Nonlinear Analysis of Reinforced‐Concrete Shells

Abstract

Nonlinear finite element procedures are presented for the analysis of reinforced‐concrete shell structures. Cracked concrete is treated as an orthotropic material using a smeared rotating crack approach. The constitutive model adopted for concrete compression response accounts for reductions in strength and stiffness due to the presence of transverse cracks. The model used for concrete in tension represents the tension stiffening effects that significantly influence postcracking response. A heterosis‐type degenerate isoparametric quadrilateral element is developed using a layered‐element formulation, which rigorously considers out‐of‐plane shear response. Selective integration is used to avoid shear‐locking and zero‐energy problems. Good stability and convergence characteristics are provided by the iterative, full‐load secant stiffness solution procedure employed. Simple test elements are used to confirm the analytical procedure's ability to accurately model behavior under conditions of membrane load, flexure, and out‐of‐plane shear. Plate specimens and column‐slab strip specimens are used to investigate the ability to model complex structural behavior influenced by geometric and material nonlinearities.