Effect of Prestress on the Fatigue Life of Concrete

摘要

The report presents results of a series of regression analyses carried out on data from both the Portland Cement Association and The University of Texas at Austin's test program on fatigue of prestressed concrete beams. Among the topics investigated were (1) the effect of prestress on the fatigue life of concrete, (2) the interaction of the static stresses due to prestressing and the dynamic stresses due to vehicular loadings, (3) the effect of prestress in delaying micro-crack propagation in concrete, and (4) the effect of prestress on the elasto-plastic behavior of prestressed concrete. As a result of the investigation, some salient facts about current fatigue design considerations for prestressed concrete pavement emerge. (1) Present fatigue design is too conservative because it does not consider the beneficial effect of prestressing in helping to delay crack propagation and (2) Prestressing helps in maintaining elasto-plastic behavior, which is ignored in current fatigue design.