矩形钢管混凝土构件弯曲性能试验研究

Experimental Study of Bending Behavior of Rectangular Concrete-Filled Steel Tube Component

为了解矩形钢管混凝土梁在弯矩作用下的受力性能及加劲肋对其弯曲性能的影响,设计制作flat试件(无加劲肋)、rib试件(设置普通加劲肋)和PBL试件(设置PBL加劲肋)共3个矩形钢管混凝土试件,进行纯弯试验,研究各试件的荷载~位移曲线、中性轴移动规律、混凝土和钢材应变规律、破坏模式等,并基于AISC规范方法计算各试件的抗弯承载力,对比填充混凝土对钢梁抗弯承载力的影响。结果表明:在用钢量相同的前提下,flat试件的混凝土与钢管之间产生了滑移,rib试件在横向集中荷载的作用下局部混凝土开裂严重,PBL试件的钢管混凝土整体性较好,混凝土无滑移;填充混凝土对设PBL试件和rib试件的抗弯承载力有显著提高,对flat试件的抗弯承载力提高很小。

To investigate the mechanical behavior of the rectangular concrete-filled steel tube （CFST） beam under the action of the bending moment and the influences of the stiffening ribs in the beam on the bending behavior of the beam, totally 3 rectangular CFST specimens of the flat specimen （without the stiffening ribs） , rib specimen （with the common stiffening ribs） and the PBL specimen （with the PBL stiffening ribs） were designed and made. The pure bending tests for the specimens were carried out and the load？displacement curves,neutral axis moving laws, con-crete and steel strain and the failure modes of the different specimens were studied. The bending capacity of the specimens was calculated according to the method as provided in the AISC specifica-tion and the influences of the filled concrete on the bending capacity of the steel beam were com-pared. The results reveal that on condition that the usage amount of the steel is the same, the slip between the concrete and steel tube of the flat specimen takes places. Under the action of the transverse concentrated load, the local concrete of the rib specimen cracks severely while the integ-rity of the CFST of the PBL specimen remains good and the concrete in the tube of the specimendoes not slip. The filled concrete can significantly improve the bending capacity of the PBL and rib specimens, however, the improvement of the concrete on the bending capacity of the flat specimen is very little.