According to IS 456:2000, Incase of flexural members in limit state design, Steel will reach its maximum strain of (0.87fy)/Es +0.002 first. But that doesnot mean steel will fail or fracture, since there is some reserve strength because of which it can elongate more till concrete reaches its maximum strain of 0.0035 (strain compatibility in bending) at the outermost compression fibre. which is known as secondary compression failure.