SRC-RC竖向混合结构转换柱型钢保护层厚度分析

Concrete cover of shape steel in transfer columns of SRC-RC hybrid structure

对16根试件进行了低周反复荷载试验研究.研究发现:由于转换柱试件的剪切作用明显,因此增加箍筋数量能够明显提升转换柱屈服后的变形能力,改善抗震耗能能力;影响型钢翼缘保护层厚度的主要因素包括试件的构造措施、轴压力大小以及钢与混凝土之间的粘结性能;当构造措施无法避免临界剪切斜裂缝的出现时,型钢翼缘保护层承担了较大的轴压力,存在负荷过大而压溃的可能,这种破坏方式将导致箍筋约束作用无法得到充分发挥,转换柱的抗震性能无法得到保证.为了保证型钢与混凝土之间的共同工作效果,防止转换柱破坏前型钢翼缘保护层压溃,型钢翼缘保护层不应小于0.2倍的截面高度,且不小于50 mm.

The low cyclic shear experiments of 16 transfer column specimens were carried out. The re- sults show that due to the shear effect of specimens, the increased arrangement of stirrups can obviously improve postpeak behavior and energy dissipation ability of the transfer columns. The parameters of steel skeleton configuration, axial compressive ratio, bond performance between concrete and shape steel can affect the critical concrete cover thickness of steel flanges remarkably. If critical shear cracks are engen- dered mainly due to the serious shear effect fi＇om partially existence of shape steel, the concrete cover is maybe crushed under axial compression. The bearing capacity is decreased markedly with diminished re- striction of stirrups on cracks, and the seismic behavior demand of transfer columns can not be satisfied. To improve the bond performance between two materials and prevent the crush of concrete cover, the con- crete cover thickness of steel flanges should not less than the maximum of fifth section height and not less than 50 into.