Bending performance of concrete-filled multi-cell pultruded beams reinforced with lattice-webs

Multi-cell structures reinforced with lattice-webs have exhibited great local buckling resistance and pseudo-ductile manner. Therefore, a concrete-filled multi-cell glass fibre-reinforced polymer (GFRP) pultruded tubular beam reinforced with lattice-webs (MCPL) was proposed to address the premature bending failure of concrete-filled pultruded tubes. Four-point bending experimental studies were carried out to evaluate the flexural response of the MCPL. The effects of the thicknesses of face sheets, lattice-webs, and fibre arrangements on bending behaviour were systematically investigated. The test results revealed that the brittle failure manner of the concrete-filled pultruded tubes could be improved by multi-cell structures; progressive failure manner was shown in specimens reinforced with lattice-webs with cracks developed gradually along the height; applications of lattice-webs delayed the local buckling thus improving the delamination resistance performance, but too thick lattice-webs reduced the integrity of specimens resulting in negative effects; increasing the thickness of face sheets showed the best improvement efficiency on the bearing capacity and pseudo-ductile performance of specimens. Furthermore, analytical models were developed to predict the bending stiffness and load-bearing capacity of the MCPL, and the results were consistent with the test results.