刘家峡大桥钢管混凝土桥塔黏结滑移力学试验研究

Mechanical Experimental Research of Bond-slip of CFST Pylon of Liujiaxia Bridge

刘家峡大桥首次在国内采用大规模钢管混凝土构件作为悬索桥桥塔。为保证该桥桥塔在施工各阶段的安全性,模拟刘家峡悬索桥桥塔实际受力制作1/10缩尺比例模型进行加载试验,并采用ANSYS软件建立有限元模型对试验结果进行验证与对比,研究钢管混凝土结构钢管与混凝土的黏结滑移力学性能。研究结果表明:当试验荷载超过钢管与混凝土黏结力后,钢管和混凝土的相对位移与试验荷载呈线形变化关系;钢管应变从受力端向构件中部逐渐减小,受混凝土材料的不均匀性、钢管壁的粗糙程度不同等因素的影响,钢管应变与距加力端距离呈非线性变化关系,但总体呈逐渐增加趋势;通过试验结果得到的黏结强度及滑移位移均大于有限元软件计算结果,但两者相差不大,说明有限元结果可用于实际工程,并偏于安全。

The large-scale Concrete-filled Steel Tube （CFST） members are first used in domestic for the suspension bridge pylon of Liujiaxia bridge. In order to ensure the safety of the pylon during construction, a 1/10 scale model of original Liujiaxia suspension bridge pylon is constructed for loading test, and the verification and comparison with the test result are performed by establishing finite element model using ANSYS software to study the bond-slip mechanical performance of the concrete and steel of CFST structure. The result shows that （ 1 ） the relative displacement of concrete and steel tube is proportional to the test load when the test load exceeds the bond force; （2） the strain of steel tube decreases gradually from stress end region to the middle part, due to the effect by inhomogeneity of concrete and difference of the wall roughness of the steel tube and other factors, the strain of steel tube has a non-linear relation with the distance from stress end region, but it overall shows a trend of increase gradually; （3） the bonding strength and slip displacement obtained by test are greater than the finite element calculation result, but it is a little difference between the 2 results, so the finite element result can be used in the practical engineering, and it is rather safe.