低周反复荷载下型钢高强混凝土柱受力性能试验研究

通过20个混凝土强度为65.3～84.9MPa的型钢高强混凝土柱的低周反复加载试验,研究型钢高强混凝土柱在压、弯、剪共同作用下的破坏形态和抗震性能。试验中考虑剪跨比、轴压比、配箍率、混凝土强度4个参数的影响,由试验获得型钢高强混凝土柱的主要破坏形态和滞回曲线,分析各参数对构件延性、滞回特性、耗能性能以及承载力衰减的影响。结果表明,与型钢普通强度混凝土柱一样,在压、弯和反复剪力共同作用下,型钢高强混凝土柱的破坏形态主要为弯曲型破坏、剪切黏结破坏、剪切斜压破坏,破坏形态主要与剪跨比有关;箍筋能显著提高大剪跨比试件的延性和耗能能力,但对小剪跨比试件的延性与耗能性能改善有限;随着轴压比与混凝土强度的提高,试件的承载力衰减速度加快,后期变形能力减小,抗震性能越来越差;与钢筋混凝土柱相比,型钢高强混凝土柱的等效阻尼比远大于前者,耗能能力强,抗震性能好;提出型钢高强混凝土柱位移延性系数的计算公式,公式的计算结果与试验结果符合较好,可供工程设计应用参考。

Experimental study on the performance of steel reinforced high-strength concrete columns under low cyclic reversed loading

To investigate the seismic performance of steel reinforced high-strength concrete columns, twenty steel reinforced high-strength concrete columns with concrete strengths of 65.3 to 84.9 MPa are constructed and tested under low cyclic reversed loading. Four parameters, shear span ratio, axial compression ratio, stirrup ratio and concrete strength, are taken into consideration. The main failure patterns as well as hysteretic curves of those columns are obtained, and influence of each of the four parameters on the ductile behavior, ability of energy dissipation and law of strength degeneration are analyzed. Test and analytical results indicate that similar to steel reinforced concrete columns, for steel reinforced high-strength concrete columns under axial compressive force together with reversed horizontal load, flexure failure, bond failure and diagonal compression failure are the main patterns of failure. Stirrup improves the energy dissipation and ductility of columns of large shear span ratios, whereas the effects on columns of small shear span ratios are limited. When the axial compression ratio and concrete strength increase, the rate of strength degeneration accelerates, and the capacity of ultimate displacement decreases. Comparing with reinforced concrete columns, steel reinforced high-strength concrete columns are extraordinary in energy dissipation, indicating excellent seismic performance. A formula for calculating the displacement ductility coefficient is proposed.