摘要
该文基于一种新型高韧性低收缩ECC材料-LSECC,提出了两种后浇LSECC装配整体式框架节点方案,以达到提升高烈度区装配整体式框架节点抗震性能并简化配筋的目标。以节点模型为基础构建了对应的梁式构件,完成了5根后浇LSECC装配整体式梁的静力单调加载试验。通过对承载力、刚度、破坏形态与裂缝发展的分析,初步论证了LSECC应用于装配整体式节点的可行性和优势,并对界面(包括热接和冷接)构造、纵筋锚固等关键基础问题进行了探究,提出了合理的构造措施,为后续大比例梁柱节点抗震性能试验奠定了基础。试验表明:采用LSECC的装配整体式梁具有等同现浇梁的承载力和延性,且裂缝宽度相比混凝土梁明显减小;梁跨中采用ECC的范围越大,初始刚度越低,在加载过程中刚度退化越缓慢;ECC与钢筋具有更好的协同工作能力和粘结强度,其锚固搭接长度相比混凝土节点可显著降低,在装配整体式节点处应用该材料能够保证足够的粘结锚固能力;适当的界面构造配筋可有效提升后浇ECC与预制混凝土界面的力学性能,确保界面不成为薄弱面。
This paper proposes two kinds of monolithic precast frame joint schemes based on a new type of ECC material,named high-toughness low-shrinkage ECC(LSECC),to achieve high aseismic performance and simple reinforcement details in high earthquake intensity regions.According to the joint schemes,five assembled monolithic precast LSECC beams are constructed and tested under static monotonic loading.Based on the analysis of loading capacity,stiffness,failure mode and cracking behavior,the feasibility and advantages of application of LSECC in monolithic assembled joints are preliminarily verified.The critical problem such as interface details(including hot and cold connections)and longitudinal bar anchorage are carefully studied,and proper construction details are proposed,which effectively guides the subsequent study on the aseismic performance of large-scale monolithic precast beam-column joints.The test results show that the loading capacity and ductility of a monolithic assembled LSECC beam are equivalent with those of a cast-in-place beam while the crack width in ECC region is obviously smaller than concrete.The larger range of ECC used in the beam span leads to lower initial stiffness and slower stiffness degradation.Better deformation compatibility and higher bonding strength can be found between ECC and rebar,and the anchorage length is significantly reduced compared to the concrete joint.Therefore,the application of ECC in the assembled joints can ensure sufficient bonding and anchoring capacity.Proper reinforcement details can effectively improve the performance of the ECC-precast concrete interface,thus providing sufficient crack controlling capacity.
作者
丁然
芶双科
樊健生
张君
DING Ran;GOU Shuang-ke;FAN Jian-sheng;ZHANG Jun(Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education,Tsinghua University,Beijing 100084,China;Beijing Engineering Research Center of Steel and Concrete Composite Structures,Tsinghua University,Beijing 100084,China)
出处
《工程力学》
EI
CSCD
北大核心
2018年第10期56-65,74,共11页
Engineering Mechanics
基金
清华大学自主科研基金项目(20161080103)
国家自然科学基金项目(51708328)
中国博士后科学基金项目(2016M601039
2017T100083)