Akbar Vasseghi - Assistant Professor, IIEES, Tehran, I.R. Iran,

Web of plate girders in bridges are usually reinforced by transverse welded stiffeners in order to improve their shear capacity. Due to problems associated with field welding and fatigue, welded stiffeners are not suitable for seismic retrofit of existing bridges. Bolted stiffeners are a practical alternative for strengthening girders that are expected to experience shear stresses in excess of their design shear capacity. These stiffeners are far more suitable than welded stiffeners because field welding would not be required for their installation.The design requirements in various building and bridges specifications are based on experimental and analytical studies of plate girders with welded transverse stiffeners. Such requirements may not entirely applicable for plate girders with bolted stiffeners. This report presents results of an analytical study about shear strength and behavior of plate girder whose web is reinforced by bolted transverse stiffeners. The current design requirements are also evaluated for such girders