Title: Cracking in Partially Prestressed Beams Under Static and Fatigue Loading

Author(s): M. H. Harajli and A. E. Naaman

Publication: Symposium Paper

Volume: 113

Issue:

Appears on pages(s): 29-56

Keywords: beams (supports); cracking (fracturing); cyclic loads; crack width and spacing; fatigue (materials); partial prestressing; prestressed concrete; Structural Research

Date: 4/1/1989

Abstract:
Study was conducted to evaluate cracking in partially prestressed concrete beams under both static and cyclic fatigue loading. It comprises two parts: an experimental investigation and an analytical modeling of crack width increase under cyclic fatigue loading. In the experimental part, 12 different sets of beams were tested in four-point bending. Each set comprised two identical beams. One beam was tested to failure under monotonically increasing load, while the second beam was tested in fatigue at a constant load range simulating full live load. In the analytical part of the study, a model for computing the increase in crack width under cyclic fatigue loading is developed. The model accounts for the effect of change in steel stress due to cyclic creep of concrete in compression, the increase in slip due to bond redistribution, concrete shrinkage, and cyclic creep of concrete in tension. Results predicted by the model were found to be in good agreement with the experimental results observed in this study, as well as results reported elsewhere.