Title: Further Tests of Dynamically Loaded Beams

Author(s): F. T. Mavis and J. J. Stewart

Publication: Journal Proceedings

Volume: 55

Issue: 5

Appears on pages(s): 1215-1223

Keywords: no keywords

DOI: 10.14359/11417

Date: 5/1/1959

Abstract:
Twenty-seven beams, identical except for amount and grade of reinforcement were tested to destruction by spring-actuated impulse loads applied at the third-points of an 8-h simple span. Loads reactions, bar strains and deflections were recorded simultaneously throughout each test by a motion picture camera at speeds of 2000 pictures per sec. Frame-by-frame analysis of the pictures showed: (1) all beams were destroyed when deflection reached about 6 in. (or 6 percent of span length) at midspan; (2) at the onset of destructive failure steel strain was less than 4 percent; (3) no reinforcing bar fractured in any test; and (4) beams with hard grade bars consistently outperformed beams with intermediate or structural grade bars under otherwise identical conditions.