Minimum Bar Spacing as a Function of Bond and Shear Strength


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Title: Minimum Bar Spacing as a Function of Bond and Shear Strength

Author(s): Phil M. Ferguson, Robert D. Turpin, and J. Neils Thompson

Publication: Journal Proceedings

Volume: 50

Issue: 6

Appears on pages(s): 869-887

Keywords: no keywords

Date: 6/1/1954

Results of investigations to establish minimum allowable bar spacings in reinforced concrete members are reported. This required considerable study on what bond strengths could be developed without any special provisions against splitting from the action of radical forces induced in the concrete by the inclined compressive forces set up by bearing of the lugs of deformed bars. An eccentric pull-out test was used to measure bond strength in specimens. Results indicate conservatism in the ACI Building Code on the matter of minimum bar spacing under some conditions, accompanied by inadequate protection against failure in bond under other circumstances.