Development of moment-rotation model equations for flush end-plate connections

This paper presents the development of Ramberg-Osgood and Three-Parameter Power model prediction equations for the moment-rotation (M-θ) behavior of flush end-plate connections with one row of bolts below tension and compression flanges. A finite element model (FEM) of the connection region along with the connected beam and column is developed for load deformation analyses, which included material, geometric, and contact nonlinearities. The FEM model was verified with test results conducted and reported for flush end-plate connections in the literature during the 1980s. A matrix of test cases was obtained by varying the geometric variables of flush end-plate connections within their practical ranges. The connection M-θ data for these test cases were obtained by FEM analyses, which were then curve fitted to Ramberg-Osgood and Three-Parameter Power model equations to obtain parameters defining these equations. Finally, prediction equations were developed for parameters of the model equations as functions of geometric variables of the flush end-plate connections.