高温下冷成型不锈钢方矩管的腹板压跛性能及设计方法研究

不锈钢是高性能的绿色环保建筑材料，在工程结构中具有广阔的适用性；不锈钢结构外观精美，通常不采用任何防火措施以体现出色的建筑表现力，而其材料自身耐火性能羸弱，须对不锈钢结构在高温下的受力特性开展专门的基础研究。腹板压跛是冷成型不锈钢结构构件最典型的破坏形式之一，高温下的腹板压跛破坏机理和设计方法是亟待研究的重要课题。本项目将以目前工程应用最为广泛的冷成型不锈钢管为研究对象，采用试验研究、数值模拟和理论分析相结合的方法，系统研究高温下冷成型不锈钢方矩管腹板压跛的力学性能，揭示高温下冷成型不锈钢方矩管的腹板压跛破坏机理，剖析其高温极限承载力的影响机制，提出高温-集中荷载耦合以及高温-集中荷载-弯矩耦合作用下的腹板压跛承载力计算方法。研究成果对不锈钢结构抗火设计理论提供重要补充，为确保不锈钢结构安全使用和完善相关设计标准提供有力支撑，具有十分重要的理论研究意义与工程应用价值。

Stainless steel is a type of high-performance green constructional material and is suitable to be used in a variety of engineering structures. Stainless steel structures have aesthetic appearance in nature and therefore are commonly constructed without any fire protection; hence, it is of great importance to conduct fundamental research on the structural behaviour of stainless steel structures at elevated temperatures. Web crippling is a typical failure for cold-formed stainless steel structural members while its failure mechanism and design rules at elevated temperatures remain as key unsolved issues in the research field. In this project, cold-formed stainless steel square and rectangular hollow section tubes, which have been recognized as one of the most widely employed stainless steel structural products, are selected to be investigated. Comprehensive experimental investigation, numerical modelling and theoretical analysis will be systematically employed in order to study the web crippling behaviour and design of cold-formed stainless steel square and rectangular hollow section tubes at elevated temperatures. The web crippling failure mechanism at elevated temperatures will be revealed and key influencing factors for the web crippling strength will be identified and analysed. Web crippling design rules will be developed for the determination of cold-formed stainless steel square and rectangular hollow section tubes subjected to elevated temperature-concentrated load coupling as well as elevated temperature-concentrated load-bending moment coupling effects. The expected research output of this project will be of significant academic and practical importance to enrich the existing structural fire design and enhance the safety of stainless steel structures with possible relevant design provisions for codes of practice to be established.