or abrasion resulting fromabrupt offsets (SI' Note below 7.2.1.1 ) on thoeesurfacel of open-flow spillways that may besubject to bigh velocity flow. Abrupt offsets onsuch surfaces should not be permitted. The offset,if there is any, should be completely eliminatedby grinding to the required bevels according toflow velocity as set forth in Table 2. Abrupt offset.away from the flow or parallel to the flow shouldonly be required to meet the maximum allowablelimit for the specified finish as provided inTable 3.
7.2.2 Temp,ralu" Conlrol
For control of concrete cracking and developmentof high thermal stresses, temperature controlof concrete is necessary, This may be achievedby precooling of concrete in gradients so asto obtain desirable placement temperature ofconcrete. The concrete, as deposited, shouldhave a temperature of not more than the stipulated value (usually 15 to 2100 for spillwayconcrete in hot climate ). The temperature of theconcrete should be not less than 5°0 in moderateweather or 100 e when the mean daily temperatureis lower than 5°C. As an additional precautionwhen the mean daily temperature is lower than5°0, one percent calcium chloride by mass ofcement may be used to bring the concrete to astage of greater maturity at the end of thespecified period of protection. Reference may bemade to IS 7861 ( Part 1 ) : 1975 and IS 7861( Part 2 ) : t981 for further details.
7.2.3 'SeqUlne, ofPouring
Concrete should be poured from downstream faceside towards upstream face side. The surface ofeach pour may be provided with upward slope ofabout 1 in 100 in downstream direction.
7.2.4 Cold, Transturse and Longitudinal Joints
7.2.4.1 Cold joint between two lifts should beavoided. This may be done by adopting thefollowing .tepa:
a) Green cutting of top surface of fint lift;
b) Sand blasting and cleaning of top surfaceof previous lift; and .
c) Anchor bars may be provided, if necessary.
.1 11155 • 1994
Table 1 Coacrete Mb Itrea.tII aDd Allftlate Sbe(a tIllS, 7.1_2 )
I. No. a....c.... ........SIs. 0' A8.......e1__-
(1) (2) (S)
i) Spillway m... CODcret. 150
Ii) ArouDd opeDiDI witb reinforcemeDt 40iii) 1-5 to 2·5 m tblck OD upltream face excludiDI 150
crest of spillwayiv) Spillway cr.lt (miDlmum 1-5 In thick OD 80
surface ), dowDitream spillway racev) Spillway bucket, .tUIiDI buia
.) all CODcrete in the top 0-6 ID iacludiDI 40baffle waU., end .ill., chute blocks, etc
b) all ccaerete below 0-6 m from top 80lurface
vi) Ret.iDiDI walls of Ipillway.) miDimum 1-5 III OD race 150b) interior 150
c) reiaforced retaiDiDI walla 80vii) Irreaularitiel of fouodatioD 40
viii) Spillway pien aDd brealt walla 80is) Spillway bridle deck
a) Beam. 40b) Deck 20
x) Truh rack .tructure 40ai) Block out. 20
D...... MIaI...eoDe..e•• On..
(4)
MISM20M20
M20
M25
M20
M20M 15
M20M 20M20
M20M20
M20~{ 20
Table 2 Ofr.et aDd Grladbal Toler.ace for HI•• Velocity Flow
( Claus, 7_2.1.2 )
SI No.
nii)
iii)
V.lodt)' a..... Metre.peW' Secoad
10 to 2525 to 35Over 35
GrhuU•••eyel, Ratio 01Hn.hc to Le• .-Ia
1 to 201 to 50
1 to 100
Tabl. , Madmam Allowaace ollrrelularitie. ID Surface Fial..·( Claus, 7.2.1.2 )
81 No.
i)
ii)
iii)
Type 0'Iw~...ladtle.
Depre••ioDGradual
Abrupt
....... ( POl'IDeci Sarlac. )1)
Maximum Permissible,..-__-A
Fl F. F. F.25-0
10·0 3·0 3·03-0 1·5 Not
allowed
Flm...·) ( Uaformed S...I.c. )1)
Value in Millimetre.,.--- A __--,
Us U. U,
iv) All .urf.cet
I)Allowuce in millimetre. - measured from 1-5 metre template,
"For el..n of fiai•• ref.r IS 457 : 1957.')AlJowaDce ia milllme.r.. - me.lured from 3 metre template.
s
10·0 5-0 5-0
IS 11155 : 1994
7.2.4.2 A high quality of bond and water tightness in a horizontal construction joint is beltassured when the concrete, and specially that inthe upper portion of the lift, has the least slumpthat will permit proper working and consolidation. Wtt mixes, particularly, should be avoided.Their tendency to segregate and bleed badlyresults in weak concrete and a heavy layer ofJaitance at the surface which makes clean updifficult. .
7.2.4.:1 The quality of the joint depends on thequality of the concrete and on the clean up to thejoint surface. Footprint, protruding pieces of largeaggregate or depressed keys interfere with accom-plishment or good clean up. Such features alsomake necessary complete removal of free waterdifficult, which, if not accomplished, may preventgood bond even though the surface is otherwiseproperly cleaned. Proper use of vibrator usuallyleaves the surface suitably even.
7.2.4.4 Sur/QC' oj construction and contraction joints
The surface of construction joint should be clean,rougb and damp when covered with fresh concrete.CLeaning should consist of the removal of alllaitance, loose or defective concrete, coatings,land, sealing compound, if used, and other foreignmaterials. Cleaning should be accomplished bywet sand blasting, followed by thorough washing.The joints in mass concrete, and where practicable in other concrete, should be cleaned andwashed immediately before concrete in the nextlift is placed. Where it is not practicable to cleanthe joints after forms ate set, the joints should bewet sand blasted and washed at the last opportunity prior to setting the forms and the Jointsshould be washed thoroughly with air-water jetsimmediately prior to placement of the adjoiningconcrete. The method to dispose of waste waterused in curing and washing of concrete surfacesshould be such that the waste water does Dotstain,discolour, or affect the exposed surfaces of thestructures. All embedded pipes, recesses, or openings used for disposing of waste water should,after they have served their purpose, be filledcompletely with concrete mixed in the proportionsspecified. All pools of water should be removedfrom the surfaces of construction joints before thenew concrete is placed. The surfaces of all contraction joints should be cleaned thoroughly ofaccretions of concrete or other foreign materialby scraping, chipping or other satisfactory means.All concrete surfaces of contraction joints shouldbe pointed with two coats of coal tar pitch.
7.2.4.5 Pla,i", oj an,hors in eoner,t,
Anchor bolts, structural shapes, plates and bearings required in connection with the installationof gatel, gate hoists, operating machinery andother apparatus should be placed in concrete aashown on the drawings or as found necessary.
Wherever practicable, anehors should be installedbefore the concrete is placed and, except as otherwise provided, drilling for installation of anchor.in concrete should not be permitted. Where theinstallation of anchors prior to placing the concrete is not practicable, satisfactory formedopenings should be provided and the anchorsshould be grouted into the openings at some latertime. Anchor bolts for machinery may be placedin approved pipe sleeves to facilitate installationof machinery and the sleeves should be completely filled with grout after the locations of thebolts are finally determined. In order to avoidcracking of face concrete, the bonded anchorsshould be insulated to a minimum of 500 mmlength from the trunion.
7.2.f.6 Placing of anchors i" roclc
Wherever necessary, holes should be drilled intothe rock to receive bars for anchoring concretewalls, spillway buckets, stilling basins and groundmats to the rock. The diameter of .anchor barholes should be not lesl than l: 5 times the diameter or greatest transverse dimension of theanchor bar specified for that hole. Anchor barsshould be cleaned thoroughly before being placed,The holes should be cleaned thoroughly. keptflagged until placing the bars and should be filledcompletely and compactly with grout or mortar. Allwater should be removed from the hole when theanchor grout is placed. The anchor bar shouldbe forced into place before the grout or mortarhas taken its initial set and where practicable,should be vibrated or tapped until entire surfaceof the embedded portions of the bars is in intimatecontact with the grout. Anchor bars should beplaced in advance of concrete operation to allowthe grout to set. Special care should be taken toprevent movement of the bars after they havebeen set.
7.2.4.7 Embedment ofpip,s
Metal pipes required in connection with drillingof grout holes and drainage holes from the galleryshould be placed in the concrete. For detailsreference may be made to IS 10135 : 1985.
7.2.4.8 Chipping and rough,ning ofconer,', sur/a"
At places. as directed by the inspection agency,concrete surface upon or against which additionalconcrete is to be placed should be chipped androughened to a depth of not more than 25 mm ofthe surfaces. The roughening should be performedby chipping or other satisfactory methods and insuch a manner as not to loosen, crack, or shatterany part of the concrete beyond the roughenedsurface. After being roughened, the surface of theconcrete should be cleaned thoroughly of allloose fragments, dirt. lime and other objectionablematerials and should be sound, hard and in suchcondition as to assure good mechanical bond
6
between old and new concrete. Concrete whichis not hard, dense and durable, should be removedto the depth required to secure a satislactorysurface.
7.2.4.9 To stop seepage of water through transverse joints double .seals are generally used. Forseals at contraction joints reference may be madeto IS 4461 : 1979 and IS 12200 : 1987.
7.2.5 The following should be kept in view:
a) It is desirable to have surface slope of 1 inIOU rising from upstream face to downstream face for better shearing stability.
b) Formed construction joints should beavoided wherever practicable as they resultin planes of weakness susceptible to theformation of cracks and to the passage ofwater unless effective water stops areprovided.
c) The joints shouJd be provided with chamfers at the upstream and downstream faceto avoid cracking of concrete due tothermal expansion when stress concentration may occur at the edges. The size ofsuch chamfer may be kept as 25 X 25 mmor 40 X 40 mm. The chamfer may bereduced on the downstream face of overflow sections since the joint lies centrallyin each bay and bigger recess may giveundesirable flow conditions.
1.2.6 Concreting Around Opening.f
7.2.6.1 For concreting around openings likegalleries, sluices and block-outs it should beensured that the centering, formwork and permanent steel lining where provided are properlyerected in place and are in proper line and levelbefore placement of concrete. Reinforcement,where necessary) should be accurately placed andsecured in position before placement of concrete.7.2.6.2 If concrete is placed monolithically aroundopenings having vertical dimensions greater than0·6 m, or if concrete in decks, floor slabs, beams,girders or other similar parts of structures isplaced monolithically with supporting concrete.following instructions should be strictly observed:
a) Placing of concrete should be delayed by notless than one hour nor more than threehours at the top of openings and at the bottom offillets UDderdecks, floor slabs, beams,girders or other similar parts of structureswhen fillets are specified and at the bottomof such structural members when fillets arenot specified, but in no case should theplacing be delayed so long that the vibrating unit will not of itl own weight readilypenetrate the concrete placed before thedelay. When consolidating concrete placedafter the delay. the vibrating unit shouldpenetrate and revibrate the concrete placedbefore the delay.
7
IS 11155 I 1994
b) The last 0·6 metre or more of concreteplaced immediately before the delay shouldbe placed with as Iowa slump as practicable and should be thoroughly compacted.
c) The surface of concrete where delays aremade should be clean and free from looseand foreign material when concrete placingis started after the delay.
d) Concrete placed over openings and indecks, floors. beams, girders and othersimilar parts of structures should be placedwith as low a slump as practicable andspecial care should be exercised to effectthorough consolidation of concrete.
7.2.6.3 The concrete should be worked into thecorners and angles of the forms and around thereinforcement, instruments and other embeddeditems, without permitting segregation. Whileplacing concrete it should be ensured that thereinforcement, instruments and other embeddedparts are not displaced. Care should be taken inplacing concrete around the forms and permanentsteel lining to avoid damage to them. The concrete should not be dumped directly from bucketson them.
7.2.7 Botching; Mixing dnd Plac""ent oj CO"",,.
7.2.7.1 The batching and mixing plant should beable to accurately determine and control theprescribed amount of various ingredients of theconcrete by separate weighting. For other detailsreference may be made to IS 457: 1957.
7.2.7.2 The batching and mixing plant should beso designed as to ensure uniform distribution ofall ingredients throughout the mass at the end ofthe mixing period.
7.2.7.3 The concrete should be conveyed from thebatching and mixing plant to the forms as rapidlyas practicable by the methods which will preventseparation or loss of ingredients.
7.2.7.4 The concrete should be placed in its finallocation within 30 minutes after mixing. Placingof concrete should be done preferably with bottomdump buckets with arrangements for positiveregulation of the amount and the rate of placement of concrete.
7.2.8 CompGCtion oj COlleTe',
7.7.8.1 The concrete should be compacted toobtain the maximum practicable density uniformlyover the whole mass. Vibraton of proper designshould be used for the purpose and the intensityand duration of vibration should be sufficient toproduce satisfactory compaction. The vibratorsshould be checked periodically. Vibrators havingvibrator head 100 mm or more in diameter shouldbe operated at least 6 000 rev/min when immersedin concrete. Vibrators having vibrator head lessthan 100 mm in diameter should be operated at
18 11155 I 19M
least 7 OCO rev/min when immersed in the concrete.7.2.1.2 Systematic spacing of the points of vibration should be established to ensure that noportions of the concrete are missed, The entiredepth of a new layer of concrete should be vibrated and the vibrator should penetrate severalcentimetres into the layer below to ensurethorough union of layers. Excessive vibrationcausing segregation and laitance or that tendingto bring excessive amount of water to the lurfacemould be avoided. In DO case should the vibratorsbe used to transport concrete inside the forms.Care ahould be taken to avoid contact of thevibrators with the surface of tile forms or displacement of the reinforcement, instrument orembedded parts.7.2.' Finish,sR.ecommended finishes for formed and unformedsurfaces are given in Table 4.
Table t Flal•••• lor FormeclaadV.formeel S...rae••
7.2.10 Tol"anc,s
All concrete structui es should be constructed toexact lines, grades and dimensions established.However, inadvertent variations from the established lines, grades and dimensions should bepermitted to the extent set forth in Annex B.
7.2.11 Proper quality control should be ensuredin accordance with IS 457 : 1957.
7.3 The concrete placement may be done by anyof the following methods:
a) Trestle and crane system;b) Oableways;c) Multi-trestle system;
d) Concrete pump;e) Truck mixers. dump trucks; orf) Belt conveyors.
8 MASONRY SPILLWAYS
8.1 GeD~ral
In masonry dams, it is a general practice toprovide concrete lining on the crest as well as theglacis. For details of construction of masonry,reference may be made to IS 8605 : 1977.
8.2 Concrete LiDlaa
It is important to ensure proper bonding of thelining with the underlying masonry and to provide smooth surface finiah conforming to designprofile. The concrete should be homogeneous andwell compacted by vibrators. The lining shouldbe provided with concrete of grade M 20•
8.2.1 Lining 011 Upstream Fa"
The lining should be provided from an elevationwhere tension starts developing and is taken upto the crest. The thickness of lining should bedesigned on the basis of tension developed witha minimum of 1'0 m, with thickness increasingtowards crest. Anchor bars of 25 mm diameter at1-5m centre to centre both ways should be provided, embedded 1·5 m into the mosonry. Reinforcement in lining should be provided inaccordance with design requirements. A typicalsection of spillway. showing these details is givenin Fig. 6.
8.2.2 M,lUUr,s of S"pagl Control Through Upst"QmMason,,, Fill'
8.2.2.1 In order to achieve adequate imperviousnell and thereby to reduce the seepage of waterthrough the upstream face of muonry IpilJway t
seepage control arrangement should be provided.Several such preventive meuurel are described
Fa
Us
u.
Type ofWI.....l)
(3)FJ
(2)
Upltream face or concrete dam belowMDDL aDd lurrac@1 UPOD 01'a.a1Dlt wbich fill materia' or COD-crete il to be placed.
Galleries and adill; retaiDiDI waUl,bridle. DOt promiDeDtly exposed topublic iupectioD aDd surfacel DotpermaDendy cODc~aled by fillmaterial. or COQcreteor Dot required to receive 8Bi,hel Fl, Fa aDdF••
St'ructurea permaDeDtl, expoled topublic view, that is parapetI,•piJJway pier., interior aDd exteriorwalla 0' hoitt elevator towen andother decorative feacure••
Spillway crest, Ipillway face, apr.ywalll, part of intake for canal, penstocka, outleta for caDal .tructurelaDd river sluice cODduit. and allIurface. for wbich accurate alilnment uad eVeDDeli of surCace areimportant from the stand poiDt ofetimiDatiDI deltructive efFectl ofwater .ChOD.
R.oad lurf.cel/otber lurfaeel thatwill be covered by fill materiallccncreted ( screeded &Disb ).
Floor. of Ipillway outlet works aadItilliDI buiD. floor. of gallery aDdexpOied face of spillway bridle••
Top of parapet., Itair tread" I.Ueryfloon aDd Ipiltway buckets/hydrau-lic jump type ItilliDI buin.
NOTE - Whea waterftow velocitiea on uDformedCODcrete lurface or outlet worb, Ipil1wayl, etc, .r.calculated to dceed 15 mIl, further limitatioDi OD U.aad/or UI &ailhel Ibould be cOD.ider~ for the allowable irreluJaritiel to preveat caviration.S)For typel of fiai.h J reference may be made to IS 457:1957.
v)
il)
vi)
(1)i)
iv)
iii)
vii)
II No.
8
1111155 • 1994
RECOVERYGRADE
The concrete membrane may be eitherthin, about 1·5 to 2 m, with surface temperature reinforcement (sel Fig. 8) orthick, about 3 m, without temperaturereinforcement ( s" Fig. 9 ).
c) Sa"dwi,h concnt« membra", - A sandwichconcrete membrane between the upstreamface stone masonry and the hearting ( orcore) masonry may be provided as shownin Fig. 10 to act as an intercepting curtain,The thickness of the concrete membraneshould be about 1·5 m. It should be constructed simultaneowly with the lift. of theupstream and downstream masonry work.Suitable keys in concrete and dowel barsbetween concrete and masonry should beprovided as shown in Fig. 10 to havemonolithic action of the concrete membrane and the "masonry. No temperaturereinforcement is necessary as the membraneis Dot exposed.
d) P"la,k,d sandwic" concret« - A membraneof prepacked sandwich concrete may beused as shown in Fig. II. In this methodthe space to be concreted is prepackedwith well graded coarse aggregate andthen sand cement mortar is pumped into itfrom bottom up by means of perforatedpipes already laid in the aggregates.
HE IGHT OF STEP, 0·6 m
1 TO 1·5 m CEMENT CONCRETE
MAIN BARS( AS PER STRUCTURAL DESIGN)
RADIAL GATE
'\\~
tl....-.- DRAINAGE GALLERY~- (FOR DETAilS REFER
II \' IS ·10135 -'982», ,
O/S TRAINING WALL
~'--"'-t.'-"~.....-~--DIST. BARS (AS PER STRUCTURAL UESIGN)
below, of which a suitable alternative may beadopted:
a) Coursld rubbl« masonry (Khandki ja,ingupstream ) willi adjae,nt rich mortar ~on'
The upstream masonry in about 2 to 3 mthickness should be constructed in richcement mortar (1 cement : 3 sand) withcoursed rubble ( khandki ) facing upstream( se, Fig. 7 ). A khandki is a selected stone600 to 900 mm long, 400 to 500 mm wideand 200 to 300 mm high. Its face to beexposed upstream is properly dressed on thesurface and the periphery is also dressedevenly to a depth of 50 to 70 mm insidefrom the surface, The dressed peripheryfacilitates provision of uniform and tightmortar joints. The rest of the masonrybeyond the rich zone should be constructedaccording to the proportion and workmanship specified.
b) Upstream concreu facing - A concrete membrane on the upstream face replacingkbandki as in (a) backed with richmasonry may be provided. The concretemembrane should be properly bonded tothe dam masonry by means of keys andanchor bars to prevent separation of concrete from the masonry either due toshrinkage of concrete or due to build-upof hydrostatic pressure at the interface.
KHANOKIFACING ---...I~
lONE A --..........
NOTESI ZONE A : Muonry ia rich cement mortar proportioa 1 : 3.2 ZONE B : Muouy in lean cemeat mortar proportion 1 : 5.3 For detall. or draiD&learraDlemlnt, refer IS 10135 : 1985.
Flo.6 TYPIOAL a.OSS-SEOTION OF SPILLWAY
9
18 11155 • 199f
CREST,
KHANOKIFACING ---.....,...
(Scc DETAil A)
2 TO 3 m THICKMASONRY IN C.M1~3WITH U/SKHANOKI FACING
lUIS FilLET NOl SHOWN)
HEARTINGMASONRY
DETAIL AT A
Flo.7 KHANDKI FAOING WITH RIOH MASONRY ZONE ON UPSTRBAM
CREST,
KEYS
1·5 m lHICK CONeM 20 WITH TEMPSTEEL -----+....
(uls FtLLE 1 NOT SHOWN)
HEARTINGMASONRY
G I SEALS
CONSTRUCTIONJOINT @ 1·5 m
......-..,............- f1125mm DOWELS0·5 m LONG@3·0m c/c
HEARTINGMASONRY
SHEAR KEYS(;)1,5 m ere
DETAIL AT A
FlO. 8 THIN COllc.aft MaIlD.Alta WITH RBJNFOaCBMBNT ON UPITaBAJI FAC.
10
IS 11155 I 1994
3·0m THiCKM 20 CONCRETE
(u/s FILLE T NOT SHOWN)
4» 25 mm DOWELS2·0 m LONG@1·S0m c/cBOTHWAYS
.........._-'-- SHEAR KE YS@1·Sm clr
AT A
+2Smm DOWELS1·00m LONG @ 3 00 m tic
U/s FACE OFSPILLWAY
M 20CONCRETE
GLACIS CONCRETe:
HEARTINGMASONRY
,CREST
u/s FAce OFSPILLWAVS--.......
FlO. 9 THIOK CONCRBTE MaMBRANE ON UPSTRBAII FACE
(U/S FILLEl NOT SHOWN)
A~I
\
SHEAR KEYS <I'·5m ete
/
M 20 MASS CONCREt E
G I SEAL ~ 2S mm DOWELS,/ O'5m LONG @ 30m c/c
q25mm DOWEL,1·0m LONG@t 5 m Cole
DETAIL AT A
U/S FACE OFSPILLWAY
0·5_0 5leO·5 m (I',5 m c/c BOTHWAYS4£~.L£.r----t--........t-:h
GLACISCONCRETE
HEARTINGMASONRY
•CREST
'5m THICK RRMASONRY wrTHCOURSEQ DRESSEDSTONE IN 1.3CEMENT MORTAR
FlO. 10 SANDWICH CONORaTB MaIlS.ANB ON UP.TIl_AII FAC.
11
1111155 sIllf
HEARTrNGMASONRY
................. '.Sm THICKPREPACKEDCONCRETE
"5m THle-1< R.R.MASONRY WITHCOURSED DRESSED ~STONE FACING IN '~CEMENT MORTAR ~
1:3-----......
CREST
(u/s FILLET NOT SHOWN)
FlO. 11 PaBPACItBD SANDWICH COMORSTB MEMBRANB ON UpsTRaAIi FACB
8.2.2.2 Guniting with rich cement mortar may beresorted to for reducing the seepage from the upstream face ( s" IS 13645 : 1993 ). This techniqueshould, however, be considered more as a remedial measure rather than a preventive measurefor seepage control.
8.2.3 Lini"g 0" Crlsl and Downstream Glacis
Lining of uniform thickness is provided on thedownstream glacis between the tangent points forcrest and tangent points for bucket. Lining of athickness of 1'5 m for major dams and 1·0 m formedium dams is normally provided. Masonry incontact with the: lining should be constructed instepa of about 0-6 m. Anchor bars of 25 mmdiameter should be provided at 1'5 m centre tocentre both ways and embedded 15m into
. masonry. These bart are provided horizontallyas well as vertically for achieving bond betweenthe masonry and concrete. TypicaJ d~tajl. arcshown in Fig. 6.
9 DRAINAGE HOLES
Drainage holes should be provided in accordance
with the provisions contained in IS 10135 : 1985.
10 INSTRUMENTATION
It is very important that proper instruments areinstalled and monitored in the structure to keepa watch on its structural and hydraulic behaviour.Such information is of immense help in takingprecautionary corrective measures well ahead ofany possible failure. For details of installatioDand observation of instruments reference may bemade to IS 4967 : 1968, IS 6524 : 1972, IS 7436(Part 2): 1976, IS 8282 (Part 1): 1976,IS 10334 : 1982 and IS 10434 ( Part 1 ) : 1982.
11 INSTALLATION OF GATES ANDHOISTING ARRANGEMENTS
An appropriate arrangement of gates and hoistsshould be provided. Reference may be made toIS 4623 : 1984, IS 10096 ( Part l/Sec 1 ) : 1983,IS 4622 : 1992, IS 5620: 1985, IS 9349 : 1986and IS 7718 : 1991.
12
IS 11155 I 1994
ANNEX A( Clause 2 )
LIST 0' REPERRED INDIAN STANDARDS
IS No.
269: 1989
456 : 1978
457 : 1957
1344 : 1981
1489( Part 1 ) : 1991
1489( Part 2 ) : 1991
1727 : 1961
2541 : 1991
3812 : 1981
4461 : 1979
4622 : 1992
4623 : 1984
4967 : 1968
5620 : 1985
6066 : 1994
Till,
Specification for 33 gradeordinary Portland cement(fourth "vision)Code of practice for plain andreinforced concrete (thi,drmision )Code of practice for generalconstruction of plain and reinforced concrete for dams andother massive structures
Specification for calcined claypozzolana ( second revision )
Specification for PortlandpozzoJana cement : Part 1 Flyash based ( third revision )
Specification for Portlandpozzolana cement: Part 2Calcined clay based (thi,drevision )
Methods of tests for pozzolan icmaterials (first rmision )
Code of practice for preparation and use of lime concrete( second recision )
Specification for fly ash for useas pozzolana and admixture(firJt revision )
Code of practice for joints insurface hydro-electric powerstations (first "vision )
Recommendations for structural design of fixed wheel gates( second "vision)
Recommendations for structural design of radial gates( SI&Olld '61J;S;on)
Recommendations for seismicinstrumentation for rivervalley projects
Recommendations for structural design criteria for lowhead slide gates (sIcond,.,ilion )
Recommendations for pressuregrouting of rock foundationsin river valley projects ( sIco"dr,vision )
IS No.
6512 : 1984
6524 : 1972
7436( Part 2 ) : 1976
7718 : 1991
7861( Part I ) : 1975
7861( Part 2 ) : 1981
8112 : 1989
8282( Part I ) : 1976
8605 : 1977
9103 : 1979
9349 : 1986
9461 : 1980
9759 : 1981
13
Title
Criteria for design of solidgravity dams (first reoision )
Code of practice for installation and observation of instru-menta for temperaturemeasurement inside dams,resistance type thermometers
Guide for types of measure-menta for structures in rivervalley projects and criteriafor choice and location ofmeasuring instruments: Part 2Concrete, and masonry dams
Recommendations for inspection, testing and maintenanceof fixed wheel and slide gate.(first "vision )
Code of practice for extremeweather concreting: Part 1Recommended practice forhot weather concreting
Code of practice for extremeweather concreting : Part 2Recommended practice forcold weather concreting
Specification for 43 gradeordinary Portland cement(first "visian )
Code of practice for installation, maintenance and observation of pore pressuremeasuring devices in concreteand masonry dams: Part 1Electrical resistance type cell
Code of practice for construction of masonry in dams
Specification for admixtures ofconcrete
Recommendations for structural design of medium andhigh head slide gates (firstrnision )
Guidelines for data requiredfor design of temporary riverdiverslon works
Guidelines for de-wateringduring construction
IS 11155 I 119~
10084 Criteria for design of diversion( Part 1 ) : 1982 works: Part 1 Coffer dams
10084 Design of diversion works-( Part 2 ) : 1994 Criteria: Part 2 Dlversion
channels and open cut orconduit in the body of dam
IS No. Titl,
9795 Guidelines for the choice of( Part 1 ) : 1981 the type of diversion worb :
Part 1 Coffer dams
10096 Recommendations for inspec-( Part l/Sec 1 ) : tion, testing and maintenance
1983 of radial gates and theirhoists : Part 1 Inspection, testing and assembly at themanufacturing stage, Section 1Gates
Titl,
Code of practice for selection,splicing, installation and providing protection to the openends of cables used forconnecting resistance typemeasuring devices in concreteand masonry dams
Guidelines for installation,maintenance and observationof deformation measuringdevices in concrete andmasonry dams: Part 1 Resistance type jointrnetersCode of practice for construction of diversion works: Part 1Cellular coffer damsCode of practice for provisionof water stops at transversecontraction joints in masonryand concrete damsGuniting the upstream ofmasonry dams - GuidelinesClosure of diversion channeland open cut or conduit inthe body of dam - Code ofpractice
13645 : 1993
12200 : 1987
10788( Part 1 ) : 1984
13912 : 1993
10434( Part 1 ) : 1982
/SNo.
10334 : 1982
Code of practice for drainagesystem for gravity dams, theirfoundations and abutments(fiTst revision )
10135: 1985
ANNEX B( Clause 7.2.10 )
CONSTRUOTION TOLERANCES FOR MASS CONCRETE STRUCTURES
8-1 MASS CONCRBTE STRUCTURES
8-1.1 All structures:a) Variation of the constructed linear outline
from established position in planb) Variation of dimensions to individual
structure features from established positions
11-1.2 a) Variation from the plumb, from thespecified batter or from the curved surfacesof all structures including the lineal andsurfaces of columns, walls, piers, buttresses, arch sections, vertical joint grooves,and visible arrisee
b) Variation from the level or from thegrades in slab., beams, soffits, lintels, sills,horizontal joint grooves, and visible arrises
8-1.3 a) Variation in cross-sectlonal dimensions ofcolumns, beams, buttresses. piers, and.imilar members
In 6 metresIn 12 metresIn 24 metres or moreIn buried construc-
tion twice the valuesspecified above
In 3 metresIn 6 metresIn 12 metres or moreIn buried construc-
tion twice the valuesspecified above
For water tight jointsse« B-l.5
In 3 metresIn 6 metresIn buried construc
tion twice the valuesspecified above
- 6mm+12mm
12mm20mm32mm
12mm20mm30mm
6mm12 mm
14
b) Variation in thickness of slabs, walls. archlections and similar members
8-1.f Footing for columns, piers, walls, buttressesand similar member.a) Variation of dimensions in plan
b) Misplacement or eccentricity
c) Reduction in thicknesl
B-l.5 Variation from the plumb and levels for sidewaUl and sills for gates and similar watertight joints
8-1.6 Variation in the sizes and locations of sleeves,floor openings and wall of opening.
B-J.7 Variation in stepsa) In a flight of stairs
b) In consecutive steps
B-2 REINFORCED CONCRETE CONSTRCanON
8-2.1 Variation from the plumba) In the lines and lurfaces of columns, piers,
walls and in arriles
b) For exposed corner columns, control-jointgrooves and other conspicuous Iines
8-2.2 Variation from the level or from the grades:a) In floors, ceilings. beam soffits and in
arrises
b) For exposed lintels, sills, parapets, horizontal groove. and other conspicuous lines
8-2.3 Variation of the linear building lines fromestablished position in plan and related position of columns, waUs and partitions
B-2.t Variations in the sizes and locations insleeves, floor openlags and wall openings
B-2.5 Variation in cross-sectional dimensions ofcolumns and beams and in the thickness ofslabs and waUs
8-2.6 Pootings
a) Variation of dimensions in plan
15
-6mm+10mm
-12mm+ 50mm2 percent of footing
width in the direction of misplacement but not morethan 50 mm
5 percent of specifiedthickness
Not greater than arate of 3 mm in 3metres
6mm
Rise 3 mmTread 6 mmRise 1-5 mmTread 2 mm
In 3 metresIn 6 metresIn 12 metresor more
In any bay or6 metres
10 12 metresor more
In 3 metresIn any bay or
6 metres maximumIn 12 metres or moreIn any bay or
6 metres maximumIn 12 metre. or more
In any bay or6 metres muimum
In 12 metres or more
6mm
-6mm+12mm
-12mm+ 50mm
18 11155 I 1994
6mmIOmm20mm
6mm
12mm
6mmlOmm
20mm6mm
12mm
12mm
25 inm
18 11155 I 199f
b) Misplacement or eccentricity
B-3 CONDUITS
8-3.1 Departure from estabUshed alignment or fromestablished grade
8-3.2 Variation in thickness at any point
Oonduits
Conduits
8-3.3 VariatioD from inside dimensions conduits
16
2 percent of the footing width in thedirection of milplacement but not morethan 50 mm
High-velocity con-duits
- 2 percent or 6 mmwhichever is greater+ 5 percent or 12 mmwhichever is greater
1/2 percent
12mm
Bruea. of I.dlan Standardt
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Re,iew of ladlu Stud.rd.
Amendments are issued to standards as the need arises on the basis of comments. Standards are alsoreviewed periodically; a standard along with amendments IS reaffirmed when such review indicates thatno changes are needed; if the review indicates that changes are needed, it is taken up for revision.Users of Indian Standards should ascertain that they are ID possession of the latest amendments oredition.
This Indian Standard has been developed from Doc No. RVD 10 ( 60 ).
Ameadments Issued SIDce Publlcatlo8
Amend No.
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Date of Issue
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Text Affected
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