Effect of Dynamic Load Redistribution in Reinforced Concrete Flat-Plate Structures Under Collapse

Abstract An initial punching shear failure or column loss in a reinforced concrete flat-plate structure may lead to the dynamic load redistribution to the surrounding connections. The dynamic demand and capacity at these connections will determine if subsequent failures occur leading to collapse of the structure. Therefore, the effect of dynamic load needs investigation in order to evaluate the collapse potential of the structure. This paper analyzes previous experimental work as well as new computational models to determine the effect of the dynamic load in terms of the dynamic load amplification as well as the dynamic capacity. The dynamic load amplification in flat-plate structures may be much less than what is used in current design guidelines. In addition, while the dynamic strength is relatively unchanged from the static, the ductility may be greater for connections with low reinforcement ratios. The results show that including the dynamic capacity can increase the load of the flat-plate system considered in this study to resist collapse progression by only approximately 0.5 kN/m2 (10 psf).