Title:
Small Bar Spacing or Cover-A Bond
Problem for the Designer
Author(s):
Phil M. Ferguson
Publication:
Journal Proceedings
Volume:
74
Issue:
9
Appears on pages(s):
435-439
Keywords:
bond (concrete to reinforcement); bonding; bond stress; cover; reinforced concrete; reinforcing steels;solicing; splitting tensile strength; stirrups.
DOI:
10.14359/11021
Date:
9/1/1977
Abstract:
Two recent research reports about bond and development length indicate that both bar cover and bar spacing are very critical factors. For example, #9 bars, within heavy stirrups and having 2.1 in. clear cover over the bars, developed only 55 percent as much bond resistance when spaced on 2.5 in. centers as when spaced on 4.2 in. centers; and the latter spacing developed only 90 percent of that assumed in the 1977 ACI Building Code requirements for development length. Pending further Code revisions, the author suggests what the designer can do to avoid this weakness.