www.springer.com/journal/13296 International Journal of Steel Structures 17(2): 1-13 (2017) DOI 10.1007/s13296- ISSN 1598-2351 (Print) ISSN 2093-6311 (Online) Seismic Performance of Reduced Web Section Moment Connections Seyedbabak Momenzadeh 1, *, Mohammad Taghi Kazemi 2 , and Masoud Hoseinzadeh Asl 3 Ph.D. Candidate, Department of Civil, Construction and Environmental Engineering, Iowa State University, IA, USA, 50011 Associate Professor, Department of Civil Engineering, Sharif University of Technology, Tehran, P.O. Box:11155-9313, Iran Assistant Professor, Department of Civil Engineering, Tabriz University, Tabriz, P.O. Box: 51666-14766, Iran Abstract Seismic behavior of beam-to-column connections can be improved by shifting the location of inelasticity away from the column’s face. Such connections can be achieved by reducing the flange area at a specific distance from the beam-column connection, called reduced beam section (RBS), or by reducing web area by introducing a perforation into the web, called reduced web section (RWS). This paper presents a parametric study that is carried out on the effect of the perforation size, perforation location, and the beam span length in the RWS connections, using finite element modeling. Next, an interaction formula is derived for design purposes, and a step by step design method is developed. Finally, a frame is analyzed to verify the reliability of the proposed design process and assess the impact of the RWS connections on the behavior of special moment frames. The study concludes that RWS connections can effectively improve seismic performance of special moment frames, causing plastic hinges to form around the perforation away from the column’s face. Keywords: reduced web section, plastic hinge, shear-moment interaction, beam-column connection 1. Introduction Many brittle fractures were observed in the beam-to- column connections of steel moment resisting frames (SMRFs) after the Northridge earthquake in 1994 and the Kobe earthquake in 1995 (Miller, 1998). In order to overcome this issue, some approaches have focused on increasing the stiffness of the connection, while others have focused on shifting the location of inelasticity away from the beam-column connection. In the latter case, the beam section can be intentionally weakened at a specific distance from the beam-column connection. As a result, plastic hinges will form within the reduced section of the beam away from the column’s face. Intentional reduction can be introduced in the flanges of the beam, creating a reduced beam section (RBS), or reduction can be introduced in the web of the beam, creating a reduced web section (RWS). Extensive experimental studies confirm that RBS connections develop high inelastic deformations and sustain acceptable plastic rotations (Engelhardt et al., 1998; Chen, 2001; Jin and El-Tawil, 2005; Ricles et al., 2004; Itani et al., 2004). However, investigations about the RWS connections are still scattered and scarce. The results of limited analyses carried out by Kazemi and Hoseinzadeh Asl (2001) showed that the frames with RWS connections can provide at least the same level of seismic improvement as frames with RBS connections. Lepage et al. (2004) used the reduced web section beams in SMRFs, and the reduced zones of the beams were modeled using uncoupled rigid-plastic springs. Moreover, nonlinear behavior and ultimate capacity of plate girders utilizing circular or rectangular web openings were investigated by Shanmugan et al. (2002). It is important to note that utilizing RBS connections can cause a reduction in frame stiffness, and this reduction may lead to at least 4 percent increase in story drift ratio (Lee and Chung, 2007). However, introducing a perforation in the beam web does not have a significant effect on the lateral stiffness of the frame. Experimental studies have shown that seismic energy will be dissipated by local deformation in the perforated regions of the beams in the case of severe earthquake action. In these beams, the expected failure mode of a ductile frame, i.e., ‘strong column but weak beam’ and ‘strong connection but weak component’, will be reached, which will improve the seismic behavior of SMRFs (Qingshan et al., 2009). Previous investigations have demonstrated that RWS steel beams with various opening shapes and sizes behave similarly in terms of deformed shapes under a wide range of applied bending Received 00000 00, 2016; accepted 00000 00, 2016; published online June 30, 2017 © KSSC and Springer 2017 *Corresponding author Tel: +1-515-708-5797, Fax: E-mail: babakm@iastate.edu