预应力部分外包钢组合梁变形性能试验研究

为探究预应力部分外包钢组合梁在竖向加载下的变形性能,对12片预应力部分外包钢组合梁进行竖向两点加载试验,探究其裂缝开展、挠度与延性性能等变形性能。采用分型维度理论对各试件裂缝开展情况进行分析;利用Euler梁理论与Timoshenko梁理论分别推导梁的挠曲线方程,进而推出梁的跨中挠度计算值;计算预应力部分外包钢组合梁位移延性系数、截面曲率延性系数与能量延性系数,并采用灰度关联分析法进行3种延性系数的影响因素分析。结果表明,施加一定程度预压应力的部分外包钢组合梁在破坏时裂缝开展最充分;基于Timoshenko梁理论的挠曲线方程与跨中挠度计算值最接近真实值;截面面积是试件位移延性系数与曲率延性系数最重要的影响因素,而型钢锚固形式则为能量延性系数最重要的影响因素。

Experimental study on deformation performance of prestressed partially steel-encased concrete composite beams

In order to explore the deformation performance of the prestressed partially clad steel composite beams under vertical loading, a vertical two-point loading test is carried out on 12 prestressed partially clad steel composite beams to explore the deformation performance such as crack development, deflection and ductility. In this paper, the fractal dimension theory is used to analyze the crack development of each specimen. Based on the Euler beam theory and Timoshenko beam theory, the flexural equations of beams are derived respectively, and then the mid-span deflection of beams is calculated. The displacement ductility coefficient, section curvature ductility coefficient and energy ductility coefficient of prestressed partially clad steel composite beams are calculated. Influence factors of three ductility factors are analyzed by gray correlation analysis. The results show that the cracks develop most fully when the partially clad steel composite beams with a certain degree of pre-compressive stress are applied. The deflection equation based on the theory of Timoshenko beam and the calculation value of mid-span deflection are closest to the real value. The section area is the most important factor affecting the ductility coefficient of displacement and the ductility coefficient of curvature, and the anchoring form of section steel is the most important factor affecting the ductility coefficient of energy.