Guidelines for Construction Project Supervision

Guidelines for Construction Project Supervision
Introduction


All construction works shall be carried out in accordance contract agreement as per the approved drawings and the relevant specifications as laid down in MORT&H Specifications, IRC, BIS ,I.S Codes and as per provisions made in Tender Documents. The procedure for carrying out construction activities are provided in SOP's. The information provided here is based on the general construction practices followed in infrastructure projects and can be used as guideline for site supervision activity. The information provided in these sections does not supersede information provided in any contract document or its part.
For the details of Source, Receipt, Storage, Sampling & Testing, Issuing etc. of Materials involved in execution of each items, Material Management Manual & Quality Control Manual or any other document shall be referred.

BRIDGE /FLYOVER / ROB / UNDERPASS /OVERPASS/

Setting Out

Working Bench Marks shall be established first and the same shall be tied with the reference Bench mark in the area soon after taking the possession of the site.
The Centre line of the structure must be accurately established and the same should be referenced which shall be maintained until the works are finished.
The setting out of the alignment, measurement of angles, measurement of distances etc shall be done by using Total Station.

Site Clearance

The cutting, removing and disposing of all materials such as trees, bushes, shrubs, stumps, roots, grass, weeds, top organic soil not exceeding 150mm in thickness, rubbish etc would be done soon after taking the possession of the site.
Disposal of materials shall be done as per specifications and as per contract agreement .

Earthwork

This work shall be consist of excavation, removal and satisfactory disposal of all materials necessary for the construction of structures, roadway, side drains, waterways etc in accordance with requirements of the specifications and the lines, grades, and cross sections shown in the drawings or as indicated by the UICPL’s representative.
It shall also be consist of earthwork in filling for embankment for roadways, solid approaches and for filling behind structures etc. in accordance with requirements of the specifications.

Concrete Work
The following provides for useful guidelines for Concrete Works
  1. Reinforcement
  2. Reinforcement should be clean and free of rust, dust, mud and oil.
  3. Anti corrosive coating, if any, should be done prior to placing of reinforcement in position. These should be handled carefully to avoid damage to the coating and any damage should be rectified by touching up immediately after positioning.
  4. Reinforcement should conform to the details given in the bar bending schedule which in turn should be prepared from the good for construction drawing.
  5. Position the reinforcement and check if they have been tied or wielded correctly. Also ensure that the size of bar, spacing between bars, correct bends, proper laps, curtailment of bars, type of binding wire, adequate binding, welding or splicing, binding wire bent inside, enough chairs kept in proper position and cover blocks are all in order. If not found in order, get the same rectified. If found to be in order certify the pour card (Format enclosed) for placement of reinforcement check.

Staging and Formwork


For general structures conventional staging can be used and no drawing and mock up will be required.
  1. For complex structures or if specifications warrant, prepare schematic drawings before starting the work. Do mock-up for complex structures.
  2. Ensure that staging is in order before you check the formwork. The staging should rest on firm ground or strong brackets anchored well to the concrete structure below.
  3. The formwork should be designed to take the load of concrete poured, particularly when concrete is placed by pumping or the height of lift exceeds 3m. Suitable tie rod should be provided if required.
  4. The formwork should be in line, level and plumb. It should be free from holes and gaps. Approved shuttering oil should be applied before placing of reinforcement.
  5. If the above points are found in order then pour card shall be certified.

Concrete Production

  1. Concrete shall be supplied preferably from a centralized batching plant.
  2. The weighing hoppers, water meter and admixture dispensers should be calibrated at least once in a month and rectification is made if required.
  3. Moisture in aggregates should be checked daily before preparation of batch sheet (Format Enclosed) for the days concrete supply.
  4. The workability of concrete should be checked at the batching plant.

Construction Joint

  1. These should be provided as per procedure given in the technical specification
  2. If specification is silent then the same can be prepared by any of the available methods like checking, application of surface retarders, washing with water jet (green cutting) after about 2 to 4 hours since concreting for exposed surfaces, acid etching etc.The prepared surface should be cleaned, inspected and certified.

Clearance for Concreting

  1. The pour card should have been filled, completed and certified by the inspecting authority.
  2. The batching plant should have received all required materials as per approved mixed design.
  3. Batch sheet should have been prepared at the Batching plant.
  4. Batching plant should have been informed about the time of starting, grade of concrete, quantity of concrete, rate of pour and location of pour. The requisition for concrete should be sent in format enclosed to the batching plant as soon as pour card is cleared.
  5. Machinery and manpower required for concreting should be made available.

Concrete Pouring

  1. Concrete of required grade and workability should be poured within one hour since mixing. Check trip sheet (format enclosed) before unloading.
  2. Concrete should not be segregate while conveying and placing.
  3. Concrete should be placed as near as possible to its final location. Practice of moving the concrete over long distance using vibrator should be avoided.
  4. For large areas having several layers such as mass foundations, place concrete systematically in a stair-step manner.
  5. For placing concrete on a slope placing should be started at the bottom and move up.
  6. Concrete should be placed in layers not exceeding 300mm and compacted using immersion type needle vibrators.
  7. Always use vertical drop chute at the end of sloping chutes or belt conveyors to avoid segregation.
  8. Vibration should be applied systematically to cover all areas immediately after placing the concrete.
  9. The vibrator needle should penetrate the layer of concrete vertically and in to the under laying layer previously placed and vibrated if possible.
  10. Stop vibrating when the concrete flattens and takes up a glistening appears, the rise of entrapped air ceases, the coarse aggregate blends in to the surface but does not completely disappear and the vibrator after an initial slow down when inserted resumes its speed.
  11. Withdraw the vibrator slowly to ensure closing of the hole resulting from insertion
  12. Always follow correct placing and techniques.
  13. Ensure that the top level of concrete is as require and finished suitably.
  14. Ensure that the fresh concrete has been sampled for workability test and cube casting. The details should be recorded in format (Enclosed). Frequency of sampling should be as per technical specification.

Formwork Removal

  1. Form should be removed after elapsing of the period as mentioned in specifications.
  2. All blemishes and defect if any should be rectified immediately.
  3. The removed formwork should be cleaned and stacked properly till it is used again.

Curing

  1. Use approved water only for curing.
  2. Curing compound can be applied if permitted.
  3. For large unformed area structures like slabs, mass foundations, start curing as soon as concrete sets.
  4. For formed surfaces, start curing as soon as formwork is removed.
  5. Cure concrete till it achieves the design strength.

Reinforcement

Bar Bending Schedule

  1. Prepare Bar Bending Schedule based on the latest “Good for Construction Drawings”.
  2. Bar Bending Schedule should clearly specify – Rebar Material Specification, Bar diameter, Numbers, Cutting length, Details of bends, Cranks, Hooks, and their exact location.
  3. Bar Bending Schedule should take in to account the following design requirement: Lap lengths, Desirable location of laps, Staggering of laps, Development length / Anchorage length.

Cutting, Bending and Placing

  1. Reinforcement should be clean and free of rust, dust, mud and oil.
  2. Anti corrosive coating, if any, should be done prior to placing of reinforcement in position. These should be handled carefully to avoid damage to the coating and any damage should be rectified by touching up immediately after positioning.
  3. Reinforcement should conform to the details given in the bar bendingSchedule.
  4. If welding of reinforcement is required, the entire welding operation, including method, material, amount of pre heat, if any, should be decided based o n chemical analysis.
  5. All bending should be in cold condition. If heating is to be adopted, a separate procedure should be established and got approved from the designer.
  6. Place the reinforcement as per the details given in the drawings and ensure that the following aspects are properly taken care of Size of bar, number of bars, location of bends, cranks, hooks, location and length of laps, splices, curtailment of bars, length and quality of welding, if any. Incase of two way reinforcement, the correctness of direction of reinforcement in various layers.Size of Cover Blocks, Adequate number of chairs and cover blocks,Binding wire is bent inside
  7. The sequence of reinforcement placing should be correlated with fixing of inserts, sleeves, conduits, anchors and formwork.
  8. If heating is permitted to bend bars that have been embedded in concrete, it must be controlled to avoid splitting of the concrete or damage to bars.
  9. Mechanical Splicing (Crimping) of reinforcement, if any, should be done only after confirming the strength through appropriate tests.
  10. If bundled bars are used, they should be tied or otherwise fastened together to ensure remaining in position whether vertical or horizontal.
  11. If all the above points are found in order, certify the pour card for placement of reinforcement check.
Formwork

Preparation of Scheme
  1. Selecting the material to suit the required finish of concrete as per specification
  2. Preparing sketches showing scheme taking in to account unusual conditions, if any, like heavy beams, sloping area, cantilevered slabs, large openings etc.
  3. Incase of proprietary system follow the recommendations of manufacturer with regard to design parameters and system application.
  4. Architectural requirement of Form Finish should be taken in to account while choosing the material and size of sheathing, tie locations, form surface treatment, etc.
  5. For complex structure or if specification warrant, prepare scheme drawings and do mock up.
  6. Formwork shall be strong enough to take pressure or weight of fresh concrete and other loads without distortion, leakage, failure or danger to workman.
  7. Design of Formwork should also take in to account the concrete placing equipment, rate of pour etc. Pressure by fresh concrete on formwork should also be calculated and taken in to consideration. The design of the formwork shall confirm to provisions of IRC: 87 and BIS Specifications.
  8. The scheme should clearly indicate the pour sequence, construction joints and time / strength criteria for removal of Formwork.

Erection / Assembly of Formwork

  1. The shutters are properly cleaned to remove concrete and protruding nails.
  2. Check to eliminate damaged components.
  3. Erect staging / shuttering as per scheme drawing / sketches. The arrangement should be such that the deshuttering can be done easily.
  4. Prepare a check list prior to concreting and carry out the check. (Format Enclosed)
  5. Checking location, line, levels, dimension, verticality/plumb etc with allowable tolerance.
  6. Provide bracing at proper place and intervals as per manufacturer’s recommendation / manual.
  7. Check for proper alignment and firm fixing.
  8. Form oil / coatings as releasing agents should be applied before reinforcement is placed.

Inspection During and After Concreting

  1. Formwork should be continuously watched during and after concreting by a competent person assigned specifically for this
  2. Incase of leakages, bulging and sagging, promptly make an adjustment by tightening wedges or by jacking, but all adjustment must be made before the concrete takes its initial set.
  3. Continue the watching of Formwork until the concrete has set sufficiently to bear the self load.

Removal of Form

  1. Remove the formwork after the minimum period stipulated in IS 456

Open Foundation

Formwork, Concrete, and reinforcement for open foundation shall conform to relevant sections of construction procedures given in this document. The work shall cover furnishing and providing plain or reinforced concrete foundation placed in open excavation in accordance with the drawings and specifications

Pile Foundation

CAST-IN-SITU PILE
  1. Boring :It shall be carried out by using Hydraulic Rig Machine or rotary or percussion type equipment
  2. Providing MS Liner: A minimum of 2m length or of suitable length up to refusal level from top of the bore shall invariably be provided with Liner to ensure against loose soil falling in to the bore.
  3. Any Liner or bore hole which is improperly located or shows partial collapse that would affect the load carrying capacity of the pile shall be rejected or repaired at the cost of the Contractor.
  4. Lowering the Reinforcement Cage: Prior to the lowering of the reinforcement cage in to the pile shaft, the shaft shall be cleaned of all loose materials. Cover to reinforcing steel shall be maintained by suitable spacers.
Concreting: The concreting must be completed in one continuous operation.
  1. The finishing of bore, cleaning of bore, lowering of reinforcement cage and concreting of pile for full height must be accomplished in one continuous operation without any stoppage.
  2. The Trimie pipe should always penetrate well in to the concrete with an adequate margin of safety against accidental withdrawal if the pipe is surged to discharge the concrete.
  3. The pile should be concreted wholly by trimie and the method of deposition should not be changed part way up the pile to prevent the laitance from being entrapped within the pile.
  4. All tremie tubes should be scrupulously cleaned after use.
  5. Care shall be taken during concreting to prevent as far as possible the segregation of the ingredients. The concrete should be done with the Tremie with a funnel to avoid the segregation.
  6. Care shall also be taken to avoid the displacement or distortion of reinforcement during concreting.
  7. The minimum embedment of cast-in-situ concrete piles in to pile cap shall be 150mm.
  8. Any defective concrete at the head of the completed pile shall be cut away and made good with new concrete.
  9. The clear cover between the bottom reinforcement in pile cap from the top of the pile shall be not less than 25 mm.
  10. The reinforcement in the pile shall be exposed for full anchorage length to permit it to be adequately bonded in to the pile cap.
Well Foundation

Formwork, Concrete and reinforcement for well foundation shall conform to relevant sections of construction procedures given in this document.
The construction of well foundation will consist of taking it down to the founding level through all kinds of sub-strata, plugging the bottom, filling the inside of the well, plugging the top and providing a well cap in accordance with the details shown on the drawing and as per specifications or as directed by the Engineer.

Pile Cap / Well Cap

Formwork, Concrete and reinforcement for Pile Cap/ Well Cap shall conform to relevant sections of construction procedures given in this document.
A minimum offset of 150mm shall be provided beyond the outer faces of the outermost piles in the group.
If the pile cap is in contact with earth at the bottom, a leveling course of minimum
100mm thickness of M15 Nominal mix shall be provided.
A portion of the pile top shall be stripped off concrete and the reinforcement anchored in the cap as per specification.Concreting shall be carried out in dry conditions.

SUPER STRUCTURE

Pier / Abutment

Formwork, Concrete and reinforcement for Piers/Abutments shall conform to relevant sections of construction procedures given in this document.No Vertical construction joint shall be provided.
In case of tall piers and abutments, use of slipform shall be preferred. The design, erection and raising of slipform shall be subject to special specifications and arrangement which shall be furnished by the contractor for the prior approval.
The surface of foundation/well cap/ pile cap shall be scrapped with wire brush and all loose materials removed. Just before commencing concrete, the surface shall be thoroughly wetted.
The surface finish shall be smooth except the earth face of abutment which shall be rough finished.

Pier Cap / Abutment Cap

Formwork, Concrete, and reinforcement for Pier Cap/Abutment Cap shall conform to relevant sections of construction procedures
The location and levels of pier cap / abutment cap / pedestals / bearings shall be checked carefully to ensure alignment in accordance with the drawings of the bridge.

Dirt/Return wall/Wing wall

The construction of these components shall be done in accordance with the procedure laid down

Bearing

Neoprene Elastomeric Bearing

This work shall be executed as per procedure laid down contract agreement and section 2005 of MORT&H may be referred.

POT-PTFE Bearing

  1. Provisions of IRC-83 (Part I) shall be applicable for all Metallic elements. While provisions of IRC-83 (Part II) shall be applicable for all Elastomeric elements.
  2. For the elements not covered by IRC-83 (Part I and II), the same shall be as per guidelines provided in BS-5400 (Sections 9.1 and 9.2) except that no natural rubber shall be permitted.
  3. Materials: The basic materials shall conform to the specification in section 2006.3 of MOST.
  4. Test: As per the specification in section 2006.5 of MOST.
Installation

  1. Pockets commensurate with the sizes of the anchors shall be kept in pedestals during concreting of the same.
  2. The pedestal shall be cast approximately 15- 25mm short of the required finished level. Careful control shall be exercised to cast at the exact required level.
  3. Anchors shall be fitted to the bearing bottom with elastomer washers and anchor screws.
  4. The bearing assembly shall be seated in the location on steel chairs / packs.
  5. The anchors fitted below the bearing shall go in to pockets in the bed block.
  6. The level and alignment of the bearing shall be checked.
  7. It shall be ensured that the bearing sits in a horizontal plane.
  8. The gap below the bearing assembly including anchor pockets shall be grouted with cement based grout which fulfills the criteria of MOST Clause 2006.6.1(VI).
  9. During the casting of Superstructure (Slab / Diaphragm Wall), the formwork around the bearing shall be carefully sealed to prevent leakage.
  10. Sliding plates shall be fully supported and care should be taken to prevent tilting, displacement or distortion of the bearings under the weight of wet concrete.
  11. Bearing shall be protected during concreting operation. Any mortar contaminating the bearing shall be completely removed before it sets.
  12. The load shall be transferred on to the bearings only when the bedding materials have developed sufficient strength. The props for the formwork shall only be removed after lapse of appropriate time. In special cases this can be ensured by suitable devices like jacks etc.

Superstructure

The work of Concrete Superstructure shall cover furnishing and providing of superstructures in accordance with the drawings as per the specifications and methods laid down or as directed by the Engineer.

Pre-stressing of Girders

Sheathing:

Spiral corrugated type conforming to IS: 513. The thickness of sheathing should not be less than 0.3mm, 0.4mm, and 0.5mm for sheathing ducts having internal diameter of 50mm, 75mm and 90mm respectively.

  1. The length of Coupler should be less than 150 mm but should be increased up to 200mm wherever practicable.
  2. The joints between the ends of the coupler and the duct shall be sealed with adhesive sealing tape to prevent penetration of cement slurry during concreting.
Anchorages: Conforming to BS: 4447.

  1. No damaged anchorage shall be used.
  2. Steel parts shall be protected from corrosion at all times. Threaded parts shall be protected by greased wrappings and tapped holes shall be protected by suitable plugs until used. The Anchorages components shall be kept free from mortar and loose rust and any other deleterious coating.
  3. All materials shall be delivered in time for tests to be made well in advance of anticipated time of use.
  4. Tendons shall be free from loose rust, oil, grease, tar, paint, mud or any other deleterious substances.
  5. Tendons of any type that are damaged, kinked or bent shall not be used.
  6. The packing of pre-stressing wire / strand shall be removed only just prior to making of cable for placement.
Positioning

Positioning for Post-Tensioning

  1. Pre-stressing tendons shall be accurately located and maintained in position, both vertically and horizontally as per drawings.
  2. Tendon arrangement should have a smooth profile without sudden bends or kinks.
  3. Locationing of Prestressed cables shall be such as to facilitate easy placement and vibration of concrete in between the tendons.
  4. High capacity tendon shall be used to reduce the number of cables thereby eliminating the necessity of grouping.
  5. Where two or more rows of cables have to be used, the cables shall be vertically in line to enable easy flow of concrete
  6. The clear vertical and horizontal distances between any two cables shall in no case be less than 100 mm anywhere. For precast segment the clear distance should be at least 150mm.
  7. Sheathing shall be placed in correct position and profile by providing suitable ladders and spacers. Such ladders may be placed at 1m intervals. Sheathing shall be tied rigidly with such ladders/spacer bars so that they do not get disturbed during concreting
  8. As far as possible tendons should not be placed in sheath until immediately prior to stressing.
  9. Tendons shall be handled with care to avoid damage or contamination to either the tendon or the sheathing. Any tendons damaged or contaminated shall be cleaned or replaced.
Positioning for Pre-Tensioning

  1. Prestressing tendons shall be accurately located and maintained in position, both vertically and horizontally as per drawings.
  2. Tendon to be positioned securely to prevent movement during concreting.
Cutting

Strand or wire cutting shall be done by suitable mechanical or flame cutters.
The location of flame cutting shall be kept beyond 75 mm of where the tendon will be gripped by the anchorage or Jacks.

Protection of Pre-stressing Steel

Pre-stressing steel shall be protected against corrosion until grouted.

Sheathing:

The joints of all sheathings shall be water tight.

A Sheath making machine should be positioned at the site of work for large projects so that sheathing can be prepared as and when it is required for the construction.

Grout Vent: Grout Vents of at least 20mm diameter shall be provided at both the ends of the sheathing and all valleys and crest along its length. Grout vent should be provided with a plug or similar device capable of withstanding a pressure of 1.0MPa. without the loss of air pressure, water or grout.

Anchorages: The anchorages shall be recessed fro m the concrete surface by a minimum cover of 100mm.

Pre-stressing Equipment

  1. The means of attachment of the prestressing steel to the jack or any other tensioning apparatus shall be safe and secure.
  2. Where two or more wire / strands constitute a tendon, a multipull stressing jack shall be used which is capable of tensioning simultaneously all the wires / strands of the tendon. Suitable facilities for handling and attaching the multipull jack to the tendons shall be provided.
  3. The tensioning equipment shall be such that it can apply controlled total force gradually on the concrete without inducing dangerous secondary stresses in steel, anchorage or concrete.
  4. Means shall be provided for direct measurement of the force by use of dynamometers or pressure gauges fitted in the hydraulic system itself to determine the pressure in jacks. Facilities shall also be provided for the linear measurement of the extension of prestressing steel to the nearest mm and of any slip of the gripping devices at transfer.
  5. Pressure gauges shall be concentric scale type gauges accurate to within two percent of their full capacity. The minimum nominal size of gauge shall be 100mm. The gauge shall be so selected that when the tendon is stressed to 75% of its breaking load, the gauge is reading between 50% and 80% of its full capacity.
  6. Suitable Safety devices shall be fitted to protect pressure gauges against sudden release of pressure.

Post-Tensioning

  1. A Complete record of Prestressing operations along with elongation and Jack Pressure data shall be maintained. (Format Enclosed).
  2. The load is applied to the concrete member when it attains the strength specified on the drawing or as stipulated by the prestresssing system supplier, whichever is more.
  3. Tensioning force shall be applied in gradual and steady steps and carried out in such a manner that the applied tension and elongations can be measured at all times.
  4. The sequence of stressing, applied tensions and elongations shall be in accordance with the approved drawing.
  5. The difference between calculated and observed tension and elongation during prestressing operations shall be regulated as per the provisions given in MOST Specification.
Grouting of Prestressed Tendons

Grouting shall be done conforming to Appendix 1800-III of MOST Specification.
A record of grouting operations shall be maintained

Pre-Tensioning

The prestressing planning for Pre-tensioning involves arrange the tensioning bench, abutment at location of anchorage, steam curing system, formwork of the concrete elements and arrangement for demoulding, lifting, stacking and transportation of the pre-tensioned concrete elements.

Stressing Bed for Pre-tensioning

  1. The abutments and bed for pre-tensioning of tendons shall be designed to withstand the total tensioning force.
  2. A notice shall be displayed adjacent to the stressing bed showing the maximum tensioning force permitted.
  3. In the long line method of prestressing , sufficient locator plates should be distributed throughout the length of the bed to ensure the position of wire properly during concreting.
  4. Sufficient Space shall be left in between the ends of concrete elements to permit access for cutting the strands / wires after transfer.
  5. The tensioning force shall be determined by direct reading of the pressure gauges and by the measured elongation after slip.
  6. The contractor shall submit method of tensioning the tendons including the arrangement and layout of prestressing beds, calculations and design details etc.
  7. The Contractor shall carry out trial stressing operations to establish the frictional resistance offered by the hold-downs and the slip during anchoring.
Prestressing Procedure for Pre-tensioning

  1. The tensioning of wires and strands shall be done not much in advance of concreting.
  2. The tensioning force shall be applied gradually and uniformly.
  3. In order to remove slack and to lift tendons off the bed floor, an initial force shall be applied to the tendons. Allowance shall be made for this bin calculating the required elongation.
  4. Tendons shall be marked for measurement of elongation after the initial force has been applied. The tendons shall be marked at both the jacking end and dead end of the stressing bed and at couplers if used so that slip and draw-in may be measured.

Transfer of Pre-stress

Transfer of pre-stress force to the concrete element take place once the concrete attains the strength specified in the drawings.

The sequence of transfer of pre-stressing force shall be done strictly as indicated in the drawings and ensuring that eccentricities of the prestressing force in the vertical and horizontal directions of the concrete element is a minimum during the entire sequence.

The maximum slip of any tendon during transfer shall not exceed 3mm at any end of the concrete element.

Safety precautions during Prestressing

  1. Care shall be taken during tensioning to ensure the safety of all person in the vicinity.
  2. Jack shall be secured in such a manner that they will be held in position, should they lose their grip on the tendons.
  3. No person shall be allowed to stand behind the jacks or close to the line of the tendons while tensioning is in progress.
  4. The operations of the jacks and the measurement of the elongation and associated operations shall be carried out in such a manner and from such a position that safety of all concerned is ensured.
  5. During actual tensioning operation warning sign shall be displayed at both ends of the tendon.
  6. After prestressing, concrete shall neither be drilled nor any portion cut nor chipped away nor disturbed without approval of Engineer.
  7. No welding shall be permitted on or near tendons nor shall any heat be applied to tendons.
  8. Launching the Girder
  9. Launching shall be done as per the detailed methodology duly approved by Engineer and conforming to BIS, IRC and MOST Specifications.
Expansion Joint

STRIP SEAL EXPANSION JOINT

Fabrication

  1. Edge Beams shall be cut to size of actual requirements by means of a special saw.
  2. Alignment of the cut-to-size steel profiles then be made in accordance with the actual bridge cross-section on work tables.
  3. After the steel profiles are aligned, they will be chucked to the tables by means of screw clamps and tacked by arc welding.
  4. Anchor Plates shall be cut to the required size by gas cutting. These shall be welded to the edge beams.
  5. Anchor loops shall be bent to the required shape and welded to anchor plates.
  6. Finally assembled joints shall then be clamped and transported to the work site.
  7. Transportation shall be done after putting the joints in to auxiliary brackets.
  8. Joints should be stored under cover on suitable lumber padding by the contractor to prevent damage. Any damage occurring after delivery shall be made good at Bridge Contractor’s expense to the satisfaction of the Engineer.
  9. Manufacturer shall supply either directly to the Engineer or to the Bridge Contractor all the materials of strip seal joints including sealants and all other accessories for the effective installation of the jointing.
  10. Installation

  • The surfaces of the recess shall be thoroughly cleaned and all dirt and debris removed.
  • The exposed reinforcement shall be suitably adjusted to permit unobstructed lowering of the joint in to the recess.
  • The recess shall be shuttered in such a way that dimensions in the joint are maintained. The formwork shall be tight.
  • Immediately prior to placing the joint, the presetting shall be inspected for any required correction / adjustment. After adjustment the brackets shall be tightened again.
  • The joint shall be lowered in the in a pre-determined position in the recess.
  • The joint shall be leveled and finally aligned and the anchor loops on one side of the joint welded to the exposed reinforcement bars of the structure. The same procedure shall be followed for the other side of the joint. Thereafter the auxiliary brackets shall be released.
  • High quality concrete (not less than M35) shall then be filled in to the recess. The packing concrete must feature low shrinkage and have the same strength as that of the superstructure. Good compaction and careful curing of concrete is particularly important. The movable installation brackets shall only be removed once the concrete has cured.
  • Rolled up neoprene strip seal shall be cut in to the required length and inserted between the edge beams by using a crow bar pushing the bulb of the seal in to the steel grooves of the edge beams.
  • Expansion joint shall not be exposed to traffic loading before the carriageway surfacing is placed.
  • The carriageway surfacing shall be finished flush with the top of the steel sections. The actual junction of the surfacing / wearing coat with the steel section shall be formed by a wedge shaped joint with a sealing compound.

Bridge Appurtenances

This work shall include bridge appurtenances such as Wearing Coat, Railing, Approach Slab, Drainage spouts, Weep holes in conformity with the details shown on the drawing and specifications. The construction shall be done as per procedure laid down

RE Wall

This work shall be executed in accordance

Protection Work & River Training Work

This work shall include the construction of Guide bunds, Guide walls, Bank protections, floorings, and approach embankment protection as required for ensuring the safety of the bridge structure and its approaches against damage by flood / flowing water. Construction of all these components shall be done as per the procedures laid down

ROAD WORK

Subgrade / Earthwork in Embankment / Excavation

This work shall be executed in accordance with the Clause no. 300 of MORT&H Specifications and IRC Special Publication-11.

Control Blasting

  1. The rock blasting shall be controlled so that vibrations generated during the blasting do not cause damage to the building and installation around built up areas.
  2. Similarly, the rock pieces should not fly off the pits and thus damage the buildings and installation and life and limb of people around.
  3. Apart from the general precautions mentioned in the specifications, protective measures mentioned under following paras shall be taken. The contractor shall carefully check the site conditions and submit the details of the scheme they propose to adopt for controlling the blast.
  4. Short delay blasting with light charges shall be used.
  5. The blast hole shall be covered with 0.6 to 1.0 sq.m. mild steel plate of minimum 6 mm thickness.
  6. Reinforcement rod mesh not less than 20 mm dia at 150 mm centers in both directions shall be placed over the steel plates.
  7. Steel plate and reinforcements shall be inspected after every blasting operation and all twists shall be removed before reuse to the satisfaction of the Engineer.
  8. The thickness of the covering plate and the kind of dead weight is to be duly approved by the Engineer.
  9. When blasting is necessary adjacent in partially or completely built structures the contractor shall take all precautions necessary to prevent flying rock from causing damage to the structures.
  10. No blasting shall be allowed for any of the excavation until freshly placed concrete of nearby structures has reached a minimum strength.
  11. Normally, blasting shall be resorted to only after 7 days of concreting work in case of OPC (10 days in case of PPC) in adjacent structures. In no case shall blasting be allowed closer than 15 m to any structure after concrete placing has started.
  12. It is generally recommended that where the blasting is to be done within 20 metres of the nearest point of permanent building, the area shall be line drilled on periphery before blasting.
  13. After the blast, the supervisor must carefully inspect the work and satisfy himself that all the charges have exploded. After the blast takes place in underground works, the workmen shall not be allowed to go to the face till toxic gases have disappeared from the face.
  14. If it is suspected that part of the blast has failed to fire or is delayed, sufficient time shall be allowed to elapse before entering the danger zone. When fuse and blasting caps are used, a safe time should be allowed and then the supervisor alone shall leave the shelter to inspect the blasting zone.
  15. Excavation by blasting will be permitted only under the personal supervision of competent and licensed blasters and trained workmen.