内爆荷载作用下PC箱梁桥的动态响应过程

采用三阶段连续耦合有限元方法,对预应力钢筋砼(Prestressed reinforced concrete,PC)箱梁桥在内爆荷载作用下的动态响应过程进行了数值模拟,综合考虑了结构自重和预应力的影响,得到了PC箱梁桥局部和整体的破坏模式,并分析了破坏机理。结果表明:三阶段连续耦合有限元方法再现了PC箱梁桥局部破坏导致整体垮塌的物理过程;初始应力阶段,PC箱梁桥应力施加符合工程实际;局部响应阶段,腹板与顶板连接部位产生裂缝,顶板与底板在中央位置形成破口;整体响应阶段,在重力和预应力的作用下,箱梁桥先向上起拱,后向下垮塌,最终发生弯曲破坏。

Dynamic Response Process of PC Box-Girder Bridge under Implosion Load

In this work,a numerical simulation was performed on the dynamic response process of the prestressed reinforced concrete(PC)box-girder bridge under implosion load via three-stage continuous coupling finite element method.Taking gravity and prestress into account,the damage mode of PC boxgirder bridge was obtained.Besides,the failure mechanism was analyzed.It is shown that the PC box-girder bridge’s physical process from partial destruction to overall collapse can be theoretically reproduced by the three-stage continuous coupled finite element method.At initial stress stage,the stress of the PC box-girder bridge meets the requirement of the actual project.At local response stage,cracks occur at the connection between the web and the roof,and a break around the top and bottom flanges comes into being in the center.At overall response stage,influenced by the gravity and prestress,the box-girder bridge first arches up,then collapses and finally makes a bending failure.