Demand on Stiffeners in Stiffened Extended End-Plate Connections

Abstract

The paper reports a study on the effect of stiffeners on stiffness and strength of T-stubs to find out the strength and stiffness demand on stiffeners. The tensile capacity of triangular stiffeners is first analyzed and is compared with that of a long rectangular one, an efficiency factor formula is proposed. A triangular stiffener with length-to-width ratio of 2:1 is suggested be used in practice. By requiring stiffened T-stubs have a similar strength and rigidity to the unstiffened T-stub having 41% percent thicker endplate, it is found that the stiffener must be able to transmit 85% of the total tension force, based on this requirement, the stiffener thickness is determined. Three unstiffened T-stub connections and six stiffened T-stub connections with 1:1 and 2:1 triangular stiffeners were tested monotonically. The load carrying capacity, relative deformations of endplates and strains on stiffeners and endplates were measured. The load-deformation curves of the connections and load-strain curves were presented. The influences of different shapes of stiffeners on loading resistance and rotational stiffness characteristic of stiffened T-stub connections were evaluated. The test results showed that the short stiffeners in current Chinese practice yield or/and buckle prematurely, and the stiffeners designed by the proposed method in this paper are able to change the extended portion of endplates from one side clamped to 2 panels fixed on two adjacent sides.