Title: Dapped ends of prestressed concrete thin-stemmed members: Part 1, experimental testing and behavior 
Date Published: March-April 2017
Volume: 62
Issue: 2
Page Numbers: 61-82
Authors: Amir W. Botros, Gary J. Klein, Gregory W. Lucier, Sami H. Rizkalla, and Paul Zia
https://doi.org/10.15554/pcij62.2-05

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Abstract

This paper describes the behavior of dapped ends of prestressed concrete thin-stemmed members based on an extensive experimental program conducted to identify the most effective reinforcement schemes and develop design guidelines for dapped ends. Experimental research findings presented in this paper were used to develop design guidelines that are presented in a companion paper.

Each end of 10 full-scale single-tee prestressed concrete beams with dapped ends was tested to failure (20 tests in total). Six different reinforcement schemes were investigated in the experimental program: the vertical L, inclined L, vertical Z, custom welded-wire reinforcement, vertical C, and CZ schemes. The experimental program also examined the influence of several parameters believed to affect the behavior, including the prestressing of the nib, concrete strength, web shear reinforcement, nib height, and splice length of the hanger reinforcement. The experimental results indicated that the extent of cracking at service load, the ultimate strength, and the failure mode are influenced by the reinforcement arrangement at the dapped end. Service load cracking can be controlled to acceptable levels through proper design and detailing of the reinforcement within the end region.

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