Thermal Insulation of Hybrid GFRP-Lightweight Concrete Structures

This paper presents a numerical study on the thermal effect of the insulation of lightweight concrete in hybrid GFRP-concrete structures. In these hybrid structures, the GFRP profiles are totally covered by normal and lightweight concrete and subjected to thermal loads. The problem with GFRP structures is their weak thermal resistance, even at moderately high temperatures. To promote some thermal insulation, it is recommended to cover the GFRP profile with concrete, but this increases its weight. Therefore, lightweight concrete may be a good solution due to its insulation capabilities. For this study, the thermal loads used in the numerical campaign are based on a nominal fire-curved ISO-834, and the temperature is measured at several points. Using these temperatures, it is possible to conclude that the effect of lightweight concrete may provide structural benefits when compared with classical standard structural concrete for covering GFRP profiles using different cover values (from 5.0 cm to 2.5 cm). For this work, commercial finite element software was used for the thermal nonlinear analysis. It was possible to conclude that with lightweight concrete, it is likely to have half of the cover and still maintain the same level of insulation as regular concrete.