预制装配式ECC/混凝土组合框架结构抗震性能和设计方法研究

In this study, engineered cementitious composites (ECC), which is a class of high performance composites with ultra-high ductility, are proposed to substitute concrete at the locations of columns of first floor, beam-column joints and the connection zones of precast structural members in precast concrete frame structures. Firstly, component tailoring of ECC material by means of micromechanical model will be conducted for designing ECC materials with different compressive strengths. Based on mechanical tests and theoretical analysis, constitutive models of ECC under uniaxial tension or compression will be proposed, as well as flexural toughness of ECC materials. Then, the bond behaviors between ECC and high-strength steel bars and between ECC and fresh/hardened concrete will be experimental investigated, resulting in bond slip relations between ECC and high-strength steel bars and the analytical model of bond strength between ECC and concrete. Then, a number of high-strength steel reinforced ECC columns and precast ECC/concrete composite frames will be tested under reversed cyclic loading to study the effects of different parameters on its seismic performance, resulting in hysteretic models for R/ECC columns and ECC/concrete composite frames under earthquake action. Then, shaking table tests will be carried out on a precast ECC/concrete composite frame model and a conventional RC frame model to obtain the dynamic characteristics and study the effects of different seismic waves on the dynamic behaviors and seismic responses of the frames. Finally, an elastoplastic method and nonlinear time history analysis method will be used to analyze the seismic behaviors of the precast ECC/concrete composite frame structure. Based on the experimental and theoretical results, a performance-based seismic design method for the precast ECC/concrete composite frame structures will be proposed.

本课题提出采用超高延性纤维增强水泥复合材料（ECC）来浇筑预制混凝土框架结构的底层柱、梁柱节点和构件连接区域来提升结构的整体性和抗震性能。首先，基于细观力学方法对ECC的组成配比进行优化设计并制备不同强度等级的ECC材料，并通过试验和理论研究建立其单轴拉压下的本构关系和弯曲韧性性能。然后，对ECC与高强钢筋和干湿混凝土的粘结性能进行研究，建立ECC与高强钢筋的粘结滑移关系以及其与混凝土的粘结强度模型。对高强钢筋增强ECC柱和装配式ECC/混凝土组合框架进行低周反复荷载试验和数值分析，建立其在地震作用下的恢复力模型；对装配式ECC/混凝土组合框架结构模型进行振动台试验，得到其动力特性参数和不同地震输入下模型的动力响应，研究其抗震性能和损伤机理。最后，采用靜力弹塑性和弹塑性时程分析法分析装配式ECC/混凝土组合框架结构的抗震性能，建立基于性能的装配式ECC/混凝土组合框架结构的抗震设计方法。

装配式建筑能有效减少建筑垃圾和扬尘污染，缩短建造工期，提升工程质量。发展装配式建筑是实现建筑工业化的重要途径，是我国未来建筑发展的方向，也是当前国内外研究的热点问题之一。但是，装配式混凝土结构是由预制构件现场拼装或浇筑而成的，只有确保预制构件之间具有可靠连接，才能保证预制混凝土结构具有较好的整体性和抗震性能。本课题提出采用超高延性纤维增强水泥复合材料（ECC）来浇筑预制混凝土框架结构的底层柱、梁柱节点和构件连接区域来提升结构的整体性和抗震性能。首先，基于细观力学和先进微观测试技术，采用国产纤维及无机参合料制备了不同抗压强度且极限应变稳定达到3%的ECC 材料；研究了ECC 与钢筋粘结粘结性能，并提出了钢筋与ECC粘结滑移本构模型，基于有限元数值计算分析不同参数对钢筋与ECC粘结性能的影响；研发了装配式框架结构中钢筋连接用灌浆套筒，并获得授权发明专利；对高强钢筋增强ECC 柱，装配式ECC/混凝土组合节点，ECC/混凝土组合框架结构进行水平低周反复荷载试验，建立其恢复力模型，分析了不同参数（轴压比、配箍率等）对其抗震性能的影响；对装配式ECC/混凝土组合框架结构缩尺模型进行振动台试验，得到其动力特性参数和不同地震输入下的动力响应，掌握其地震作用下的破坏机理；基于非线性有限元法对ECC 柱、ECC/混凝土组合框架结构进行地震作用非线性时程分析，得到不同参数对ECC柱和组合框架结构抗震性能的影响；提出装配式ECC/混凝土组合框架结构的抗震性能指标，对ECC/混凝土组合框架结构进行弹塑性时程分析，提出了组合框架结构优化设计方法。以上研究成果的推广应用将有助于装配式混凝土结构在我国特别是高烈度抗震设防地区的推广应用，促进我国建筑业的转型和升级。