Influence of Creep on the Stability of Pultruded E-Glass/Polyester Composite Columns at Elevated Service Temperatures

Abstract

This study is an experimental investigation pertaining to the creep behavior of slender pultruded fiber-reinforced polymeric (FRP) columns subjected to sustained concentric axial loading at elevated service temperatures. Six creep tests were performed on columns having a slenderness ratio of 49 at different combinations of axial load and temperature for a duration of at least 1,000 hours. The axial loads used represented 33%, 67%, and 90% of the critical buckling load for the column selected. For each load level, one test was performed at 22.8℃ (73℉) and one test was performed at 65.5℃ (150℉) Knife-edge end supports were utilized to simulate pinned-pinned boundary conditions. Midheight lateral deflection and axial shortening were recorded incrementally for the duration of the testing. Following termination of the creep tests, the columns were allowed to recover and tested for buckling strength. A semi-empirical model for long-term behavior of concentrically loaded FRP columns at elevated service temperatures is proposed based on experimental results.