Experimental investigations on the compression capacity of rectangular steel tubular columns strengthened with intermittently welded angle steel

Abstract

Many steel structure buildings in China were built from the 1970s to the 1980s, and they have been in service for decades. However, due to factors such as changes in their functionality, prolonged disrepair, and erosion of the surrounding environment. Studying the strengthening of many existing steel structures will become an important measure during the “reinforcement period.” Welding angle steel on the surface of steel columns for reinforcement is a commonly used method in practical engineering. However, the traditional continuous welding of angle steel to reinforce rectangular steel tube columns results in a relatively large welding workload on the construction site, extending the construction period and increasing the engineering cost, which cannot guarantee high welding quality. To reduce the workload of on-site welding and the cost of construction reinforcement, intermittent welding is proposed. This article designed 9 test specimens for axial and eccentric compression tests to obtain the failure modes, ultimate bearing capacity, and stress distribution of the cross-section of steel tube columns reinforced with different intermittent welding angle steels. The experimental results indicate that intermittent welding can replace continuous welding for the reinforcement of steel tube columns, significantly reducing on-site welding workload and fully utilizing the role of angle steel reinforcement. If the length of the intermittent welding is too large, local buckling will occur, thereby weakening the reinforcement effect of the angle steel. The existence of batten plates can improve the ultimate bearing capacity of intermittent welded angle steel tube columns. Comparative analysis was conducted using a finite element model, which revealed the force transfer mechanism and ultimate bearing capacity of intermittent welding angle steel reinforced steel tube columns. The optimal weld spacing and weld length for intermittent welding of angle steel to reinforce rectangular steel tube columns provide a theoretical reference for the design and application of practical reinforcement engineering.