NEW RESEARCH REPORT: Improving the Safety of Rebar Cages by Using Innovative Connectors
The Charles Pankow Foundation (CPF) in partnership with the American Society of Civil Engineers, the Concrete Reinforcing Steel Institute Foundation, PJ's Rebar, Nucor, Parsons Corporation, Kiewit, Keller, Siefert Associates, Williams Form Engineering, and the ASDC - International Association of Foundation Drilling, are pleased to announce the new research report, Application of U-bolt Connector for Improving the Safety of Rebar Cages, is available for free download along with several associated products. These products complete CPF Research Grant Agreement #01-20.
This research was conducted at the University of Nevada Reno and led by Principal Investigators Hamed Ebrahimian and Ahmad Itani. Rebar cages are commonly used in reinforced concrete construction. These cages consist of longitudinal and transverse reinforcing bars usually connected by tie wires. Numerous incidents of rebar cage failure and collapse have been reported at construction sites, often leading to injuries, fatalities, construction schedule delays, and added costs. Using mechanical connectors such as U-bolts instead of tie wires can improve stability and strength of rebar cages. This paper aims to investigate the mechanical behavior of U-bolt connections through experimental tests and to explore the potential application to rebar cages through analytical models. Experiments were conducted on U-bolt connectors to determine the force-deformation response behavior in different degrees of freedom and for different rebar conditions. Then, the data obtained from a previously completed experimental study on a full-scale tie-wired rebar cage was used to develop and calibrate a nonlinear finite-element model of the test specimen. The force-deformation response of U-bolt connections was then included in the model, replacing the tie wires, to investigate the effect of mechanical connectors on the lateral stiffness and strength of the rebar cage. The results showed that application of mechanical connectors for cross-bar connections in the rebar cages can increase the lateral strength of rebar cages, rendering U-bolt connectors as a potential solution to improve stability and safety of rebar cages.
Industry Champions were Mark Bennier, Tanner Blackburn, Ray Fassett, Angie Hunter, Danielle Kleinhans, Brett Lord, Katerina Lachinova, Justin Ramer, Brian Ruegge, Vincent Siefert, Lyle Sieg, Peter Speire, and Jeff Veilleux.
CLICK HERE TO DOWNLOAD THE RESEARCH SUMMARY