Criterion of punching shear failure for RC beams under low-velocity impact
A lot of previous low-velocity impact tests have shown that the failure mode of static flexural-dominant RC members designed by existing standards will transfer to punching shear failure under impact load.To make the mechanism and criterion of punching shear failure clear for RC beams under low-velocity impact,the reliability of the adopted constitutive models,parameters and numerical simulation method is verified by numerically recurring the flexural failure and shear failure modes,impact force-,reaction force-,and mid-span displacement-time histories in six drop hammer tests.The mechanism analysis of punching shear failure was conducted by the verified numerical simulation method to assess the influence on punching shear failure mode by drop hammer weight,sectional dimension,impact velocity,concrete strength,stirrup ratio,longitudinal reinforcement ratio,and shear span ratio.The result shows that the above parameters have a significant influence on the occurrence of punching shear failure for RC beams by changing the local velocity response or dynamic shear capacity of RC beams,except for longitudinal reinforcement ratio and shear span ratio.Further,based on the results of 330 numerical simulated scenarios,the empirical formulas of dynamic shear load Vd sd and dynamic shear capacity Vd sc in the key section were proposed,and the explicit criterion of punching shear failure for RC beams was established.The criterion was validated by 71 drop hammer tests(accuracy 90％),which can assist the impact-resistant assessment and design for RC structures.
国家科技期刊平台
NSTL
万方数据
维普
