负弯矩作用下预应力钢-混凝土组合梁的受力性能

为了研究负弯矩作用下预应力钢-混凝土组合梁的受力性能,对3根组合梁试件进行了单调静力试验,其中包括非预应力组合梁、体内预应力组合梁和体外预应力组合梁各1根.试验结果表明:负弯矩作用下,3根试件的破坏均始于钢梁的受压屈服,在达到极限承载力时钢梁均发生了屈曲；与非预应力试件相比,体内预应力试件的开裂荷载、屈服荷载和极限荷载分别提高了120％、35.1％和18.7％；体外预应力试件的开裂荷载较非预应力试件提高了24％,但屈服荷载和极限荷载略有降低；施加体内预应力可以有效地提高组合梁的极限变形能力,但对延性不利；施加体外预应力对组合梁的延性有一定的提高作用.

Mechanical Behavior of Prestressed Steel-concrete Composite Beams Under Negative Moment

In order to study the mechanical behavior of prestressed steel-concrete composite beams under negative moment,monotonic static tests were conducted on three beams including one non-prestressed composite beam,one prestressed composite beam with internal tendons and a prestressed composite beam with external tendons.The results showed that failure of the composite beams all started from the yield of steel girders,and buckling of steel girders occurred when the ultimate loading capacity was reached.The cracking load,the yield load and the ultimate load of the beam prestressed with internal tendons improved by 120%,35.1% and 18.7% separately compared with the non-prestressed composite beam.The cracking load of the externally prestressed specimen similarly increased by 24%,but the yield load and the ultimate load reduced slightly.Adding internal prestress effectively improved the ultimate deformability of the composite beam under negative moment,while it had negative effect on the ductility.Adding external prestress improved the ductility of the composite beam to a certain extent.