Predictability evaluation of the existing punching shear formulas using failure test and probability-based approach

摘要

This study is to investigate the predictability of the existing punching shear formulas and to evaluate the best predictable punching shear formula including probabilistic evaluation method including the level of 95% probability. The considered punching shear formulas are existing 10 formulas, which are based on the standard codes and newly developed and verified by experimental data. For FRP reinforced concrete slabs, it is more important that the probable uncertainty of predicting formulas for material characteristics, structural dimension, and modeling errors should be considered. The random variables for probabilistic analysis were simulated by Monte Carlo Simulation. The best predictable punching shear formula and its components were analyzed with two analysis methods; the test-to-predicted ratio of punching shear strength and the nominal-to-95% probability ratio which is the ratio of nominal punching shear strength to that at the level of 95% probability. From the test-to-predicted ratio analysis, the important effect of modulus of elasticity of the reinforcement for predicting formulas was found. As using the resulted formula, this study provides a preliminary approach for suggesting a new punching shear formula of concrete slabs reinforced by either FRP or steel bar.