World Applied Sciences Journal 30 (6): 685-695, 2014 ISSN 1818-4952 © IDOSI Publications, 2014 DOI: 10.5829/idosi.wasj.2014.30.06.14092 Corresponding Author: Fattouh M.F. Shaker, Department of Civil Engineering, Faculty of Engineering, Helwan University, Mataria, Cairo, Egypt. 685 Behavior of Flush and Extended End-Plate Beam-To-Column Joints under Bending and Axial Force Fattouh M.F. Shaker and Waseem M. Abd Elrahman Department of Civil Engineering, Faculty of Engineering, Helwan University, Mataria, Cairo, Egypt Abstract: Because of the ease of fabrication and erection, end-plate beam to column joints have the priority of interest to be studied by researchers. These types of joints are often subjected to a combination of bending and axial forces. Many of design codes neglect the effect of axial force in the connection analysis as it is usually low. The level of axial forces in the joint may be significant in case of: sway frames under horizontal loads, pitched roof portal frames and irregular frames. The objective of this paper is to discuss the behavior of flush and extended end-plate connections under a combination of bending and axial tension or compression forces. The analytical investigation utilizes nonlinear finite element modeling techniques using ANSYS program, considering both geometric and material nonlinearities. 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 finite element models were verified and they were found to be close with those of the experimental and analytical models found in the literature. Results are compared with those presented in Eurocode 3 which limits the axial force acting on the joint to 5% of the design plastic resistance of the connected member cross section. Key words: Axial force End plate connection Finite element analysis Pre-tensioned bolts Semi-rigid * * * * connections INTRODUCTION rules do not take account of any co-existing axial force End-plate connections, which consist of two main connected member exceeds 5% of the design plastic types, flush and extended end-plate connections, are resistance of its cross section. The aim of this research is used widely in steel structures, [1-3]. These types of to study the behavior of semi-rigid steel connections connections are often subjected to a combination of under combination of bending and axial force and to bending and axial forces. Although in many regular evaluate the ratio given by EC3-1-8. To achieve this building frames the level of axial force coming from the target, two types of connections were chosen; flushed beam is usually low, it can reach significant values in end plate, FEP and extended end plate, EEP. Many many instances, such as: regular frames under significant researchers studied the behavior of semi-rigid horizontal loading (seismic or extreme wind), especially for connections under bending only. Recently, researchers sway frames; irregular frames under gravity or horizontal tend to predict the behavior of these types of loading, especially with incomplete floors; and pitched- connections under combination of bending and axial roof portal frames. Currently, no specific procedures are force. Pertold et al. [5] performed two experimental tests available for the analysis and design of beam-to-column on beam-to-beam and beam-to-column joints. For both joints under bending and axial force. Part 1.8 of Eurocode tests, failure occurred at the column flange in the 3, EC3-1-8 [4] gives quantitative rules to represent the compression zone. Unfortunately, no test with only semi-rigid connection behavior based on the moment- bending moment was performed, which prevented the rotation, (M- ), characteristics of the joint. This is called determination of the influence of the axial force in the component method. EC3-1-8 states that these quantitative joint response. Lima et al. [6, 7] and Simo˜es da Silva [8, 9] and thus should not be used if the axial force in the