摘要
为研究重载运输条件下的铁路预应力混凝土梁的承载能力,通过对32m高度预应力混凝土梁进行静载试验,分析了具有斜裂缝和完整情况下的预应力梁的力学性能。试验结果表明:斜裂缝使桥梁的整体承载能力减弱,梁的应力增量与变形均增大。在不同荷载条件作用下,梁体具有斜裂缝时跨中挠度和应力增量值比完整情况下最大多25.8%;当同一孔内的2片并置梁中有1片梁有斜裂缝时,具有斜裂缝的梁挠度较大。剪应力是影响梁端斜向裂缝的主要因素。与完整情况相比,梁端截面的各应力(剪、主拉、主压应力)增量测量值最大相差达25.5%,说明梁端的斜裂缝使得结构承载能力在不同程度上都有所下降。2种状态梁端剪应力增量测量值均大于主拉应力增量实测值,最大相差达13.8%。
To study the bearing capacity of railway prestressed concrete beams under the condition of heavy load transportation,the static load test of 32m high prestressed concrete beams is carried out,and the mechanical properties of prestressed beams with diagonal cracks and without cracks are analyzed.The test results show that the diagonal cracks weaken the overall bearing capacity of the bridge,and increase the stress increment and deformation of the beam.Under different load conditions,the deflection and stress increment of the beam with diagonal crack are 25.8%more than that of the beam without cracks at most;when one of the two parallel beams in the same hole has diagonal crack,the deflection of the beam with diagonal crack is larger.Compared with the no track case,the maximum difference between the measured values of each stress increment of the beam end section is 255%,which shows that the diagonal crack at the beam end makes the bearing capacity of the structure decrease to some extent.The measured value of shear stress increment at the end of beam in two states is greater than the measured value of main tensile stress increment,and the maximum difference is 13.8%.
作者
杜胜男
DU Shengnan(No.1 Engineering Co.,Ltd.of China Railway 18th Bureau Group,Zhuozhou,Hebei 072750,China)
出处
《建筑施工》
2020年第5期857-859,共3页
Building Construction
关键词
重载运输
预应力混凝土梁
裂纹
挠度
应力增量
heavy load transportation
prestressed concrete beam
crack
deflection
stress increment
