To solve the problems of steel tube column joints

such as insufficient anchorage strength and complex construction

steel tube column joints assembled by high strength steel core tube-bolt assemblies were proposed. The assemblies were composed of high strength steel core tubes embedded in steel tube columns and normal bolts. To study the static behavior of the new connections

six full scaled specimens of steel tubular column frame exterior joints were tested under monotonic loading. The research parameters included the types of the steel core tube

the thickness of the steel core tube plate

the bolt diameter

and the end-plate thickness. The stress distribution of the specimen key parts

the deformation capacity

the failure modes

the bolt tension stress

and the joint types were analyzed. Results show that the specimens were semi-rigid joints

and all joint failure modes belong to steel beam plastic hinge mechanisms. When the plate thickness of the enclosed type core tube was equal to the bolt diameter

the joint could satisfy the strength conditions of the rigid joint in the Chinese code. The deformation of the joint panel zone could be ignored

and the rotations of the core tubes were less than 10% of the total rotation. When the core tube plate thickness decreased

the width of the gap between the end-plate and the column would increase rapidly

and the bolt might be pulled out. The steel plate-bolt assembly tension force design value could be calculated as 70% of the tension bearing capacity of the threaded hole in high strength steel plates.