拉索火灾升温和灾后降温全过程构件性能演变规律研究

The key component of the prestressed steel structure system is the cable member, which are spun helically by different steel kinds of wires in several layers. The thermal performance and mechanical performance of the cable member are influenced signally by the cooperative performance of steel wires in the cable member. However, the research on the cable member performance during the complete process of fire is scarce. Therefore the fire-resistant performance of the cable member is not clear, which is seriously restricting the development of analysis and design theory based on fire-resistance of the prestressed steel space structure. Above all, theoretical analysis, numerical simulation and experimental study will be used in this topic. Based on the prominent twisting characteristics of the cable member, the variation of the thermal expansion and the mechanics performance of the steel wire during the complete process of fire will be studied. The variation of the cooperative performance of steel wires in the cable member during the complete process of fire will be analyzed. The fine finite element model will be built to accommodate the numerical simulation analysis during the complete process of fire. The empirical formula of the cable expansion coefficient will be deduced. The evolvement rule elastic modulus and strength of the cable member will be further explored with the effect of the arbitrary thermal-mechanical coupling approach considered. At last, an experimental investigation will be carried out to verify the validity of the theoretical analysis and the veracity of the fine finite element model. In the general, the performance of the cable member will be revealed during the complete process of fire. This study will been successfully applied to research the fire-resistance performance. Similarly, the in-depth development of related research will be promoted.

预应力空间钢结构体系核心构件拉索由中心钢丝和外层钢丝扭捻构成，其构件性能（热膨胀性能和高温力学性能）受钢丝之间的协同工作性能影响显著。然而目前尚缺乏关于拉索火灾升温和灾后降温全过程构件性能的系统研究，导致拉索构件抗火性能不清晰，严重制约预应力空间钢结构抗火分析设计理论的发展。基于此，本课题拟采用理论分析、数值模拟与试验研究相结合的方式，围绕拉索构件扭捻构成这一突出特点，考虑火灾升温和灾后降温全过程，研究钢丝热膨胀性能和力学性能变化规律，分析拉索构件钢丝之间协同工作性能的变化规律，建立适用于火灾全过程模拟分析的精细化有限元数值模型，推演拉索构件线膨胀系数变化规律的经验公式，探索任意力-热耦合作用途径下拉索构件弹性模量和强度指标变化规律，最后通过试验验证理论分析的正确性和精细化有限元数值模型的准确性，全面揭示拉索火灾升温和灾后降温全过程构件性能演变规律，为预应力空间钢结构抗火性能研究奠定基础。

预应力空间钢结构体系核心构件拉索由中心钢丝和外层钢丝扭捻构成，其构件性能受钢丝之间的协同工作性能影响显著。然而目前尚缺乏关于拉索火灾升温和灾后降温全过程构件性能的系统研究，导致拉索构件抗火性能不清晰，严重制约预应力空间钢结构抗火分析设计理论的发展。本项目将采用理论分析、数值模拟与试验研究相结合的方法，围绕拉索构件火灾全过程中拉索构件性能演变规律核心问题，对拉索构件精细化力学性能、热膨胀性能、高温蠕变性能开展了较为系统研究，建立了钢拉索精细化仿真分析模型；推导并验证了钢拉索力学性能、热膨胀性能、蠕变性能分析计算公式；获得了Galfan索和不锈钢索高温力学性能指标（抗拉极限强度、屈服强度、弹性模量）退化规律；揭示了Galfan索火灾高温作用下的力学行为。这些研究成果可以直接应用于已建成的预应力空间钢结构抗火性能评估与高温火灾后安全评定和待建的预应力空间钢结构性能化抗火分析设计。为完善预应力空间钢结构抗火分析设计理论奠定基础，从而推动预应力空间结构体系的防灾减灾技术的发展，具有显著的科学意义和工程应用价值。