Bond fatigue tests of beams simulating pretensioned concrete crossties

Abstract

One-hundred and eight tests of rectangular beams simulating pretensioned concrete crossties were performed. Repeated loads were applied to one of four selected locations near the end of each beam. The maximum load was either that required to open a crack of 0.001 in. width or a value of 15 percent greater than the crack opening load. Three strand surface conditions and two methods of prestress release were used to produce test specimens with a wide range of realistic transfer lengths. Conclusions about the effect of load location on the strand transfer length necessary to obtain a bond fatigue life of three million cycles are given. Finally, design recommendations are put forth. /Author/