REINFORCEMENT SPLICING – AS PER IS 456 -2000 It Is recommended that splices (Lap) in flexural member should not be at sections where the bending moment is more than 50 percent of the moment of resistance; and not more than half the bars shall be spliced at a section. Where more than one-half of the bars are spliced at a section or where splices are made at point of maximum stress, special precaution shall be taken, such as increasing the length of lap and/or using spirals or closely-spaced stirrups around the length of the splice. Notes:- 1. Lap splices shall not be used for bars larger than 36 mm ; for larger diameters, bars may be welded; in cases where welding is not practicable, lapping of bars larger than 36 mm may be permitted, in which case additional spirals should be provided around the lapped bars. 2. Lap splices shall be considered as staggered if the centre to centre distance of the splices is not less th...
WORKABILITY OF CONCRETE - AS PER IS-456-2000 The concrete mix proportions chosen should be such that the concrete is of adequate workability for the placing conditions of the concrete and can properly be compacted with the means available. Placing Conditions Degree of Workability Slump(mm) Blinding concrete; Shallow sections & Pavements using pavers Very low In the ‘very low’ category of workability where strict control is necessary, for example pavement quality concrete, measurement of workability by determination of compacting factor will be more appropriate than slump ( see IS 1199 ) and a value of compacting factor of 0.75 to 0.80 is suggested. Mass concrete, Lightly reinforced sections in slabs, beams, walls, columns, Floors; Hand placed pavements; Canal lining; Strip footings Low 25-75 Heavily reinforced sections in s...
DIMENSIONS - Dimensions shall be measured to nearest 0·01 m except for the thickness of slab which shall be measured to nearest 0·005 m. Areas shall be worked out to nearest 0·01 square metre. Cubic contents shall be worked out to nearest 0·01 cubic metre. STAGE OF MEASUREMENT- Work shall be measured under the following categories in convenient stages stating the height or depth: Below ground/datum level. Aboveground/datum level. NOTE- The ground/datum level shall be dcfined in each case. CEMENT CONCRETE WORKS Concrete works shall be measured under the following categories. Works in plain/reinforced/prestressed concrete shall each be measured separately. Works in precast and cast in situ concrete shall be kept separate. Unit of Measurement-Unless otherwise stated all concrete work shall be measured in cubic metres. DEDUCTION- No deduction shall be made for the following- Ends of dissimilar materials for example, beams, posts, girders...
Comments
Post a Comment