UHPC缀板-钢管混凝土复合柱关键受力性能及设计方法研究

The composite concrete-filled steel tubular (CFST) columns is widely applied in the high pier bridge. The ultra-high performance concrete (UHPC) battened plate-CFST composite column is presented, which use UHPC batten plate to replace reinforced concrete batten plate, to solve the mismatch problem of bearing capacity between the reinforced concrete batten plate and the chords. With good matching, high bearing capacity, excellent seismic performance, it would be a new type of composite structure with developing potential..Based on the researches of cooperative force mechanism, ductility mechanism and failure mode of this new type composite column, as well as coordinate numerical simulation with experiment analysis, this project is expected to deeply investigate on its static and hysteretic properties, energy dissipation capacity, ductility, stiffness degradation and other seismic performances. Furthermore, the reasonable construction measures with calculation method of ultimate bearing capacity and restoring force model will be established. Significantly, This project reveals the failure evolution mechanism, sensitivity of each parameter and rules of failure mode which would be affected by force transmission mechanism, energy dissipation, structural deformation development and local damage evolution, and then the structural design control indicators will be proposed..Many innovative achievements of this new type of composite column, such as bearing capacity calculation method, ductility mechanism and design method which based on the failure modes can be obtained, as to provide theoretical support for the relevant standards and engineering design, which has important significance for promoting the innovation and development of our country's composite structure.

钢管混凝土复合柱在高墩桥梁中得到广泛应用，而使用超高性能混凝土（UHPC）作为缀板与钢管混凝土（CFST）柱肢组合形成的UHPC缀板-CFST复合柱可解决钢管混凝土复合柱中混凝土缀板和柱肢之间承载力不匹配的问题，且具有协同性好、承载力高、抗震性能优等特点，是一种具有发展潜力的新型组合结构。本项目拟以这种新型复合柱的协同受力机理、延性机制、失效模式为主线开展研究，综合运用数值模拟和试验方法，探讨其静力性能和滞回特性、耗能能力、延性、刚度退化等抗震性能，提出其构造措施、极限承载力计算方法及恢复力模型；揭示其失效演化机理；系统考察传力机制、耗能性能、结构变形发展及局部损伤演化等对失效模式的影响规律和各参数的灵敏度，提出结构设计控制指标。本项目可取得这种新型复合柱的承载力计算方法、延性机制和基于失效模式的设计方法等创新成果，为相关工程实际应用提供理论支撑，对促进我国组合结构创新和发展具有重要意义。

UHPC复合柱是以钢管混凝土四肢柱为柱肢、钢筋UHPC板为连接缀板的箱型多肢柱，具有承载能力高，抗震性能好，施工工艺简单等优点，有望成为我国高烈度地震带山区桥梁的高墩（超高墩）结构形式之一。本项目首先以柱肢钢管壁厚和UHPC缀板板厚为参数，开展了UHPC复合短柱轴压试验研究。通过试验研究了解结构中不同构件之间的传力机理、破坏形式和极限承载能力，结合有限元分析方法和扩展参数分析，提出合理的构造措施，得到短柱极限承载力的实用计算方法。其次，以偏心率为参数，开展了UHPC复合短柱偏压试验研究和有限元分析，得到了UHPC复合短柱偏心率折减系数和N-M曲线的计算方法。并以长细比和偏心率为试验参数，开展了UHPC复合柱双参数试验研究和有限元分析，提出UHPC复合中长柱极限承载力计算方法。此外，为了探讨此类结构在往复荷载作用下的受力性能滞回特性和耗能能力，本项目还进行了UHPC复合柱的滞回试验研究。在有限元和理论分析的基础上，提出峰值位移和极限位移的简化算法。同时，增加UHPC复合柱在主余震作用下的拟动力试验，提出地震作用下UHPC复合柱的屈服荷载位移、基底剪力和柱顶位移峰值的预估方法。最后，分析各参数对UHPC复合柱失效模式的影响规律，系统考察柱肢和缀板的匹配度、延性、耗能性能、刚度退化等参数对复合柱失效模式的灵敏性；提出UHPC复合柱的设计控制指标和设计准则。