偏心受拉作用下预应力CFRP筋型钢混凝土结构体系受力行为及地震灾变控制研究

In our country, there are many eccentric tension members, such as steel structure truss transfer layer straining beam, low-rise building corner column. At present, there is no design specification for these members and the members will appear large area cracks during normal use stage. Aiming at these problems, this paper puts forward the prestressed CFRP tendons steel reinforced concrete structure system which can not only effectively restrain the crack, but also is lightweight, high-strength, anticorrosive. It is necessary to further study eccentric tension mechanism, structure seismic performance and catastrophe control method. By means of experiment and theoretical analysis, the bond slip and joint working performance of concrete and prestressed CFRP tendons are studied in order to establish the design method of prestressed CFRP tendons steel reinforced concrete eccentric tension members. By analyzing dynamic characteristics and time history nonlinear seismic responses of the structure, the transformation characteristic and evolution rule of damage accumulation in structural member and the structure under earthquakes are revealed. The seismic design method based on seismic damage performance is put forward. Study on the internal force transmission mechanism, failure mode and collapse mechanism of the prestressed CFRP tendons steel reinforced concrete eccentric tension members under the earthquake action. The damage-reduction based structural optimization design model is established to realize the damage control of the structure. The project features the combination of new structure and new technology, and has great significance on the development of steel structures and earthquake resistance and disaster mitigation of buildings.

为了解决我国型钢结构桁架转换层拉杆、低层角柱等偏心受拉构件无设计规程，且其在正常使用阶段就出现大面积拉裂缝的问题。本课题提出能有效抑制裂缝的产生，轻质高强、防腐的预应力CFRP筋型钢混凝土结构体系，对其偏心受拉机理、结构的抗震性能、灾变控制方法进行深入系统的研究。通过试验及理论分析，研究型钢与预应力CFRP筋混凝土部分粘结滑移及共同工作性能，据此建立预应力CFRP筋型钢混凝土偏心受拉构件的设计方法；进行结构动力特征及非线性地震响应全过程分析，揭示地震作用下损伤积累在构件、结构两种不同尺度的转换特征及演化规律，提出基于地震损伤性能的抗震设计方法。通过研究预应力CFRP筋型钢混凝土偏心受拉构件在高层、大跨结构在地震作用下内力传递机制、破坏模式及倒塌机制，建立基于分灾模式的结构优化设计模型，以实现结构的灾变控制。本项目以新结构与新技术结合为特色，对我国型钢结构的发展、建筑的防震减灾具有重要意义。

为解决我国型钢混凝土结构体系在偏心受拉作用下易出现大面积拉裂缝的问题，本项目创新提出预应力CFRP筋型钢混凝土结构体系(Prestressed CFRP reinforced steel concrete structure system)。项目结合静力试验与低周反复试验，并通过理论分析与有限元模拟的方法，探究了预应力CFRP筋型钢混凝土组合构件在偏心受拉荷载作用下与拉-弯-剪复合荷载作用下的受力性能，同时进一步研究了预应力CFRP筋型钢混凝土桁架转换结构体系在竖向受拉与水平力往复荷载作用下各构件的受力行为。在预应力CFRP筋型钢混凝土组合柱试验的基础上，推导出预应力CFRP筋型钢混凝土组合构件偏心受拉承载力计算公式与侧向挠度计算公式，提出了预应力CFRP筋型钢混凝土偏拉组合柱受拉开裂计算方法，最后，建立了区分型钢约束区与非约束区计算截面的预应力CFRP筋型钢混凝土组合结构有限元计算模型。在预应力CFRP筋型钢混凝土桁架转换结构试验的基础上，提出了预应力CFRP筋型钢混凝土桁架斜腹杆预应力损失计算方法，建立了预应力CFRP筋型钢混凝土桁架转换结构体系有限元模型，并进行了基于轴压比与预应力张拉水平的参数分析，并建立基于分灾模式的结构优化设计模型。通过整理目前预应力CFRP筋型钢混凝土结构体系的研究成果，对于推广我国预应力CFRP筋型钢混凝土结构体系的工程应用，具有重要参考意义。