RESEARCH ON THE PRACTICAL USE OF SD490 REBARS FOR THE AXIAL REINFORCEMENTS OF RC BRIDGE PIERS

It is useful in an urban expressway to reduce a section of concrete bridge piers used high strength reinforcing bars. There is a JIS standard for SD490 bars, but the standard provides for lower elongation to failure than ordinary bars. There was concern that lower elongation fatigue failure lead to early failure of the axial bars. The cyclic loading test was carried out on a specimen bridge pier using D490 for the axial reinforcements. It was found that the ultimate displacement could be calculated with seismic design. In fatigue tests of deformed bars with buckling, it demonstrated that SD490 bars had fatigue strength in the same class as SD345 bars. Utilizing the rebar fatigue life obtained from these results, it was found to be possible to use Miner's rule to compute failure cycle of axial reinforcements in a reinforced concrete bridge pier.