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 esti mates moment-rotation characteristics of top- and seat-angle with double we b-angle connections. To efficiently simulate the real behavior of connectio ns, finite element analyses are performed with following considerations: 1) all components of connection (beam, column, angles and bolts) are discreti zed by eight-node solid elements; 2) shapes of bolt shank, head, and nut ar e precisely taken into account in modeling; and 3) contact surface algorith m is applied as boundary condition. To improve accuracy in predicting momen t-rotation behavior of a connection, bolt pretension is introduced before t he corresponding connection moment being surcharged. The experimental resul ts are used to investigate the applicability of FE method and to check the performance of three-parameter power model by making comparison among their moment-rotation behaviors and by assessment of deformation and stress dist ribution patterns at the final stage of loading. This research exposes two important features: (1) the FE method has tremendous potential for connecti on modeling for both monotonic and cyclic loading; and (2) the power model is able to predict moment-rotation characteristics of semi-rigid connection s with acceptable accuracy.