一、概述桁梁桥中的公路混凝土板常作为恒载加之于主桁,但板桁组合桥梁中的板,则不仅作为路面承重,且与主桁弦杆共同承受外载,能发挥混凝土桥面板与主桁平纵联的作用,增强结构的抗弯刚度、抗扭刚度及抗动力性能,因而能减轻结构自重,改善路面的连续性,在西德、丹麦、日本等国家相继被采用。在设计计算方法上,日本有将这类结构当成三个系统作平面问题近似分析的,但偏载计算时很繁琐,且不能计算水平荷载情况及空间自振特性。本文用有限单元位移法作立体分析,用改进的子结构波前法解方程组,用改进的雅可比方法计算自振特性,采用的程序及其说明详见“桁梁箱梁及板桁组合桥梁空间计算通用程 I. Overview Truss girder bridge in the road slab often as a plus plus the main girder, but the plate girder combination of the bridge, not only as a road load-bearing, and with the main truss chord share the external load, can play the concrete bridge The effect of the panel and the main truss is vertical and horizontal, which enhances the flexural rigidity, torsional rigidity and dynamic performance of the structure. Therefore, it can reduce the weight of the structure and improve the continuity of the road surface. In West Germany, Denmark, Japan and other countries have been adopted. In the design and calculation method, Japan has used this kind of structure as three systems to carry on the approximate analysis to the plane problem, but the partial load calculation is very complicated, and can not calculate the horizontal load condition and the spatial self-vibration characteristic. In this paper, the finite element displacement method is used for three-dimensional analysis. The modified substructure wave front method is used to solve the system of equations and the self-vibration characteristics are calculated by the improved Jacobian method. For details of the procedures and their descriptions, Bridge space calculation universal process