Web crippling behavior of pultruded GFRP rectangular hollow sections

This paper presents an experimental investigation on the web-crippling behavior in glass fiber reinforced polymer (GFRP) pultruded profiles with rectangular hollow section. There is evidence that GFRP pultruded profiles are particularly susceptible to transverse compressive loads, owing to the much lower mechanical properties in the direction transverse to the pultrusion axis. Although very relevant, the understanding about the web-crippling behavior in GFRP pultruded profiles is still very limited, as attested by the lack of information available in design codes and guidelines. End-two-flange (ETF) and interior-two-flange (ITF) loading conditions were adopted, with specimens seated on a bearing plate. Specimens were also placed on the ground with end (EG) or interior (IG) bearing load to simulate the loading conditions of floor joist members. The effects of the loading positions (end loading or interior loading) as well as the supporting conditions (on a bearing plate or on the ground) on the web crippling behavior are discussed. In addition, tests were performed with three different bearing lengths: 50 mm, 100 mm and 150 mm. Finite element models were developed to numerically simulate the tests performed in the experimental investigations in the terms of ultimate loads and failure modes. Based on the results of the parametric study, a number of design formulas proposed in this paper can be successfully employed as a design rule for predicting web crippling ultimate capacity of pultruded GFRP rectangular hollow sections under four loading and boundary conditions.