火灾作用下斜拉索桥梁结构力学响应研究

Analysis on mechanical response of cable-stayed bridge structure under fire

通过有限元软件Midas/Civil建立两跨的斜拉桥有限元模型,考虑到不同区域的斜拉索火灾作用情况,对斜拉桥在斜拉索火灾作用下的结构力学响应进行分析,得到了斜拉桥主梁竖向位移、主塔的纵向位移以及斜拉索的应力变化。模拟结果表明:斜拉索不同区域受火时对主梁竖向位移、桥塔纵向位移影响均不相同;长索对主梁位移作用要远远大于中索、短索;1区受火时,主梁跨中竖向位移以及桥塔测点A纵向位移最大;受火拉索的应力值锐减,附近拉索的应力值急剧增加。

A two-span cable-stayed bridge finite element model was established by Midas/Civil.The mechanical response of cable stayed bridge under the effect of cable fire in different regions was analyzed.The vertical displacement of the main girder,the longitudinal displacement of the bridge tower and the variation of the stress of the stay cable were obtained.The results showed that：the vertical displacement of the main girder and longitudinal displacement of the bridge tower were different under the cable fire indifferent regions;the displacement of long cable on fire was far greater than that of middle cable and short cable on fire;the vertical displacement of main beam mid-span and the longitudinal displacement of point A was the biggest,when the 1-part was under fire;the stress value of the cable under fire is reduced and that of the adjacent cable increases rapidly.