Fabrication and Installation Technology of Steel Truss Arch Bridge

Since the 1990 s, China's steel production has more than ten years in a row in the world, and the types of steel products, the quality has the very big enhancement, has reached the world advanced level in, the steel bridge in such aspects as design, manufacture, construction research and technology is increasingly mature, and steel truss arch bridge as a classic of bridge structure, with its stiffness of truss arch and downy derrick structure combination, form a sofe landscape architecture^[3], has been widely used in bridge construction in our country. Because the horizontal thrust of steel truss arch bridge is large and the structure form is complex, it is necessary to integrate its structural characteristics, construction environment, equipment and other factors, and make a practical construction scheme on the premise of ensuring the construction quality and safety to achieve the purpose of cost reduction and efficiency increase.
Taiyuan Jinyang Bridge is a 204 m span steel truss arch bridge. The arch ribs are truss structure composed of upper chord, lower chord and X-shaped girder. The arch axis vector height of the upper arch rib is 48. 5 m, and the arch axis vector height of the lower arch rib is 42. 2 m. The main beam is connected with the tie beam and the arch ribs by welding. Through the analysis of the difficulties in rod making and site installation, the welding quality and welding deformation control measures of the tie beam and arch rib are formulated. The construction scheme is compared and selected and the key technologies such as steel beam bulk, arch rib pre-assembly and truss plate making are formulated. Combined with the structural characteristics and construction environment, some protective measures for aerial work are formulated.
The practice shows that the welding quality of the tie beam and arch rib is good, and the welding deformation meets the design and standard requirements. The steel girder adopts bulk packing scheme to increase the field working surface, improve the installation progress, and avoid the adverse effects of the increase of butt welding seam, the reversal difficulty and the long cycle caused by the general assembly. The implementation of the on-site pre-assembly and truss fabrication scheme ensures the quality of the truss fabrication, reduces the labor intensity and improves the installation precision of the truss. The protective measures for high altitude operation are practical and easy to operate, and good protective effect has been achieved.