不同结构体系斜拉桥抗冲击动力响应

为了探讨斜拉桥抗常规武器冲击的动力响应,为重要桥梁设施工程防护和修复提供重要的理论依据,用LS-DYNA非线性动力有限元程序,针对长杆射弹冲击桥塔的危险情况,对不同结构体系———刚构体系、支承体系和漂浮体系斜拉桥抗冲击动态响应进行了数值模拟分析,比较了结构体系不同对斜拉桥抗冲击动力响应的影响.研究表明,桥塔纵桥向被撞击区域的局部变形最大,3种结构体系中漂浮体系被撞击区域的局部变形最小;刚构体系中塔抗冲击的塑性动力变形最大,冲击破坏危险性最大,其桥面系主梁的振动响应也最明显.

Dynamic Responses of Cable-Stayed Bridges with Different Structural Systems to Impact

The purpose of this research is to probe into the dynamic responses of cable-stayed bridges to the attack of a conventional weapon to provide an important reference for the feasibility studies of engineering protection and repair technology of important bridges.A nonlinear finite element program,LS-DYNA,was used to simulate the dynamic responses of cable-stayed bridges with different structural systems,i.e.,suspension system,rigid-frame system and support system,to a long-rod projectile impact when bridge pylon is attacked.The effects of structural systems on the dynamic responses were compared.The numerical results show that the local deformation in the region of collision is largest when bridge pylon is subjected to impact load parallel to the bridge axis,and the local deformation of the suspension system is least in the three systems.To a rigid-frame system,the dynamic plastic deformation of the intermediate column of pylon under impact is largest,and the danger of bridge pylon fracture and the vibration responses of the main longitudinal girder are most obvious.