三主桁连续板桁组合桥空间计算方法研究

Spatial Calculation Methods of Three Main Trusses Continuous Plate-truss Composite Bridge

针对三主桁连续板桁组合桥的构造特点,通过构造结合梁单元的位移模式,利用势能原理推导结合梁单元的刚度矩阵,提出2种结合梁法,结合梁法一的特点是把桥面板作为主桁架弦杆的上翼缘并与主桁架弦杆形成钢-混结合梁,结合梁法二的特点是把桥面板作为纵、横梁的上翼缘并与纵、横梁形成钢-混结合梁;而常规的板梁组合法的特点是桥面板为连续各向同性的薄板并与纵、横梁组成桥面系共同承受荷载;并通过试验结果与理论结果的比较分析验证了3种空间计算方法的有效性及结果的正确性。

According to the structural features of three main trusses continuous plate-truss composite bridge,two composite-beam methods are presented by constructing the displacement mode of composite-beam elements and deriving the stiffness matrix of composite-beam elements.The characteristic of composite-beam method one is that the bridge slab is taken as the top flange of the chord of main truss and combined with the chord of main truss to form a steel-concrete composite beam;the characteristic of composite-beam method two is that the bridge slab is taken as the top flange of longitudinal and traverse beam and form a steel-concrete composite beam with longitudinal and traverse beams.And as for the conventional plate-beam composite method,the slab is characterized by forming bridge slab system with continuous isotropic sheets and longitudinal and traverse beams to bear load.Also,the comparison between theoretical results and experimental ones verifies the effectiveness of the above three methods.