Low Damage Moment Resisting Connection Using Blind Bolts

Concrete Filled Steel Tubes (CFSTs) are being used as columns in moment resisting frames in many parts of the world. Because of their aesthetic appearance, favourable ductility and large load bearing capacity, they are popular with architects and engineers. The use of CFSTs is limited in some countries (like Australia) due to the problems and cost associated with the connection of steel beams to the closed column section, unlike open H-shaped columns where ordinary structural bolts can be used. In this paper, a structural system is proposed which uses moment resisting frames as the lateral load resisting system. This system eliminates the use of welds at the site, which is the most common method, although expensive, which is used to achieve a moment resisting connections. The proposed system uses double T-stub connections to connect universal beams on opposite sides of the CFST column, and headed anchored blind bolts are used to connect those T-stubs to the column. This system provides sufficient stiffness and strength to be used in low to mid-rise buildings in low to moderate seismic regions. The proposed system uses a capacity design method to limit the load and non-recoverable damage in the connection (especially in the anchorage). One of the components in the connection, the web of the bottom T-stub, is designed as a fuse to create a low damage system for very rare earthquakes.