An Investigation on Aseismic Connection with Opening in Beam Web in Steel Moment Frames

Abstract

Providing an opening in a beam web (OBW) is a possible approach to improving the aseismic behaviour in beam-to-column connections in steel moment frames. The finite element analysis in this paper shows that the behaviour of the OBW connection depends on a size of the opening, R, and the opening location, b. When parameters are properly selected, Vierendeel hinges form in the weakened areas resulting in a beam with high ductility. Quasi-static tests were carried out based on the finite element analysis results. The test results showed that Vierendeel hinges formed in the weakened areas and brittle weld fracture was avoided in the OBW connections. The performance indicators of the OBW connection are not reduced with a weakened section. Aseismic behaviour of the beam-to-column connections are improved with an opening in the beam web. To explain the failure mechanism of the OBW connection, the stress distribution obtained from the finite element analysis was studied. The stress distribution around the opening was found dramatically changed because of the provision of the opening. Four plastic zones formed in the web around the opening under the interaction of normal and shear stresses at the critical locations resulting in ductile Vierendeel hinges.