Nonlinear Stability Analysis Of Concrete Shell Structures

Concrete shell structures,which have reasonable stress distribution and save materials,are widely used in large-span spatial structures.Performance of this kind of structure depends on its characteristic of stability.Some concrete shell structures have collapsed due to partial instability,resulting in heavy losses.Therefore,the study of its stability is always the focus of researchers and engineers.There are various forms of concrete shells.Stability of each kind can be different,but there are rules to follow.This paper studies stability of concrete shell structures.It applies the finite element method(FEM)to analyze several representative concrete shell structures,using finite element software ABAQUS.(1)This paper carries out load-displacement complete process analysis of concrete spherical shells.Influences of nonlinearity on the ultimate load-bearing capacity of concrete shells are analyzed based on the consideration of impacts of geometric nonlinearity,material nonlinearity and initial geometric imperfections.Besides,this paper compares results of the FEM with calculation results of the stability checking formula provided by Specification for design of reinforced concrete shell structures(JGJ22-2012)and International Association for Shell and Spatial Structures(IASS),and then validates the feasibility and rationality of the FEM in analyzing concrete shell structures.(2)This paper analyzes factors of concrete shell structure stability.It investigates the effects of initial geometric imperfection,reinforcement,rise-span ratio and radius-thickness ratio on the stability of concrete shell under uniformly distributed load and vertical uniformly distributed load.The safety factor applied to FEM result has been discussed preliminarily.(3)To combine with engineering practice,this paper takes the reinforced concrete hyperbolic cooling tower as an example of concrete shell structures.It applies the dynamic elastoplastic analysis of the reinforced concrete cooling tower using finite element software,to study the nonlinear dynamic stability.Furthermore,it provides references for designers to judge the structural safety and to adjust structural schemes by comparing results of the FEM with results of the stability checking formula provided by Code for hydraulic design of fossil fuel power plants(DL/T5339-2006).