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Assalam o alaikum dear fellows, Why we need more temperature steel ratio for lesser grade of steel as shown by following relation? For Fy = 40 ksi As(min) = 0.002bh For Fy = 60 ksi As(min) = 0.0018bh Moreover, According to 7.12.1.2, it says 7.12.1.2 — Where shrinkage and temperature movements are significantly restrained, the requirements of 8.2.4 and 9.2.3 shall be considered. And in its commentary it says R7.12.1.2 — The area of shrinkage and temperature reinforcement required by 7.12.2.1 has been satisfactory where shrinkage and temperature movements are permitted to occur. Where structural walls or columns provide significant restraint to shrinkage and temperature movements, the restrain of volume changes causes tension in slabs, as well as displacements, shear forces, and flexural moments in columns or walls. In these cases, it may be necessary to increase the amount of slab reinforcement required by 7.12.2.1 due to the shrinkage and thermal effects in both principal directions (see References 7.7 and 7.16). Kindly tell how to increase this amount? Thanx.

Assalam o alaikum dear friends, It is quite basic level question but I am wondering how steel resists temperature and shrinkage cracks? Co-efficient of Thermal expansion for both steel and concrete is nearly same. Which shows if concrete contracts at an amount steel would also contracts at the same amount. So I m wonder which exactly phenomenon is involved in resisting shrinkage cracks? Thanks in advance.