双向地震作用下型钢-混凝土组合框架结构损伤机理和设计方法研究

Closely combined with the engineering practice of our nation, damage evolution and failure mechanism of steel reinforced concrete (SRC) composite frame structures subjected to bi-directional loading are studied through model test, numerical simulation and theoretical analysis. Force mechanism, hysteretic performance and energy dissipation capacity are analyzed. Section yield criterion, failure criterion and restoring force model considering biaxial coupling effect are studied. The modeling theory and method for SRC composite frame structures subjected to bi-directional earthquake action are put forward. The optimization of damage mechanism, failure pattern and its rational evaluation criterion are established for SRC composite frame structures subjected to bi-directional earthquake actions. The relationship among damage degree, plastic deformation and bearing capacity for the damage location, where SRC composite frame structures happened in optimal failure mode, are studied. And damage limit value and its control criterion are established for structures under various performance levels. Seismic performance level, performance parameter and performance index for SRC composite frame structures under biaxial earthquake action are put forward, and the seismic design method based on damage mechanism control is proposed. This project research can afford basic data and technical support for seismic performance design for SRC composite frame structures subjected to bi-directional earthquake actions.

紧密结合我国工程实际，针对型钢-混凝土组合框架结构，通过模型试验、理论分析和数值模拟，揭示其在双向加载下的损伤演化规律和破坏机理，考察双向加载下型钢混凝土组合柱的受力机理、滞回性能及耗能能力等，建立考虑双轴耦合效应的截面屈服准则、破坏准则和恢复力模型，提出型钢-混凝土组合框架结构双向地震作用下的建模理论和方法；研究双向地震作用下型钢-混凝土组合框架结构的最优损伤机制和破坏模式，并建立最优损伤机制合理性的评价标准与方法；研究基于最优损伤机制结构损伤部位损伤程度与其塑性变形和承载力之间的关系及其在不同性能水准要求下的损伤程度限值和损伤程度控制准则。建立双向地震作用下型钢-混凝土组合框架结构的抗震性能水准、性能参数及性能指标，提出其基于损伤机制控制的抗震设计方法。此项目研究可为双向地震作用下型钢-混凝土组合框架结构的抗震性能设计提供基础资料和技术支撑。

紧密结合我国工程实际，采用理论分析、试验研究和数值模拟方法，全面系统的研究了双向地震作用下型钢-混凝土组合（SRCC）柱的损伤演化、抗震性能及双向地震作用下SRCC框架结构的响应分析。首先，借助有限元软件，研究了配钢形式、轴压比、加载路径、循环次数、位移幅值增量和变轴力作用对SRCC柱抗震性能的影响。其次，通过试验研究，分析了不同加载路径形式和配钢形式下SRCC柱的滞回性能、刚度退化、承载力退化、位移延性系数、耗能能力和钢板及钢筋应力水平等，揭示了双向加载作用下SRCC柱的损伤过程和受力机理，探明了加载路径、循环次数、幅值增量和变轴力作用等不同加载制度下组合柱内力和弹塑性变形分布规律。结果表明：在变轴力作用下柱表现出明显的不对称性，且其抗震性能明显较定轴力作用下更为不利。在相同含钢率下方钢管型钢混凝土柱的变形能力比十字型钢混凝土柱的大；加载路径对试件滞回特性影响显著，在非对称路径加载下，滞回特性亦表现出明显的非对称性；与单向循环加载试件相比，双向循环加载试件的峰值荷载小、刚度退化快、屈服位移小、延性差及破坏位移角小，但其累积滞回耗能明显大于单向循环加载时的情况；在位移加载后期，双向循环加载试件纵筋及型钢应变增长明显较单向加载试件的快。最后，建立了双向偏心受压组合柱正截面承载力计算方法和双向地震作用下SRCC框架结构谱分析和两阶段Pushover分析，分析表明，所提方法计算结果精确。项目研究成果对丰富和补充型钢混凝土组合结构的抗震设计理论与方法具有较重要的意义。