基于UHPC连接技术的新型预制混凝土框架结构抗震性能与设计理论

In recent years, there have been many important progresses on ultra high performance concrete(UHPC) all of the world, including preparation technology without thermal curing, improvement of mechanical properties, along with significant cost reduction, which makes UHPC have good application prospects in the field of precast concrete structure. The aim of this project is to develop a new precast concrete frame structure system based on UHPC connecting technique, which can improve ductility of frame connections by optimizing setting of UHPC beam ends, and achieve efficient anchorage of the reinforcements in beams and columns by using UHPC in core region. The project will systematically carry out experiments and theoretical researches on the bond-anchorage behavior of reinforcements in beam and column, as well as the seismic performance of precast members and frame structures. Through the studies, bond-slip constitutive model of reinforcing bar in UHPC will be established, seismic design method of the frame members and the connections considering the high tensile strain-strengthening characteristic of UHPC will be proposed, meanwhile the corresponding restoring force model and its calculation method of characteristic parameters will be installed. Additionally, the seismic performance of the structure system, with emphasis on damage mechanism, optimal failure mechanism and its controlling approach, will be systematically studied to determine the maximum applicable height of the structure under different seismic fortification intensities. Based on the above works, the project will systematically develop a performance-based seismic design theory of high-rise frame structure based upon multiple performance indexes. The results of this project will provide theoretical bases for the application of UHPC in the precast concrete frame structures and the draft of the relevant design standards.

近年来国内外在超高性能混凝土（UHPC）的常温制备技术和物理力学性能提升等方面取得了重要进展，材料成本也显著降低，这使得UHPC在预制混凝土结构领域具有良好的应用前景。本项目首先研发基于UHPC连接技术的新型预制混凝土框架结构体系，该体系通过优化设置UHPC梁端提升框架节点延性，并利用UHPC实现节点区梁柱钢筋的高效锚固。拟系统开展梁柱钢筋粘结锚固性能以及构件与结构抗震性能的试验与理论研究，建立UHPC中钢筋粘结滑移本构模型；提出考虑UHPC高拉伸应变强化特性的梁柱构件与框架节点抗震设计方法，建立相应的恢复力模型及其特征参数计算方法；研究地震作用下高层框架结构的损伤机理，提出最优破坏机制与控制方法，优化确定结构在不同抗震设防烈度下的最大适用高度；在上述研究基础上，系统提出高层框架结构基于多种性能指标的抗震设计理论。本项目成果将为UHPC在预制混凝土框架结构中的应用以及标准编制提供理论基础。

近年来国内外在超高性能混凝土（UHPC）的常温制备技术和物理力学性能提升等方面取得了重要进展，材料成本也显著降低，这使得UHPC在预制混凝土结构领域具有良好的应用前景。因此，本项目系统开展了基于UHPC连接技术的新型预制混凝土框架结构抗震性能与设计理论。提出了UHPC连接优化方案，研发了基于UHPC连接技术的预制混凝土框架结构体系。通过32组拔出/梁式试验和双排搭接试验，建立了UHPC中钢筋的粘结-滑移本构模型，提出了UHPC中钢筋锚固长度与搭接长度计算方法和设计建议。通过6个足尺模型的拟静力试验和20个有限元模型非线性模拟，研究了基于UHPC连接技术的预制构件抗震性能，优化确定了梁、柱构件中UHPC段长度，得到了轴压比、配筋率等关键参数对构件抗震性能的影响规律，并提出了构件的恢复力模型。基于大型商用有限元软件ABAQUS，开展了该预制混凝土框架结构的拟静力和时程分析，揭示了结构的破坏机制。基于标准单元的子结构虚拟混合试验（MATLAB-OpenSees混合试验平台），优化确定了子结构的边界条件，揭示了不同地震动水准下该预制混凝土框架结构的抗震性能演变规律。在上述研究工作的基础上，提出了该预制混凝土框架结构基于性能的抗震设计建议。本项目成果已纳入上海市标准，为基于UHPC连接技术的预制混凝土框架的工程应用提供了技术依据。项目发表或录用高水平SCI论文11篇、EI论文2篇。授权发明专利1项，申请发明专利3项，获批软著2项。主编地方标准1部。培养博士研究生5名、硕士研究生3名。