GAIL (India) Limited

24ii)iii)In framing the beam at different elevation, 75 mm below the lowest soffit of thebeam and in case of projection from beams and slabs 75 mm from the tope surface ofthe beam/slab or at the top surface of beam/slab whichever facilities formwork.For columns below flat slabs, 75 mm below the lowest soffit of the slab.b) In Walls (Horizontal Construction Joints)Note:i) For Walls Projecting From Base Slab, 300 mm from top of base slab.ii) For Walls supporting the suspended slab, 75 mm from the lowest soffit of the slab.In the case of water retaining structures and structures under the influence of ground water,approved water bars of suitable size shall be provided to make the joint completely watertight.c) In BeamsBeams shall be cast, as a rule, without a joint. But if provision of a joint is unavoidable, thejoints from simply supported beam shall be vertical and at the middle of the span; incontinuous beam, the same shall be at the point of minimum shear force.d) In Suspended Slabsi) In slab of small span, there shall be reconstruction joints.ii) In slabs of large span and continuous slabs, the Construction joint, if allowed by theEngineer, shall be vertical at the middle of span and at right angles to the principalreinforcement.e) In Walls (Vertical Construction Joint)As a rule, walls shall be cast monolithically without any vertical construction joint, unlessspecified in the drawing. However, for a long wall, Engineer may allow vertical constructionjoint and the same shall be at the place of minimum shear force.f) In Slabs Resting on Groundi) For Plain ConcreteConcreting shall be done in alternate panels not exceeding 10 m2 in area. The largest paneldimension shall be 5 m.ii)iii)For Nominally Reinforced SlabThe area of pour shall not exceed 40m2 and the maximum panel dimension shall not exceed8m.For the Basement Slabs Which Act as Structural MemberThese shall be no construction joint.g) In Ribbed BeamsThe beams shall be monolithically with the slab in one continuous operation.3.24 Cold JointsAn advancing face of pour, which could not be covered before expiry of initial setting time forunexpected reasons, is called a cold joint. The Contractor shall remain always vigilant to avoid coldjoints. If however, a cold joint is formed due to unavoidable reasons, the following procedures shall beadopted for treating it:1. If the concrete is so green that it can be removed manually and if vibrators can penetrate thesurface without much effort, fresh concrete can be placed directly over the old surface and thefresh concrete along with the old concrete shall be vibrated systematically and thoroughly.