U形RPC预制梁外壳装配整体式框架结构性能与设计研究

In this project, a assembly integrated frame structure using precast RPC U-shell beams are proposed to improve the performance of the assembled integrated reinforced concrete frame structure. The precast reinforced U-shell is made by RPC with ultra high strength and high cracking strain, and the core cast normal concrete (NC) to solve the traditional composite beam poorly integrity. The composite beam can meet the demand for long span building. To secure the design idea “strong component-weak joint”, plastic hinge relocation method will be used. The interface strength and combining work behavior between RPC and NC were studied by the experimental and theoretical analysis. Degradation mechanism of the bond behavior was analyzed, and constitutive model of composite concrete will be put forward. The tests on mechanical property of precast reinforcement RPC U-shell and RPC-NC composite beam would be carried out, the failure mechanism will be analyzed. The calculation formula of cracking moment will be deduced, which consider the influence of longitudinal tensile bar. The influence of tensile stress in RPC on the stiffness and ultimate bearing capacity will be evaluated quantitatively, and the calculation method will be proposed. Based on quasi static test of assembly integrated beam-column joint and frame structure, the seismic performance and failure mechanism will be analyzed. A formula for calculating the shear carrying capacity of assembly integrated beam-column joint will be proposed. The seismic design methods of the assembly integrated frame structure will be developed, including the limit value of maximal inter-story displacement angle under different performance level of structure. The results can provide theory basis for the seismic design of assembly integrated RC frame structure.

本项目以提高装配式混凝土框架结构的性能为目标，提出了一种使用U型RPC预制梁外壳的装配整体式框架结构。采用具有超高强、高开裂应变的RPC预制U型外壳兼做梁模，能满足结构大跨度、大空间的需求，核心后浇普通混凝土（NC），克服传统叠合梁整体性差的缺点。采用塑性铰外移的设计保证强节点、弱构件。通过试验和理论分析研究RPC-NC协同工作性能及界面黏结性能，提出RPC-NC黏结退化机理及RPC-NC组合截面材料本构模型；通过预制RPC梁外壳、RPC-NC组合截面梁性能试验研究其受力破坏机理，提出考虑纵筋贡献的开裂弯矩计算方法和考虑RPC拉应力影响的组合截面梁承载力、刚度计算方法。通过拟静力试验研究装配整体式RPC-NC组合节点及框架抗震性能及破坏机理，建立节点受剪承载力计算公式，提出不同抗震性能水平的层间位移角限值及抗震设计方法。为装配整体式RC结构的抗震设计提供理论依据。

活性粉末混凝土（RPC）具有超高强、高开裂应变的新型超高性能混凝土材料。采用RPC制作U形预制梁模板兼做永久模板，内部浇筑普通混凝土（NC），在克服传统叠合梁整体性差的基础上，满足了结构大跨度、大空间的需求。. 本项目通过预制U形RPC梁外壳的受弯、受剪性能试验，得到了预制U形RPC梁外壳的受力破坏过程及破坏形态，分析了预制模板底面厚度、侧壁宽度、配筋对其破坏形态的影响。基于RPC受拉本构模型，分析了受拉区RPC应力对永久模板抗弯承载力贡献的计算方法，提出了预制U形RPC永久梁模板受弯、受剪破坏的开裂弯矩、极限承载力计算方法。为U形RPC永久梁模板在装配式结构中的应用奠定了基础。. 通过劈裂抗拉、单槽抗剪试验得到了界面粗糙度、钢纤维体积掺量及RPC水胶比对界面粘结的影响机理。确定了开槽密度、NC强度对于RPC-NC抗剪强度的影响规律，提出了粘结面抗剪强度的计算公式。.通过RPC-NC组合梁的受剪试验，得到了叠合梁开裂、屈服、极限状态下的荷载，分析了RPC与NC的协同工作性能，研究了剪跨比、核心混凝土NC强度等级、配箍率等参数对RPC-NC叠合梁抗剪承载力的影响规律。通过RPC-NC组合梁的受弯试验，研究RPC与NC粘结性能对于组合梁受弯承载力的影响，提出了RPC与NC粘结的最佳处理方式。. 通过拟静力试验，得到了装配整体式 RPC-NC组合梁柱节点的连接筋构造、梁内延伸长度等对节点的失效机制、恢复力、承载力等特性的影响，提出了塑性铰外移的设计方法； 基于钢筋应变分布，采用曲率等效的方法确定了试件的等效塑性铰长度，建立了考虑附加筋参数的等效塑性铰长度计算方法。并得到了考虑附加筋长度的极限转角计算方法。通过拟静力试验得到了装配整体式 RPC-NC组合框架的滞回特性、承载力、延性、耗能等，研究其合理的耗能机制，验证了装配整体式 RPC-NC组合框架具有比现浇框架更高的抗震性能。