六边形桥墩柔性抗船撞装置抗弯刚度

Equivalent bending stiffness of a hexagonal flexible crashworthy device for bridge piers

针对中国自主研发的桥梁柔性抗船撞装置,构建该装置模型:由两个相似的六边形梁为内外钢围以及均布且垂直于六边形各边的防撞圈构成。分析该模型得到在冲击载荷作用下六边形梁的控制方程及相应的初边值条件。利用Laplace变换和数值Laplace逆变换对该方程进行求解,揭示六边形梁在冲击载荷作用下的动态响应。并进一步分析外钢围等效抗弯刚度对抗船撞装置动态响应的影响,发现外刚围结构在冲击载荷作用下存在临界等效抗弯刚度。当外钢围等效抗弯刚度达到该临界值后,该外钢围在冲击载荷作用下可以近似为刚性。

An analytical model is established to study the flexible crashworthy device which is devel- oped independently in China. The model is composed of a distributed springs linking and supporting two hexagonal-shape box-beam structures that encircle the bridge pier. The governing equation to- gether with adequate boundary conditions and initial conditions is deduced for the outer beam under dynamic impact loading. This governing equation is solved by the method of Laplace transform and the numerical inverse Laplace transform to get the dynamic response of the outer beam. The influence of the equivalent bending stiffness on the dynamic response of the outer beam is analyzed, and the critical equivalent bending stiffness is obtained. When the equivalent bending stiffness of the outer beam is more than the critical value, the beam can be considered as a rigid one under impact load.