Pultrusion is a mechanical moulding process combining pulling with extrusion. The construction industry uses a form of the process involving fibre-reinforced polymers (FRPs) for reinforcing structural beams and columns. The EU-funded PFRPSTRUJOIN (Structural joints for building frames of pultruded fibre reinforced polymers) project prepared new building design guidelines. The scientifically based recommendations are relevant to mechanically fastened connections and joints in building frames composed of reinforced polymer composites. Work began with a literature review of the construction industry's current experimental and analytical methods concerning the type of joints in question. Researchers discussed the conclusions drawn from the review, focusing on present gaps in design knowledge regarding composite mechanically fastened joints. As a result, the team identified research required to fill such gaps. Topics identified include a reliable failure analysis of composites, using the finite element method (FE), modelling of intra-laminar failure modes and de-lamination, plus implementation. Additionally, the project validated the FE model – using two different types of specimen – and virtually tested bolted connections. The latter included development and validation of a non-linear FE modelling method, and considered implications of geometric characteristics on structural failures. The work yielded a set of design recommendations. Lastly, the consortium examined tying resistance and structural robustness of bolted joints. Project work contributed data concerning structural FRP materials, which helped to establish a new Eurocode. The research also contributes to Europe's 2020 strategy goals in terms of resource efficiency.
Building frames, connections, joints, pultrusion, construction industry, fibre-reinforced polymers