01.07: Numerical investigation on the semi-rigid behaviour of austenitic stainless steel connections

In steel structures, connections are provided to transmit member end actions i.e. axial forces (tension or compression), bending moments, shear forces, or torsion. Experimental studies on the traditional carbon steel connections show that top and seat angle with or without double web angle (DWA) bolted connections are able to transfer not only the vertical reaction, but also share some end moment behaving like partially restrained or semi-rigid connection in nature. With the recent advancements in structural use of stainless steel alloys, this paper numerically investigates the performance of two types of austenitic stainless steel connection – top-seat angle and top-seat with DWA bolted connections. Moment-rotation behaviour of stainless steel connections was simulated using commercial finite element (FE) package ABAQUS, where all components of the connection (beam, column, angles and bolts) were discretised using 3D solid elements; shapes of the bolt shank, head and nut were precisely taken into account in modelling, and contact surface algorithm was applied in modelling boundary condition. Actual experimental procedures and loading methods such as bolt pretension were introduced appropriately prior to applying the corresponding loading. The developed FE models were verified using those currently available for similar connection types produced from carbon steel. A comprehensive parametric analysis was carried out by changing the key geometric properties such as beam depth, angle thickness, gauge distance, and bolt size for appropriate understanding of the connection response, and to generate useful data for developing reliable analytical models.