Seismic performance of flat plate structures in punching shear modelled with non-layered and layered shell elements

Abstract

The seismic performance of flat plate structures is a critical area of research in the field of structural engineering.Nonlinear analysis through modeling software considers the nonlinear behavior of materials, such as concrete and steel, which allows for a more realistic prediction of the structural response to extreme lateral loading conditions. This research aims to study the nonlinear effect on punching shear due to seismic loading in flat plates using layered shell models and compare them with thick shell models. Three types of aspect ratios type A (53m × 29.26m), type B (53m×22.4m) and type C (38.41m×29.26m) have been used in this research,with a panel size of6.4m×6.858m. Number of stories, material properties and slab thickness have been varied to generate total 36 model types. All models have been designed using layered shell slab and thick shell slab to perform parametric study using the nonlinear static analysis procedure. Three earthquake hazard levels Maximum Considered Earthquake (MCE), Design Basis Earthquake (DBE) and Serviceability Earthquake (SE) have been taken into consideration to analyze the seismic performanceof structures. The buildings are designed as dual system frame structure with special moment resisting frame in moderate seismic zone (Zone 2) as per BNBC 2020. ‘Displacement Coefficient Method’ according to ASCE 41 has been used to determine nonlinear behavior of the structures, such as - maximum displacement, base shear capacity, hinge formation and punching shear stress. The layered shell models exhibit higher stiffness than thick shell models in linear static analysis resulting in lower displacement and drift. Nonlinear static analysis also indicates better performance of layered shell models including higher base shear capacity, a smaller number of plastic hinges and lower plastic rotation. None of the models exhibited punching failure as the observed punching shear stresses were considerably lower than the slab capacity.The stress resultants obtained from layered shell models are much higher than the thick shell models.The results of this research will provide insights into a preferable analytical modeling technique for seismic design using layered shell elements and aid researchers in understanding punching shear behavior in seismic analysis of flat plate structures.