T形配钢钢骨混凝土柱抗震性能数值分析

为研究非对称配钢钢骨混凝土柱的抗震性能,基于12根T形配钢钢骨混凝土柱的拟静力试验研究进行非线性数值模拟,了解其破坏机制、承载力、延性及耗能能力,探讨轴压比、配钢率、剪跨比对抗震性能的影响。结果表明,低周反复荷载作用下T形配钢钢骨混凝土柱滞回曲线饱满,具有良好的延性和耗能能力。在峰值荷载前,数值模拟结果与试验结果吻合较好。轴压力在一定范围内提高了试件承载力,但降低了延性;增大配钢率能提高试件的承载力、刚度和延性,使得峰值荷载后试件的性能退化趋于平缓;剪跨比对试件破坏形态有显著影响,随剪跨比的增大试件延性性能提高。

Numerical Analysis of the Seismic Performance of Steel-reinforced Concrete Columns with a T-shaped Steel Cross-section

To study the seismic behavior of asymmetrical steel-reinforced concrete columns, nonlinear numerical analysis was carried out based on the quasi-static test of 12 columns with a T-shaped steel section. The concrete, steel, and reinforcing bar elements were simulated by using the Solid65, Solid45, and Link8 modes of the finite element software ANSYS, respectively. The model of multi-linear kinematic hardening (MKIN) was fully adopted for analyzing the concrete, whereas the model of bilinear kinematic was adopted for analyzing the steel and reinforcing bars. Constant axial compression and lateral cyclic loading were applied on the models. Failure mechanism, bearing capacity, ductility, and energy dissipation ability were also investigated. Three failure modes were observed in the experiment process, including bending failure, shear bond failure, and shear diagonal compression failure. In addition, axial compression ratio, shaped steel ratio, and shear span ratio were analyzed to determine the effects on seismic performance. The results indicated that the asymmetrical steel-reinforced concrete column possessed a plump hysteresis loop, which showed good ductility and energy dissipation ability. For the hysteretic curves, the load and displacement increase linearly in the early stage but increase nonlinearly in the elastic-plastic stage; moreover, residual deformation appears after unloading. The numerical simulation agreed well with the results of the experiment before the peak load. With increased axial compression ratio in a certain range, the peak load increased but the corresponding displacement decreased; moreover, the bearing capacity improved and the slope became steep, thus indicating poor ductility. The bearing capacity, stiffness, and ductility of the specimens improved with the increase of the shaped steel ratio, which mitigated the performance degradation after the peak load. Furthermore, the peak load obviously increased, and the corresponding displacement was kept constant. The shape of the curve was roughly the same. Meanwhile, with the increase of shear span ratio, the initial stiffness of the specimens decreased and the ascending branch became particularly smoother. The corresponding displacement of the peak load slightly increased. The declining branch also became gentle and the ductility improved, which had a significant effect on failure mode.