Response of Stay Cables to High-Amplitude Vibration

The development of cable-stayed bridges has included the discovery of unique phenomena such as rain-wind induced cable vibration. Excessive lateral motion of cables, supporting structures such as the Fred Hartman Bridge, has prompted the need to assess the degree of bending fatigue damage sustained by these cables. Characterization of vibration events has been attempted through strain measurements in the field. Finite element analyses of stay cables have indicated large steel and grout stresses near the anchorage region. Similar modeling of laboratory specimens has led to a geometry that mimics the curvature profile of an actual stay cable. A full-scale diameter, 32-foot long specimen was fatigue tested under cyclic transverse load to validate the finite element models. The long-term goal of this research is the establishment of a set of procedures for evaluating stay cable fatigue damage that will allow their condition to be identified, reliably predicting the current lifespan of individual bridge cables.