International Concrete Abstracts Portal

Title: Early-Age Shear Strength of Reinforced Concrete Beams

Author(s): S.P. Shah, R.A. Miller, and T.E. Virding

Publication: Special Publication

Volume: 95

Issue:

Appears on pages(s): 71-92

Keywords: age-strength relation; beams (supports); ductility; flexural strength; shear strength; stirrups.

Date: 10/1/1986

Abstract:
A study was conducted to determine if the current design formulas can adequately predict the capacity of reinforced concrete beams tested at early ages and to determine the effectiveness of stirrups in young beams. Three sets of reinforced concrete beams were tested-with the main variables being beam age and stirrup spacing. It was found that the ACI-318 ultimate strength design method provides a lower bound to flexural strength of young reinforced concrete beams. For beams failing in shear, however. the current code provisions appear unsatisfactory. For example,the contribution of shear reinforcement was observed to be less than that predicted by the code when beams failed in shear at early ages. A change in mode of failure was often observed at early ages and the ductility of young reinforced concrete beams , was less than that for the 28 day old beams.