Aiming at the key joints of the new steel concrete slab-truss composite girder-steel-concrete joint at the top of the auxiliary pier,of the long-span railway-cum-road cable-stayed bridge-Hongqili Bridge with a main span of 808 m,the multi-scale finite element model of the whole bridge with partial segment refinement of steel truss-concrete slab composite girder is established using ANSYS software.The stress law and force transmission characteristics of the joint of the side-span composite girder under the most unfavorable working conditions were analyzed,and the influence laws of the structural parameters such as cross-sectional area of the lower chord and other members on the stress and force transmission mode of the key joint were discussed.The results show that under the most unfavorable combined working conditions,the most unfavorable Mises stress of the steel structure at the auxiliary pier top joint of the side-span composite girder is 265.9 MPa,and the maximum local nominal tensile stress of the concrete is 9.2 MPa,resulting in local cracking and force transfer to the steel structure.Under the influence of the local negative bending moment at the top of the auxiliary pier,the stress distributions at the inner and outer joint plates are'inverted V'shape,and the top and bottom surfaces of the concrete are'saddle'and'inverted saddle'shape respectively.The lower chord(including the concrete in the tube)and the vertical rod at the joint are the main longitudinal and vertical force transmission components,which transmit 77.86％and 40.15％loads respectively.The thickness change of concrete deck has a significant impact on its own stress.The thickness of the concrete deck and the cross-sectional area of the bottom chord have a significant impact on the longitudinal force transfer ratio.The cross-sectional area of the vertical pole has a relatively significant impact on its own vertical force transmission.When the coefficient of concrete thickness and the section coefficients of the lower chord,the tilted belly poles and the vertical rod are between 0.8-1.1,the stress and force transmission ratio of each component of the key joint of the composite girder are reasonable.
关键词
公铁合建斜拉桥/钢混板-桁组合梁/关键节点/受力特性/传力机理
Key words
Rail-cum-road cable-stayed bridge/Steel-concrete plate-truss composite girder/Key joints/Force characteristic/Force transfer mechanism
维普
万方数据