Deflection and Cracking of Reinforced Concrete Under Repeated Loading and Fatigue
J. M. Lovegrove and Salah El Din
Appears on pages(s):
beams (supports); cracking (fracturing); crack width and spacing; cyclic loads; deflection; deformation; fatigue (materials); fatigue tests; reinforced concrete; research; structural design.
Reinforced concrete beams of different sizes and reinforcement arrangements were repeatedly loaded at frequencies of 0.5 and 1 Hz. Curvature and deflection are presented as ratios of the initial values and a unique relation is obtained between each of these ratios and the logarithm of the number of load repetitions. Each ratio increases gradually in a curved form to about 0.5 x l06 repetitions from where it takes a straight line form with a slope varying between 0.2 and 0.225. The long term deflections of beams tested in earlier investigations are predicted with good agreement. A similar expression is given for maximum crack width and predicted long term values are in reasonable agreement with those measured by earlier investigators.