Title: Development of design guidelines for ledges of L-shaped beams
Date Published: March - April 2018 
Volume: 63 
Issue: 2
Page Numbers: 32-43
Authors: Mohamed K. Nafadi, Gregory W. Lucier, Sami Rizkalla, Paul Zia, and Gary J. Klein
https://doi.org/10.15554/pcij63.2-05

Click here to view the full journal article.

Abstract

The design procedure presented in the seventh edition of the PCI Design Handbook: Precast and Prestressed Concrete for ledges of L-shaped beams has been called into question by many engineers and researchers. Research findings from previous experimental studies have indicated that the PCI ledge design equations can overestimate ledge punching shear strength. This paper presents the development of the design procedure for the eighth edition of the PCI Design Handbook to evaluate the punching shear strength of ledges of L-shaped beams. Based on the failure surfaces observed throughout a comprehensive experimental program, an idealized failure surface was determined. The results of extensive finite element analyses and a large experimental program were used to evaluate the effects of global stress on ledge capacity, and a procedure to evaluate the punching shear strength of the ledge was developed. The proposed procedure is presented in this paper and is intended to provide an improved margin of safety for ledge capacity under a wide range of loading conditions. Consideration was given to ensure simplicity and practicality of the proposed design procedure.