Review of IS 456:2000

Review of IS 456:2000

there is lots of importing point provide on IS456:2000 code book,which is used in practical civil engineering practices, some of them are listed below

1. PH of water shall not be less than 6 (clause 5.4.2)
2. Spacers or chairs should be placed at a maximum spacing of 1 m.(clause 12.3.2)
3.  Maximum permissible free fall of concrete may be taken as 1.5m (clause 13.2)
4. The tremie pipe shall be not less than 200mm in diameter
5. Structural exceeding 45m in length are designed with one or more expansion joint.(clause 27.2)
6. Table 2, shows different grade of concrete
7. Modulus of elasticity of steel shall be taken as 200 kn/mm2 (clause 5.6.3)
8. Crossing bar should not be tack-welded for assembly of reinforcement unless permitted by engineer in charge.(clause 12.2.1)
9. Tolerance for cover. (clause 12.3.2)
10. Transportation and handling of concrete.(clause 13.1 & 13.1.1)
11.  Flexural strength of concrete = 0.75 sqrt Fck (clause 6.2.2)
12. Adjustment to minimum cement content for aggregate other than 20mm nominal maximum size.(Table 6)
13. Proportion for nominal mix concrete is provided in table 9.
14. Minimum number of main steel reinforcement bar provided in reinforced cement concrete are for rectangle column = 4 and for circular column = 6.
    
15. When the bar of two different diameter are to be spliced, the lap length shall be calculated on the basis of diameter of the smaller one.(clause 26.2.5.1)
16. The main reinforcement bar in column should not be less than 12mm diameter.(clause 26.5.3.1 d)
17. Stripping time of form work is provided in clause 11.3.1.
18. Standard deviation is shown in table 8 of IS456:2000.
19. Spacers, cover block should be concrete of same strength or Pvc.(clause 12.3.2)
20. The detail on compaction is provided on IS2505, IS2506, IS2514, and IS4656.
21. Reinforcement shall be bent & fixed in according with procedure specified in IS2502.(clause 12.1)
22. The diameter of reinforcing bar shall not exceed 1/8^th of total thickness of slab.(clause 26.5.2.2)
23. Lap splices shouldn’t be used for bars larger than 36mm,we should prefer welding instead.(clause 26.2.5.1 a)
24. Modulus of elasticity of concrete = 5000 sqrt Fck. (clause 6.2.2)
25. Minimum cement content, maximum w/c ratio and grade of concrete for different exposure with 20mm nominal maximum size. This is explained in table 5 of IS456:2000.
26. Nominal mix concrete may be used for concrete of M20 or lower.(clause 9.3)
27. Detailed explanation of placing of concrete is provided in clause 13.2.
28. Unit weight of Pcc is 24kn/m3 and Rcc is 25kn/m3.(clause 19.2.1)
29. Deflection in flexural member in mm is 40l^2/D.(clause 17.6.3.1)
30. Clause 12.3.1 shows the tolerance on placing of reinforcement.
31. The structure should be subjected to a load equal to full dead load of the structure plus 1.25 times the imposed load for a period of 24 hours.(clause 17.6.2)
32. Clause 17.6.3 shows what if allowable maximum deflection exceeds 40l^2/D.
33. IS code for calculation of DL is shown in clause 19.2.1.
34. Clause 15.2.2 shows frequency of sampling.
35. Minimum curing period of concrete is shown in clause 13.5.1.
36. Load considered for structural design. (Clause 19.1).