Pultruded FRP sections are gaining increasing usage in construction due to their high strength to weight ratio and corrosion resistance. Their use is particularly promising in civil infrastructure with a long design life such as bridges. Due to their recent introduction in construction, design guidance is not as mature as design in traditional structural materials such as steel and concrete. Furthermore, their high strength leads to small section thicknesses which makes pultruded structural sections prone to instabilities such as local buckling. The structural response of pultruded sections is further complicated by their anisotropic material response, which further complicates their local buckling response as the post buckling of slender pultruded sections is directly influenced by the Young’s modulus in both the longitudinal and the transverse direction, the Poisson’s ratios and the in-plane shear modulus.
Advanced design methods based on cross-section slenderness such as the Direct Strength Method can potentially provide a good estimate of the buckling load of poltruded sections. To this end the slenderness of the sections considered under the specified action (compression, major axis bending, minor axis bending) needs be defined, which necessitates the determination of the elastic critical local buckling stress. Previous studies on steel cross-sections have produced explicit emprirical equations that allow for the effect of element interaction between the flange and the web on the critical buckling stress. This project aims to extend these studies to poltruded RHS-sections.
- Develop explicit empirical equations for the determination of the elastic critical local buckling stress of RHS sections.
- Undertake a literature review to enhance understanding of the behaviour of pultruded sections failure by local buckling.
- Develop a Finite Stip model using CUFSM that will allow the determination of the elastic critical buckling stress of channel sections subjected to compression, major axis bending.
- Carry out parametric studies to investigate the effect of key parameters, such as material properties and section aspect ratio on the elastic critical local buckling stress.
- Based on the results, propose empirical equations for the buckling coefficient of poltuded channel sections that incorporate both geometrical and material parameters