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槽形钢-混凝土组合梁是近年来提出的一种新型下承式桥梁结构。对截面尺寸几何比例为1∶3、构件长度比例为1∶4的简支单线槽形组合梁模型进行两点对称加载的静力试验。对槽形组合梁的抗弯承载力、刚度、应力和裂缝分布特征等基本受力性能开展研究。试验结果表明,通过栓钉连接,试验模型中钢板与混凝土的协同工作性能良好,最终破坏时,表现出较明显的弯曲破坏形态。梁上翼缘的侧向水平位移整体形态为支座处外张,中部内收,但其最大值远小于梁跨中的竖向挠度,表明该模型截面具有良好的抗扭性能。钢梁底板纵向应力沿板宽的分布表现出一定的剪力滞现象,混凝土底板的剪力滞效应不及前者明显。采用截面分析法对模型梁的承载力和变形进行计算分析,其结果与试验结果吻合良好。此外,通过抗弯承载力分析表明,槽形钢-混凝土组合梁的极限抗弯承载力不能套用全截面应力的矩形图分布模式进行计算,应考虑适当折减。
Grooved steel-concrete composite beams are proposed in recent years, a new type of under-bridge structure. The static test of two-point symmetrical load was carried out on the simple-supported single-line grooved composite beam model with the geometric ratio of the cross-section of 1: 3 and the component length ratio of 1: 4. The basic mechanical properties such as flexural capacity, stiffness, stress and fracture distribution of slotted composite beams are studied. The experimental results show that the joint performance of the steel plate and concrete in the test model is good through the peg connection, and the obvious failure mode is shown when the steel plate is finally damaged. The lateral horizontal displacement of the upper flange of the beam is in the form of outer flaps at the support and the middle adduction, but its maximum value is much smaller than the vertical deflection in the beam span, indicating that the section of the beam has good torsional resistance. The longitudinal stress distribution along the plate width of the steel beam shows a certain shear lag phenomenon. The shear lag effect of the concrete slab is less than that of the former. The bearing capacity and deformation of the model beam are calculated and analyzed by the method of cross-section analysis. The results are in good agreement with the experimental results. In addition, the analysis of flexural capacity shows that the ultimate flexural capacity of slotted steel-concrete composite beams can not be calculated by using the rectangular profile distribution mode of full cross-sectional stress, and the appropriate reduction should be considered.