Structural performance of a large-scale space frame assembled using pultruded GFRP composites

A space frame structure assembled by pultruded circular hollow section (CHS) GFRP members is presented. This large-scale structure was built with the span length of 8 m, width of 1.6 m and depth of 1.13 m, but weighing only 773 kgf. The structural details and design considerations are developed for potential pedestrian bridge applications and may be further extended for roof structures with pedestrian activity. Experiments were conducted under three-point bending to understand the structural stiffness, load-carrying capacity, and failure modes. The structure showed satisfactory overall stiffness and load-carrying capacity in terms of potential pedestrian bridge applications. It was further found that the second order bending of critical compressive members might cause large nonlinear deformation of the overall structure. This is because bending of the critical compressive members resulted in a decrease in structural stiffness, with maintenance of the load applied and increase of deformation until the ultimate material failure. The structural behavior can be well described by FE modeling considering realistic initial imperfections such as out-of straightness, eccentricity of members, and additional eccentric compressive forces.