Abstract:Tests of reinforced concrete (RC) and prestressed reinforced concrete (PRC) beams with 500MPa steel bars were carried out in Tongji University in order to popularize the application of high strength steel bar. The results verified the equations from new code GB 50010-2010 in calculating short term flexural stiffness of concrete beams with high strength steel bars, and indicated that the deformational response of beams was influenced mainly by three parameters including initial elastic flexural stiffness, longitudinal reinforcement ratio and load level. Based on the tests, a simpler unified formula is suggested after theoretical analyses for predicting short term deformation of concrete beams using high strength steel bars. Comparison with calculations from different codes at home and abroad exhibits that the suggested formula is precise and practical for both RC and PRC beams. Keyword：cold-rolled ribbed steel wires; concrete slab; static load test; flexural behavior
