BANGLADESH POWER DEVELOPMENT BOARD TENDER ... - BPDB

17.6.13 FORMWORK AND TIMBERINGFormwork and timbering shall be so designed and constructed that the requiredfinishes in concrete works are achieved. Formworks shall be constructedaccurately to the required shape, position and level and shall have sufficientstrength to withstand the compaction pressure. The materials to be used forformwork, shall be approved by the Board.Forms shall be removed without damage to the concrete. The use of form oil orother release agents shall be approved by the Board.The removal time of formwork and timbering shall be as followsWalls, beams, columnBeam soffits (props left under)Slab soffits (props left under): 3 days: 3 days: 4 days17.6.14 WATERSTOPS AND EXPANSION JOINTSThe Contractor shall place waterstops, water proofing membranes and expansionjoints at locations as are necessary for the proper construction of the concretestructure. The materials to be used shall be submitted in advance to the Board forapproval.17.6.15 FINISH AND REPAIR OF CONCRETE(1) GeneralThe classes of finishes and the requirement for finishing concrete surfaces shallbe as specified in this clause or as shown on the approved drawings. Surfaceirregularities in finishes shall be distinguished from construction tolerances, whichare allowable deviations from established lines, grades and dimensions, asdescribed herein.Surface irregularities are designated "abrupt" and "gradual" for purposes ofclassifying finishes. Offsets resulting from displaced, misplaced, or mismatchedforms or by loose knots in forms, or other similar forms of defects shall beconsidered "abrupt" irregularities and will be checked by direct measurement. Allother surface irregularities shall be considered "gradual" irregularities and will bemeasured as a departure from the testing edge of three meter template.Finishing of concrete surfaces shall be performed only by skilled workmen.Concrete surfaces shall be free from imperfections such as honeycombs andcracks. The Contractor shall at his own expense repair honeycombs, cracks, andirregularities promptly as directed by the Board.(2) Concrete Construction TolerancesVariations in alignment, grade and dimensions of the structures from theestablished alignment, grade and dimensions shown on the approved drawingsshall be within the tolerances specified in the following tables. Concrete work thatGhorasal 200 MW to 300 MW Gas Turbine Peaking Power Plant Project (Vol-2 of 3)172