Based on the construction advantages of dry connection mode of precast shear wall with high-strength bolts, steel plates and other components, a new type of prefabricated shear wall with the function of friction energy dissipation was proposed. Three shear wall specimens with the scale ratio of 1.54 were designed, and the control parameters were the axial compression ratio and the longitudinal reinforcement ratio of edge components. The quasi-static tests were carried out and the results show that the final failure mode of the three specimens are similar, which is the bending-shear failure that diagonal cracks in the wall develop to the concrete spalling in the compression area. The reduction of axial compression ratio or longitudinal reinforcement ratio of edge components have adverse effects on the seismic performance of the new prefabricated shear wall, which is manifested in the weakening of hysteretic performance and the reduction of ultimate bearing capacity. Combined with the finite element analysis results, the five-fold skeleton model and restoring force model of the new prefabricated shear wall were established. The proposed restoring force model is in good agreement with the test results, which can provide reference for the elasto-plastic seismic response analysis of the new prefabricated shear wall.
为增强装配式剪力墙的耗能能力,提高其施工效益,提出一种具有摩擦抗剪与耗能功能的新型装配式剪力墙结构,并进行了抗震性能试验.为弥补试件数量不足以及精确确定最优起滑荷载的设计需求,结合新型装配式剪力墙抗震性能试验结果,探讨相应高精度有限元模型建立方法,并进行多参数结构抗震性能影响分析.最后,基于有限元分析结果和新型装配式剪力墙工作原理,确定最优起滑荷载.研究结果表明:所提出的新型装配式剪力墙具有良好的滞回耗能能力;螺栓预紧力、钢材摩擦因数、螺栓总距等对结构抗震性能影响显著,应作为相应结构设计的主要参数,竖向荷载、钢板厚度、钢材弹性模量影响较小,可以忽略不计;当起滑荷载设定为墙体屈服荷载时,结构模型耗能达到峰值,同时耗能系数开始明显降低,因而将结构的最优起滑荷载确定为屈服荷载.
Considering the failure mechanism and weaknesses of traditional fabricated shear wall structures under strong earthquakes, a new type of fabricated shear wall with functions of energy dissipation and shock absorption was proposed. On the basis of model test and numerical simulation, seismic performance tests were carried out on four specimens with scale ratio of 1∶1.54 and shear span ratio of 1.52. Further analysis was conducted to investigate the effects of bolt number, axial compression ratio, and reinforcement ratio of edge members on the seismic performance of the new fabricated shear wall, including failure modes, hysteretic performance, bearing capacity, displacement ductility, stiffness degradation, and energy dissipation capacity. Test results show that the four specimens experienced shear compression failure, which was the same as the cast-in-place shear wall with the same shear span ratio. However, the proposed shear wall had better hysteretic performance and energy dissipation capacity, and the energy dissipation capacity was higher than that of the cast-in-place shear wall at the failure point. When the number of bolts decreased, the hysteretic performance of the new fabricated shear wall decreased, the wall deformation increased, while the bearing capacity remained almost unchanged. When the axial compression ratio or reinforcement ratio of edge members decreased, the bearing capacity decreased, and the ultimate displacement increased. Finally, the finite element model of the specimens was established by ABAQUS program. Comparisons of numerical results and test results showed a good agreement, verifying the correctness of the model, which can be applied to the analysis of the new fabricated shear wall.
Through the low cycle loading test of three full-scale enhanced-performance recycled aggregate concrete frame joints, the damage evolution and accumulation are analyzed according to the traditional ductile damage model (single parameter) and the improved Park-Ang damage model (double parameters): when the characteristic displacement of each specimen equals 20 mm, the specimen has been damaged, but the calculated results are negative according to ductile damage model; when the characteristic displacement exceeds 100 mm, the calculated results of the improved Park-Ang damage model show that all the specimens have been completely destroyed and cannot continue to bear load, but the actual results of the specimens still show certain bearing capacity and energy dissipation capacity. Therefore, it is necessary to modify the aforementioned damage model to make it suitable for enhanced-performance recycled aggregate concrete structures. Based on the foregoing test results, the fiber coefficient a, displacement coefficient alpha, and correction coefficient of energy coefficient k were proposed and fitted for the improved Park-Ang damage model. In addition, a corresponding modified Park-Ang damage model was established. Finally, using the proposed damage model, the error analysis of damage index was carried out with the example of HF-RAC2. The results show that the average error is within 6%, so the proposed two-parameter damage model can be applied to the analysis of seismic damage assessment of EC-RAC frame joints.