带小跨高比RUHTCC连梁的联肢剪力墙抗震性能及设计方法研究

Aimed at concrete structural wall with small span-depth ratio coupling beam, a new coupled-wall system with ultra-high toughness cementitious composite material that has advantages of high ductility, high energy and high damage-tolerance is investigated in the present project. It is expected that the use of ultra-high toughness cementitious composite (UHTCC) in the coupling beam and wall could improve seismic loading capacity, ductility and energy dissipation of the coventional concrete coupled-wall, reduce the amount of stirrups in wall as well as lessen wall damage. Low-cycle tests,nonlinear finite element simulations and time-history analysis are planned on the new coupled-wall system and conventional ones. The main concerns are to understand enegy dissipation mechanisms, seismic performance as well as evaluate the improvement of seismic performance of RC coupled wall due to UHTCC. Besides, the present project is also for the purposes to establish the calculation expression of coupling ratio for obtaining strong wall-weak beam energy dissipation mechanism, to propose allowable deformation limit for RUHTCC/RC coupled wall corresponding to the different performance level and subsequently to suggest a new performance-based design approach for RUHTCC/RC coupled wall. The resluts of this project will provide a new solution to concrete coupled-wall with high ductiliy, high energy dissipation and low damage, which is of significant guidance for the application of UHTCC in the practical structural wall.

本项目将超高韧性水泥基复合材料UHTCC应用于带小跨高比连梁的剪力墙，利用超高韧性水泥基复合材料高延性、高耗能及耐损伤的性能，提高普通钢筋混凝土联肢墙的抗震承载力、延性和耗能，减少墙肢配箍用量，同时减轻墙肢的损伤。采用低周往复循环试验，有限元数值模拟和弹塑性时程分析相结合的方法，对该RUHTCC/RC组合联肢墙的抗震性能进行研究，以期揭示RUHTCC/RC联肢墙的抗震耗能机理，评估UHTCC材料对RC联肢墙抗震性能的改善作用，建立RUHTCC/RC联肢墙实现强墙弱梁耗能机制的耦联比控制计算式，提出不同性能水准下RUHTCC/RC联肢墙的变形限值，形成基于性能的RUHTCC/RC组合联肢墙抗震设计方法。研究成果为钢筋混凝土联肢墙实现高延性、高耗能和低损伤提供一种新技术途径，对推动UHTCC在剪力墙结构的应用具有重要工程指导意义。

项目将具有高延性、高耗能及耐损伤的超高韧性水泥基复合材料UHTCC应用于抗侧力剪力墙体系，以期提高普通钢筋混凝土剪力墙结构的抗震承载力、延性和耗能，减少墙肢整体配箍用量，同时减轻墙肢的损伤。采用低周往复循环试验、理论分析和数值模拟相结合的方法，对该新型UHTCC增强剪力墙体系的抗震性能和耗能机理进行了研究，评估了UHTCC材料对RC剪力墙抗震性能的改善作用。试验研究结果显示，UHTCC受压损伤对其受拉性能有影响，尤其是UHTCC遭受峰值损伤后受拉性能急速衰退，卸载与再加载残余变形的差异是一个变量并非常数，其随卸载应变增大差异逐渐明显；UHTCC作为护套或面层或全部代替混凝土应用于剪力墙体系关键构件或关键部位包括连梁、边柱、连梁与边柱节点以及墙体可在维持较高承载力下拥有高延性、高耗能和低损伤的抗震优势，同时也可明显减少箍筋用量和纵筋锚固长度，减轻施工难度，降低工程成本，可认为是钢筋混凝土剪力墙结构抗震减灾的一种新的高效技术。基于试验，建立了UHTCC循环拉压本构模型，能够较为准确反映循环拉压所经受的4个路径区，修正了箍筋约束UHTCC本构模型，基于拉压杆受力机制模拟了连梁整个非线性受力全过程，基于应力莫尔圆理论提出了UHTCC连梁的承载力计算公式，给出了考虑UHTCC贡献的边柱和节点的设计简化公式，提出了UHTCC面层增强剪力墙的压弯和压剪设计公式，提出了修正的抗震损伤评估模型，形成了基于性能的RUHTCC/RC组合剪力墙抗震设计方法，对推动UHTCC在剪力墙结构的应用具有重要工程指导意义。