A detailed 2D finite element model for the seismic assessment of steel frames with top-and-seat angle with double web-angle connections

Early work on predicting the moment-rotation response of semi-rigid connections was conducted through simplified linearized and curve fitting models compared to experimen-tal data. The models were developed using monotonic tests with ambiguity in the loading and boundary conditions used. As a result of such, the models often failed to predict the actual response of the connection particularly when the connection is cyclically loaded. With ad-vancements in computational techniques and power, attention was shifted to developing 3D models which have proven to be capable of capturing the true behavior of the connection. Notwithstanding their effectiveness, 3D models are hard to construct and are computationally expensive, thus their ability to conduct large parametric studies is limited. This paper presents an overview of a new 2D inelastic finite element model (FEM) for predicting the mo-notonic and cyclic response of semi-rigid connections with top-and-seat angle with double web angle. The model comprises 2D plane strain elements and includes various behavioral features including bolt preload, friction between faying surfaces, connection slip, the effect of bolt-hole ovalaization and hot-rolling residual stresses in the angles. Characterized by its re-duced number of nodes and elements, the model is computationally inexpensive and is capa-ble of capturing the true behavior of the connection.