Cross-laminated timber (CLT) has been widely discussed as a relevant industrialized construction solution. Numerous publications have considered CLT as a structural wood-based panel, but other documents have mentioned it as a building or even a construction system. Many authors address its application in multistory buildings, although single-family houses and lower building applications have become desirable topics as well. Given these gaps, this review study addresses a systematic method to evince the functions of cross-laminated timber in construction. The elucidation and discussion were led by technical and scientific contents through publications present in scientific websites and the Google web search engine. Intricate perceptions about the knowledge and reference of CLT functions were identified. From prospections, it was possible to state that CLT is a timber-forest product created in Europe, whose function acts as a structural composite panel of the engineered wood product category. However, CLT has been mentioned by many publications as a building or a construction system. Suggestions were raised to clarify to all readers with respect to misconceptions, and elucidate the construction systems capable of using it as the main resource. Discussions evinced the characteristics and potentials of this wood product. Even with its increasing application in tall buildings, the commercial application of CLT in low-rise buildings may be boosted by the possibility of large-scale production of industrialized houses.
Carbon fiber-reinforced polymer (CFRP) sheets have been used to reinforce cross-laminated timber (CLT)–concrete systems in recent years. The existing studies have indicated that the use of CFRP rebars as shear connectors in CLT–concrete panels can improve the structural performance of these elements. However, the application and understanding of CFRP rebars as shear connectors still need to be improved, since comprehensive studies on the subject are not available. Therefore, this research aimed to evaluate the structural performance of CLT–concrete panels with CFRP rebars as shear connectors through finite element (FE) numerical simulation. A parametric study was conducted, varying the connector material, the number of CLT layers, the connector insertion angle, and the connector embedment length. According to the results, panels with CFRP connectors showed a higher maximum load, bending strength, and maximum bending moment than panels with steel connectors. The regression models revealed that the parameters analyzed explained between 80.2% and 99.9% of the variability in the mechanical properties under investigation. The high explanatory power (R2) of some regression models in this study underscores the robustness of the models. The number of CLT layers and the connector material were the most significant parameters for the panels’ maximum load, displacement at the maximum load, ductility, bending strength, and maximum bending moment. The number of CLT layers and the connector insertion angle were the most significant parameters for the panels’ effective bending stiffness. This research highlights the importance of studies on CLT–concrete composites and the need to develop equations to estimate their behavior accurately. Moreover, numerical simulations have proven very valuable, providing results comparable to laboratory results.
15 November 2024 in International Journal of Adhesion and Adhesives
Este estudo visou avaliar parâmetros de fabricação e seu impacto na qualidade da colagem de elementos de MLC. Foram realizadas três etapas de pesquisa com madeiras de Eucalipto grandis e Pinus elliottii, usando diferentes adesivos, analisando a porcentagem de delaminação e da resistência ao cisalhamento das linhas de cola. Foram testadas diferentes pressões de colagem com adesivos comerciais, quantificando os modos de ruptura na zona de colagem, diferentes proporções de adesivo natural nos elementos de MLC e diferentes espessuras das lamelas com um adesivo poliuretano bicomponente. Resultados indicaram que pressões de 0,7 MPa para o Pinus e 1,2 MPa para o Eucalipto estavam em conformidade com a norma brasileira. Diferenças significativas foram observadas na resistência ao cisalhamento entre lamelas externas e internas do Pinus. O adesivo natural demonstrou boa resistência ao cisalhamento, mas problemas na delaminação. A espessura de 3,5 cm apresentou melhor qualidade de colagem. As recomendações da NBR 7190-6 se mostraram eficazes no controle da qualidade da colagem de elementos de MLC.
There are several technologies to recover and strengthen timber structures. Two usual alternatives are: the use of steel plates screwed and carbon fiber mats glued with epoxy adhesive. A gap was observed in the literature regarding the study of reinforcement in hardwood timber beams with cross-section loss, commonly found in attacks by biotic or abiotic agents. This study aimed to analyze the flexural stiffness recovery capacity of steel plate screwed to a timber beam with different cross-sectional losses, with a special interest in the effect caused by different bolt arrangements. The results were compared with simulations made using a carbon fiber mat (CF). It was possible to observe that, despite presenting lower efficiency than the CD, the use of steel plate screwed could return the initial stiffness in some models, and the specification of the bolts is relevant in obtaining the results.
8 May 2025 in Case Studies in Construction Materials