Slotted Bolted Connections in Aseismic Design for Concentrically Braced Connections

The use of concentrically braced steel frames to satisfy lateral force requirements is a common design practice in regions of strong seismicity. They provide a very efficient means of fulfilling the dual objectives of earthquake resistant design, that is, damage control and collapse prevention. While tensile yielding and inelastic buckling of bracing elements provide the basic energy absorbing mechanism, there are inherent problems with member behavior under multiple cycles of inelastic deformations. Inelastic energy dissapation, however, may also be provided by friction resistance in slotted bolted connections, thus eliminating the need for inelastic member buckling. Limited laboratory tests indicate that this concept may be a viable alternative for use as a lateral force resisting system for both new construction and the seismic upgrading of existing structures.