混合梁斜拉桥钢混结合段试验与传力机理研究

武汉二七长江大桥为三塔混合梁斜拉桥,为验证其主梁钢混结合段构造的合理性,设计并制作了几何缩尺比为1∶3的主梁钢混结合段试验模型.对模型进行了试验研究,分别考察了在正常使用荷载作用下、设计极限荷载作用下及1.7倍设计极限荷载作用下钢混结合段钢构件与混凝土构件的应力分布情况及钢混结合段的承载性能,基于对钢混结合段钢板与混凝土之间2种不同连接方式的假设,分别建立了相应的有限元计算模型,研究2种不同的传力机理.模型试验和有限元计算分析表明：武汉二七长江大桥主梁钢混结合段的承载能力满足设计要求,剪力钉的剪切刚度对钢混结合段的受力与传力影响较大.

Model test and transfer mechanism of steel-concrete composite structure for hybrid girder cable-stayed bridges

The Wuhan Erqi Changjiang River Bridge is a hybrid girder cable-stayed bridge with three pylons.In order to test and verify its rationality of the connections construction of the main beam steel-concrete composite structure,a scale model of the main beam steel-concrete composite structure was designed for static experiments.In the model,the ratio of the scale model to the original structure was 1∶3.The model test was used to check the normal stress distribution and the bearing capacity of the main beam steel-concrete composite structure under the normal service load,design ultimate load and 1.7 times design ultimate load.It is assumed that there are two difference connection ways between the steel plate and the concrete box girder of the steel-concrete composite structure.Then two difference finite element models were established,and two difference force transmission between the steel plate and the concrete box girder of the steel-concrete composite structure were investigated.Through the comparison between the static experiment measuring result and the finite element calculating result,the conclusions were obtained as follows: the bearing capacity of the main beam steel-concrete composite structure of Wuhan Erqi Changjiang River Bridge can meet the requirements for the design and it can be seen that the shear stiffness of the shear studs has great influence on the force bearing and transfer mechanism of the steel-concrete composite structure.