预应力轴心受力钢构件抗火性能

The pre-stressed steel members are important components in the large space steel structures. How the pre-stress affects the fire resistance of pre-stressed member under axial tension and compression is an interesting topic in the structural fire resistance. The object of the applying project is to explore the mechanism of influencing of pre-stress on the fire resistance of pre-stressed members under axial load at high temperatur.To study the influence of pre-stress on the fire resistance of structural link- members, the applying project focuses on the fire resistance of the pre-stressed members under axial load by means of the theoretical analysis, the experiment study and numerical simulations based on the tension test and creep experiments of stayed cable at high temperature.To verify the aforementioned theoretical analysis and numerical simulation, the experiments of members under axial tension and axial compression at high temperature will be conducted in the lab of structural fire resistance objected to ISO834. In the project, the key issues to be solved are about the variation of internal force of core column, stayed cable and the axial stiffness of axial tension and compression members with time at high temperature. By the systematic research about the pre-stressed members at high temperature in the project, the basic laws of fire resistance of pre-stressed members under axial tension and compression can be revealed. The basic law about the fire resistance of prestressed members at high temperature is significant for the design of the fire resistance of prestressed members The basic results of the study in the project will supply the important references for the setting of code for fire resistance design of prestressed steel members in building.

预应力轴心受力构件是预应力钢结构的重要组成部分。火灾作用下，预应力对轴心受力构件的抗火性能产生怎样影响，是预应力结构抗火设计的核心问题。项目以火灾高温下预应力轴心受拉和轴心受压构件的抗火性能为研究对象，在进行预应力材料高温本构关系和蠕变试验基础上，采用理论分析、试验研究和数值分析手段进行预应力钢构件在火灾下的力学性能研究。辅以典型预应力轴心受力钢构件在火灾作用下的试验，研究火灾中的预应力刚性构件及索的内力、轴向刚度随时间的变化规律、破坏形态及临界温度，同时对理论分析和数值计算方法的可靠性进行验证。在此基础上，通过参数分析，甄别影响预应力钢构件高温抗火性能的主要因素。探索预应力轴心钢构件火灾高温下的内力变化、刚度变化及破坏的形成机制。通过理论分析、数值计算建立预应力构件火灾高温下计算模型和承载力验算方法。研究成果有助于加深预应力钢构件火灾下的性能的认识，促进预应力钢构件在工程中的应用。

预应力轴心受力构件是预应力钢结构的重要组成部分。火灾作用下，预应力对轴心受力构件的抗火性能是预应力结构抗火设计的核心问题。项目以火灾高温下预应力轴心受拉和轴心受压构件的抗火性能为研究对象，在进行预应力材料高温本构关系和蠕变试验基础上，采用理论分析、试验研究和数值分析手段进行了预应力钢构件在火灾下的力学性能研究。通过预应力钢绞线火灾下的蠕变试验，提出了工程中1860级钢绞线的蠕变模型。另外，进行了预应力轴心受力钢构件在火灾作用下的试验，研究了火灾中的预应力刚性构件及索的内力、轴向刚度随时间的变化规律、破坏形态及临界温度，同时对理论分析和数值计算方法的可靠性进行验证。在此基础上，通过参数分析，确定了影响预应力钢构件高温抗火性能的主要因素。明确了预应力轴心钢构件火灾高温下的内力变化、刚度变化及破坏的形成机制。通过理论分析、数值计算建立了预应力构件火灾高温下计算模型和承载力验算方法。在全面分析和研究基础上，提出了预应力钢构件抗火设计的实用设计方法。