Contribuição ao estudo do CLT – Cross-Laminated Timber – em elevadas temperaturas via simulação computacional

Abstract

Cross-Laminated Timber (CLT) is a contemporary product in civil construction, and therefore has undergone great evolution in terms of its constructive applicability in Brazil and around the world. Despite being a product made from a combustible material, many studies regarding the use of CLT have emerged, and one of the main aspects is its performance in a fire situation, which can compromise a structure. Through computer simulations, using the Ansys software, thermomechanical analyzes were carried out on CLT panels, floor-to-floor type, joined by countersunk screws, varying the thickness in 3, 5 and 7 layers of lamellas, called panels P1, P2 and P3. To this end, the behavior of the panels in a fire situation was investigated, imposing temperature levels between 200ºC, 400ºC, 600ºC, 800ºC, 1000ºC and 1200ºC, with a maximum exposure time to fire of 60 minutes, with the objective of check the effect of heat transfer on the wood and connections as well as their mechanical behavior. As a result, as the temperature of the wooden panels increased, it was progressively linear in terms of heat transfer within the piece, reaching a maximum time of 60 minutes, with all models exceeding the carbonization point when reaching the level of T400ºC at 45min. However, for thermal analysis, the number of layers inhibited heat transfer in the screws, with only panel P1 obtaining a significant value of 162.27ºC maximum temperature in relation to panels P2 and P3, with 5 and 7 layers. As for the glued displacements, the wooden panels had small deflections, with panel P1 moving 6.3% more in relation to panel P2, and 8.2% more in relation to panel P3. And the displacement of the screws was also small, largely due to the applied support condition, reaching a maximum of d = 5.28x10-3 mm for panel P3. Thus, the investigations carried out indicated that as the thickness of the lamellas in the panels increases, the elements tend to acquire better thermomechanical results.