薄壁型钢混凝土梁抗弯性能试验研究

Experiment on the Flexural Behavior of Thin-Walled Steel Reinforced Concrete Beams

为研究薄壁型钢混凝土(thin-walled steel reinforced concrete,TSRC)梁试件的抗弯性能,设计制作了5根TSRC梁并进行四点弯曲试验,探究不同抗剪螺杆布置方式、截面形式、剪跨比以及混凝土保护层厚度对TSRC梁试件抗弯性能的影响。研究结果表明:TSRC梁的失效模式为薄壁钢管加载点处发生局部屈曲,外围混凝土保护层出现贯通斜裂缝,混凝土保护层沿抗剪螺杆开裂;TSRC梁试件在加载过程中未发生脆性破坏,表现出较好的延性;TSRC梁开裂荷载较小,在0.11P_(u)~0.15P_(u)之间,裂缝总数较少,稳定在6~10条;满跨布置螺杆、增大钢管截面尺寸、减小剪跨比以及增加保护层厚度均可提高TSRC梁试件的承载力。基于试验结果,建立适用于TSRC梁的极限抗弯承载力和抗弯刚度计算公式,可为该构件在实际工程中的应用提供参考。

In order to investigate the flexural performance of thin-walled steel reinforced concrete(TSRC)beams,five TSRC beams were designed,and subjected to four-point bending tests.The study aimed to examine the effects of different arrangements of shear screw,cross-sectional shapes,shear-span ratios,and concrete cover thicknesses on the flexural performance of TSRC beams.The results show that the failure mode of TSRC beams is local buckling at the loading point of the thin-walled tube,with diagonal cracks appearing in the outer concrete cover and cracking along the shear bolts.The TSRC beam specimens did not exhibit brittle failure during the loading process and showed good ductility.The cracking load of TSRC beams is relatively small,ranging from 0.11P_(u)~0.15P_(u),with a small number of cracks,typically 6 to 10.Full span arrangement of screws,increasing steel tube cross-section,reducing shear-span ratios,and increasing corcrete cover thicknesses can all improve the load-bearing capacity of TSRC beam specimens.Based on the experimental results,the equations for calculating the ultimate flexural capacity and stiffness of TSRC beams are proposed,which can provide a reference for the application of this component in real engineering projects.