Serviceability and ultimate performance of new ‘Fibre-PolyCell’ beams – feasibility study

Steel cellular beams are primarily used in various industries due to their numerous benefits such as the easy integration of services and increasing the beam’s strength without increasing its weight. Existing research on cellular beams is also limited to steel. The use of FRP rather than steel though has many benefits, including its lightweight and low maintenance. This paper presents research on the development of pultruded FRP cellular beams through experimental studies on the behaviour of full FRP cellular beams in bending and shear. Two FRP cellular beams were tested, and neither were strengthened. Under the three-point bending test, the beam failed at mid-span due to 45-degree shear cracks propagating into the cells. The restraints were successful in preventing any torsional failure mechanisms, and twisting of the beam only occurred after failure. In comparison, the beam under distributed load failed at the right support due to web buckling and shear cracks which propagated at 45 degrees towards the cell. The specimen under a distributed load also had a higher ultimate load at 60.6 kN compared to 30.3 kN, along with a lower deflection due to the spread of large shear and moment concentrations shifting the failure to the supports.