Abstract
This study proposes and examines a new structural retaining wall system using pultruded glass fibre reinforced polymer (GFRP) composites. The flexural behaviour of the two section types (double-H-planks and round-piles) are investigated at various spans under four-point bending. The effects of shear span-to-depth (a/d) ratio and sectional geometry on the structural capacity, stiffness and failure mode are studied. The effectiveness of the mechanical interlocking system between double-H-plank and round-pile for a continuous assembly is evaluated. Results suggest that the a/d ratio plays an important role in determining failure modes and ultimate capacities of double-H-plank and round-pile specimens. Additionally, a low a/d ratio or a larger depth incurs premature local crushing rather than flexural or shear failure. The mechanical interlocking system used to connect components together was found to be reliable as it effectively transfers bending loads from the double-H-plank to adjacent connected components even when the connection rotation is greater than 12°. Finally, FE modelling showed a good agreement with the experimental failure modes and satisfactorily estimated the failure loads and structural stiffness.