Experimental and Analytical Behaviour of Prefabricated Pretensioned Mo-ment-Resistant Column-to-Column Spliced Joints

Abstract

To facilitate the rapid construction of steel or steel-concrete structures, a new type of spliced joint, called a prefabricated pretensioned moment-resistant joint, was designed to splice H-shaped steel columns. Two supporting plates, sustained by two stiffened ribs, were welded near the end of the column, which could be prefabricated in a factory. Two segments of the H-shaped steel column were linked by longitudinal high-strength bolts (LHSBs), which were pretensioned to provide precompression in the milled flange of the column. In this paper, reversed cyclic loading tests were conducted on three specimens of this innovative joint to investigate its failure modes and load-bearing capacity influencing factors. A finite element(FE) model of the tested specimens was developed, and the results obtained from the FE modelling were verified against those from the test results. The results indicate that the LHSBs have such a remarkable connection ability that the load-bearing capacity is strong even if buckling deformation occurs in the flange of the column. The joint was damaged due to the loosening of the LHSBs accompanied by the separation of the two flanges of the column. Parametric studies were conducted to investigate the influence of steel strength, bolt pretension force, flange bolt diameter, etc, on the behaviour of the connection. The results show that the ratio β and pretension of the LHSB have a great influence on the joint performance. When a pretension of 0.8P is applied(P is pretension of high-strength bolt), the ultimate moment can be reduced by 15.8%; when a pretension of 0.6P is applied, the ultimate moment can be reduced by 24.5%. When the ratioβis large, the flange at the column splicing joint is prone to local instability, thus accelerating the failure of the joint.