Nonlinear finite element analysis of top-and seat-angle with double web-angle connections

Four finite element (FE) models are examined to find the one that best estimates moment-rotationcharacteristics of top- and seat-angle with double web-angle connections. To efficiently simulatethe real behavior of connections, finite element analyses are performed with following considerations: 1) allcomponents of connection (beam, column, angles and bolts) are discretized by eight-node solid elements;2) shapes of bolt shank, head, and nut are precisely taken into account in modeling; and 3) contactsurface algorithm is applied as boundary condition. To improve accuracy in predicting moment-rotationbehavior of a connection, bolt pretension is introduced before the corresponding connection moment beingsurcharged. The experimental results are used to investigate the applicability of FE method and to checkthe performance of three-parameter power model by making comparison among their moment-rotationbehaviors and by assessment of deformation and stress distribution patterns at the final stage of loading.This research exposes two important features: (1) the FE method has tremendous potential for connectionmodeling for both monotonic and cyclic loading; and (2) the power model is able to predict moment-rotationcharacteristics of semi-rigid connections with acceptable accuracy.