Pultruded FRP composites for modular structural assembly: Applications to space frame structures and built-up composite beam systems

Fibre Reinforced Polymers (FRP) exhibit many advantageous properties such as high strength, low thermal conductivity and lightness in weight, and have shown potential for use in civil structural applications. Pultruded FRP made with Glass Fibres (GFRP) are economical and provide excellent environmental properties such as low energy consumption and low carbon dioxide emissions compared to steel or concrete. However, the low material stiffness of FRP means that design is usually governed by serviceability limit state criteria. Material orthotropy and low shear strengths render connection design a particular challenge, especially at joints connecting FRP members in spaceframe structures. Furthermore, FRP is brittle and hence catastrophic failure can occur suddenly without warning. Ductile failure modes, such as those seen in steel structures through yielding, are preferred in civil design as warning can be provided prior to catastrophic failure through the development of large deformations while maintaining load-carrying capacity. Recent developments in FRP composites for structural construction can address these challenges via innovative structural design such as sandwich construction to improve structural stiffness or innovative space frame or truss structures to provide large nonlinear deformations. Such developments presented in this paper include an all-composite 9 m-spanning FRP composite beam system with a built-up sandwich deck, and space-frame structures made of tubular FRP members with innovative connection design.