Analytical Behavior of Steel Pre-tensioned Bolted Connections with Flushed and Extended End Plates under Bending

The connection between beam and column is repeatedly used in steel structures. Only rigid and pin connections are considered in many steel codes such as Egyptian code (ECP).Floor beams with high reactions need so large number of bolts to be connected with other elements and then these connections do as semi rigid connections. Semi rigid connection can resist some of internal bending moment in steel beam according to connection stiffness and then beam can be redesigned with saving in its weight. The stiffness of semi rigid connection is affected by many parameters as; type of connection end plate (flushed or extended), plate thickness, bolt diameter and stiffening of column panel zone. The analytical investigation utilizes nonlinear finite element modeling techniques using ANSYS program, considering both geometric and material nonlinearity. The functions of ANSYS are used to simulate the pretension force in bolts, as well as the interface between each of end plate, column and bolts accurately. The results of the finite element models were verified and they were found closed with those of experimental and analytical models. The main purpose of this paper is to study the effect of all effective parameters on the stiffness of semi rigid connections according to the basis of the moment-rotation curves. Recommendations are presented to the Egyptian Code of Practice, ECP.