预应力型钢超高强混凝土梁抗弯性能试验研究
EXPERIMENTAL STUDY ON FLEXURAL BEHAVIOR OF PRESTRESSED STEEL REINFORCED ULTRA-HIGH STRENGTH CONCRETE BEAMS
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摘要: 预应力型钢超高强混凝土梁是融合了超高强混凝土材料、钢结构和预应力技术所形成的一种新型组合构件。为了研究预应力型钢超高强混凝土梁的抗弯性能, 进行了14根预应力型钢超高强混凝土简支梁在竖向静力荷载作用下的受弯性能试验, 分析了试件受力过程、破坏形态、裂缝开展与分布规律等相关试验数据。结果表明:超高强混凝土脆性破坏显著, 导致预应力型钢超高强混凝土梁极限状态后承载力骤降, 但内置型钢有效提高了试验梁极限状态后的持载能力;预应力型钢超高强混凝土梁以普通受拉纵筋屈服作为试验梁进入屈服阶段的标志, 以受压区混凝土崩裂作为试验梁达到极限状态的标志;荷载达到0.9之前, 试验梁跨中控制截面基本符合平截面假定。在不考虑型钢与混凝土粘结滑移的基础上, 采用ANSYS有限元程序对预应力型钢超高强混凝土梁进行数值模拟计算, 试验梁开裂荷载、屈服荷载以及极限荷载的计算值与试验值吻合较好, 验证了有限元模型的正确性。Abstract: The prestressed steel reinforced ultra-high strength concrete beam is a new type composite beam that consists of ultra-high strength concrete, steel structures and prestressed technology. Fourteen specimens were tested to investigate the flexural behavior of prestressed steel reinforced ultra-high strength concrete beams. Test results such as failure mode, failure mechanism, and crack development in the beams are studied. The test results indicated that the bearing capacity of the specimens reduced dramatically after the maximum strength was reached due to the brittle failure of ultra-high strength concrete. But the embedded steel beams increased the ductility of the specimens. The specimens reached the yield strength when the longitudinal rebars yielded and reached the ultimate strength when the concrete in the compression area crushed. The mid-span section of specimens followed the plane section assumption until the load reached 0.9. The finite element program ANSYS was used to simulate the prestressed steel reinforced ultra-high strength concrete beam, and the slip between steel and concrete was ignored in the analysis. The cracking load, yield load, and ultimate load from the analysis model agreed with the experimental results well, which verifies the correctness of the finite element model.