斜腿倾角对斜腿刚构桥主梁受力特性的影响研究

Study on Effect of Inclination Angles on Mechanical Characteristics of Main Girder of Slant-leg Rigid Frame Bridge

以河南少林寺至洛阳高速公路某斜腿刚构桥为工程背景,通过MIDAS CIVIL建立不同斜腿倾角的斜腿刚构桥有限元模型,研究了自重、预应力、整体温度、温度梯度、混凝土收缩徐变作用等各条件下斜腿倾角对斜腿刚构桥主梁受力特性的影响,得到了斜腿倾角对斜腿刚构桥主梁挠度和应力的影响规律。研究表明:与温度梯度作用下相比,整体温度作用下斜腿倾角的变化对斜腿刚构桥主梁的受力特性影响相对较大;预应力荷载作用下,斜腿倾角较小时,斜腿与主梁的结合位置将发生下挠,导致斜腿刚构桥中跨的起拱效果减弱,而对边跨的起拱效果影响不大;在混凝土收缩徐变作用下,随着斜腿倾角的增大,斜腿刚构桥的跨中挠度逐渐下降。

With the slant-legged rigid frame bridge from Shaolin Temple of Henan to Luoyang Expressway as the engineering background,the finite element model of slant-legged rigid frame bridge with different inclination angles was established by MIDAS CIVIL. The influences of the slant leg inclination angles on the mechanical behaviors of the main girder of the slant-leg rigid frame bridge were studied under the conditions such as the dead load,pre-stress,bulk temperature,temperature gradient and concrete shrinkage and creep action etc. The influence law of the slant leg inclination angle on the deflection and stress of the main girder of the slant-leg rigid frame bridge was obtained. The research shows that,compared with the conditions of temperature gradient,the variation of the inclination angles of the slant-leg under the overall temperature has a relatively large influence on the mechanical characteristics of the main girder of the slant-leg rigid frame bridge. Under the prestressed load,when the inclination angle of the slant-leg is small,the joint position of the slant-leg and the main beam will be deflected downward,which results in the weakening of the arching effect of the mid-span of the slant-leg rigid frame bridge,but has little effect on the arching effect of the side span. Under the effect of concrete shrinkage and creep,the mid-span deflection of the slant-leg rigid frame bridge gradually decreases with the increase of the inclination angle of the slant-leg.