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SECTION V

TECHNICAL SPECIFICATION

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EXCAVATION, FILL AND BACKFILL

SCOPE OF WORKThe scope of work covered under this specifications pertains to excavation of

foundations, trenches, pits and over areas, in all sorts of soils, soft and hard rock,correct to dimensions given in the drawing including shoring, protections of existingunderground utilities if any, such as water lines, electric cables etc., dewatering andshoring if necessary , stacking the useful materials as directed within the leadspecified, refilling around the foundation and into the plinth with selected usefulexcavated earth and disposing off the surplus earth./materials within specified leadand finishing the surface to proper levels, slopes and camber etc., all complete.

SITE CLEARANCE

Before the earth work is started the area coming under cutting and filling shallbe cleared of all obstructions, loose stones, shrubs, rank vegetation, grass, brush-wood, trees and saplings of girth up to 30 cm measured at a height of one meterabove ground and rubbish removed up to a distance of 150 meters outside theperiphery of the area under clearance. The roots of trees shall be removed to aminimum depth of 60cm below ground level or a minimum of 30cm below formationlevel whichever is lower and the hollows filled up with earth, levelled and rammed.

This work is deemed to be included in the earth work items and no separatepayment will be admissible for the work.

The trees of girth above 30cm measured at a height of one meter aboveground shall only be cut after permission of the Engineer-in-charge is obtained inwriting. The roots shall also be removed as described in the preceding sub-para.Payment for cutting and removing roots of such trees shall be made separately. Anymaterial obtained from the site will be the property of the Department and the usefulmaterials as decided by the Engineer-in-charge will be conveyed and properlystacked as directed within the lead specified.

SETTING OUT AND MAKINGPROFILES

Masonry or concrete pillars will be erected at suitable points in the area toserve as bench marks for the execution of the work. These bench marks shall beconnected with permanent bench mark approved by the Engineer-in-charge.Necessary profiles with pegs, bamboos and strings or Burjis shall be made to showthe correct formation levels before the work is started. The contractor shall supplylabour and materials for setting out and making profiles and Burjis for the work at hisown cost and the same shall be maintained during the excavation work. Thedepartment will show grid Co-ordinate or other reference points. It shall be theresponsibility of the contractor to set out centre lines correctly with reference to thedrawings and install substantial reference marks. Checking of such alignment by theDepartment will not absolve the contractor from his responsibility to execute the workstrictly in accordance with the drawings.

EXCAVATION, FILL AND BACKFILLThe scope of work covered under this specifications pertains to excavation of

foundations, trenches, pits and over areas, in all sorts of soils, soft and hard rock,correct to dimensions given in the drawing including shoring, protections of existingunderground utilities if any, such as water lines, electric cables etc., dewatering, andshoring if necessary, stacking the useful materials as directed within the leadspecified, refilling around the foundation and into plinth with selected usefulexcavated earth and disposing off the surplus earth. Materials within specified leadand finishing the surfaces to proper levels, slopes and camber etc., all complete.

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EXCAVATIONThe contractor shall notify the Engineer-in-charge before starting excavation

and before the ground is disturbed, to enable him to take existing levels for thepurpose of measurements. The ground levels shall be taken at 3 to 5 metersintervals in uniformly sloping ground and at closer distance where local mounts, pitsor undulations are met with ,as directed by the Engineer-in-charge. The ground levelshall be recorded in fields books and plotted on the plans, which shall be signed bythe Contractor and the Engineer-in-charge, before the earth work is actually started.The labour required for taking levels, shall be supplied by the contractor at his owncost. The contractor shall perform excavation in all types of soils, murrum, soft andhard rocks, boulders etc., in foundation , over areas and in trenches to widths ,lines,levels ,grades and curves as shown in the drawing or lesser widths ,lines and levelsas directed by the Engineer-in-charge and as per items in the schedule of quantities.

LIMITS OF EXCAVATION:The contractor shall perform excavation to the given lines and levels as

directed by the Engineer. The bottom and sides of excavation shall be dressed toprepare levels, slopes, camber etc as directed by the Engineer by removing highslopes and filling up hollows. If the excavation taken up beyond to the specified

levels and lines, it shall be filled and duly consolidated by the contractor at his owncost.

Classification of Earth work:The earth work shall be classified under the following main categories and

measured separately for each categorya) All types of soils, murram, boulders.b) Soft rock/Weathered Rock.c) Hard rock.

a)All types of soils, Murrum, BouldersThis includes earth, murrum, top deposits of agricultural soil, reclaimed soil,

clay, sand or any combination thereof and soft and hard murrum, shale etc., which isloose enough to be removed with spades, shovel and pick axes. Boulders not morethan 0.03 cum in volume found during the course of excavation shall also fall underthis classification.

b) Excavation in soft rock:This shall include all material which are rock or hard conglomerate, all

decomposed weathered rock, highly fissured rock, old masonry, boulders biggerthan 0.03cum in volume but not bigger than 0.5cum and other varieties of soft rockwhich can be removed only with pick axes, crow bars, wedges and hammers withsome difficulty. The mere the fact the contractor resorts to blasting and or wedgingand chiseling for reasons of his own, shall not mean the rock is classified as hardrock. The excavation of existing road if any shall be included under this item of softrock.

c) Excavation in Hard Rock:This includes all rock other than soft rock mentioned in the relevant Para

(Excavation in soft rock), occurring in masses, boulders having approximate volumemore than 0.5cu.m plain or reinforced cement concrete, which can best be removedby blasting or chiseling and wedging where blasting cannot be permitted owing toany restriction at site

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Excavation in Hard Rock by Blasting:Where blasting is permitted the excavation in the rock shall be done by

means of blasting. No heavy blasting will be permitted and only Controlled/muffledblasting will be permitted at the discretion of the Engineer-in-Charge. The contractorshall be governed by the relevant statutory laws, rules and regulations onexplosives, pertaining to the acquisition, transport, storage, handling and use ofexplosive which shall be rigidly followed and shall obtain him all necessary materialsand equipment for blasting. Blasting shall be executed through a licensed blasterwith a prior permission from police authorities. Prior to blasting sufficient notice shallbe given to concern parties to avoid danger to people, material and near bystructures. All the damages caused by careless blasting if any shall be made goodby the contractor at his own expenses.

a) Excavation in Hard Rock by Chiseling and Wedging:Where Blasting is not permitted and if the Engineer-in-charge so desires, theexcavation shall be done by chiseling and wedging / any other agreed method.

Note: All the excavated hard rock obtained shall be stacked properly and neatlywithin the specified lead by the contractor as directed by the Engineer-in-charge.

EXCAVATION:The excavation under all classifications in areas in trenches or in pits shall becarried out systematically. Cutting shall be done from top to bottom and underpinning under or under cutting will be allowed. The bottom and sides of excavationshall be dressed to proper level, slopes, steps, camber etc., by removing high spots,and ramming thoroughly as directed by the Engineer-in-charge.

All the excavation shall be carried out strictly to the dimensions given in thedrawing .The width shall generally be of the width of mud mat concrete and depth asshown in drawing or as directed by the Engineer-in-charge, according to availabilityof the desired bearing capacity of soil below .Any excavation if is taken below thespecification depths and levels, the contractor shall at his own cost fill up such over

cut to the specified level with cement concrete 1:4:8 in case of excavation in all typesof soils and with cement concrete 1:2:4 in case of excavation in soft and hard rock.

After the excavation is completed, the contractor shall notify the Engineer-in-Charge to that effect and no further work shall be taken up until the Engineer-in-charge has approved the depth and dimensions and also the nature of foundationmaterials. Levels and measurements shall also be recorded prior to taking up anyfurther work.

SHORING:Unless separately provided for in the schedule of quantities, the quoted rate

for excavation shall includeexcavation of slopes to prevent falling in soil by providing

and /or fixing, maintaining and removing of shoring, bracing etc., The contractorwould be responsible for the design of shoring for proper retaining of sides oftrenches, pits etc., with due consideration to the traffic, superimposed loads etc.,shoring shall be of sufficient strength to resist the pressure and ensure safety fromthe slips and to prevent damage to work and property and injury to persons. It shallbe removed as directed after items for which it is required are completed. Should theslips occur, the slipped material shall be removed and slope dressed to a modifiedstable slope. Removal of the slipped earth will not measure for payment.

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PAYMENT OF EXCAVATION

The excavation on soil, soft/weathered rock and hard rock shall be made asper relevant schedule of items. The payment shall not be made beyond the limits ofexcavations as shown in the drawing.

DEWATERING:Unless specifically provided for as separate item in the schedule of quantities,

rate shall also include bailing or pumping out all water which may accumulate in the

excavation during the progress of further works such as mud mat concrete, R.CFootings, shuttering etc., either due to seepage, springs, rain or any other cause anddiverting surface flow by bunds or other means. Care shall be taken to ensure thatthe water discharged sufficiently away from the foundations to keep it free fromnuisance to other works in the neighborhood.

Payment:The cost of dewatering, if any, shall be included in the quoted rate of

excavation item.

DISPOSAL OF EXCAVATED MATERIALS

a) ANTIQUITES:Any findsof archaeological interest such as relies of antiquity, coins, fossils or

other articles of value shall be delivered to the Engineer-in-Charge and shall be theproperty of the Government.

b) USEFUL MATERIALS:

Any material obtained from the excavation which in the opinion of theEngineer-in-charge is useful shall be stacked separately in regular stacks as directedby the Engineer-in-Charge and shall be the property of the Government.

No material excavated from foundation trenches of whatever kind they may be

are to be placed even temporarily nearer than about 3 m from the outer edge ofexcavation. Discretion of the Engineer-in-Charge in such case is final .All materialsexcavated will remain the property of the Department Rate for excavation includessorting out of the useful materials and stacking them separately as directed withinthe specific lead.

Materials suitable and useful for backfilling or other use shall be stacked inconvenient place but not in such a way as to obstruct free movement of materials.Workers and vehicles or encroach on the area required for constructional purposes.It shall be used to the extent required to completely backfill the structure to originalground level or other elevation shown on the plan or as directed by the Engineer-in-Charge. Materials not useful in anyway shall be disposed off, levelled andcompacted as directed by the Engineer-in-charge within a specified lead. The site beleft clean of all debris and leveled on completion.

MODE OF MEASUREMENTS

All excavated in areas having depth more than 30 cm. pits trenches etc., shallbe measured. The dimensions for the purpose of payment shall be reckoned on thehorizontal area of the excavation at the base for foundations of the walls, columns,footings, rafts or other foundations, multiplied by the means depth from the surface

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of ground determined by levels. Excavation on square meter basis. Mentioning theaverage depth of excavation.

Reasonable working space beyond concrete dimension required forwaterproofing and shuttering where considered necessary in the opinion ofEngineer-in-Charge will be allowed in execution and considered for payment forunderground water tank, sump ,septic tank etc.,

Wherever direct measurements of rock excavation are not possible, volume ofrock is calculated on the basis of length, breadth and depth of stacks shall be madeat site. The net volume shall be worked out by reducing it by 50%, taking the voidsinto consideration as 50%.Similarly to arrive at net quantity to be paid in the case ofsoil, reduction @ 20 % of corresponding stack/truck measurements shall be made.

The rate for excavation shall include caring and disposing and leveling theexcavated materials within the specified lead. The rate shall also be inclusive of costof all tools, plants, explosive, shoring, dewatering at various stages, Labour,materials etc., to complete all the operations specified.

The backfilling and consolidation inside the trenches, sides of foundation,

plinth etc. with excavated material will not be paid for separately. The rate quoted forexcavation shall be deemed to have been included the cost of stacking of excavatedmaterials, conveying within the specified lead, picking of selected stacked material,conveying it to the place of final backfill, compaction to the required proctor densityetc.

The rate quoted is for cum. For item of excavated is deem to include thenecessary additional quantity of excavation involved beyond the plan dimensions ofthe work which may be necessary to be carried out for carrying out the work in anengineering manner, decided upon by the contractor .Therefore no extra paymentwill be made for any excavation done other than required quantity as per the plandimension indicated in the drawings.

Measurement for excavation over area shall be determined by level. Levels ofsite shall be jointly taken and recorded by the Engineer-in-Charge or hisrepresentatives and the contractor, before commencement of the work and aftercompletion of the work and the quantity of work done shall be computed based onthese levels.

BACK FILLING/FILLING TRENCHESFilling in trenches for pipes and drains shall be commenced as soon as the

joints of pipes and drains have been tested and passed. Where the trenches areexcavated in soil, the filling shall be done with earth on the sides and top of pipes.Workers and vehicles or encroach on the area required for constructional purposes.It shall be used to the extent required to completely backfill the structure to original

ground level or other elevation shown on the plan or as directed by the Engineer In-charge. Materials note useful in anyway shall be disposed off, levelled andcompacted as directed by the Engineer-In-charge within a specified lead. The siteis left clean off all debris and levelled on completion.

BACKFILLING INSIDES THE FOUNDATION, PLINTH, UNDER FLOOR ETC.,The back filling shall be done after the concrete or masonry has fully set and

shall be done in such a way as not to cause under-thrust on any part of thestructure. Where suitable excavated material is to be used for back filling, it shall bebrought from the place where it was temporarily deposited and shall be used in

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backfilling. The scope of work for back filling/filling in foundation, plinth, under floorsetc., shall include filling for all the buildings covered under the contract. Surplusearth available from one building if required, shall be used for backfilling /filling forother buildings also within the specified lead mentioned in the item.

All timber shoring and form work left in the trenches, pits, floors etc., shall beremoved after their 'necessary ceases and trash of any sort shall be cleared outfrom the excavation. All the space between foundation masonry or concrete and thesides of excavation shall be backfilled to the original surface with approvedmaterials in layers not exceeding 150mm in thickness, watered and wellconsolidated by means of rammers to at least 90% of the consolidation obtainableat optimum moisture content (Proctor density). Flooding with water for consolidationwill not be allowed. Areas inaccessible to mechanical equipment such as areasadjacent to walls and columns etc shall be tamped by hand rammer or by hand heldpower rammers to the required density. The backfill shall be uniform in characterand free from large lumps, stones, shingle or boulder not larger than 75mm. in anydirection, salt, and clods, organic or other foreign materials, which might rot. Thebackfilling in plinth and under floors shall be done in similar way in layers notexceeding 150mm thick and shall be well consolidated by means of mechanical orhand operated rammers as specified to achieve the required density.

FILLING IN PLINTH AND UNDER FLOORS:

After the available suitable excavated materials are exhausted as backfilling,the contractor shall notify the Engineer-in-charge of the fact and levels taken jointlywith Engineer-in-Charge. The earth, murram, sand, gravel etc. or such materialsuitable for filling proposed to be filled under floors and so mentioned in the item ofschedule of quantities shall then be brought to site from approved locations andsources.

Payment for filling and consolidation inside the trenches, sides of foundations,plinth etc., with selected materials brought by the contractor other than excavatedmaterial, shall be paid for separately as per the rates in schedule of quantities whichincludes cost of such materials/excavation , royalty ,its conveyance within the

specified lead, watering, consolidating, dressing etc., Actual quantity of consolidatedfilling shall be measured and paid in cubic meters up to two places of decimal.

a) Earth filling:The earth, soft murram etc., so brought shall be filled up in layers of 15cm

depth, each layer being well watered and consolidated by approved hand ormechanical tampers or other suitable means to achieve the required density.

b) Gravel or Sand Filling:Gravel if required under floors, shall be single washed gravel of approved

quality and of size varying from 12 mm to 20 mm it shall be uniformly blinded withapproved type of soil and/or sand to obtain full compaction. Gravel shall be filled in

specified thickness shall be well watered and rammed entirely to the satisfaction ofthe Engineer-in-Charge.

If sand is required to be filled under floors, it shall be clean, medium grainedand free from impurities. The filled in sand shall be kept flooded with water for 24hrs to ensure maximum consolidation. The contractor at his own cost shall do anytemporary work required to maintain sand under flooded condition. The surface shallthen be well dressed and got approved from Engineer-in-Charge before any other istaken over the fill.

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is separate stock piles is not possible and to prevent contamination of the stock pilesfrom the ground or rubbish or wind blown dust.

To get effective control on quality, materials which do not conform to I.S.specifications shall not be brought to site of work. Washing, grading, etc. ofaggregate shall be done away from the job site. Storage piles of aggregate shallhave good drainage, preclude inclusion of foreign matter, and preserve thegradation. Sufficient live storage shall be maintained to permit segregation ofsuccessive shipments, placement of concrete at required rate such procedure asinspection and testing.

f). SAND:

The sand to be used shall be obtained from a source approved by theEngineer-in-charge. Sand shall be natural sand, crushed gravel or crushed stone. Itshall be well graded, course in texture, clean gritty to the touch, hard, strong, durableand free from salt, mica, clay earth, coal, any animal vegetable and bituminousmatter, any soluble sulphate, gypsum and any other harmful material. Use of seasand is prohibited. Unless initially clean, all sand shall be thoroughly and carefullycleaned by screening and washing in fresh and clean water to remove all

objectionable foreign matter to meet the specifications and standards.

Sand/fine aggregate shall conform to the grading specified in fine aggregatesclass A in IS code No. 383 latest revision.

I.S. SieveDesignation

Percentage passing by weightNatural sand

10.00 mm 100

4.75 mm 90-100

2.36 mm 60-95

1.18 mm 30-70

600 Micron 15-34

300 Micron 5-20

150 Micron 0-10

g) COARSE AGGREGATE:

Coarse aggregate shall consist of hard, strong durable particles of crushedstone and shall be free from thin elongated soft pieces, vegetable matter or otherdeleterious matter. It shall have no adherent coating.

The aggregate shall be graded from fine to coarse in accordance with I.S.code which is reproduced below:

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GRADING

Percentage Passing For Graded Aggregate of Nominal Size byWeight

IS SieveDesignation

40 20 16 12.580 mm 100 - - -63mm - - - -40 mm 95 100 100 - -20 mm 30 70 95 100 100 100

16 mm - - 90 -100 -12.5 mm - - - 90 10010mm 10-35 25-55 30-70 40-854.75 mm 0 5 0 10 0 10 0 10

The testing and maximum size of aggregate shall be in accordance with theI.S. 383 or as specified under the Schedule of Quantities.

h) WATER:

The water quality shall conform the requirement of IS: 456:2000 and also

clean and free from deleterious matter, such as oils, acids, alkalis, sugar andvegetable matter. Every attempt shall be made to use water that is fit for drinkingand wherever possible water shall be used direct from the supply mains. Waterstored for construction shall be kept clean at all times, and adequate storage to lastfor 24 hours at least shall be arranged at site by the contractor. The PH value of thewater shall generally not less than 6.

i) ADMIXTURES:

Admixtures shall be used in concrete only with the approval of the Engineer.Admixtures shall be supplied by the contractor and also mixed in the concretewithout extra cost. The cost of admixture is included in the rate of contractor.

j) CLASSES OF CONCRETE:

Unless otherwise specifically stated as Ordinary Concrete, all concreteproposed under this specification shall be taken to mean Controlled concrete. Formix design, IS: 10262 shall be referred and also satisfies the requirement of IS:456:2000.

k) Controlled concreteControlled concrete means that the mix proportions are determined by

preliminary mix designs and laboratory tests. These shall be carried out at intervalsof change in source of aggregates, cement, water and also whenever the Engineerhas reasons to believe that there has been a change in thequality/properties/grading etc. of any of the constituents of concrete, which in hisopinion would impair its strength and/or durability. A prefix and two numbers shallidentify each class of concrete. Prefix M would denote Normal concrete). The twonumbers e.g. 30/20 would denote the crushing strength of concrete cubes(characteristic strength) at 28 days age in N/mm2and maximum size of coarseaggregate in mm respectively.

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The characteristic compressive strengths on 15 cm cubes at 28 days for allthe types of concrete as mentioned above shall be same as given in tables forrespective types of concrete.

l) Characteristic StrengthClass Characteristic Compressive

strength on 15 cm cubes at28 days in N/Sq. mm

Maximum aggregatesize in mm

N15/20 15 20N20/20 20 20

N25/20 25 20

N30/10 30 10N30/20 30 20

Note:Compressive strength tests with the approval of the Engineer shall be

conducted on 15 cm. diameter and 30cm high cylinders in accordance with IS: 516instead of on cubes. Where cylinder strength figures are adopted, the compressivestrength figures given in respective tables below for every grade of concrete shall

be modified according to the formula.

Minimum cylinder compressive = 0.8 times compressiveStrength required strength specified for 15 cm.

Cubes. The controlled concretedesignation shall be of the followingrequirements.

When requirement arises for other grades of concrete such as N32.5, N37.5,N42.5 etc. and varying maximum size of aggregate to 12.5 mm, the same shall beaccommodated with the approval of the Engineer.

Normal concrete shall have a net unit weight of not less than 2450 kilograms

per cubic meter.

m) MINIMUM CEMENT CONTENTSFor any particular mix, minimum cement content mix and water cement ratio

shall be selected so that strength, workability and durability requirements are met forspecified work. Reference shall be made to Table 5 and 6 of IS- 456: 2000 unlessspecified otherwise.

n) TRIAL CONCRETE MIXESThe proportions of cement, fine aggregate, coarse aggregate, additives and

water necessary to produce a concrete mix which will fulfill the requirements of thisspecification for each grade of concrete shall be determined on the basis of trialmixes conducted with the samples of the material as used in the work site inpresence of the Engineer in field laboratory by the Contractor.

o) MIX DESIGN OF CONCRETEThe Contractor shall carry out mix design of concrete for various grades such

as M 20, M 25, M30, M45 etc. using different sizes of aggregates as directed by theEngineer to produce concrete of the required strength, workability, durability andother properties. Concrete shall be proportioned to obtain workable mixes for thepurpose intended and to adequately meet the strength and finish requirements.

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Primary mix design shall be established through several trial studies by thecontractor well in advance so as to meet the time schedule of the work. During mixdesign/trial studies, contractor shall use the ingredients, which are qualified /approved for actual work at work site.

p) Proportioning for Maximum DensitySuitable proportions of sand and the several sizes of coarse aggregates for

each class of concrete shall be selected to give as nearly as practicable, themaximum density. This is to be determined by mathematical means, laboratorytests, field trials or other means. If necessary, the gradation of the aggregates shallbe corrected by changes in the aggregate plant and the processing methods so thatmaximum density and good workable concrete can be produced to comply with therequirements of the jobs.

q) Proportioning by W/C RatioOnce a mix, including its water cement (W/C) ratio has been determined and

specified after trial studies & approved by the Engineer, that W/C ratio shall bemaintained. The Contractor shall determine the water content of the aggregatefrequently as the work progresses and the amount of mixing water entering themixer shall be changed to compensate for the water content in aggregates so as to

maintain specified W/C maintained at all the time.

r) W/C Ratio ValuesThe actual W/C ratio to be adopted shall be determined in each instance by

the Contractor, so as to have workable mix without affecting the specified/requiredproperties of concrete in its fresh and hardened state. Permissible tolerance in w/cratio shall be maintained to + 0.02 of the specified value. In case of any change inany of the properties, mix design shall be redone and tested for its specifiedproperties.

s) Consistency and SlumpThe concrete shall have a consistency such that it will be workable in the

required position. It shall be of such consistency that when properly vibrated, willflow around reinforcing steel, and all embedded parts. The slump for concrete asdetermined by slump tests as per IS 1199 shall not exceed the maximum slumpsindicated below for each type of construction unless otherwise approved or directedby the Engineer. Whenever concrete is needed to be pumped, slump shall be variedwith the approval of the Engineer. In such events, contractor shall carry out freshtrial studies to establish the desired properties.Sl.No

Workability Slump in mm

Min. Max.Type of Construction

1 Self levelling 150 200Raft where reinforcement layoutis congested.

2 Low 25 75 Plain footings, caissons, sub-structurewalls etc.

3 Medium 50 100Reinforced beams, columns, walls,etc.

4 Medium 40 80Reinforced foundation, walland footings.

5 Low 25 75 Pavements, mass concrete

6 High 100 150Trench fill, In situ piling and Tremieconcrete

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The Contractor shall not place concrete having a slump outside the limitsspecified without the approval of the Engineer. The slump results shall not differ by+ 25mm or + 1/3 of the required value whichever is less.

Slump tests shall be conducted immediately in the first mix of every grade ofconcrete and necessary correction shall be made. In addition the same test shallbe carried out during the following circumstances:

(a) At least one test in each grade per shift.(b) At the time of casting the cubes for compressive strength.(c) At least one test for every 50 cu. m concrete or part thereof(d) Whenever the visual inspection demands(e) More frequently, if there is distinct change in job condition(f) If required by the engineer at least one test per air content test

t) Acceptance CriteriaAcceptance criteria shall be as per IS 456-2000.

u) Failure to meet Strength RequirementIn the event that concrete tested fails to meet the specification, the Engineer shallhave the right to insist on any one or all of the following and the contractor at his ownexpense shall carry out all such measures as directed by the Engineer.

1) Changes in the concrete mix proportions for all the balance work.

2) Core-cutting and testing of the concrete represented by the tests that failed asper IS: 456

3) Extended curing of the concrete represented by the specimen.4) Load tests on part of structures as per IS: 4565) Replacement of any such portions of the structure.6) Suitable NDT of such concrete which indicates a low strength.

If the result of the test(s) is not satisfactory, the Engineer shall instruct that the

part of the works concerned shall be dismantled or cut out and reconstructed tocomply with this specification, or that other measures shall be taken to make theworks secure at contractor's cost.

Concrete during transport and placement shall be ensured during rains also. Ifthere is any sign of washing of cement and sand, the concrete shall be entirelyremoved immediately.

The methods of delivering and handling the concrete shall be such as tofacilitate placing with minimum of re-handling and without damage to the structure orthe concrete.

v) CONCRETE QUALITY:In proportioning the concrete of various grades the quality of cement shall be

determined by weight. The quantities of fine and coarse aggregates will be either bybatched and mixed in approved weigh batching system or by equivalent volumebatching.

Where ordinary concrete with nominal mixes are specified batching ofmaterials may be done by volume. Due allowance is to be made for building of fineaggregate according to I.S. 456 latest edition. Ordinary Portland cement shall betaken to weigh 1442 kg. Per Cu.m.

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w) CUBE TEST:Samples of concrete shall be taken as often as considered necessary by the

Engineer and work tests carried out in accordance with the procedure laid down inI.S. code of practice (I.S. 516). Samples shall be taken from each 50 cu.m. ofconcrete made during the progress of the work, or when a days concrete work doesnot amount to 50 cu.m from each days pour. Six cubes 150 mm x 150 mm x 150mm shall be made tested after 7 days, and the remaining three after 28 days. 90percent of the test samples shall show strength higher than the prescribed strength.The average of the strength of the three specimens taken at a time may be assumedas the difference between the maximum and the minimum strengths of the threespecimens does not exceed 15 percent of the average strength of concrete with 7days age will not be less than 2/3rd of the concrete cubes shall be furnished by theDepartment. All the materials and labour for making necessary tests will be at thecost of the contractor. The results of the test conducted by the Department orarranged by the Department in any of the recognized laboratories shall be taken finaland binding on the contractor. In case the compressive strength obtained from thetest samples of concrete is less than the minimum specified strength the work isliable to be rejected.

The contractor shall submit his proposed design mixes for the approval of the

Engineer. Once approved he has to strictly adhere to the same. In case of changein the materials he will have to submit fresh design for the mixes for the approval ofthe Engineer. If in actual practice, the strengths obtained are less than the specifiedone the work will be rejected. If, however, the strengths are higher than the specifiedones due to excellent control or otherwise, the Contractor will have no claim for extrapayment.

y) MixersMixers may be stationary mixers of either the tilting or non-tilting type of

approved design.

z) Maintenance

The mixers shall be maintained in satisfactory operating condition, and mixerdrums shall be kept free of hardened concrete. Mixer blades shall be replaced whenworn down more than 10 percent of their depth. Should any mixer at any timeproduce unsatisfactory results, leak mortar or cause waste of materials, its use shallbe promptly discontinued until it is repaired.

Stationary Mixers

Mixers, which have a rated capacity not exceeding 200 litres of mixedconcrete, may be tilting type. Mixers, that have a rated capacity of 200 liters or moreof mixed concrete, shall be non-tilting types. Mixers shall not be charged in excess ofthe capacity recommended by the manufacturer. Mixers shall be capable of

combining the materials into a uniform mixture and of discharging this mixturewithout segregation. The mixers of mixing plant shall include a device for countingthe total number of batches of concrete mixed. The mixers shall be operated at thedrum speed designated by the manufacturer on the nameplates.

Mixing time

The mixing periods specified herein are to ensure proper quality control. Themixing time will be increased when such increase is necessary to secure therequired uniformity and consistency. Excessive over mixing requiring addition of

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water will not be permitted. Mixing time shall be in accordance with therecommendation of the batching plant manufacturer.

Provision of inspection

The complete plant assembly shall include provisions to facilitate theinspection of all operations at all times.

Maintenance of records

All records and charts of the batching and mixing operations shall beprepared as specified herein and promptly handed over to the Engineer.

Sampling facilities

Suitable facilities shall be provided for readily obtaining representativesamples of aggregate from each of the batchers, and suitable devices for obtainingrepresentative samples of concrete for slump tests, unit weight, air content anduniformity tests shall be made by the Engineer. All necessary platforms, tools andequipment for obtaining samples shall be furnished at the start of work.

Concrete specimen:

Concrete specimen shall be prepared from the mixes used in the work andtested to determine the adequacy and accuracy of control for the materials enteringinto the concrete mix. The Contractor shall perform preparation, storage and testingof the specimen in presence of the Engineer to his entire satisfaction.

TRANSPORT AND PLACING:No concreting work shall be started until the surface on which it is to be

deposited shall be checked and approved by the Engineer. Concrete shall betransported from the mixer to the place of final deposit as rapidly as practicable, andby methods, which will prevent segregation or loss of ingredients. Equipment forchuting, pumping and pneumatically conveying concrete shall be of such size anddesign as to ensure a practically continuous flow of concrete at the delivery andwithout any separation of the materials. The chute shall be of metal lined wood, withslope not less than 1 vertical to 3 horizontal and not more than 1 vertical to 2horizontal. The discharge end of the chute shall be provided with a baffle plate toprevent segregation.

Concrete shall be deposited as nearly as practicable in its final positionwithout segregation due to rehandling or flowing. The Concreting shall be on at sucha rate that the concrete is at all times plastic and flows slowly into the space betweenthe bars. No concrete that has partially hardened or been contaminated by foreign

materials shall be deposited on the work, nor shall retempered concrete be used.

Then concrete is once started, it shall be carried on as a continuous operationuntil the placing of the panel or section is completed.

The top surface shall generally be made level as far as practicable. Infoundation trenches or such other situation, it shall be carefully deposited and notthrown from a height. If transported to the work in barrows, the barrow may betipped from a height of not more than one metre above the bottom of the layer beingdeposited. If the height exceeds one metre the concrete must be tipped on to aninclined plane or spout. Water shall be removed from excavation before concrete is

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deposited. No flow of water shall be diverted through over freshly depositedconcrete. Dewatering shall be done till the concrete is sufficiently hardened. Therate for concrete shall include the cost of such dewatering operations.

Before fresh concrete is deposited upon or against concrete, which hasalready hardened, the surface of the hardened concrete shall be well roughened. Ifnecessary by chipping, and all laitance removed and the surface shall then be sweptclean with wire brushes, thoroughly wetted, covered with the thin layer of mortarcomposed of equal volumes of cement and sand. An excess of cement shall beprovided in the concrete in contact with the old work. The rate for concrete shall beinclusive of various surface preparations, as detailed above and no extra claim wouldbe admitted on this account. Concrete footings shall be placed upon undisturbedclean and hard surface of specified bearing capacity.

COMPACTION:

The concrete shall be fully compacted through out the full extent of the later.It shall be thoroughly worked against formwork and around any reinforcement andother embedded items without displacing them. Successive layers of the same liftshall be thoroughly worked together. Each layer shall be compacted by mechanicalinternal vibrating equipment supplemented by hand spading, rodding and tampingas directed. Vibrators shall in no case be used to transport, concrete inside forms.Use of form vibrators will not be permitted. Duration of vibration shall limited to timenecessary to produce satisfactory consolidation without causing objectionablesegregation. The vibrator shall not be inserted into lower coursed that have begun toset. Concrete shall be poured in lifts to avoid formation of voids around embeddeditems. The contractor shall' have at least 4 immersion type vibrators of varyingneedle sizes with frequencies not less than 7000 RPH for R.C.C. work. In addition toabove, sufficient numbers of petrol vibrators shall be kept available at site at alltimes in good condition.

Finishing of Concrete:

Slight honey comb and minor effects shall be patched after chisellingoutloose material with cement mortar of one part cement to two parts fine aggregateswith approval Engineer. The patches will be square/rectangular and will be properlyfinished to match. No separate rate will be of payable for carrying out any repair orfor finishing.

Grouting:

Grout for anchor bolts, sleeves and other items shall be composed of equalparts of sand and Portland cement, with sufficient water to produce requiredconsistency.

Curing and protection:

Curing of concrete shall start after 8 hours of placement and in hot weatherwithin four hours of placement. All cement concrete after laying, shall be coveredwith a layer of sacking, canvas, Hessian or similar absorbent material and kept forcontinuously not less than fortnight. In case of Portland Pozzolano cement, thecuring is required to be continued for 21 days from the date of concreting. For curingof concreting pavements, sidewalls, floors, flat roofs or other level surfaces theponding method curing is preferred. All water used both in the preparation and finalwetting is to be cleaned, free from sediment of any kind and generally fit for drinking.The work shall be protected from drying winds and direct sun rays.

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MEASUREMENT AND PAYMENT.

a) Actual volume of work shall be measured in Cu.munlessotherwise specifiedin the schedule of quantity. Deductions, pipes, ducts, etc., shall be made butno deductions shall be made for opening up to 0.1 Sq.m in area each (for theopening up to 0.1 Sq.m in area each, shuttering shall not be paid forseparately). No additions and deduction shall be made for embeddedfixtures.

b) Pre-cast concrete shall be measured the same way as specified aboveunless other wise stated. No separate payment shall be made for form work,shuttering, curing, handling, placing in position and jointing wherever requiredas per specification and schedule of quantity.

c) No deduction shall be made for volume occupied by reinforcement. Volumeoccupied by drainage water pipes, conduits, etc., not exceeding 100 Sq.cmeach in cross sectional area shall not be deducted.

d) Treatment of bearing with cement plaster shall not be measured.

e) Drip mould, grooves, chamfers shall not be measured.

f) Concrete perforated units shall be measured on gross area of units. Noseparate payments shall be made for fixtures.

g) Unless otherwise specified in the schedule of quantity nothing extra shall beadmissible for lying at an angle, any particular shape of the sectioncantilevered part or any projections or portions sunk.

h) Unless otherwise specified no separate payments shall be paid for placing atvarious lifts.

*****

STEEL REINFORCEMENT:

All reinforcement bars supplied by contractor shall be of grade Fe 415 TMTbars conform strictly to I.S. 432/1786 latest revision. Reinforcing rods shall befabricated to shapes and dimensions shown and shall be placed where indicated onthe drawings, or required to carryout intent of drawing and specifications. Beforebeing placed, reinforcement shall be thoroughly inspected and cleaned.Reinforcement shall not be bent or straightened in manner injuries to the material.Bars with kinks or bends not shown on drawings shall not be placed. Thereinforcement shall be cleaned of rust and scales at all stages of work without extracost to the Department. Reinforcement shall not be spliced at points of maximumstress. Laps for reinforcement shall 40 times the dia for column, beam, slab etc.

unless otherwise specified in the drawing. The intersections of 4 rods crossing eachother shall be bound with 16 SWG binding wire such that joints will not be displacedin the process of placing concrete.

The cost of steel used by the Contractor in the reinforcement of beam, slabsand columns etc. will be paid as per rate for reinforcement only up to the extentshown in the drawings. Any laps and hooks provided by the Contractor for his ownconvenience shall not be measured for payment. Splices in adjacent bars shall bestaggered. The reinforcing bars shall be placed as directed by the Engineer and shallbe kept rigidly in position while the concreting is being done. The correct clearancefrom the formwork, as indicated under Para 'Concrete cover over reinforcement'

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below shall be maintained by using either pre-cast blocks or metal chairs to beprovided by the Contractor without extra charge. The pre-cast blocks used forspacing will be properly cast and cured and will be of the same mix, as of theconcrete. Spacers and supporting chairs provided for correct positioning of variouslayers of reinforcement will be provided without any extra charge.

a) STORAGE:The reinforcement steel shall not be kept in direct contact with ground but

stacked on top of an arrangement of timber sleepers or the like. Reinforcement steel

shall be coated with cement wash before stacking to prevent scale and rust if it hasto be stored for longer time. Fabricated reinforcement shall be carefully stored toprevent damage, distortion, corrosion and deteriorations.

b) QUALITY:All steel shall be Grade Fe 415 as per 1786 quality unless specifically

permitted by the Engineer-in charge. No re-rolled material will be accepted. Thecontractor shall submit the manufacturers test certificate for steel of eachconsignment delivered at site. If demanded by the Engineer-in-charge the contractorshall submit the third party test certificate for each 50 MT. The department shallperform random tests on steel supplied by the contractor as per relevant IndianStandards. All costs incidental to such tests shall be at Contractors expense. Steelnot conforming to specifications shall be rejected. All reinforcement shall be clean,free from grease, oil, paint, dirt, loose mill, scale, loose rust, dust, bituminousmaterial or any other substances that will destroy or reduce the bond. All rods shallbe thoroughly cleaned before being fabricated. Pitted and defective rods shall not beused. All bars shall be rigidly held in position before concreting. No welding of rods toobtain continuity shall be allowed unless approved by the Engineer-in-charge. Ifwelding is approved, the work shall be carried as per I.S. 2751, according to bestmodern practices and as directed by the Engineer-in-charge. In all cases ofimportant connections, tests shall be made to prove that the joints are of the fullstrength of bars welded. Special specifications, as specified by the Engineer-in-charge shall be adhered to in the welding of cold worked reinforcing bars and bars

other than mild steel.

c) Splicing of Reinforcement Bars:

Lap splicingLapping of reinforcement bars shall be done at locations as shown in the drawings oras directed by the Engineer. However not more than 50% of the splices shall beprovided in one location. The lap length shall not be less than that specified in thedrawings. If not specified, the lap length shall be decided by the Engineer. Splices inadjacent bars shall be staggered and the locations of all splices, except thosespecified on the drawings shall be approved by the Engineer. The bars shall not belapped unless the length required exceeds the maximum available lengths of bars.

At such locations, whereby providing lap splice is giving rise to congestion ofreinforcement or wherever required as per Engineer, such splice shall be replacedwith welding/ mechanical splicing at the discretion of the Engineer.

d) BENDING:All bars shall be accurately bent according to the sizes and shapes shown on

the detailed working drawing bar bending schedules. They shall be bent gradually bymachine or other approved means. Reinforcing bars shall not be straightened andre-bent in a manner that will injure the materials. Bars containing cracks or splitsshall be rejected. They shall be bent cold, in all diameters. Bars incorrectly bent shall

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be used only of the means used for straightening and rebinding in the opinion of theEngineer-in-charge injures the material. No reinforcement bar shall be bent when inposition in the work without approval, whether or not it is partially embedded inhardened concrete. Bars having kinks or bends other than those required by designshall not be used.

e) BENDING AT CONSTRUCTION JOINTS:Where reinforcement bars are bent aside at construction joints and afterwards

bent back into their original position, care should be taken to ensure that at no timethe radius of the bend is less than 4 bar diameters for plain mild steel or 6 bardiameters for deformed bars. Care shall also be taken when bending back bars toensure that the concrete around the bar is not damaged.

f) FIXING/PLACING AND TOLERANCE ON PLACING:Reinforcement shall be accurately fixed by any approved means maintained

in the correct position as shown in the drawings by the use of blocks, spacers andchairs as per IS.2502 to prevent displacement during placing and compaction ofconcrete. Bars intended to be in contact at crossing point shall be securely boundtogether at all such points with number 16 gauge annealed soft iron wire. Thevertical distances required between successive layers of bars in beams or similar

members shall be maintained by the provision of mild steel spacer bars at suchintervals that the main bars do not perceptibly sag between adjacent spacer bars.

g) TOLERANCE ON PLACING OF REINFORCEMENT:Unless otherwise specified by the Engineer-in-charge reinforcement shall be

placed within the tolerances given in IS 456-2000

h) COVER TO REINFORCEMENT:

The cover shall be as specified in the drawings. Unless otherwise specified,the cover shall be given as per IS 456-2000.The minimum clear distance betweenreinforcing bars shall be in accordance with IS-456 or as shown in drawing.

i) INSPECTION:Erected and secured reinforcement shall be inspected and approved by

Engineer-in-charge prior to placement of concrete.

j) MODE OF MEASUREMENT FOR REINFORCEMENT FOR RCC WORKS:Reinforcement as detailed in schedule of quantities shall be measured for

payment linearly as per the cutting length nearest to a centimeter shown in barbending schedule submitted by the contractor and approved by the Engineer-in-charge and weight calculated based on the standard weights. The unit weight ofsteel shall be taken as given below.

No allowance shall be made/be measured in the weight for rolling margin.Only authorized laps shall be measured. As far as possible, laps in bars shall beavoided. Any laps and hooks provided by the contractor other than authorized as perapproved bar bending schedule will be considered to have been provided by thecontractor for his own convenience and shall not be measured for payment. Pins,chairs, spacers shall be provided by the contractor wherever required as per drawingand bar bending schedule and as directed by the Engineer-in-charge and shall bemeasured for payment. Fan hooks as required shall be provided by the contractorunder this item and shall be measured for payment.

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The rate shall be the cost of all materials and labour required for all above,operations including transport, wastage straightening, cutting, bending, binding andthe binding wire required, and the cost of the cover block.

a) Bar or any other type of reinforcement used for reinforced concrete shall bemeasured by weight in M.T.

b) Standard hooks, authorized chairs, cranks, bends authorized laps etc. shallbe measured.

c) Separate pieces between two or more layers of steel shall be measured.d) No separate payment shall be made for binding wires.e) No payment shall be made for the waste in cut pieces of bars etc.f) Fan hooks shall be measured as part of reinforcement.

g) The rate shall include for straightening the bars/coils and cleaning as perspecification. No separate payment shall be made for placing at various lifts.

The contractor shall record the date upon which each part of the work is concretedtogether with the date upon which the shuttering is removed. No shuttering orcentering shall be removed until an approved period has elapsed since the last dateon which the concrete was placed in the parts of the work, concerned.

Notwithstanding the approval of the Engineer any damage or other consequencearising there from shall be the contractor's entire responsibility.

*****FORM WORK:

The form work shall consist of shores, bracings, sides of beams and columns,bottom of slabs etc, including ties, anchors, hangers, inserts etc. complete whichshall be properly designed and planned for the work. The formwork shall be soerected and fixed that up and down vertical adjustment can be made smoothly.

The formwork shall be so constructed that it is rigid enough to remain freefrom any bulging, sagging or any movement during the placing of the Concrete andthat it can be subsequently removed without damaging concrete. The formwork shallbe sufficiently watertight to prevent loss of liquid from the concrete. All form worksshall be fixed to proper elevation. The contractor shall undertake no concreting workuntil the level, size, suitability etc, is approved by the Engineer. Unless otherwisespecified all forms in contact, with concrete should be steel forms of requiredthickness. Surface of forms in contact with concrete shall be properly planned. Allrubbish shall be removed from the interior of the forms and the 'surface of formworkto come in contact with concrete shall be cleaned and thoroughly treated with oil.The oil shall be applied before the reinforcement is placed, and care shall be takenso that no oil comes in contact with steel while it is being placed in position. The joints of forms shall be made watertight by plugging them with good clay jute or by

other approved means before applying oil. The forms shall be so fixed that only slightmarks are visible on the surface of the concrete after stripping the forms. Steel formsshall be with prior approval of the Engineer. Approved form emulsions shall be usedfor application to the form surfaces in such a way as to prevent discoloration of theoriginal cement colour. Steel formwork used shall be free from bulges, and shall beplane and unbent. Plates shall be closely and properly jointed. No plugs, bolts, tiesor any appliances whatsoever for supporting the shuttering shall be fixedpermanently in the structure not be placed temporarily in such a manner the damageto the structure would result from their removal at the time of striking the forms andsupports. Forms for beams should be laid with a camber of 1/480th of the Span.

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a) DESIGN OF FORM WORK:The design and engineering of formwork as well as its construction shall be

the responsibility of Contractor and as per IS 14687 - latest revision. If so instructed,the drawings and calculations for the design of the form work shall be submitted wellin advance to the Engineer-in-Charge for approval before proceeding with work, atno extra cost to the Department. Engineer-in-Charges approval shall not however,relieve Contractor of the full responsibility for the design and construction of theformwork. The design shall take into account all the loads vertical as well as lateralthat the forms will be carrying including live and vibration loadings. Steel props shallonly be used for scaffolding purposes.

b) TOLERANCE:Tolerance is a specified permissible variation from lines, grade or dimensions

given in drawings. No tolerances specified for horizontal or vertical building lines orfootings shall be constructed to permit encroachment beyond the legal boundaries.Unless otherwise specified the following tolerances will be permitted.

c) TOLERANCE FOR RC BUILDING:

(i) Variation from the plumb

a.

In the line and surfaces of columns, piers,

walls and in buttresses

5mm per 2.5mts, but not more

than 25mm

b.For exposed corner columns and otherconspicuous lines

b.1 In any bay or 5mts maximum (+/-) 5mmb.2 In 10mts ore more (+/-) 10mm(ii) Variation from the level or from the grades indicated on the drawings

a. In slab soffits, ceilings, beam soffits andin arises

a.1 In 2.50mts (+/-) 5mma.2 In any bay or 5mts maximum (+/-) 8mm

a.3 In 10mts or more (+/-) 15mm

b. For exposed lintels, sills, parapets,horizontal grooves and other conspicuouslines

b.1 In any bay or 5mts maximum (+/-) 5mmb.2 In 10mts ore more (+/-) 10mm

(iii) Variation from the level or from the grades indicated on the drawings

a.1 In any bay or 5mts maximum (+/-) 10mm

a.2 In 10mts or more (+/-) 20mm(iv) Variations in the sizes and locations of

sleeves, openings in walls and floors

except in the case of and for anchor bolts.

(+/-) 5mm

(v) Variations in cross-sectional dimension ofcolumns and beams in the thickness ofslabs and walls.

(+) 10mm/(-) 5mm

(vi) Footingsa. Variation in dimensions in plan (+) 50mm/(-) 5mm

b. Misplacement or eccentricity 2% of footing within the directionof misplacement but not morethan 50mm.

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c. Reduction in thickness (-)5% of specified thicknesssubject to maximum of 50mm

(vii) Variation in steps

a. In a flight of stairs

a.1 Riser (+/-) 3mma.2 Tread (+/-) 5mmb. Consecutive steps

b.1 Riser (+/-) 1.5mm

b.2 Tread (+/-) 3mmTolerances in other concrete structure

A All structurea.1 Variation of the constructed linear outline

from established position in plana.1.1 In 5mts (+/-) 10mm

a.1.2 In 10mts or more (+/-) 15mmb.1 Variation of dimension to individual structure features from established

positions in planb.1.1 In 20mts or more (+/-) 25mm

b.1.2 In buried constructions (+/-) 150mm

c.1 Variation form plumb from specified batteror from curved surfaces of all structures.

c.1.1 In 2.5mts (+/-) 10mm

c.1.2 In 5.0mts (+/-) 15mmc.1.3 In 10.0mts or more (+/-) 25mm

c.1.4 In buried constructions (+/-) Twice the above limits.d.1 Variation from level or grade

indicated on drawings in slabs, beams,soffits, horizontal grooves and visiblearises

d.1.1 In 2.5mts (+/-) 5mm

d.1.2 In 7.5mts or more (+/-) 10mmd.1.3 In buried constructions (+/-) Twice the above limits.

E Variation in cross-sectionaldimensions of columns, beams,buttresses, piers and similar members.

(+) 10mm/(-) 5mm

F Variation in the thickness of slabs, walls,arch sections and similar members.

(+) 10mm/(-) 5mm

Water Proof Plywood shall be used for exposed concrete surfaces; wherecalled for Sawn and wrought timber may be used for unexposed surfaces. Insidefaces of forms for concrete surfaces, which are to be rubbed finished, shall be

planed to remove irregularities or unevenness in the face. Formwork with lining willbe permitted.

All new and used from lumber shall be maintained in a good condition withrespect to shape, strength, rigidity, water tightness, smoothness and cleanliness ofsurfaces. Form lumber unsatisfactory in any respect shall not be used and if rejectedby Engineer-in-Charge shall be removed from the site. Shores supporting successivestories shall be placed directly over those below or be so designed and placed thatthe load will be transmitted directly to them. Trussed supports shall be provided forshores that cannot be secured on adequate foundation.

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Formwork during any stage of construction showing signs of distortion ordistorted to such a degree that the intended concrete work will not conform to theexact contours indicated on the drawings, shall be repositioned and strengthened.Poured concrete affected by the faulty formwork, shall be entirely removed and theformwork corrected prior to placing new concrete.

Excessive construction camber to compensate for shrinkage settlement etc.that may impair the structural strength or members will not be permitted.

Forms for substructure concrete may be omitted when, in the opinion ofEngineer-in-charge, the open excavation is firm enough to act as the form. Suchexcavations shall be slightly larger than required by the drawings to irregularities forirregularities in excavation and to ensure the design requirement.

B Footings for columns, piers, walls, buttresses and similarmembers:

A Variation in dimensions in plan (+) 50mm/(-) 10mm

bMisplacement or eccentricity 2% of footing within the direction

of misplacement but not morethan 50mm.

CReduction in thickness (-)5% of specified thickness

subject to maximum of 50mm

d) FORMWORK REQUIREMENTS:Forms shall conform to the shapes, lines, grades and dimensions including

camber of the concrete as called for in the drawings. Ample studs, washer braces,straps, shores etc. shall be used to hold the forms in proper position without anydistortion whatsoever until the concrete has set sufficiently to permit removal offorms. Forms shall be strong enough to permit the use of immersion vibrators inspecial cases; form vibrators may also be used. The shuttering shall be closeboarded. Timber shall be wall seasoned, free from sap, shakes, loose knots, wormholes, warps or other surface defects in contact with concrete. Faces coming in

contact with concrete shall be free from adhering grout, plaster, paint, projectingnails, splits or other defects. Joints shall be sufficiently tight to prevent loss of waterand fine material from concrete.

Forms shall be so designed and constructed that they can be stripped in theorder required and their removals do not damage the concrete. Face formwork shallprovide true vertical and horizontal joints, conforming to the architectural features ofthe structure as to location of joints and be as directed by Engineer-in-Charge.

Where exposed smooth or rubbed concrete finishes are required, the formsshall be constructed with special care so that the desired concrete surfaces could beobtained which require a minimum finish.

e) BRACINGS, STRUTS AND PROPS:Shuttering shall be braced, strutted, propped and so supported that it shall not

deform under weight and pressure of the concrete and also due to the movement ofmen and other materials. Bamboos shall not be used as props or cross bracings.

The shuttering for beams and slabs shall be so erected that the shuttering onthe sides of beams and under the soffits of slab can be removed without disturbingthe beam bottoms.

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Re-propping of beams shall not be done except when props have to bereinstated to take care of construction loads anticipated being in excess of thedesign load. Vertical props shall be supported on wedges or other measures shall betaken whereby the props can be gently lowered vertically while striking theshuttering.

If the shuttering for a column is erected for the full height of the column, oneside shall be left open and built upon sections as placing of concrete proceeds, orwindows may be left for pouring concrete from the sides to limit the drop of concrete

to 1mts or as directed by Engineer-in-Charge.

f) INSPECTION OF FORMWORK:Following points shall be borne in mind while checking during erection of

formwork and got approved by the Engineer-in-Charge before placing ofreinforcement bars:

a) Any member which is to remain in position' after the general dismantling isdone, should be clearly marked.

b) Material used should be checked to ensure that, wrong items Irejects are notused.

c) If there is any excavation nearby which may influence the safety of form works,corrective and strengthening action must be taken.

d) i). The bearing soil must be sound and well prepared and the sole platesshall bear well on the ground.

ii) Sole plates shall be properly seated on its bearing pads or Sleepers.

iii)The bearing plates of steel props shall not be distorted.

iv) The steel parts on the bearing members shall have adequate bearing areas.

e) Safety measures to prevent impact of traffic; scour due to water etc. should betaken. Adequate precautionary measures shall be taken to prevent accidentalimpacts etc.

f) Bracing, struts and ties shall be installed along with the progress of form Workto assure strength and stability of formwork at intermediate Stage. Steelsections (especially deep sections) shall be adequately retained against tilting,over turning and formwork should be restrained against horizontal loads. Allthe securing devices and bracing shall be tightened.

g) The stacked materials shall be placed as catered for, in the design.

h). When adjustable steel props are used, they should i). Be undamagedand not visibly bent. ii). Have the steel pins provided by themanufactures for use. iii). Be restrained laterally near each end. (iv).Have means for centralizing beams placed in the fork heads.

i). Screw adjustment of adjustable props shall not be over extended.

j). Double wedges shall be provided for adjustment of the form to the requiredposition wherever any settlement / elastic shortening of props occurs. Wedgesshould be used only at the bottom end of single prop. Wedges should not be

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too steep and one of the pair should be tightened / clamped down afteradjustment to prevent their shifting.

k). No member shall be eccentric upon vertical member.l). The number of nuts and bolts shall be adequate.m). All provisions of the design and / or drawings shall be complied with.n). Cantilever supports shall be adequate.

o). Props shall be directly under one another in multistage constructions as far aspossible.

p). Guy ropes or stays shall be tensioned properly.

q). There shall be adequate provision for the movement and operation of vibratorsand other construction plant and equipment.

r). Required camber shall be provided over long spans.

s). Supports shall be adequate, and plumb within the specified tolerances.

g) FORM OIL:

Use of form oil shall not be permitted on the surface, which required painting.If the contractor desire to use form oil on the inside of form work of the otherconcrete structures, a non staining mineral oil or their approved oil CEMOL-35 ofMs.Hindustan Petroleum Co. Ltd; may be used, provided it is applied before placingreinforcing steel and embedded parts. All excess oil on the form surfaces and any Oilon metal or other parts to be embedded in the concrete shall be carefully removed.Before treatment with oil, forms shall be thoroughly cleared of dried splatter ofconcrete from placement of previous lift.

h) Working platform

The Contractor shall provide safe working platform for workmen, when working

above ground level. Safe method of approach shall be provided to reach locationsabove ground level. Handrails shall be provided for all working platforms. Hangingplatforms shall have safety net provisions. All ladders shall have handrails and shallnot be kept vertical. All platforms, ladders handrails etc. shall be firmly secured toground or on supports. No loosely supported ladders or platforms shall be used inthe works. All ladders and platforms shall have a kick plate 150mm high either MS orwooden board for safety of personnel. Ladders and platforms shall be periodicallycleaned of loose debris etc.

i) CHAMFERS AND FILLERS:All corners and angles exposed in the finished structure shall be formed with

moulding to form chamfers or fillers on the finished concrete. The standard

dimensions of chamfers and fillets, unless otherwise specified, shall be 20 x20 mm.Care shall be exercised to ensure accurate moulding. The diagonal face of themoulding shall be planed or surfaced to the same texture as the forms to which it isattached.

j) VERTICAL CONSTRUCTION JOINT CHAMFERS:Vertical construction joints on faces which will be exposed at the completion

of the work shall be chamfered as above except where not permitted by Engineer-in-Charge for structural or hydraulic reasons.

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k) REUSE OF FORMS:Before reuse, all forms shall be thoroughly scraped, cleaned, nails removed;

holes that may leak suitably plugged and joints examined and when necessaryrepaired and the inside retreated to prevent adhesion, to the satisfaction of Engineer-in-charge. Wrapped lumber shall be resized. Contractor shall equip himself withenough shuttering to complete the job in the stipulated time.

l) STRIKING REMOVAL OF FORMS:

No forms shall be removed or staging struck until it is safe to do so andapproved by the Engineer. All vertical-centering members shall be sufficiently bracedwith stiff members. Bamboos shall not be used as bracing members.

No forms shall be removed or staging struck until it is safe to do so andapproved by the Engineer. All vertical-centering members shall be sufficiently bracedwith stiff members. Bamboos shall not be used as bracing members No forms shallbe removed or staging struck until it is safe to do so and approved by the Engineer.All vertical-centering members shall be sufficiently braced with stiff members.Bamboos shall not be used as bracing members. All formwork shall be removedwithout shock or vibration and without damaging the new concrete. The side formsshall be so fixed that while removing the supporting forms and posts are not

disturbing to any extent. In no circumstances should the supporting forms be struckuntil the' concrete reaches a strength of at-least twice the stress to which theconcrete may be subject at the time of striking. Under normal conditions the periodsshown below are the minimum which should be allowed between the placing of theconcrete and removal of the forms. In case of horizontal members it is desirable thatthe supports or props should be kept for sufficiently long period in order to presentsagging of the members.

EARLIEST CONCRETE AGE AT STRIPPINGNormal weather temp.

above 20oCSl.No.

Class of structuresOrdinary Portlandcement Portland Pozzolanacement

a.Walls, columns andvertical sides of beam

After 16 to 24 hours After 72hours

b. Slab props (left under) 3days

c.Beams soffits (propsleft under)

7days

d.Removal of props toslabs

d.1 Spanning up to 4.5mts 7days 14daysd.2 Spanning over 4.5mts 14days 21dayse. Removal of propos to

slabse.1 Spanning up to 6.0mts 14days 21dayse.2 Spanning over 6.0mts 21days 28daysF Cantilever construction Not until adequate strength is developed

m) MODE OF MEASUREMENT:In case the items of concreting are inclusive of cost of formwork, no separate

measurements shall be taken for formwork. However, if the form work is to be paidseparately and the item exists in the schedule of quantities for various types of formwork the net area of exposed surface of concrete members as shown in drawings

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coming in contact with form work shall be measured under item of formwork insquare meters.

All temporary formwork such as bulkheads, stop boards provided atconstruction joints, which are not shown in the drawings, shall not be measured.

No deductions shall be made for openings/obstructions up to an area of 0.1sqmt and nothing extra shall be paid for forming such openings.

The rate includes the cost of scaffolding, shuttering materials, erectioncharges, transport, de-shuttering and removal of materials from site and inclusive ofall labour and consumables required for all such operations.

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BRICK WORK

a) SCOPE OF THE WORK:The work covered under this specification pertains to procurement of best

quality locally available stock bricks and workmanship in buildings walls of variousthicknesses in strict compliance with the specifications and applicable drawings.

b) MATERIALS:Brick shall be best quality locally available stock bricks and samples shall be

got approved by the Engineer-in charge before incorporation in the work on largescale and maintain the same for the entire work.

The nominal size of bricks (F.P.S) shall be 23 cm x11.5 cmx7.5 cm (9"x4.5x2.75). Permissible tolerance on dimensions shall be +/-3 mm in length & +/- 1.5 mmin width/thickness.

i. If the plastering to be done is more than the specified thickness to bring theplaster surface to perfect line, level and plumb with adjoining columns, beams, walls

etc., the contractor shall be responsible to provide and fix chicken wire mesh toreceive more thickness of plaster at his own cost and nothing extra will be paid onthis account.

In case the size of bricks used in the work, found more than the permissible,the contractor shall chip out the exposed edges of bricks up to the required level ofwall to receive specified thickness of plaster.

Bricks shall generally conform to IS 1077-1992. In any case minimumcrushing strength shall not be less than 35 Kg/cm and water absorption shall not bemore than 15% by the weight. The Engineer-in-charge shall have the right to rejectthe bricks obtained from any field where the soils have an appreciable quantity of

sulphate and chlorides. The specification for cement, sand and water shall be sameas described herein before under cement concrete. Bricks shall be thoroughlysoaked in water before using till the bubbles cease to come up. No half or quarterbrick shall be used except as closer. The closers shall be cut to required size andused near the end of the walls. The walls shall be raised truly to plumb. The type ofbond to be adopted shall be English bond, but vertical joints shall be laid staggered.

c) WORKMANSHIP:Four courses of brickwork with four joints should not exceed by more than 40

mm. the same bricks piled one over the other without mortar.

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Brickwork shall not be raised more than 10 courses a day unless otherwise approvedby the Engineer-in-charge. The brickwork shall be kept wet for at least 10 days.Brickwork shall be uniformly raised around and no part shall be raised more than 1.0meter above another at any time.

All joints shall be thoroughly flushed with mortar of mix as specified in theschedule of quantities, at every course. Care shall be taken to see that the bricks arebedded effectively and all joints completely filled to full depth.

The joints of brickwork to be plastered shall be raked out to a depth not lessthan 10 mm, as the work proceeds. The surface of brickwork shall be cleaned downand watered properly before the mortar sets.

The adhesion between the brick masonry surface and the concrete surface ofcolumns, beams, chajjas, lintels etc. should be proper by ensuring that the concretesurface coming in contact with brick masonry is hacked/ chipped/ keyed, cleanedand cement slurry is applied so that proper bond is achieved between the twodissimilar materials. It is the responsibility of the contractors to ensure that there willnot be any cracks/ fissures anywhere in the brick masonry.

All the courses shall be laid truly horizontal and all vertical joints shall be truly

vertical. Specified mortar of good and approved quality shall be used. Lime shall notbe used where reinforcement is provided in brickwork. The mortar should completelycover the bed and sides of the bricks. Proper care should be taken to obtain uniformmortar joint throughout the construction, the walls should be raised uniformly inproper, approved bond .In construction of the wall, first of all two end corners arecarefully laid to line and level and then in between portion is built, with a cordstretching along the headers or stretchers held in position at the ends. This helps inkeeping the alignment or the courses and maintaining them in level. Similarly allother courses are built. Care shall be taken to keep the prepends properly alignedwithin following maximum permissible tolerances:

1. Deviation from vertical within a storey shall not exceed 6 mm per 3 m height.

2. Deviation in verticality in total height of any wall of building more than onestorey in height shall not exceed 12.5 mm.

3. Deviation from position shown on plan of any brickwork shall not exceed12.5mm.

4. Relative displacement between load-bearing walls in adjacent storeyintended to be vertical alignments shall not exceed 6 mm.

No brickwork shall be carried on during frosty weather except with the writtenpermission of the Engineer-in-charge that will give special directions as to themanner in which the work is to be performed. All brickwork laid during the day, shall,in seasons liable to frost, be properly covered up at night as directed by theengineer-in-charge. Should any brickwork be damaged by frost, the brickwork shallat the discretion of the Engineer-in-charge, be pulled down and made good at thecost of the contractor.

Concrete surfaces of columns, beams, lintels; chajjas etc. coming in contactwith masonry work shall be properly chipped, washed and given a thick coat ofcement slurry before start of work. The rate quoted shall include wire brushing andcleaning brickwork covered with fungus or deleterious materials. Brickwork shall bewell watered/cured throughout the day for least a week from the date of building andthe work shall be protected from sun and rain.Materials and workmanship for a half brick or brick on edge partition wall shall be asspecified above.

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d) The rates for brickwork shall include the cost of the following:

1. Providing and fixing necessary single or double scaffolding and removingthe same after the works are completed.

2. Watering, curing, and lifting of materials to any height.3. Raking out of joints to receive plaster.4. Forming slab sittings, cutting or leaving holes for lugs of windows, doors,

sills , switch boxes etc:,5. Making good all holes, chases etc., to any depth due to conduit pipes,

holdfasts, bolts, switch and plug boxes etc;6. Bedding and pointing pre-cast lintels, sills etc. in or on walls.

For the purpose of measurements, the thickness of one brick wall and overshall be taken in terms of multiples of half brick.

e) MODE OF MEASUREMENT:

(i) For brickwork measured in cubic meters:The contractor rate shall be for a unit of one cubic meter of brick masonry as

actually done 230 mm. thick (or as specified in schedule) brick walls shall be takenas one brick thick.

All openings in brickwork for doors, windows and ventilators shall be deductedto get the net quantity of actual brickwork done.

Openings or chases required for Public Health or electrical inserts less than0.1 sqmt and bearing of precast concrete members shall not be deducted. No extrapayment shall be made for any extra work involved in making the above openings orplacements.

(ii) For brickwork measured in square meter:

Half brick thick masonry walls shall be measured in sqmt. All openings in

brickwork for doors and windows and ventilators shall be deducted to get the netquantity of actual work done. Opening or chases required for Public Health orElectric inserts less than 0.1sqmt and bearing of pre cast concrete members shallnot be deducted. No extra payments shall be made for extra work involved in makingthe above openings or placements.

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CEMENT PLASTERING FOR WALLS AND CEILINGS

SCOPE OF WORK:The work covered under these specifications consists of supplying all

materials and rendering all types of plaster / pointing finishes strictly in accordance

with these specifications, applicable drawings etc.

GENERALCement sand and water required for the work shall conform to specifications

laid down herein before under section cement concrete (plain and reinforced), exceptthat sand for finishing coat shall be fine sand conforming to I.S. 1542 -1960. Theplastering works shall generally conform I.S. 1661 1978 (Pt. III) (Code of practicefor cement and cement lime plaster finish on walls and ceilings). All generalprecautions as specified in I.S. 1661 1987 (Pt. III) clause-8, shall be taken andpreparation of the back ground shall be done as laid down in I.S. 1661 clause 12 and

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I.S. 2402 1963 shall be generally followed for rough cast and sand faced plasterwork. The contractor at his own cost shall provide scaffolding required for facility ofworking. This may be double or single according to the requirement and shall beapproved by the Engineer in charge. Stage scaffolding shall be erected whenceiling plastering is done. The contractor shall be responsible for accidents, if any,take place. The contractor shall co-operate with the other agencies also. Wheneverelectrical contractor/agency has to fix up switch boxes in walls, necessary Thiyyas,tapanish or Dhadas shall be arranged to be given in advance of actual plasteringprocess at these locations so that the boxes are fixed properly in line with finishedplaster surface. All finishing in and around these boxes as also around the conduitboxes in ceiling shall be done by plastering contractor without any extra cost to theDepartment. The decision of the Engineer-in-charge in this regard shall be final andbinding on the contractor.

PREPARATION OF SURFACE:

The surface to be plastered shall first be thoroughly cleaned of all muck andcleaned down. All joints shall be raked out in case of brick work/stone masonry andclosely hacked in case of concrete as the work proceeds. The surface to be

plastered shall be well wetted for a minimum period of 6 hours before commencingthe work. The mortar for all plaster work shall be cement mortar of mix as specifiedin the schedule of quantities.

After erection of scaffolding and before commencement of plastering work,top most junctions/joints/sides with beam/ column shall be thoroughly packed withcement mortar to prevent cracks.

Before commencement of plastering operation the contractor shall ensure thatall the service pipes, electrical conduits, boxes, switch boxes etc. have been installedin position by other agencies and the plastering surface is duly approved by theEngineer-in-charge. In order to enable other service contractors to fix the electrical

conduits, conduit boxes, EDBs, pipes, outlets etc. in proper level and line withreference to the finished surface of the plaster. Thiyyas and Tapanis i.e. finishedplaster patches shall be given by the main civil contractor on walls, ceiling at regularintervals well in advance of his plaster work at no extra cost to the department. Theentire work of preparation of surface before plastering shall thus be co-ordinated bythe main civil contractor with all other agencies working at site.

Just before actual plastering work is taken up in hand all the ceiling and wallsetc, shall be marked with Tapanis or Thiyyas indicating the thickness of plasterrequired and which shall be in true line, level and plumb. The contractor shall getthese marks approved by the Engineer-in-Charge before starting the plastering work.The contractor shall also be responsible to render the final surface true to line, level

and plumb etc.

All building operations like construction of walls, concreting etc. shall havebeen completed before plastering is taken up. The plastering operation should betaken up only after the service pipes etc. that are to be embedded in the wall orceiling are completed and suitably protected against corrosion by other agencies andokayed by the Engineer-in-charge. Damage if caused to any of the existing fittings,fixtures including doors and windows etc. during the plastering operation shall bemade good by the contractor at his own cost.

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If the surface which is to be plastered either internally or externally is out ofplumb and not in line and level and if the plastering to be done is more than specifiedthickness to bring the plastered surface to perfect line and levels, in such specificcases. Chicken wire mesh is to be provided by the contractor at his own cost and theplaster should be done to required line and level with no extra cost whatsoever.

The finished plastered surfaces shall be free from cracks, fissures, crevices,hair cracks, and blistering, local swellings and flaking. The finished surface shall betrue to line, level, plumb & plain and durable. The adhesion of the mortar with thebackground surface is of prime importance as this affects durability of plasterpreparation of surface which has to take plastering is of great importance. Beforestarting the plastering work the surface should be got approved by the Engineer-in-Charge.

In order to avoid the formation of deep and side cracks and for dispersion ofcracks at the junctions between concrete surface and brick masonry work as alsobetween junction of windows/door frames and brick masonry works, cautionarymeasures such as fastening and lapping of chicken mesh over the junction areasshould be carried out over which the plastering work has to be taken up as requiredby the Engineer-in-charge.

GROOVES:The grooves shall be or required dimensions. The same shall be made to

turn wherever necessary. The finish, inside, shall be of the same finish as that of theplaster. The lines of the grooves shall be well defined and rounded. The groovesare to be provided in plastering in internal and external surfaces and shall be paidextra in the rates give in schedule of quantities.

MIX PROPORTIONS:The mortar for plastering shall be of proportion as specified in the item

schedule. The mixes specified in the schedule are volumetric.

MIXINGCement and fine aggregates shall be mixed dry in the required proportions to

obtain a uniform colour. Water shall then be added to get the required consistencyfor the plaster.

Mixing shall be done mechanically. However, manual mixing will be allowedonly in exceptional circumstances at the discretion of the Engineer-in-Charge.Manual mixing, where adopted, shall be carried out on a clean water tight platform.After water is added during mixing, the mix shall be held back and forth for 10 to 15minutes.

In machine mixing, the mixer shall run at least five minutes after placing all the

ingredients in the drum. Only so much quantity of mortar which can be used withinhalf an hour after the addition of water shall be prepared at a time. Any mortar forplaster which is set or partially set shall be rejected and shall be removed forthwithfrom the site.

12 MM PLASTER

The plaster shall be laid with somewhat more than 12 mm, thickness andpressed and levelled with wooden ruler to a finished thickness of 12 mm. Straightedges shall be freely used to ensure a perfectly even surface. All exposed angles

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and junctions of walls, doors, windows, beams, slabs etc. shall be carefully finishedso as to furnish a neat and even surface.

20 MM PLASTER

The proportions of sand and cement shall be as specified and shall cover allirregularities, undulations, depressions due to chasing etc.