Optical fiber measurement of local strains in a ribbed bar

Ribbed bars are known for their enhanced bond to concrete. Their ribs make bar section variable along the axis and strain profile is as well, under any given applied force. Such has not been measured so far, thus stress its effect on global behavior of cannot be determined. Though optical fibers an effective means measure strains in structural members, application study still infancy. objective this research project. Specially manufactured partly smooth ribbed with were tested pure tension (bare bars) pullout from concrete investigate variability. In bare bars, part was constant (as expected), while higher but no localized effects detected, location identified. Similar obtained by 3D finite-element analysis, which merely yielded slight ups downs at ribs' locations, average that similar strain. However, pull-out tests, unbonded exhibited undulating bonded part, where peaks related locations ribs. promising results motivate further studies improve resolution proposed technique.