Mechanical properties of CFST column with bolt-welded joints under eccentric compression

Abstract

With the increase of arch bridge span and difficulty in welding construction, the traditional connection method of arch rib steel tube cannot satisfy the requirements of construction safety and economy. In this paper, a new bolt-welded connection method for arch rib of long-span Concrete Filled Steel Tubular (CFST) arch bridge is proposed, which can avoid the stress redistribution of joints of arch rib caused by cutting the joint flange in the traditional connection method. In order to study the mechanical properties of the bolt-welded joint of CFST, the eccentric compression scale tests were carried out, and the finite element model is validated based on the experiment. The parameter analysis was performed and the calculation formula of eccentric bearing capacity of bolt-welded joint of CFST is proposed. The results show that the bolt-welded joint can significantly improve the stiffness, stability and effectively avoid buckling at the joint. With the increase of steel tube strength, core concrete strength and steel ratio, the bearing capacity of bolt-welded joints of CFST significantly improved, and the bearing capacity of bolt-welded joints under small eccentric is better than welded joints. The bolt-welded area ratio is recommended not to exceed 0.3. The calculation results of the proposed formula are consistent with the experimental and simulated results.