GFRP-RPC组合双层交通梁桥的弹性性能试验研究与有限元分析

设计了一种面向双层交通的GFRP-RPC组合梁桥，该梁桥由GFRP材质的两榀桁架及带肋平板通过胶栓混合连接而成，通过浇筑自密实RPC混凝土形成组合梁桥整体。对组合梁桥缩尺模型（1:8）进行多工况的拟静力加载试验和有限元分析，并对其弹性工作性能进行研究。结果表明：浇筑RPC后，梁桥的刚度约提高2.6倍，表明此类GFRP、混凝土组合形式有利于结构合理受力，下部加载时，梁桥变形约增大10%，对结构较不利；弦杆受力符合平截面假定，组合结构受力合理；上、下弦杆分别为压弯、拉弯受力状态，上、下部加载时，下弦杆拉应力分别约为上弦杆的1.5倍和2.5倍，下弦杆为薄弱弦杆；斜腹杆受拉，直腹杆基本呈受压状态，上、下加载方式影响直腹杆的受力形式，下部承载设计时需考虑局部拉、压应力较大的情况；顶板侧面混凝土受压，底板侧面混凝土受拉，腹杆设置有利于板面混凝土均匀受力。

Experimental study and finite element analysis on elastic properties of GFRP-RPC composite double deck traffic beam bridge

A GFRP-RPC composite beam bridge for double deck traffic is designed. The bridge is composed of two GFRP trusses and ribbed plates, which are connected by glue bolts. The composite beam bridge is formed by pouring self compacting RPC concrete. The scale model (1:8) of composite beam bridge is tested and analyzed by quasi-static loading test and finite element method, and its elastic performance is studied. The results show that: After pouring RPC, the stiffness of the beam bridge increases about 2.6 times, which indicates that the combination of GFRP and concrete is conducive to the reasonable stress of the structure, and the deformation of the beam bridge increases about 10% when the lower part is loaded, which is unfavorable to the structure; the chord stress accords with the assumption of plane section, and the stress of composite structure is more reasonable; the upper and lover chords are in the force state of compression bending and tensile bending respectively, when the upper and lower chords are loaded, the tensile stress of the lower chords is about 1.5 and 2.5 times of that of the upper chords, and the lower chords are weak chords; when the diagonal web member is in tension, the straight web member is basically in compression state, and the loading mode of up and down affects the stress form of the straight web member. The design with larger local tensile and compressive stress should be considered for the lower bearing; the concrete on the side of the top plate is compressed, while the concrete on the side of the bottom plate is tensioned, indicating that the setting of the web member is conducive to the uniform stress of the slab concrete.