Flexural performance of curved-pultruded GFRP arch beams subjected to varying boundary conditions

The low stiffness of pultruded glass fiber reinforced polymer (pGFRP) flexural members has been one of the main issues limiting their possible applications ever since this type of material was invented. In this regard, curved-pultrusion technique is adopted in this work to produce GFRP arch beams, and a new GFRP beam-string structure is proposed. Specifically, experimental, numerical, and analytical programs were conducted to investigate the flexural performance of curved-pultruded GFRP arch beams subjected to varying boundary conditions. The flexural strength and stiffness were successfully enhanced by up to 27% and 109%, respectively, which was attributed to the arch mechanism enabled by proposed GFRP beam-string structure. In addition, the progressive failure of GFRP material and the imperfect load-transfer between GFRP arch beam and tension string were investigated through finite element modeling. Then, web crippling strength of GFRP arch beams was predicted with modifications to an existing model, and internal forces of beam-string were analyzed. The GFRP beam-string structure proposed in this work effectively sheds light on possible approach to improve the flexural stiffness of pGFRP members, and with successful demonstration of this work, it is rationally believed that possible applications of curved-pultruded GFRP members can be greatly broadened.