关键词: 预应力混凝土, 多梁式梁桥, 全过程分析, Ottosen准则, 非线性, 组合壳单元, 数值稳定性

Abstract:

This paper aims at the nonlinear whole-process analysis of prestressed concrete（PC） multi-girder bridges.In the investigation,first,nonlinear variations of the concrete including cracking,yielding and crushing are described respectively based on the smearing crack model,Ottosen s yielding criterion and the Hinton crushing theory.Next,with the help of degraded shell element,the concrete and the common steel are simulated using the layered shell element and the prestressed steel is simulated using the combined shell element. Then, the contribution of the prestressed steel to the stiffness matrix of the combined shell element is investigated according to the displacement coordination. Moreover, a nonlinear combined-layered shell element model is established and the corresponding analytical procedure is programmed, by which a 3D nonlinear calculation is performed, finding that the calculated results accord well with the results of failure experiment of a PC multi-girder bridge, with a relative error of the ultimate bearing capacity of about 0. 13%. Finally, the regularities of stress redistribution of the prestressed steel and the common steel are analyzed, showing that the proposed nonlinear shell element with excellent numerical stability and convergence is suitable for the whole-process analysis of thin-wall structures such as PC multi-girder bridges.

Key words: prestressed concrete, multi-girder bridge, whole-process analysis, Ottosen s criterion, nonlinearity, combined shell element, numerical stability