Title:
Effect of Vertical Casting Position on Transfer and Development Length
Author(s):
J. Chris Carroll, Carin L. Roberts-Wollmann, and Thomas E. Cousins
Publication:
Materials Journal
Volume:
112
Issue:
5
Appears on pages(s):
619-630
Keywords:
bond; development length; prestressing strand; top-strand effect; transfer length; vertical casting position
DOI:
10.14359/51687852
Date:
9/1/2015
Abstract:
This investigation includes the effect of vertical casting position on transfer and development lengths of prestressing strand. Current code provisions account for the top-bar effect in the calculation of development length for standard reinforcing bars, but fail to recognize the phenomenon when calculating transfer and development lengths of prestressing strand. Historically, this phenomenon has been dependent on the amount of concrete cast below a bar or strand. Recent research shows the amount of concrete cast above a strand to be more influential. This paper presents the results of an experimental investigation on the influence of vertical casting position of prestressing strand on transfer and development lengths. The study includes data from 20 T-beam test specimens and four sets of top-strand blocks. The results from 119 transfer zones and 39 flexural tests were evaluated and compared to vertical casting position along with current code provisions.