Lateral-torsional buckling resistance by testing for pultruded FRP beams under different loading and displacement boundary conditions

This paper presents test results for Pultruded FRP (PFRP) beams failing by elastic Lateral-Torsional Buckling (LTB) under various loading and displacement boundary conditions. Beams are simply supported at both ends for major-axis flexure. Results are presented for 114 tests, comprising 19 beams of four PFRP sections at four or five spans, and six groups for mid-span load applied at three heights, with or without end fixity of lateral flexure. Buckling resistance is established either by the Southwell plot method or from the peak load. Measured LTB loads are compared with predictions obtained using closed form equations to show that these expressions will provide a safe resistance for design when the moduli of elasticity are those taken directly from pultruder's design manual.