PWD_Technical Specifications(Old Version)

8/9/2019 PWD_Technical Specifications(Old Version)

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Specifications for Civil Works by Public Work Department

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INDEX

Specification No. Name of Work Page

1. Clearing sites 1

2. Dismentling of Building and other Structures 2

3. Foundations 3

4. Well Foundations 4

5. Cement 5

6. Lime 6

7. Sand 7

8. Surkhi 8

9. Brick Ballast 9

10. Coarse Aggregate for concrete 10

11. Bricks 11

12. Lime Mortar 12

13. Lime Concrete 13

14. Composite or Lime Cement Mortar 14

15. Cement Mortar 14

16. Cement Concrete 14

17. Reinforced Concrete 19

18. Precast Concrete 31

19. Coursed Rubble Masonry 31

20. Dry Rubble Masonry or Dry Stone Walling 34

21. Dry Stone Pitching or Revetments or Embankments 35

22. Brick Work, First Class 36

23. Brick Work in Arches 38

24. Brick-Nogging 40

25. Reinforced Brick-work Walls 42

26. Reinforced Brick-work Lintels 44

27. Lime Plastering 44

28. Cement Plastering 46

29. Composite Plastering 46

30. Pointing 46


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31. Brick on Edge Flooring 47

32. Barquet (Wooden Block) Flooring 49

33. Tile Flooring 50

34. Concrete Floor with cement concrete Surface 51

35. Coloured Concrete Floor Finish 5336. Timber Flooring, Butt-Jointed 54

37. Timber Flooring, Tongued and Grooved 54

38. Carpentry and Joinery 55

39. Square and Round Posts and Timber Piles 57

40. Doors & Windows 60

41. Doors & Windows Frames 65

42. Glaziers Work 6643. Timber Walling, Butt-Jointed and Splined 67

44. Timber Walling, Tongued and Grooved 68

45. Weather Board Walling 69

46. Corrugated Iron Walling 69

47. Mat Walling 70

48. Mat Walling Mud Plastered 70

49. Trellis Work 71

50. Teak Shingle Roofing 71

51. Mangalore Tiled Roof 73

52. Corrugated Iron Roof 74

53. Corrugated Asbestoe-Cement Sheet Roofing 76

54. Thatch-Roofing 77

55. Wagat-Roofing 78

56. Valley Guttering 79

57. Lead and Zinc Flashing 79

58. Asbestos-Cement Sheet Ceiling 80

59. Tongued and Grooved Plunk Ceiling 80

60. Iron Work-General 81

61. Painting 84

62. Varnishing 89


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CONSTRUCTION CORPORATION

SPECIFICATION FOR GENERAL WORK

No.1 CLEARING SITES

1. Clearing Rubbish and Trees, - The site shall be cleared of all obstruction, loose stones and

materials, rubbish of all kinds, as well as weeds and brush-wood the roots being entirely grubbed up. No trees shall be cut down and removed without the permission of the Executive Engineer. But thosewhich are cut shall be grub bed up and the roots entirely removed.

2. Disposal of cleared materials. The products of the clearing shall be stacked in such place andmanner as may be directed by the Executive Engineer, and all these products shall be the property ofGovernment and shall be disposed of as the Executive Engineer may direct.

3. Filling Holes. - All holes or hollows, whether originally existing or produced by digging upthe roots shall be filled with earth and leveled off, or may be filled with the products of the clearingand covered with earth, if so directed.

4. White-ants. - In the case of buildings, in order to clear out white-ants, the whole area proposed th beoccupied by the building, together with an extra width of 10 feet all round shall be excavated to adepth of 6 inches and soaked with water.Spreading wet straw over the area brings the ants to the surface. If a white-ants nest exist on the site,its presence will be come evident in a few days, whereupon the nest should be completely dug out ,the queen and destroyed, and the nest flooded with boiling hot water containing a solution of arsenic.The area where from the top loose soil has been removed shall be refilled with earth from a sourceapproved by the Executive Engineer and properly levelled. It should be observed that no earth-fillingis to be done in cases where the holes dug to remove the white ants nest go below the bottom offoundation level. Concrete filling will in such cases be done under the orders of the ExecutiveEngineer and the contractor will be paid for the extra quantity of concrete, at his agreement rate forsame.

No,2. DISMANTLING OF BUILDING AND OTHER STRUCTURES

1. Extent of dismantling - The buildings or other structures defined in the schedule and handedover shall be dismantled down to ground level or to bottom of foundations, or the posts, ironworks, etc. which are specified shall, be dug up if below ground level all as may be specified inthe schedule item wording.

2. Avoiding accidents. - The method of dismantlement shall be in accordance with theExecutive Engineers written instructions regarding the precautions to be taken to avoid accidentsthe contractor being liable for all the consequences that may ensure through disregard of suchinstructions or other necessary precaution to ensure safety.

3. Damage to materials. - Special care shall be taken that the materials are damaged as little as possible in the process of dismantling. The value of materials broken or damaged throughcarelessness shall be recovered from the contractor.


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4. Disposal of serviceable materials. - All serviceable materials shall be removed and stackedor disposal of as may be directed by the terms of the contract or by the Executive Engineer.

5. Disposal of Rubbish. - All mere rubbish shall be collected in heaps for disposal as may be

directed by the Executive Engineer.

No,3 FOUNDATIONS

1. Excavation to be according to drawings. - The excavation of foundations shall be in strictaccordance with the drawings of the work with the exception of such deviations as the ExecutiveEngineer may direct, in writing. Any extra work caused by unauthorized excess excavation shall

be rectified as directed and executed free of cost by the contractor.

2. Sides of Excavation. - The sides of the excavation shall be vertical where the soil admits of it;

where the soil is likely to fall in, the sides should be shored up with timber or stopped of sloped back as the Executive Engineer directs.

3. Bottom of foundations. - Where practicable, foundation trenches shall be taken out levelthroughout, and where the ground necessities it, the trenches shall be stepped longitudinally, eachstep being horizontal. The contractor shall bring to notice all holes, soft places or other defects inthe foundation trench, which defects shall be made good by digging out and filling with concrete,or by such other method as may be directed by the Executive Engineer.

4. Finish. - The bottom of the foundation pits if in each shall be dressed level in all directions andon completion shall be slightly watered and well rammed. No earth filling will be allowed inleveling. If in rock, the rock shall be dressed as level as possible, inequalities being filled in withconcrete or other filling as may be directed.

5. Measurement. - The contractor, before commencing the concrete, shall be responsible that theearthwork in the foundation pits is measured and that the measurements are passed by competentauthority and that the necessary endorsement is made in the measurement book. Should he fail todo so, he shall be liable to be paid in accordance with the directions of the Executive Engineer orto have his work dismantled and re-done at his own expense.

6. Filling in trench. - As soon as a building is finished to plinth level, and for other works as may be directed by the Executive Engineer, the space between the masonry of brickwork and thesides of the foundation trenches shall be filled in with earth or other material as directed laid in 6inch courses well watered and rammed.

When the superstructure of a building is 2 feet above ground level, the plinth shall be filled inwith earth or other material as directed, well watered and rammed in 6 inch layers; care beingtaken that the surface of the material is sufficiently high so that no more filling is necessary at thetime of laying the floor concrete.


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7. Deposition of spoil. No material excavated from foundation trenches shall be placed within twofeet of the edges of excavation.

All spoil earth shall be dealt with as shown on the drawings or as directed by the terms ofthe contract or by the Executive Engineer in writing.

8. Unwatering. - Where water is met it shall be the duty of the contractor to obtain the orders of

the Executive Engineer or his representative before undertaking any unwatering.

9. Rate. - The contract rate for excavation of foundations will include all incidental chargessuch as shoring, sheeting, planking, strutting, pumping baling, etc., unless otherwise specified.Where there are to be any departures from this inclusive method of payment, the conditions will bedefined in the tender notice and arrangements sanctioned in writing by the Executive Engineer

before any charges apart from the unit rate for excavation are incurred.

10. Bad Ground. - When bad ground or unsuitable soil is met during excavation, the authorityaccording technical sanction should be intimated and its instruction a waited.

No,4 WELL FOUNDATIONS

1. Excavation. - Unless otherwise specified, open excavation shall be carried down to waterlevel, before the well curb is laid.]

2. Sinking in water. - Sinking in water consists of(a) Dry island method and(b) Specified method as directed by C.C. headquarters.

(a) Dry island method - An island of earth shall first be formed having a diameter of at least tenfeet more than the outside diameter of the well to be sunk. The earth forming this island must befree from all stones, brick or hard material which are liable to impede the sinking of the well.The island shall be brought up at least twelve inches above water level, before the well curb islaid.

(b) Specific method - The method specified by the C.C. Headquarters with necessarydrawings depending on the nature of site.

3. No blasting. - Whether the steining be sunk, or constructed in open excavation by baling asnecessary blasting must never be resorted to without obtaining prior permission of theExecutive Engineer. If unauthorized blasting results in creaking or damaging the steining orother structures the steining shall be completely removed and rebuilt at the contractorsexpense and all other damage caused shall be the contractors liability.

4. Well Curbs. - The well curb should be made in conformity with the sanctioned planstherefore and to the following specifications as regards construction and assembly.

5. Wood Curbs. - For wells of six-foot maximum inner dimension and under to be of twothicknesses of timber and for wells above that size, of three thicknesses or more unlessanother design is shown on the plans or ordered by the Executive Engineer.


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The timber shall satisfy specification No.38 as regards quality. It shall be shownaccurately to sizes and shapes shown on drawings and no patching shall be allowed. Whencurb rings cannot be made of one piece across the width of curb, the

concentric rings shall break joint; successive layers of the curb shall also break joint with therings above and below them. Segments of each ring shall be strongly dovetailed together andsuccessive rings held together with hard wood dowels and iron bolts as ordered by theExecutive Engineer. (Vide Sketch below)

6. Steel Curb. - Steel curbs shall be in a accordance with drawings supplied. Steining shall not

be commenced until the curb has been inspected and passed by the Engineer-in-charge.

7. Concrete Curb. - Concrete curbs shall be in accordance with drawings supplied and ingeneral accordance with specification No.1 for Reinforced Concrete.

8. Tie Rods. - Tie Rods shall be fixed in accordance with the drawings supplied.

9. Steining. - Steining shall be of first class brickwork in cement mortar or cut stonemasonary in cement mortar or cement concrete blocks as specified and must be executed to


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the relevant standard specification, for the masonry specified. If the well is circular themasonry cross joints should radiate truly to the centre of well.

No. 7 SAND1. Quality and source. The sand shall be hard, sharp and clean, gritty to the touch and free

from any admixture of clay, loam, salts, organic matter or other impurities. The source of

supply of the sand shall be subject to the approval of the Engineer-in-charge.2. Cleanness. - The sand shall be screened before use and if dirty when brought to site, it must be washed clean in water.

A useful test is to take a handful of sand and shake it in a glass of clear water. If afterstanding for one hour the precipitation of mud on the sand exceeds 5 per cent the sand should

be washed.

3. Sea sand not to be used. - Fine drift sand, sea sand, or sand containing saline impuritiesshall on no account be used except with the express approval of the Engineer-in-charge, whowill instruct the contractor regarding the treatments to be given to the sand before use.

4. Grading for mortar. - For brickwork or masonary mortar and ordinary plaster, sand shall begraded from 1/8 in, downwards so as to give a minimum of voids.

5. Grading for fine work. - Sand for final coats of plastering, pointing and for fine workshall pass through a sieve of 20 meshes to the linear inch.

6. Grading for concrete. - For concrete, the sand or fine aggregate shall pass through asieve having meshes 1/16 inches square, measured in the clear and be graded to give aminimum of voids.

7. Grading for Bituminous Concrete. - For bituminous concrete in road work the sand shall pass through a sieve of 1/10 inches square mesh and be wholly retained on a sieve of 200meshes to the lineal inch.

No. 8 SURKHI1. Source and Manufacture. - Surkhi shall be made by pounding or grinding fully burnt

bricks, bats, delone free from earth or other matter.

2. Fineness. - The material shall be pounded or ground fine enough to pass through a screenof 20x20 meshes to the square inch, but not to pass one of 50x50 meshes per square inch.

3. Storage. - After manufacture the surkhi shall be kept quite dry and free from dust, clayand other foreign matter.

4. The Bulking of the fine aggregate or sand. - (Extract from building Research Station Degest No.44 UNITED KINGDOM).


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When the quantities of materials to be used in a mix are specified by volume, thesequantities refer to the dry materials.

The volume occupied by given quantity of course aggregates is about the samewhether it is dry or wet, but fine aggregate or sand occupies a much larger volume when it isdamp than when it is dry. This increase in volume is called BULKING.

The degree of bulking can readily be determined on the site, a suitable method is as

follows:A paralled sided watertight container is partly fitted with the damp sand, leveled off but not pressed down, and its depth measured. Water is then added and the sand is wellstirred and then allowed to settle. The volume occupied by the sand after settling is roughlyequal to that occupied by the same weight of sand where dry. The new depth of sand ismeasured. The method may be illustrated as follows: -

Let D as shown in the figure below be the depth of the sand when damp and D1, the

depth after settling under water then the percentage bilking = x100 and this additional

percentage of sand should be added to the mix to give the required proportions.

No.9 BRICK BALLAST

1. Source and gauge. - Brick ballast or broken bricks for concrete, shall be from hard, well burnt or over burnt bricks. No under burnt bricks shall be used for breaking up into ballast. They

shall be broken to 1 inch gauge, so that all must pass through a 1 inch diameter ring and not

more than 20 per cent shall be more than 2 inches in greater length. Not more than 15 per cent

should pass through screen of x inch mesh.

2. Cleanness. - The ballast shall be free from dust, clay, loam, leaves and other foreign matterand shall, if no directed by Engineer-in-charge, be washed and screened L75BGI.

3. Brick ballast from buildings. - Brick ballast shall not be obtained from the debris of oldmasonry, unless with the approval of the Engineer-in-Charge. Any material containing old mortarwill be rejected.


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No. 10 COARSE AGGREGATE FOR CONCRETE1. Materials and Source. - The aggregate shall consist of good hard tough broken stone, gravel or

shingle of the gauge specified free from dirt, clay, leaves or any organic matter or any admixtureof soft or decayed stone.

If required by Engineer-in-charge a sample should be produced for approval before

commencement of supply.2. Cleanness. - If the aggregate is dirty it shall be well washed in clean water. When a handfulis shaken with clean water is in a glass and allowed to stand form an hour, the precipitate of mudover the stone shall not exceed 5 per cent. If more than this the aggregate must be washed.

3. Screen. - Screens used for grading the aggregate shall be provided by the contractor and shall be of the square mesh specified, screens shall be of about construction and shall not be madefrom expanded metal or rabbit netting, screens shall not be set at a slope steeper than 45 to thehorizontal.

4. Grading. - The following table shows how different sized aggregates are to be graded and thekinds of work on which each is normally used. Ballast of the gauge specified in Col. 1 shall be tothe specification given in col-2.

Gauge (1) Description (2) Used in (3)

1 To pass wholly through 1 x 1 mesh

and be all retained on x . To beuniformly graded in between so that notmore than 60% or less than 30% shall beretained on a square mesh screen.

(1)Ordinary lime concrete, masscement concrete, or(2) in reinforced work whereminimum dimension of the memberexceeds 22.

1 To pass wholly through 1x1 mesh and be all retained on x mesh. To beuniformly graded in between so that notmore than 60% or less than 30% shall beretained on a square mesh screen.

(i)Unreinforced cement concreteover 4minimum dimension and

(2) reinforced cement concrete workexceeding 10 but not exceeding22 in the minimum dimension.

To pass wholly through x mesh and

be all retained on x mesh. To beuniformly graded in between so that notmore than 60% and not less than 30%shall be retained on a square meshscreen.

(1)Unreinforced cement concrete between 2 and 4 minimumdimension,(2)Concrete floors,(3)reinforced cement concrete workexceeding 5 but not exceeding 10minimum dimension.

To pass wholly through x mesh and

all retained on x mesh. To beuniformly graded in between so that notmore than 60% and not less than 30% isretained on a screen of mesh x .

All reinforced cement concretework under 5 minimum dimension.


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No. 11 BRICKS

1. Type of Kilm and moulding. - Bricks shall be moulded and shall be burnt in a Bulls kilnunless otherwise specified by the terms of the contract.

2. Classification, shape, colour and ring. - Bricks shall be classified as follows:-First Class. - Bricks shall be table moulded with sand, thoroughly and equally burntthroughout without being vitrified, good substance and shape, square and true and generally of adeep red or colour, without flaws or cracks or other blemished and having a clear ring whenstruck.Second Class, - As for first class, but not so well or evenly burnt or of such a good shape.

3. Dimensions.- The dimensions of burnt bricks, unless otherwise specified, shall be 9 x 4-3/8 x 2-3/4 . The necessary allowance for shrinkage in drying and burning, which should generally bedetermined by experiment, being allowed for in the moulds.

4. Stacking. - Bricks shall be stacked in stacks of 1000, each stack being ten courses high and two bricks thick. A space of 2 feet clear shall be allowed round each stack to facilitate inspection.

5. Sorting. - In stacking, each class of brick shall be kept separate. There shall be a space of atleast 6 feet between stacks of different classes, which preferably should be stacked in different parts

of the brick-field.6. Salts in Bricks. - Bricks made from clay containing salt, saltpeter, or particles of limestone,

shall not be accepted.7. Absorption Test. - Bricks which absorb more water than one-fifth of their own weight when dry

shall be rejected.

No. 12 LIME MORTAR

1. Composition Test. - Unless otherwise specified the proportions of the ingredients of lime mortarshall be as follows:-

Lime Surkhi Sand

For Lime Concrete and Masonry 1 1 1

For Plastering and Pointing 2 1 3

In the case of kunkar lime the mortar shall consist of pure kunkar lime or a mixture ofkunkar lime and surkhi in the proportion of one part kunkar lime to one part of surkhi by bulk as theEngineer-in-charge may direct.

2. Mixing and Grinding. - Lime, sand and surkhi shall be mixed three times dry on an approved platform of wood or brick masonry, then thoroughly ground in a mortar-mill driven by bullocks or power, just sufficient water being added from a sprinkler to make a thick paste. If a suitable concretemixer is available it may be used for mixing the ingredients. Mortar for plastering shall be ground asecond time, after storing in a damp condition for an interval of two days in the case of kunkar limeand one week in the case of fat lime, so as to ensure thorough slaking. The mortar should then beused at once.

3. Hand Mixing. - For small unimportant works grinding of the mortar may be omitted if permitted by the Engineer-in-charge.


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4. Freshness Essential. - Mortar shall be kept wet till it is used and shall be used within 12 hours after being mixed.

Any mortar which has been allowed to become dry or which has been mixed for more than12 hours shall be rejected and removed from the site of works.

No. 13 LIME CONCRETE

1. Matrix. - The matrix shall be lime mortar prepared in accordance with specification No.12 forLime Mortar.

2. Aggregate. - The aggregate shall be stone or broken bricks as described in specification No.10 forCoarse Aggregate for Concrete or in Specification No.9 for Brick Ballast.

3. Soaking of Aggregate. - The aggregate shall be well soaked for at least two hours before mixingwith the lime mortar.

4. Proportion. - The proportion shall be three parts of aggregate to one part of lime mortar by measureor such other proportions as specified by the Executive Engineer Depending on the type and gradingof the aggregate available.

5. Measuring and mixing. - The aggregate shall be measured in the usual bottom less box on asmooth level watertight platform made of bricks or planks. The ingredients of the mortar shall besimilarly measured and then thoroughly mixed in the dry. They shall then be added to the aggregateand the whole turned over until a uniform mixture is obtained. Clean water should then be poured onfrom a sprinkler and the concrete mixer is available, it should be used for mixing the lime concrete.

No more concrete should be mixed than can be laid on the same day.6. Preparation of trenches. - Before laying the concrete, the trenches shall be properly wetted,

tamed and prepared.7. Removal of old concrete. - The concrete shall be laid as soon as possible after mixing. Any

concrete not laid and properly consolidated within 12 hours of mixing shall be rejected and removedfrom the site of works.

8. Laying and ramming. - The concrete shall be laid in layers not exceeding 6 inches in thickness,and shall not be thrown from a height exceeding 1 foot. It shall then be thoroughly consolidated bytamping or ramming before the next layer is laid. No water shall be added during ramming. Noramming shall be done after the concrete has begun to set . When owing to delays the surface of alayer has been left long enough for the mortar to set, this surface shall be roughened with a pick andthoroughly cleaned and watered before the next is laid. Each layer must cover the whole of thefoundation before the next layer is added. If any layer is to be left unfinished it must be rake back asspecified in unfinished brickwork.

9. Finish. - The concrete shall be finished off true and square in accordance with the drawings.10. Watering of Masonry. - The concrete shall be kept wet after each days work and when each

part of the concrete has been completed to its full height it shall be kept wet for 10 days or untilthoroughly set whichever period is the longer. The contractor shall not cease to wet the concreteunless he gets permission to do so from the Engineer-in-charge. No masonry shall be built uponconcrete sooner than a week or until permission has been given by the Engineer-in-charge.

No. 14 COMPOSITE OR LIME CEMENT MORTAR1. 1:1:6 Mortar. - The specification for composite mortar shall be as for lime mortar with the

addition of cement in proportions to be fixed by the Executive Engineer.2. Mortar to be used within 30 minutes. - All mortar to which water has been added shall be used

within 30 minutes of gauging. Any mortar not used within that period shall be discarded.


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No. 15 CEMENT MORTAR1. Dry ingredients and proportions. - Cement mortar shall consist of (1) Cement, which shall be

supplied by the Department unless otherwise permitted by the terms of the contract, and which shallcomply with the latest edition of British Standard Specification for normal setting Portland Cementand (2) sand which shall comply with Specification No.7 for sand. The cement and sand shall be

mixed in the proportion of one part cement to three parts of sand or as directed in writing by theExecutive Engineer.2. Storage of Cement. - Cement shall be stored in a building of weather tight construction, with a

sound dry floor of timber, concrete, brick or other suitable material raised at least a foot from theground to ensure that it is damp proof. It shall be used in the order in which consignments arereceived and not stored for an unduly long period.

3. Measurement of Cement. - Cement shall be measured by weight (taking 90lbs. Cement 1curft.)unless otherwise directed in writing by the Engineer-in-charge. If measurement by volume is, for anyreason, allowed, a box with clear inside dimensions of 12in x 12in x 14in loosely filled and leveledshall be regarded as containing 90 Lbs cement.

Note - So long as the trade supplies cement in bags weighing 94 lbs. groos, the contents of one such bag shall be considered to be 1 cu-ft of cement.

4. Measurement of sand and bulking of same. - If available dry sand should be used. If only wet sand isavailable, the volume which this sand would occupy, if dry, should be ascertained, as much as 30 percent of its volume then dry. If available a Rapid Sand Tester. Should be used to determine whatactual quantity of dry sand is contained in a given quantity of damp material.

Only sand which complies with Specification No. should be used.5. Mixing by hand. - If ingredients are to be mixed by hand, the mixing should be done on an

approved brick, plank, or other clean hard platform, The quantity of cement and sand to be mixed dryat one time should not be more than can be used up in an hour. They should be mixed together dry atleast three times over.

Water should be added in a fine spray to that quantity of the dry mix which can be usedup within ten minutes of final mixing. Hand mixing should be allowed only on unimportant works.

6. Machine mixing.- Except in the case of small and unimportant works a mixer should be used, ifavailable, for mixing the mortar. The ingredients should be filled into the mixer in the proportionsspecified and the time from the charging of all the dry materials into the mixing drum to thedischarging of all the dry materials into the mixing drum to the discharging of all the mixed concreteshould not be less than 10minutes. When the mixer is to be closed down for more than an hour thedrum should be cleaned of all adhering concrete before the latter hardens.

7. Mixing water. - The mixing water shall be fresh, clean and free from oil, acid, alkali, loamy,vegetable or organic matter or other deleterious substances in suspension or solution due to pollution

from industrial waste, farmyard or similar drainage.

Only sufficient water to make the mortar workable should be added to the dry mixture ofcement and sand.

8. To be used before initial set. - Any mortar which has taken its initial set before being used in thework shall be at once rejected and removed from site. Under no circumstances shall mortar whichhas been wet mixed for more than half an hour be used in the work.

9. Curing. Cement mortar should be kept damp for a period of at least 10days, from the time themixing water disappears and the mortar gets hard enough not to be marked. It should be kept coveredwith sand, earth, sacks or other approval covering, which should be kept well wet. Cement mortar


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The cone is placed, large and down, on a board and filled with concrete in 3-inches layerseach being punnd 15 times with a 5/8 inch diameter rod 2ft., long and bullet pointed at the lower end.When the mould is filled, any surplus concrete should be struck off level at the top with the rod. Themould should then be gently lifted vertically without tilting. When the cone is removed the concreteis left on the board and any decrease in height is the measure of the slump.

The following amounts of slump, using the standard test cone are allowed:-

Hand Compaction Mechanical Vibration

Concrete deposited under water to 1

Mass concrete, e.g., foundations & footings 1 to 2 1 to 1

Ordinary floor work and R.C foundations 2 to 3 1 to 3

Reinforced concrete in columns 3 to 4 1 to 3

Reinforced concrete in beams and girders 3 to 5 1 to 3

Reinforced concrete in wall panels and floorslabs

4 to 6 Depths upon conjectionof steel

12. Laying, Ramming and Laitance. - The concrete shall be laid immediately after mixing, are beingtaken to see that it is not tipped from a height greater than three feet. In mass work it shall be laid inlayers not exceeding 6 inches in thickness. After laying, the concrete shall be forth with rammed andthe ramming completed before it has taken its initial set. On no account shall the contractor attemptto smooth the top surface by trowelling. Any laitance appearing on the surface should be skiamed off

before the concrete hardness and should be removed in such a manner that the concrete is not robbed

of cement.13. Forms. - For laying in forms see specification for reinforced concrete, No.(17) and for layingfloors see the specification for concrete floor with cement concrete surface, No. (34).

14. Preparation for placing concrete. - For foundation work, the trench shall be cleared of all debrisand all water in the trench shall be removed by pumping or bailing out. Continuous pumping or,

bailing, if necessary shall be employed to keep the trench clear of water during concreting. No concreting shall be allowed unless the above conditions are fulfilled.

15. Avoid joints if possible.- Work shall be continuous wherever possible but when stoppages arenecessary the work shall not be stopped except in the following positions:-

Slabs and Beams.- At the centre of the span with a vertical plane at right angles to the direction ofthe main reinforcements. Inclined feather joints in slabs shall be prohibited except whereconcreting will be continued in a few minutes.Columns and Piers. - Two inches below the junction of the column with the beam or haunch andshall be perpendicular to the axis of the column.Walls. - Vertical joints in sections staggered 1 foot 6 inch over each other. Beforerecommencing work the surface shall be thoroughly swilled with water and coated with neat cementmortar. Joints of long standing shall be hacked to a clean surface, brushed with a wire brush, wellswilled and coated with neat cement mortar.

16. Location of Joints. - Construction and expansion joints shall be executed at the points shown in thedrawings or as directed in writing by the Executive Engineer.


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17. Curing. - The concrete shall be cured in the same manner as or cement concrete described in para.9 of specification No. 15

18. Finishes. -(i) Imperfection and excessive honey combing of the concrete shall be rectified by dismantlingthe portion affected. Slight honey combing and other imperfections not considered structurallyunsound shall be made good by patching up with (1:3) cement mortar.

(ii) The top faces of concrete not intended to be surfaced separately shall be leveled and floatedto a smooth finish to the levels or falls shown on the drawings.

(iii)The top face of concrete intended to be covered with screed or other surfacing shall be leftwith a rough surface, or as otherwise specified.

No. 17 REINFORCED CONCRETE

1. Specification for the concrete. - The specification for materials, grading, mixing and laying ofconcrete for R.C. concrete shall be as provided in specification No. (16) for cement concrete.

2. Proportions: - Unless where otherwise specified in the Bill of Quantities, the mix shall be 1:2:4 inthe ratio of one part cement: two parts sand: four parts coarse aggregate.

3. Mixing. - As per item (8) and (9) specification No. (16).4. Water-cement ratio : - Unless where specified to the contrary, the water-cement ratio for

reinforced concrete works shall normally be from 45 to 6 and consistent with workability to producethe desert concrete, the lower ratio to be used when mechanical vibration is employed.

5. Slump Test. - As per procedure for slump test specified in item (11) specification No. (16)6. Concrete Cube Test. - For all important reinforced concrete works, concrete tube tests shall

be performed regularly. For each day of concreting, six numbers 6 test cubes are to be taken, 3 for 7days strength, and three for 28 days strength.

(a) Sampling of fresh concrete to prepare cube tests.The sample shall be truly representative of the batch and shall not be less than 1 cu-ft. in volume; the

sample shall than be taken while a batch of concrete is being placed in position. The sample shall becollected from not less than five wells distributed position, avoiding the edge of the mass wheresegregation may have occured.

(b) The moulds for the cube tests shall be 6x6x6 steel moulds with machined internal faces, and shall be in two halves bolted together. The base is a separate metal plate fastened to the mould by springsor screws and also perfectly smooth. Tolerance shall be 6 0.01 inch between opposite faces, 90 0.5 for all adjacent faces.

(c) Mould oil shall be applied thinly to all internal faces and to the joints to prevent sticking of the castspecimen.

(d) Tamping Bar

Shall be a steel bar weighting 4 lbs, 15 in. long and shall have a ramming face 1 inch square.

Note: - The tamping bar used for slump test is entirely different and shall not be used for the cubetest.

(e) Compaction : -

(i) Compacting by Hand


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The concrete shall be filled in the mould in approximately 2 inches layers and each layer shall bevibrated by mean of any electric or phaumatic hammer, or by means of a vibrating table, or by means of asuitable vibrating table.

(f) Curing of Cube specimens.

The cube shall be kept in the moulds for 24 hours after casting, in a place free from vibration, under

damp matting sacks or similar materials. After the end of the initial 24 hours, the specimens shall beremaned gently from the moulds, and shall be stored in clean water under shade until they are transportedto the testing laboratory.

7. Preparation for placing concrete.As per specification item (14) specification No. (16) for cement concrete.

8. Laying and Consolidation. The concrete shall be transported from the mixer to the point of depositin suitable containers and shall not be thrown from a height exceeding 3 feet to prevent segregationof the aggregates.

The time between completion of mixing and placing in position of the concrete shall beas short as possible and shall not in any case exceed 30 minutes, unless specially approved retardingagents are employed, in which case the time duration shall be as specified by the manufacturers.

All important or major reinforced concrete works should be consolidated by suitablemechanical vibrators.

(a) Hand Compaction: - The sides of column boxes and beam shuttering and bottom shuttering of slabsshall be knocked with wooden mallets in conjunction with the hand rodding or tamping to minimizehoney combing.

For reinforced concrete slabs, heavy timber baulks may be employed. (e.g., a 4x4member, at least 6 0 long with cross piece handles on either side and employed by two workers

tamping the concrete simultaneously until water rises to the surface.)For reinforced concrete beams, columns, walls etc., iron rods of sufficient weight and

length to give the required compaction shall be employed. Bamboo and timber rods shall not be used.Rodding shall be continuous while concrete is being deposited to obtain the maximum compaction.Roddy the tamping must be done throughout the entire surface of the member.

(b) Mechanical Compaction. - Suitable mechanical vibrators of approved make and manufacture andgiving a minimum 3600 vibrations per minute shall be employed for mechanical compaction ofreinforced concrete members.

(i) For reinforced foundation blocks and massive R.C. works, mass concrete vibrators not exceeding4 in diameter shall be used.

(ii) For reinforced concrete beams, columns, walls etc., needlie vibrators not exceeding 1 1/2diameter shall be used.

(iii ) For reinforced concrete slans: - suitable slab vibrator shall be used.

(iv) External or formwork vibrators: - shall be employed when immersion vibrators cannot beinserted.


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9. Mode of Vibration. The vibrator shall be inserted vertically and shall be with drawn in such amanner to close up the hole made by it in the concrete. Only specially trained operators shall beallowed to work the vibrator.

The vibrator shall be used in such a manner as to give the required compaction over theentire area.

On no account is the concrete to be over vibrated, only sufficient vibration to allow fullconsolidation shall be used. Vibration shall be stopped when air bubbles and water rises to thesurface.

The sides for column boxes and beam shuttering and bottom shuttering of slabs shall beknocked with wooden mallets in conjunction with the mechanical vibration.

Formworks and reinforcement shall not be vibrated when immersion vibrators are used.To ensure this the vibrator would be kept about 3 inches away from forms.

Any water accumulating on the surface of newly placed concrete shall be removed byapproved means, and no further concrete shall be placed there on until such water be removed.

10. Shuttering and formwork.(a) Shuttering for foundations and other reinforced concrete works

The Shuttering may be of sound jungle wood. Side shuttering shall be employed for all the abovemembers.(b) Shuttering for all superstructure reinforced concrete works.

The whole of the formwork is to be constructed with approved materials in an approved solid,substantial and rigid manner, all properly braced and strutted to prevent bulging and sagging duringconstruction, and shall be fabricated to facilitate easy removal and ruse. The inner surface of all formsshall be washed and all dirt, shavings and saw dust etc. removed and the whole thoroughly wetted

immediately prior to concreting.When exposed face of concrete are required to be fair without plaster, the forms are to be prepared

or lined with approved material. The concrete to be thoroughly tamped to ensure a smooth and evenfinish. All roughness, fins and board-makings etc., to be removed.

The shuttering shall be designed so that the soffits of slabs and the sides of beams, columns andwall s may be removed first, leaving the shuttering to the soffits of beams and their supports in

position. Wedges or other suitable means shall be provided to allow accurate adjustment of theshuttering and to allow it to be removed gradually without jarring the concrete.(c) General for all shuttering .- Shuttering for concrete shall be rigidly constructed or approved

material and shall be true to shape and dimensions as per drawings. Faces in contact with concrete

shall be free from adhering grout, nails , splits or other defects. Joints shall be sufficientlywatertight to prevent the leakage of cement grout and to avoid forming fins or other blemishes,and shall be caulked where necessary.

Unless described on the drawings or elsewhere to the contrary , 1x1 chamfers shall beformed on the external corners of all concrete members.

Openings for the inspection of the inside shutterings and for the escape of water used forwashing out shall be formed so that they can be conveniently closed before placing the concrete.

Connections shall be constructed to permit easy removal of the shuttering and shall be eithernailed, screwed or otherwise secured strongly to retain the correct shape during concreting . Wire


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ties passing through concrete shall not be allowed . Shuttering shall be provided for the top facesof sloping work and anchored to prevent floatation, where the slope exceeds 1 in 2 .

Shuttering shall be true to line and braced and strutted to prevent deformation under theweight and pressure of the wet concrete constructional loads, wind and other forces.

The deflection shall not exceed 1/8inch. Bottom of Beam boxes shall erected with an upwardcamber of f1 inch for each 10 feet of span.

Repropping of beams shall not be done except with the approval of the Engineer-in-charge.Vertical props shall be supported on wedges . Props for an upper storey shall be placed directlyover those in the storey immediately below, and the lowest prop shall bear upon work sufficientlystrong to carry the load.

The three sides of column boxes shall go up to the soft of the ceiling beams and the fourthside shall be built up in sections not exceeding 3ft. in height as the concreting proceeds.

An approved moulds oil or other material shall be applied to fcaces of shuttering in contactwith wet concrete to pre vent adherence of the concrete. Such material shall not dis colour theconcrete and shall not be injurious to concrete or reinforcement and shall be kept from contactwith the reinforcement.

Removal of Formwork. - Formwork shall be removed by gradual easing without jarring. Beforeand immediately after the removal of the shuttering the concrete shall be examined for defects.Minimum time for removal of Formwork. - (Normal weather and working conditions.)For beam sides, walls and columns(Unloaded) Minimum 3 daysFor slabs Minimum 14 daysFor soffits of beams Minimum 28 days

The formwork shall not be removed earlier than the periods specified above.Engineer-in-charge to be Responsible

The assessment of the period elapsing between placing the concrete and removing the

formwork, shall be the Engineer-in-Charges responsibility.11. Reinforcement

(i) General. - The reinforcement shall comprise mild steel rods or special steel fabric, asdirected in the contract and will be supplied by the Department unless other wise permitted by theterms of the contract.

Reinforcement shall be free from pitting, loose rust mill, scale , paint , oil, grease, adheringearth, or any material that may impair the bond between the concrete and the reinforcement or thatmay cause corrosion of the reinforcement or disintegration of the concrete.(ii) Preparation and placing of reinforcement.- All reinforcement shall be cleaned of

scale and loose rust with a wire brush. It shall also be free from oil or dirt and shall be

carefully placed in position as shown on the detail drawings and secured againstdisplacement by tying with tying wire between No.14 and 18 gauge and shall be supportedin position clear of the forms by small concrete blocks metal chains or spacers or by metalhangers.

(iii) Cover to main reinforcement (Minimum).Unless otherwise specified the amount of Cover measured from the outer surface of

the steel must be as follow:-For footing and ground tie 2 or diameter of bars beams (in contact with earth) which ever is greaterFor Columns


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(Unless otherwise mentioned) 11/2 - do For Beams do- 1 - do For Slabs do- 1/2 - do For main stair do- 1/4 - do For R.C works in contact with earth clear

Cover to main reinforcement do- 2 do-

End Cover to hooks do- 2 or 2d, whichever is greater.(iv) End cover to main reinforcement. - All main bars shall have a minimum end coverof 2 or twice the diameter of the bar, whichever is greater, from the outside of concrete tothe hooked ends.

(v) Spacer Rods.- 1 diameter spacer rods shall be put between every tow lagers of mainreinforcement in beams at 5ft maximum centres.

(vi) Cover Blocks. - (1:2) cement sand blocks shall be used as cover blocks for obtainingthe required bottom and side covers to main steel. These blocks are to be carefully madeand cured under water for at least 7 days before use.Sufficient number of them shall be used to support the main reinforcement adequately.

(vii) Welding of Reinforcement.- No Welding of reinforcement shall be allowed.(viii) Bends and Hooks.

The reinforcement shall be bent by a bar bending machine or other approved means producing a gradual and even motion.

Bar up to 1 inches shall be bent cold.For bars exceeding 1 inches diameter bending hot and dull red heat may be

permitted, but shall be allowed to cool down naturally without quenching. Heating ofspecial reinforcement which depends on their strength being hard drawn or cold twistedshall not be allowed since the strength will be reduced.

Bars in correctly bent shall be used only if the means used for straightening andrebending be such as shall not injure the material. No, reinforcement shall be bent when in

position 9in the works without the approval of the Engineer-in-charge, whether or not it is partially embedded in gardened concrete.

Bends shall comply strictly with the detail drawing. All bar shall be terminated by astandard hook unless where indicated to the contrary.

The internal diameter of bends shall be not less than four diameters of the bar unlessdescribed to the contrary. The internal radia of bends at corners of binders and stirrupsshall be shall the diameter of the bar embraced by the binders.

Standard U Hook Standard L bend


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H= Hook allowance = 9d (min) B = Bend allowance = 5d (min)

Taken to the nearest 1/2 Taken to nearest over

Over or not less than 5 in. Or not less than 3 in. to be added to

To be added to dimensional 1 Dimension 1

Hook Length (min) = M + 2d. Bend length (min) = B + 3d.

Size of Bar(in inches) D 3/8 5/8 3/4 7/8 1 1 1 1 1

Hook allowance(min) (in inches) H 3 3 4 6 7 8 9 10

11 12 13

Bend allowance(min) (in inches) B 3 3 3 3 4 4 5 6 6 7 7

(ix)

Splice in bars.Splice in bars shall be avoided wherever possible, but where unavoidable the overlap shall be as follow.

SPECIAL NOTE A FOR STRAIGHT SPLICE!1. Straight splice shall be used only in exceptional Circumstances were standard U Hooked splice or

bend splice L are physically impossible to be used.


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2. Number of splices in each layer of 3 or more rods shall not exceed of the rods in each layer. Fortoo rods in each layer only one rod at one layer shall be spliced, subject to a maximum of not morethan 40% of the total number of bars in any one section.

3. Since the strength of the splice depends entirely on bond every effort shall be made to ensure thatconcrete is fully compacted around the splices and no honey combing occurs.

(X) Angle of Bent-up bars.- Unless indicated to the contrary all oranking of mainreinforcement in

beams and slabs shall be 45 degrees.

(XI) Mild steel chairs. - Mild steel charis of approved shape and size shall be provided at such

intervals to support the top reinforcement in the correct position without sagging under workingconditions.(XII) M.S. Wall ties for panel walls in R.C. framed structures.

3/8 M.S. Rods 15 long shall be embedded 6 into the R.C. columns and under side ofR.C . beams and projecting out 9 at the time of casting of concrete, at no more than 4-0 centres toact as well ties for the panel brick walls. The location of such wall ties shall be so adjusted tocoincide as nearly as possible with the brick bonding.(XIII) Spacing of reinforcement. The minimum clear distance between paralled bars shall be 1 times diameter of round bars one inchnor less than 1 1/2 times maximum size of the coarse aggregatewhichever is greater.


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Maximum spacing of main reinforcement shall not in general exceed twice the effective depth but infloor or bridge slabs shall not be more than 8 inches in the clear and transverse reinforcement notmore than 12 inch. Apart.(XIV) Position and spacing of stirrups. Stirrups shall have their anchorage ends hooked and theyshall envelop to tensile reinforcement and be securely fastened there to. They should be spaced and

placed in positions exactly as shown in the drawings supplied.

12. Laying of Concrete. - The time between completion of mixing and placing in position of theconcrete should be as short as possible and should not in any case be more than 20 minutes.

Carriage from mixing place.- During carriage from place of mixing to the forms, separationor loss of the concrete should be avoided. Also during laying, dropping of the concrete from morethan a height of three feet should be avoided for the same reason. The concrete should be placed asnearly as possible in its final position, so as to avoid rehandling and in such a way surfaceapproximately horizontal.

Compacting of concrete. - During and within ten minutes after placing, the concrete should beworked under and round the reinforcement and into the corners of the forms by means of light ironor wooden rods and by tapping the outside of the forms with a hammer. This will make the concretefree from voids, air bubbles and honey combing. Smoothing off the top by trowelling should beavoided.

Concrete not to be disturbed while setting. After 30 minutes from the time of adding water to thedry mix in question, concrete to which has been placed should not be disturbed or the work shaken or

jarred until after six hours from completion of laying and compacting.13. Curing. The work shall be kept wet for a fortnight after laying, preferably by means of a

covering of wet gunny bags as prescribed in the specification for cement concrete No.16. Constant

attention shall be paid to keeping the covering material always wet from the time concreting has beencompleted.

14. Location of construction and expansion joints. All construction joints for Beams, Slabs andstairs generally shall be made near mid-span for R.C. Columns, construction joints shall be located3 below soffits of intersecting Beams, Joints details are as shown in the sketches. All joints to bemade with vertical stop boards slotted to take main bars and with a keyed fillet to obtain a rebated

joint. Stop board must be in position before concreting starts. Before placing new concrete againstconcrete that has hardened, the face of the old concrete shall be cleaned and roughened, and looseaggregate removed there from, and immediately before placing new concrete, the face shall bethoroughly wetted and a coating of cement mortar (1:2) applied there to . All Beam ribs shall be

cast monolithically with also and on no account shall it be cast separately.Expansion joints shall be excuted at the points shown in the drawing or as directed in writing

by the executive Engineer.15. Protection from external loading. No structure should be subject to external loading until twenty-

one days after the removal of the centering.16. Lean concrete Blinding Layer. For reinforced concrete foundation, unless where otherwise

specified, 3 thick lean concrete blinding layer 1:3:6 with brick aggregate, should be provided.


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No. 18 PRECAST CONCRETE1. Material. The mix for precast-concrete shall be the same used in Reinforced-concrete work in

the Concretor but with course aggregate grading from 3/16 to 3/8 only.M.S. reinforcing rods as shown in drawings shall be bent with precision and tied with soft

annealed wire in correct position.Forms and Patterns works shall be of approved material with true surfaces and shapes. All

formworks shall be subject to the approval of the Engineer-in-Charge before they are made use of .2. Processing. All formworks and fabrication of M.S. reinforcement shall be inspected, beforecasting is commenced; constant tapping of formworks and ramming is essential to obtain maximumand uniform compaction, and avoiding honey-combing and cured for at least 7days, before it isremoved from the forms and inspected. Minor defects shall be rectified and surfaces renderedsmooth with 1:3 cement mortar. Works with major defects shall be rejected and destroyed at once.Completed precast works shall be stored in damp atmosphere until use.

The method of handling precast units shall be such as to reduce handling stressed to aminimum. The methods proposed for castling, lifting and handling must be submitted to the Engineerfor approval before concreting is commenced.

No. 19 COURSED RUBBLE MASONRY1. Specification for stone and laying. The stone shall be according to sample deposited with and

approved of by the Executive Engineer and shall be free from all cracks, flames and imperfections. Itshall be laid if mortar as specified by the terms of the contract or as directed by the Engineer-in-charge.

2. Size of face stones. No face stone shall be breadth than its height, nor shall tail into the work to alength less than its height and at least 1/3 rd of the stones shall tail into the work at least twice theirheight or, in walls thicker than 2 feet three times their height.

3. Dressing of face stones. Face stones shall be squared by chisel on all joints, beds and faces. The beds to be hammered and rough dressed true and square, for at least three inches from the face and

the joints for at least 1 . The face of the stones shall be dressed so that projections or hollows donot exceed half an inch.

4. Bedding of stone. All stones shall be dressed by chisel roughly level so as to rest evenly on themortar without any pronounced hollows or projections and shall be laid to a firm bearing without theuse of chips, pinners or levellers.

5. Thickness of courses. The stones shall be laid in horizontal courses, which may vary in thicknessfrom 6 in to 10 in. All stones in each course shall be of equal height and all courses of the sameheight, unless otherwise specified, in which case no course shall be thicker than any course beneathit. All stones shall be set in full mortar in all bed and vertical joints.

6. Thickness of joints. All side joints shall be vertical and bed horizontal. The joints shall not be less

than nor more than in thickness.7. Headers and through bond stones. - At least one fourth of the stones in each course shall be

headers, evenly distributed along each course, and no header shall be less than one and a half feet inlength. In work not more than two feet wide through stones shall go through to the back of the wallat 5 ft to 6 ft apart in each course. In work more than two feet thick, when the header in the face donot go through the wall, there shall be as many headers of the same size in the back as in the face ofwall, so arranged that a header in the back comes between two headers in the face . If bond stones ofsufficient length are not available, precast (1:2:4) cement concrete blocks may be used in lieu.

8. Breaking of joints. Stones shall break joint by at least half the height of the course.


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9. Corners and angles. All corners and angles shall be laid with neatly hammer dressed selected stonelaid alternate along each face.

10. Stepping of masonry and bonding at junction. Wherever practicable the masonry in a structuremust be carried up at a uniform level throughout. Where breaks are unavoidable the joints shall bemade gradual steps. Cross walls must be carefully bonded into the main walls and all junctions are to

be formed at each alternate course into each of the respective walls so as to unite the work

thoroughly.11. Interior face. - In the case of buildings the work on the interior face shall be the same as inthe exterior face unless the work is to be plastered in which case the side joints need not be vertical.

12. Interior of wall or backing. The portion of the wall between the back and front facing stones shallconsist of flat bedded stones carefully laid on their proper beds and solidly bedded in mortar, chipsand spalls of stones being wedged in wherever necessary so as to avoid thick beds or joints ofmortar, care being taken that no dry work or hollow spaces shall be left any where in the masonry.The face work and backing shall be brought up evenly, but the backing should not be leveled up ateach course by the use of chips.

13. Underwater masonry. - In bridges and other work where the lower part of the masonry will beunder water, the courses from the top of foundation concrete up to 1 foot above low water levelshould be laid with specially selected large flat stones not less than 4 thick in cement mortar 1:2.The cement mortar should be as specified in specification No. (15) for Cement Mortar.

14. Stone to be clean and soaked. - All stones, chips, spalls, etc., shall be washed clean before use.The contractor shall provide a soak pit and the stones for each course shall be sorted and kept in this

pit for at least tow hours before being used.15. Protection and curing of Masonry. - Masonry shall be protected during construction from the effects

of sun, rain and frost, by suitable covering if necessary and shall be kept moist for a period of 3weeks after being laid or such other length of time as is specified by the Engineering-in-charge. If thecontractor fails to do this to the satisfaction of the Engineer-in-charge departmental labour shall beemployed at once at the contractors expense.

16. Masonry to be kept wet. - At the close of the days work or for other periods s or cessation ofwork, the top of all unfinished masonry id to be kept flooded with one inch of water care being takennot to disturb or wash out the mortar.

17. Masonry not to be disturbed after setting. Care should be taken not to disturb any of the masonryalready completed. If any stone is moved after being set and the joints the stone shall be removed,and the mortar thoroughly cleansed from the bed and sides of adjacent stones. The stone which has

been removed shall then be reset tin fresh mortar.\18. Plastering and painting. - If plastering or pointing is to be done, the mortar joints shall be raked

out at the close of the days work, while the mortar is still green and kept moist.If no plastering or pointing is to be done, the mortar joints at the surface shall be rubbed

smooth with a pointing tool. The mortar should be restricted to the width of the joint and finishedflush with the face of the wall.

19. Scaffolding.- Proper scaffolding having two sets of vertical supports shall be provided by thecontractor, who is responsible to see that this is sufficiently strong to carry the workmen andmaterials.

20. Completion. - All masonry shall be washed down on completion and all stains lime or otherwiseremoved from the face.


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No. 20 DRY RUBBLE MASONRY OR DRY STONE WALLING

1. General. Dry rubble masonry, commonly called dry stone walling shall be used in construction breast and retaining walls . The larges t stones available shall be used in such construction, the largerstones being used in the lower courses.

2. Batter. Unless otherwise specified, dry stone walling shall be built with a face batter of 1 in 4

and vertical back. The base as well as the courses must run at right angles to the face.3. Beds. The stones will be roughly dressed to secure the maximum bedding surface without un dulyreducing the size of the stone. Each course shall be built through the entire thickness of the wall.

4. Bond Stones. Bond stones shall be provided in each course intervals of 5 feet. Bond stones will bethe full height of the course in which they are used at least as broad, and of the greatest length

procurable. No bond stone shall be less than 2 feet in length. When the length is less than thethickness of with wall, two or more shall be used overlapping by at least 6 inches, to provide through

bond from front to back. If bond stone of sufficient length are not available, precast (1:2:4) cementconcrete blocks may be used in lieu.

All bond stones shall be separately stacked before use, and marked so that they can beidentified after having been built into the wall.

5. High walls. Dry stone walls exceeding 20 feet in height must be strengthened every ten feet by building three consecutive courses in coursed rubble masonry in lime or cement mortar.

6. Weep holes. Weep holes shall be left in dry stone walling when built against a hill side wheresprings are encountered.

7. Filling. Filling immediately behind dry stone walls must wherever possible, be done withstone refuse or chips. Earth is not to be used whe4ere stone refuse is available.

No. 21 DRY STONE PITCHING FOR REVENTMENTS OR EMBANKMENTS

1. Description. Dry stone pitching shall consist of a layer of one heavy stone of specified size, laid onal layer of backing 6 in to 1 ft thick and composed of gravel, stone sprawls, broken stone or broken

bricks as may be specified.2. Earth bed under stone pitching. The bed or slope on which the backing is to be laid should be

dressed to the correct level and grade as shown on the drawings and free from all roots andvegetation. If the bed is of made up earth, it should, if circumstances permit, be allowed to settle

before pitching laid.3. Size and quality of stone. The stones shall be perfectly sound ands as regular in shape as

possible, with their lengths equal to the thickness of the required apron on revetment and each stoneshall not be less than cubic foot in size unless otherwise specified by the Engineer-in chargehaving regard to the nature of the stone available. All large projections shall be removed by hammerdressing so that joints between stones may be as small as possible.

4. Laying of backing. Wooden pegs shall be drawn into the earth slope, at right angles and the lengthof ped projecting shall be the same as thickness of backing specified. Starting from the bottom of theslope, backing shall be laid to the tops of the pegs. The laying shall , be done in strips of a few feet inwidth. When each strip is completed, pitching stone shall be laid on it and when this strip of pitchingis completed, the laying of the backing shall be completed for another few feet in width before anymore pitching stone sis laid.

Strings should be stretched between tops of pegs as a guide in laying the backing.

5. Laying of pitching. Starting form the bottom of a slope the pitching stone shall be laid closely in position on the backing, care being taken that the specified thickness of the latter is maintained and


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that none is displaced. The broad ends of the stones shall be downwards, or against the backing sothat they may meet all around their bases, and the tops shall be as nearly as possible in the same

plane as shown on the drawings . The stones shall be malleted so securely against each other and onto their beds that no stone can be dislodged. Stones shall be laid perpendicular to the finished surfaceand so that they break joint as far as possible in the direction of the flow of water. String profilesshould be sent up to ensure that the finished surface is as per plan.

6.

Packing between pitching stones. Simultaneously with the placing in position of the pitchingstones, suitable wedge shaped chips shall be driven into the interstices with hammer to ensure tight packing of the stones. The final wedging shall be done only after obtaining the orders of heEngineer-in-charge. The largest sized chips practicable shall be used for this and they shall be drivenhome so that they cannot be removed by hand.

No. 22 BRICKWORK, FIRST CLASS.1. Specification for Bricks The bricks shall be first class according to specification No. (1) for

bricks.2. Soaking of Bricks. The bricks shall be thoroughly wet when laid, and to ensure this, shall be

soaked in water until all bubbling ceases, and in no case shall the immersion in water be less thentwo hours.

3. Mortar. The mortar shall be prepared is specified in Specifications No. (12) for lime mortar No. (15) for cement mortar o0r as directed by terms of the contract.

4. Thickness of Joints. The joints in the brick work shall not exceed three-eight of an inch inthickness.

5. Bond Unless otherwise specified English Bond shall be used with the frogs of the bricks upwards,and shall be carried throughout the wall. No bats shall be used except as closers or where necessaryto complete the bond.

6. Color. For all face work, bricks shall be selected for uniformity of colour, and no colouring shall bedone to the face work without the express permission of the Executive Engineer in writing.

7. Mortar-Joints. Each brick shall be laid in full mortar-joint and shall be worked and rubbedinto position . All vertical joints shall be filled solid with mortar.

8. Courses to be level. The starting course shall be truly level, and all courses shall be laid with a limeto ensure their being level.

9. Watering of brickwork. All brickwork shall be kept damp till the mortar has set, and in no casefor less than ten days.

10. Raking out of joints. If the face of the work is not to be plastered every joint should be neatly struckat the close of eh days work and before the mortar has set.

If the face of the work is to be plastered the joints should be well raked out while the mortaris still fresh and kept moist.

11. Raking back of unfinished work. All walls, including returns, buttresses, centre pillars, etc.,shall be carried up as level as possible along their entire length. Where the work cannot be carried uplevel,, it shall be raked back in regular steps to one course each, and where work ion the lower part isrecommended the portion raked back must be well wetted for at least four hours before the junctionis made.

12. Fixing of Iron Work. All iron work, holdfasts, etc. shall be built in as the work proceeds and thecontractor shall give every assistance and facilities for fixing, if being fixed by a different agency.


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13. Thickness to be measured by bricks. The thickness of brickwork shall be measured by bricks and not by actual measurement. Thus a brick wall be taken as 4 , a one-brick wall as 9 inches, a 1 1/2 brick wall as 13 , a two-brick wall as 18 inches, and so on.

14. Faces of brickwork. All faces of brickwork shall be turned with a straight edge and plum bob.15. Scaffolding. During construction the staging shall have a double row of uprights. Care shall be

taken when leaving out a brick for the horizontal scaffolding pole, that such brick is always a header,

and that it is properly replaced in sufficient mortar after thee removal of tee pole.16. Brick on edge coping. etc. Unless otherwise specified the top course of all parapets, plinths, steps, etc., shall be built in brick on edge with extra fine joints not exceeding 18 in thickness. Care shall

be taken that he bricks forming the corners of all such courses are properly radiated and keyed into position as shown in sketch.

17. Brick Piers. All brick piers shall be constructed from selected bricks and laid in 1:3 cement mortarunless otherwise specified, to the best possible workmanship.

18. Cut and Pin-ends, etc., Cut and pin or butt in ends of all sills, lintels, timber, steel angles andthe like into brickwork .Carry out all rough and fair cutting required. From holes , mortices ,openings etc. fro fittings , pipes etc. in the brick work which shall be made good in cement and sand(1:3) mortar. Bed all plates, lintels, templates, beam pads etc. in 1:3 cement mortar.

19. Damp-proof course. Damp-proof course shall be laid over all brick walls at the plinth level unlesswhere otherwise shown in the drawings, consisting of 1 thick 1:2:4 cement concrete with stoneaggregate to 3/16 graded as specified in Concretor ,mixed with 5% Pudlo or 2%Impermo by weight of cement, unless where otherwise specified.

The damp-proof course shall have laid continuously and no construction joints will be permitted. The concrete floor slab should connect as far as possible with the D.P.C. to form acontinuous protective course against rising dampness.

SKETCH FOR CUTTING CORNERS OF BRICK ON EDGE COURSES IN PLINTHS ANDSTEPS!

No. 23 BRICK WORK IN ARCHES

1. Execution. The work shall be executed generally in accordance with specification No.(22) forfirst Class Brick Work.

2. Bond Unless otherwise directed by the terms of the contract or shown in the drawings, all archeshaving a radius of curvature, greater than 2-6 shall be constructed in English Bond, the arch rings

being bonded together. In smaller arches the work may be executed in concentric half brick rings, butheader bricks to bond the rings together shall be inserted where directed by the Executive Engineeror his representative.


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Gauged arches or arches laid in header and stretcher bond shall be used of face workwhich is to be pointed and or all flat arches and where so indicated in the drawings.

3. Shaping of bricks and specials. All bricks for arch work shall be regularly and carefully shaped by cutting and grinding. When practicable, special bricks shall be moulded and burnt for arches, andthis shall be done where so directed by the terms of the contract.

4. Skewbacks. Before the building of an arch is started, the abutments and skewbacks shall be

completed up to the same level and the mortar in the brickwork must be fully set. Skewbacks shall beformed of specially moulded or cut bricks correctly shaped to radiate truly from the centre ofcurvature and shall on no account be packed up with mortar or chips to effect this.

5. Arch work to be carried up evenly. The work shall be carried up evenly from both abutments and,as soon as the arch is completed, the adjacent masonry shall be carried up to the height of the crownin order to load the haunches.

6. Voussoir joints.- All voussoir shall be truly radial. The bricks shall be laid in full beds of mortarand well rubbed and pressed into their beds so as to squeeze out surplus mortar and leave the jointsas thin as possible. No joint in arch work shall exceed in thickness at any point, provided thatradial joints in gauged arches (English bond) shall not exceed 1/8 in thickness.

7. Centering. Centering shall be strong enough to bear the weight of the without deflection and shall be subject to the approval of the Engineer-in Charge. In all centre the upper bearing surface shallrest on double wedges in order that it can be eased (lowered) gently.

Centering for spands of 20 feet and over. Arches over 20 feet span shall only be erected oncentering resting on special sand boxes or on jacks.

8. Easing and striking of centering. When using lime mortar, centre will ordinarily be slackenedwithin 24 hours after completion of the arch, while the mortar is still moist, so as to allow the arch tocompress itself and bring all the joints to fair bearing , but not so soon that the mortar in the lastfinished joints is still so soft that it will be squeezed out. The centres shall be struck on the next day.For arch work in cement mortar, the centering shall be eased off immediately after the arch is

finished and shall be strick the next day. In all centers, the arrangements shall be such that theslackening can be effected without any vibration being transmitted to the arch and in the case of aseries of arches, that the centres can be slackened simultaneously.

9. Flat and reveling arches. Flat arches shall be used for pointed face work requiring a horizontalsoffit and shall be built the same as gauged arches but with all voussior joints covering on the apexof an equilateral triangle described on the soffit of the arch and the cross joints and extradoshorizontal. The arch must be built with a member of one-eight of an inch per foot of span.

Reliving arches shall be built over flat arches and at such other places as shown in thedrawings. Unless otherwise ordered by the Exceptive Engineer the space between a relieving archand a flat arch or lintel must not be filled up until the wall has been completed, when it must be filled

with brickwork or concrete leaving no hollows of any sort.

No. 24 BRICKNOGGING1. Posts The timber for the main posts and frames shall be as specified in the contract. The size of the

timbers shall be as shown in the drawings, generally 6 x 6 for the main posts and 6 in x 3 in for theframes. Diagonal frames shall not be used unless specially directed. Where other consideration

justified., 6x2 frames may be used in lien for brick noggin with both sides plastered and 5 x 2frame may be used for brick noggin with one side pointed and one side plastered. Where frames actas door and window frames, the thickness shall be 3 inches. Where the frame bridges across an


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thickness of brick on edge. The brickwork shall be reinforced every fourth course or as otherwisespecified with Ex-met B.R.C fabric, hoop iron or round steel rods laid in ce4ment mortar. All othercourses being in lime mortar.

2. Bricks. Bricks shall be in accordance with specification No.(11) Brick.3. Lime Mortar. Mortar shall consist of equal parts by measurement of lime, sand and surkhi and shall

comply with Specification No.(12) Lime Mortar

4.

Cement Mortar. Cement mortar shall consist of one part of cement to two or three parts of sandas directed and shall comply with specification No.(15) Cement Mortar . The cement and sandshall comply with their respective specifications.

5. Width of Reinforcement. For a 4 1/2 wall, the reinforcement if Ex met, hoop iron or B.R.C.fabric should not be more than 3 inches wide and if steel rods the outer edges of he rods should not

be more than 3 wide and if steel rods the outer edges of the rods should not be more than 3 apart.For 3 walls the reinforcement should not exceed 1 in width.

6. Joints in reinforcement to be avoided as much as possible and brick nogging walls.Joints in reinforcement should be avoided as much as possible. In brick nogging walls, the

reinforcement should be continuous form joint of the brickwork as far as the available length ofreinforcement will permit, and the vertical length between the joints should be firmly nailed up alongthe side of the timber upright which abuts against the end of the brickwork panel.

7. Ordinary brick walls and overlap in reinforcement. In reinforced brick walls without timber framesthe reinforcement should run from end to end of the wall without any joint, if the available lengths ofthe reinforcement permit of this. When joints in reinforcement are unavoidable the lap should not beless than three inches.

8. Joints containing reinforcement. Joints containing reinforcement should be thick and should be well filled with cement mortar so that the reinforcement gets good cover.

9. Jointing R.B partition to ordinary brick walls. Two slots at least 4 deep should be cut in thewalls between which the partition has to be built and the partition shall be built into these slots, theslots being flushed full joint with 1:3 cement mortar as the work proceeds.

10. Partition walls carried upon a floor with no foundation wall, beam or other additional support beneath them should have the bottom course reinforced and be built in cement mortar to act as areinforced brick beam to carry the partition.

11. At junctions of ordinary brick walls and 4 reinforced brick walls cross bonding shall be done asfar as practicable.

When the main wall has to be built first due to unavoidable reasons footing shall be left everyother course and the brick reinforcement shall be embedded on the walls every fourth course and the

brick reinforcement shall be embedded on the walls every fourth course starting from the bottommost course and projecting at least 9 to which the main reinforcement shall be fully lapped.

12. For connection of R.B walls to R.C . Columns and R.C. Walls.One diameter M.S. Rod shall be left embedded at least 4 with a hook inside the cast

concrete and projecting out at least 12 and shall be tied securely to the brick reinforcement everyfourth course, lapping at least 9.

No.26 REINFORCED BRICKWORK LINTEL1. Execution: The brickwork shall be according to the specification for First Class

Brickwork in Cement Mortar. Bond requirements may only be relaxed in the bottom course where itis necessary to have a continuous joint to contain the reinforcement. The brick shall be speciallyselected for well burnt and soundness. Cement mortar shall be 1:3.


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2. Centering: Centering shall be strong enough to bear the weight of the finished lintel as well asextra load which may be composed by materials or workmen. It shall not be removed earlier than 10days after completion on the lintel. Care must be taken not to jar the work when removing centering.

3. Reinforcement: Reinforcing bars as shown in the drawings shall be laid in the centre of jointsand so supported as to remain in position with the bottom of the bars ., above the centering. As faras possible, joints in reinforcing bars should be avoided, but if unavoidable a lap of 40 diameters

should be given with standard hooks. The ends of bars at the supports of the lintel must also beterminated with a standard hook.4. Joints for Reinforcement. Joints in which reinforcement is to be laid shall be of a thickness equal

to the =diameter of the reinforcing bar plus on e inch, the joints swell filled with cement mortar.5. Curing and Protection. After the Reinforced Brick lintel has been laid the work shall be kept

moist for 24 hours by sprinkling water upon it. After that period it shall be covered with sand andkept well flushed with water for two weeks. It shall be protected from extremes of temperature andfrom uneven drying a period of one month after laying.

No. 27 LIME PLASTERING1. Mortar Unless otherwise specified the mortar should be prepared in accordance with

specification No. (12) for Lime Mortar.2. Raking out of joints Before application of the plaster, the joints of the masonry or brickwork shall

be raked out of a depth of at least half an inch, and this raking out shall be done while the mortar isstill green. No plastering shall be commenced until the surface, thus prepared, has been passed by theExecutive Engineer or his representative; otherwise the contractor may be ordered to dismantle anddo the work again at his won expense.

3. Wetting of masonry and finished plaster. The surface shall be well wetted before plastering iscommenced and the mortar dust obtained from raking the joints shall be thoroughly washed off andthe work kept thoroughly damp while the plaster is being applied.

After completion the plaster shall be kept wet for ten days, or until thoroughly se t whichever

period is the longer and shall be protected for that period form extrems of temperature and weather.4. Screeds. Wooden screeds 3 inches wide and of the thickness of the plaster shall be fixed

vertically 8 ft. to 10 ft apart to act as gauges in applying the plaster.5. Application of plaster. The mortar shall be laid on the surface between screeds and the mortar

well pressed so that the raked joints are properly filled. The plaster shall then be evened off byworking a wooden straight edge across the screed. Finally the surface shall be finished off with finemortar, using a hand float and water to give a perfectly smooth surface.

6. Thickness of plaster. Brickwork shall not normally receive more than one coat of plaster and nosinge coat of plaster, for either brickwork or masonry, shall be allowed to exceed half an inch inthickness.

7. Two Coats Work. Where more than one coat off plaster is specified, The first coat shall beallowed to set completely before the second coat is applied and the surface of the previous coat shall

be left rough and freely secred in all directions to secure good bonding with the subsequent coat.8. Finishing of mouldings, cornices, angles, etc. All mouldings, cornices, etc., shall be worked

true to template, all exposed angles shall be carefully finished truly horizontal or vertical as the casemay be.

No. 28 CEMENT PLASTERING1. Mortar. Unless otherwise specified, the mortar shall be prepared and used in accordance with

specification No.(15) for Cement Mortar.


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2. Application, etc. The work shall be carried out in accordance with specification No (27) forLime Plastering.

No. 29 COMPOSITE PLASTERING1. Specification. Unless otherwise specified, the mortar should be prepared in accordance with

specification No. of Composite Mortar, The work shall be carried out in accordance with specification No (27) for Lime Plastering.

No. 30 POINTING1. Preparation of New Work When new brickwork or masonry is to be pointed, the joints shall be

raked out to a depth of at least inch. While the mortar is still green and the whole surfacethoroughly washed.

2. Preparation of Old Work. When old brickwork or masonry is to be pointed the joints shall beraked out with a hook (not a hammer), care being taken not to damage the bricks or stones. Thewhole surface should be thoroughly washed clean and kept wet for at least 6 hours before pointing isstarted.

3. Mortar. Unless otherwise specified, the mortar for cement pointing shall consist of 1 part ofcement to 3parts of sand and shall be pareparsed in accordance with specification No. (15) forCement Mortar.

The mortar for lime pointing should be of the proportions given in para 1 of specification No.(12)for Lime Mortar.

4. Colour fo Pointing. Unless otherwise specified, the colour of the pointing shall , in the case of lime pointing, be as nearly as possible the same as that of the bricks and colouring matter shall be addedto secure this effect. In the case of cement pointing, the colour of the pointing shall be the naturalcolour of the cement mortar unless otherwise ordered in writing by the Executive Engineer.

5. Mortar to be pressed well into joints. The mortar shall be strongly pressed and worked intothe joints with a pointing trowel and proper pointing tools. When finished, the mortar pointing shall

be restricted to the width of the joints and all superfluous mortar shall be removed with a trowel.6. Finish. Unless otherwise specified all horizontal joints shall be weather-struck with a trowel

and straight edge as shown in the sketch below.

All vertical joints shall be finished flush with the surface or V-notched with a triangular toolas shown in the sketch below.


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The mortar shall be confined to the width of the joint and shall no

Documents

PWD_Technical Specifications(Old Version)