空间钢构架混凝土简支深梁静力性能试验研究和设计建议

Experimental research and design suggestion on static behavior of spatial steel frame concrete simply supported deep beam

为研究空间钢构架混凝土简支深梁的静力性能,进行了4根空间钢构架混凝土深梁试件和作为对比试件的2根普通钢筋混凝土深梁在竖向对称集中荷载作用下的模型静载试验。试验参数为跨高比、配筋方式等。试验结果表明,与相同条件(除配筋方式外)的普通钢筋混凝土深梁相比,配置空间钢构架的混凝土深梁不仅刚度增大,而且其受剪承载力和变形能力也有较大幅度的提高,合理配置空间钢构架可改善混凝土深梁的延性。除配置水平和竖向分布钢筋外,沿主拉应力迹线方向配置斜向分布钢筋,或沿主压应力迹线方向设置斜向暗梁等措施可进一步提高空间钢构架混凝土深梁的受剪承载力。结合试验结果及其分析,给出了空间钢构架混凝土深梁的设计建议和构造要求,包括深梁内空间钢构架的配置范围、材料要求、混凝土保护层厚度、承重空间钢构架设计方法以及深梁内斜向分布钢筋、斜向暗梁的构造要求等。

In order to study the static behavior of concrete simply supported deep beam with spatial steel frame,four concrete deep beam models with spatial steel frame and two comparative reinforced concrete deep beam models were tested under vertical symmetrical concentrated loads.The main experimental parameters were beam span to depth ratio,steel reinforcement.The test results show that concrete deep beam with spatial steel frame have much higher stiffness,shear bearing capacity and deformation performance,compared with that of reinforced concrete deep beams.The ductility of concrete deep beam can be improved by reasonable allocation of space steel frame.In addition to horizontal and vertical reinforcement distributed over the entire span and depth of deep beams,additional reinforcement distributed along direction of the principal tensile stress trajectories,or that of principal compressive stress trajectories,can increase greatly the shear capacity of concrete deep beam with spatial steel frame.Based on the tests and analysis,the design suggestions and construction requirements of such structure are presented,including allocation range,material requirements,concrete cover thickness of spatial steel frame,design method of load bearing spatial steel frame,detailing requirements of oblique distribution reinforcement and oblique beam reinforcement of deep beam.