STATIC RESPONSE OF FIBERGLASS PRETENSIONED BEAMS

This paper presents results from an experimental study to determine th e static response of fiberglass pretensioned beams. Three sets of unde rreinforced pretensioned beams 8-ft span with cross sections of 6 in. x 8 in. (0.15 m x 0.2 m, 6 in. x 10 in. (0. 15 m x 0.25 m), and 6 in. x 12 in. (0. 15 m x 0.3 m) were tested under two-point loading. The be ams were pretensioned using three 3/8 in. (9.5 mm) S-2 glass/epoxy str ands. For comparison, three identical beams pretensioned to the same e ffective prestress by two 3/8 in. (9.5 mm) steel strands were also tes ted. The results from the study indicate that the precracking response of these fiberglass pretensioned beams was near identical to the stee l pretensioned beams, but its postcracking response was more flexible. Failure of some of the fiberglass pretensioned beams was accompanied by slip. Nonlinear finite-element analysis showed good correlation wit h the test results. Tentative equations for estimating the failure str ess and criteria for designing under-reinforced beams are proposed.