独立基础上钢筋混凝土框架子结构屈服机制研究

There exist many differences not only between real and ideal embedding performance of RC frame column bottom on single foundation under soil constraint, but also between RC frame failure mechanism with cast-in-situ floor and frame without cast-in-situ floor at ultimate state. Under loading, the bearing performance and yielding mechanism of bottom frame or whole frame depend on soil, foundation, frame, and cast-in-situ floor..Our researching interests are kept on the self bearing behavior and failure mode of RC single foundation, effective simulation of cast-in-situ floor failure process, and its influence on the yielding mechanism of RC frame structure in this applying research project. The lateral bearing test of RC single foundation in soil, plan frame substructure on RC single foundation in soil in soil will be carried out. The embedding and consraint performance, probability mode, and structural riliability of single foundation, the lateral bearing capacity, failure process and effect factors of frame substructure with cast-in-situ floor on RC single foundation in soil will be obtained..Along with the finite elemetn method verification, expandsion and further analysis, the failure mechanism and failure mode of system, made of cast-in-situ floor, frame, single foundation and soil, will be explored. The failure process and yielding mechanism of frame substructure with cast-in-situ floor on RC single foundation in soil will be analyzed and mastered in the following research work..Obtaining the rational calculation model, sensitive factors, and the most unfavorable failure mode, the realization mechanism of "beam hinge mechanism" and "strong column and weak beam" will be explored from another point of view. Some insightful contributions will be put forward, which is important and meaningful to the improve and perfect of analysis model and design theory of frame substructure with cast-in-situ floor on RC single foundation in soil.

极限状态时，地基约束下独立基础上框架底层柱下端真实嵌固性能和理想固支约束之间、空框架屈服机制与带现浇楼盖框架之间均存在差异。荷载作用下，地基、基础、框架、现浇楼盖共同决定底层框架乃至整栋框架的承载性能和屈服机制。围绕柱下钢筋混凝土独立基础承载特性和失效模式、现浇楼盖的失效过程和有效模拟、地基和楼盖对框架屈服机制的影响进行深入研究，通过柱下独立基础的单调抗侧和低周反复荷载试验、独立基础上框架子结构的单调抗侧及拟动力试验，明确独立基础嵌固特性、失效概率模型和结构可靠度、框架子结构抗侧承载力、破坏过程及影响因素。结合有限元验证、拓展和深入分析，探索现浇楼盖-框架-基础-地基系统的破坏机理和失效模式，掌握独立基础上框架子结构破坏过程和屈服机制，获取合理的计算模型、敏感参数、失效模式及其对“梁铰机制”、“强柱弱梁”形成机制的影响，对完善独立基础上框架结构抗震和抗倒塌分析模型和设计理论均具有重要意义。

极限状态时，地基约束下独立基础上框架底层柱下端真实嵌固性能和理想固支约束之间、空框架屈服机制与带现浇楼盖框架之间均存在差异。荷载作用下，地基、基础、框架、现浇楼盖共同决定底层框架乃至整栋框架的承载性能和屈服机制。围绕柱下钢筋混凝土独立基础承载特性和失效模式、及其影响因素进行深入研究。..项目主要完成了以下工作：..(1)地基－独立基础－柱子结构及复杂受力状态下子结构的性能试验研究，包括：考虑地基影响的地基模拟装置开发；考虑地基影响的独立基础－柱子结构抗侧试验；考虑地基影响的柱－独立基础节点偏压状态下抗冲切性能试验；考虑地基影响的独立基础上框架子结构抗震性能性能试验；复杂受力状态下混凝土梁-柱子结构承载性能试验。..(2)考虑地基影响的独立基础上框架子结构性能有限元数值模拟，包括：柱－独立基础子结构承载性能数值模拟与参数分析；偏心受压柱下独立基础抗冲切性能数值模拟与参数分析；独立基础上框架结构抗震性能数值模拟与参数分析；复杂受力状态下土梁－柱子结构性能数值模拟与参数分析。..(3)钢筋混凝土构件、子结构或结构抗震性能研究与分析，包括：基于ABAQUS考虑钢筋影响的混凝土收缩徐变分析；三维高层框架结构的Pushover分析顶点位移的保证率分析；装配式滑支板式楼梯对框架结构的抗震性能影响；现浇框架结构抗震倒塌可靠度及敏感性研究；基于动力特性测试的双参数地基基床系数的取值方法；考虑弯剪相关性的受弯构件承载力计算；带现浇楼板框架结构抗震性能的多因素影响分析；柱-独立基础-地基子结构抗震可靠度分析；独立基础上框架结构的抗震性能分析。..通过试验，结合有限元验证、拓展和深入分析，探索现浇楼盖-框架-基础-地基系统的破坏机理和失效模式，掌握独立基础上框架子结构破坏过程和屈服机制，获取合理的计算模型、敏感参数、失效模式及其对“梁铰机制”、“强柱弱梁”形成机制的影响，对完善独立基础上框架结构抗震和抗倒塌分析模型和设计理论均具有重要意义。

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