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为解决常规钢-预制混凝土桥道板组合梁剪力键预留孔和板间现浇接缝易开裂的问题,提出了带预埋抗剪栓钉(PCSS)剪力键的装配式钢桁-混凝土组合梁(Prefabricated Steel Truss-concrete Composite Beam,PSTC),为考察其抗裂性能,在介绍基本概念的基础上,阐述了PSTC组合梁的制作方法,进行了1组3个带预应力的PSTC组合梁负弯矩区段加载试验,并分析了在负弯矩作用的开裂极限状态下PSTC组合梁截面应变的构成特征;依据考虑滑移影响后的截面应变协调条件和PCSS联结构造的剪力-滑移本构关系,分别建立了PSTC组合梁微段内混凝土板和钢梁的静力平衡方程,推导得到了考虑滑移后PSTC组合梁的开裂弯矩计算公式。研究结果表明:PSTC组合梁首先需要在预制混凝土板内预埋带栓钉的剪力传递钢板,然后在钢桁梁上安装预制混凝土板并施加纵向预应力,最后对剪力传递钢板与钢桁梁顶面的纵缝施焊联结形成组合梁;PSTC试验梁初始裂缝出现在加载点附近的混凝土板边,开裂荷载随混凝土板预应力的增大而增大,相邻预制板间接缝的初始裂缝均略晚于板内首条裂缝出现,PSTC组合梁无明显的抗裂薄弱部位;得到的计算公式计算结果与试验数据吻合良好,可为同类桥梁提供参考。
In order to solve the problem of easy cracking of the cast-in-place joint between the shear key and the plate of the conventional steel-prestressed concrete composite deck-gate beam, a prefabricated steel truss with prestressed shear studs (PCSS) (PSTC). In order to investigate its anti-cracking performance, based on the introduction of the basic concepts, the fabrication method of the PSTC composite beam is described. One group of three prestressed concrete beams with prestressed PSTC composite beam negative section load test, and analysis of the negative moment under the cracking limit of the PSTC composite beam cross-section strain characteristics; based on considering the slip of the cross-section strain coordination conditions and the PCSS structure of the joint shear Force-slip constitutive relation, the static equilibrium equations of the concrete slab and the steel beam in the PSTC composite beam section are established, and the formula for calculating the cracking moment of the PSTC composite beam is derived. The results show that the PSTC composite beam firstly needs to be prefilled with prestressed concrete slab with shear transfer plate, and then installed on the steel truss precast concrete slab and longitudinal prestress, and finally the shear transfer plate and steel truss The initial cracks of the PSTC test beam appear on the edge of the concrete slab near the loading point, and the cracking load increases with the increase of the prestressing force of the concrete slab. The initial joint of the adjacent precast slabs The first cracks occurred slightly later than the first crack in the slab, and the PSTC composite beam had no obvious crack-resistant weak points. The calculation results obtained were in good agreement with the experimental data and could provide reference for similar bridges.