钢-混组合加固梁承载能力试验研究

Experimental study on the load-bearing capacity of steel-concrete composite strengthening beam

针对外包钢板钢—混组合结构加固方法中结合面传力机理及植筋、剪力钉数量对结构承载能力的影响问题,开展植筋、剪力钉布置不同的6组钢板—混凝土组合加固梁弯曲试验,比较植筋、剪力钉布置间距对构件的力学行为和承载能力的影响;根据试验数据以构件的破坏形态分析钢—混结合面的工作和破坏机理。结果表明:采用外包钢板加固法加固时,相对于原结构,加固的外包刚板刚度较大,对结合面的强度要求较高,通过灌浆料连接植筋、剪力钉的方式很难满足钢—混结构变形一致的要求,在一定范围内增、减剪力钉数量对加固结构的刚度和极限承载力基本没有影响,但可以防止钢板发生早期局部失稳,充分发挥外包钢板的刚度和承载能力。

This paper presents an experimental investigation on the load transition mechanism of the joint surface,and the effects of shearing stud and bar-planted placements on structural capacity for the steel-concrete composite strengthening structure with coated steel plate.Six groups of steel-concrete composite specimens with various deployments of shearing stud and bar-planted are carried out.The influences of the arrangement interval of shearing stud and bar-planted on the mechanical behavior and load-bearing capacity are compared;the working and damage behavior of the steel-concrete composite joint surface is studied based on the experimental data and failure modes.Results showed that compared with the steel-enveloped approach with greater rigidity of the reinforced structure,the structure is reinforced by the enveloped steel plate with greater rigidity,and the strength of the joint surface is higher.The grouting-connected pattern of bar-planted and shearing stud cannot satisfy the correspondence deflection requirement of enveloped steel plates and inner-concrete cores due to the stricter strength requirement of the joint surface.Although the changes in number of shearing stud nearly have no effect on the structural stiffness and the ultimate capacity of the enforced components for a certain range,the premature local instability of enveloped steel plates is prevented,by which the plasticity and ductility can be fully utilized.