Nonlinear analysis on mechanical performance of PC multi-girder structures under lateral loading

Abstract:

A computational model is studied to analyze the mechanical performance of PC multi-girder structure,which includes the propagation of cracks within the beam and diaphragm,the cracking pattern,the distribution of transverse loads and the stress redistribution in the prestressed steels.In the study,the nonlinearity of concrete material is described by using smeared crack model and other corresponding criteria.According to the mechanical characteristics of PC multi-girder structure,two typical loadcases defined as symmetric loadcase and offset loadcase are designed and then the lateral mechanical performances are analyzed and clarified in detail.Numerical results testify that the computational model is correct and the occurrence of cracks is closely related with the disposal of the acted loads.When subjected to symmetric loads,the PC multi-girder structure firstly produces cracks in its diaphragm and then in its beam;under offset loads,the crack appears earlier in the beam than in the diaphragm.Cracks in the diaphragm weaken the transverse connections between the beams,which leads to unfavorable change of the transverse loads distribution.The stress in the prestressed bar increases slowly in the elastic stage and then fast until the yielding stress is reached.