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
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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.