带压制锚具的高钒镀层拉索火灾后的力学性能（英文）

Post-Fire Mechanical Properties of Galfan-Coated Steel Cables with Extruded Anchorages

高钒镀层拉索作为一种主要受力构件越来越广泛地应用于预应力钢结构当中。若火灾后结构整体未发生倒塌,则需要对其中拉索性能的改变进行准确评估以确保安全。本文对带有工程中常用的压制锚具的高钒拉索火灾后力学性能进行了试验研究。对经历13个预定温度后的拉索试件进行拉伸试验,考虑了空气自然冷却和消防喷水冷却两种冷却方式。试验得到了试件的荷载-位移曲线、初始刚度、承载力和变形能力等力学性能,并讨论了锚具的影响。拉索试件的力学性能在经历超过400℃高温后明显改变,此外不同冷却方式的影响也非常显著:经过消防喷水冷却的拉索试件在经历700℃高温后几乎丧失了全部承载力和变形能力。最后提出了计算带压制锚具的高钒拉索火灾后力学性能的经验公式,并考虑不同冷却方式影响。

Galfan-coated steel cables are increasingly used as key load-bearing members in prestressed steel structures.Even if the general appearance of a structure is acceptable after a fire event,its effect on the behavior of the steel cables in these structures must be estimated accurately to ensure safety.Therefore,an experimental study was conducted to investigate the post-fire mechanical properties of Galfan-coated steel cables with extruded anchorages,which is a commonly-used anchorage method in prestressed steel structures.Tensile tests were performed on specimens after exposure to13preselected temperatures up to1000℃.Two different cooling methods,i.e.,air cooling and water cooling,were considered.Related mechanical properties,such as load-displacement curves,initial stiffness,loadbearing capacity,and deformation capacity,were obtained,and the effects of the anchorages are discussed.The mechanical properties of the studied cable specimens significantly changed after exposure to temperatures exceeding400℃.Moreover,the influence of the different cooling methods was remarkable;the water-cooled specimens lost most of their load-bearing and deformation capacities when the exposure temperature exceeded700℃.Empirical equations incorporating the influence of the different cooling methods are proposed to predict the post-fire mechanical properties of Galfan-coated steel cable with extruded anchorages.