Journal of Constructional Steel Research 61 (2005) 531–552 www.elsevier.com/locate/jcsr Cyclic behavior of steel frame structures with composite reinforced concrete infill walls and partially-restrained connections Xiangdong Tong a , Jerome F. Hajjar b,* , Arturo E. Schultz b , Carol K. Shield b a Walter P. Moore & Associates, Incorporated, Houston, TX 77098, United States b Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55455, United States Received 27 February 2004; accepted 26 October 2004 Abstract This paper presents an experimental study of the cyclic behavior of a composite structural system consisting of partially-restrained (PR) steel frames with reinforced concrete infill walls. The composite interaction is achieved through the use of the headed stud connectors along the steel frame–infill interfaces so that the two main components of the system share in the resistance of lateral shear and overturning moment. Having the relatively light steel frame constructed using PR connections maximizes the economy of the system, while still ensuring system integrity in the post-peak range of deformation. The one-bay, two-story test specimen was built at one-third scale. The study shows that this system has the potential to offer strength appropriate for resisting the forces from earthquakes and stiffness adequate for controlling drift for low- to moderate-rise buildings located in earthquake-prone regions. Redundancy is also exhibited in this system through alternate load paths occurring at different levels of loading, including shear stud–infill interaction, steel frame–infill strut interaction, and deformation of the steel frame. Improvement is needed for reducing the post-peak strength degradation observed in the present study. © 2004 Elsevier Ltd. All rights reserved. Keywords: Composite wall; Infill wall; Partially-restrained connection; Steel frame; Cyclic; Seismic * Corresponding author. Tel.: +1 612 626 8225; fax: +1 612 626 7750. E-mail address: hajjar@struc.ce.umn.edu (J.F. Hajjar). 0143-974X/$ - see front matter © 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.jcsr.2004.10.002