桁架式钢骨混凝土门式框架抗震性能研究

为促进桁架式钢骨混凝土框架结构在抗震设防区的推广和应用,开展了 1榀预应力及1榀非预应力桁架式钢骨混凝土门式框架试件在水平低周往复荷载作用下的拟静力试验,考察了试验过程及门式框架试件的破坏形态,研究了门式框架试件的滞回特性、骨架曲线、刚度退化、耗能能力、残余变形等抗震性能指标,分析了梁端、柱脚的弦杆和斜腹杆应变变化规律...

Seismic performance of steel-truss reinforced concrete portal frame structures

In order to promote the application of steel-truss reinforced concrete frame structures in seismic areas, quasi-static tests on one prestressed and one un-prestressed steel-truss reinforced concrete portal frames under horizontal cyclic loading were conducted, and the testing process and failure modes were examined. The seismic performance such as hysteretic characteristics, skeleton curves, stiffness degradation, energy-dissipating capacity and residual deformation were studied. Meanwhile, the strain variation of the chords and diagonal web members at beam and column ends was analyzed to observe the formation sequence of plastic hinges. Based on the tests, finite element software ABAQUS was used to simulate of mechanical properties of the steel-truss reinforced concrete portal frame specimens. The results show that the lateral load-displacement hysteretic curves for the two specimens are plump without obvious pinch phenomenon, which indicates good seismic performance. Prestressing has little effect on the ductility, energy-dissipating capacity and deformation recovery performance. However, prestressing could postpone the appearance and extension of cracks in the loading process, and reduce the damage at the ends of beam and column. The two specimens have the same plastic hinge formation sequences, i.e., from beam ends to the bottom of the column, which complies with the design requirements of “strong column and weak beam”. The failure modes, ultimate loads and skeleton curves of the two specimens obtained by finite element analysis are in good agreement with the test results. In addition, the results of parametric analysis shows that slenderness ratio and axial compression ratio are the main influential factors. With the increase of slenderness ratio of columns, the bearing capacity and lateral stiffness decrease, and the ductility of the frame increases. With the increase of axial compression ratio, the displacement and ductility of the frame decrease.