Optimization of Glulam Regular Double-Tapered Beams for Agroforestry Constructions

Abstract

This paper addresses the lack of attention paid by the scientific community to the optimization of timber structures, specifically in the context of large-span agro-industrial constructions. The study focuses on the optimization of a three-dimensional roof composed of GL32h glulam regular double-tapered beams and purlins. Firstly, MATLAB was employed to develop a calculation software and then run the proposed optimization model based on genetic algorithms, in order to optimize the different geometries of the construction elements based on cost, as well as the optimum arrangement of the purlins and the number of beams. Moreover, statistical analyses were carried out on more than 200 optimization data points to uncover the influence of different variables in the optimization process. It was found that the snow load and span have a significant influence on the prediction of the height and width of beams and purlins, as well as the purlin spacing; while, as expected, the roof length also influences the optimal number of beams. All these findings could promote the use of timber structures; thus, achieving more sustainable and efficient construction practices.

Enhancing Sustainable Construction: Optimization Tool for Glulam Roof Structures according to Eurocode 5

“…Conversely, snow load values below 0.4 kN/m 2 were excluded to ensure that in scenarios with negligible snow loads, the maintenance load is applied. Regarding the wind load, it was considered for a gable roof without openings in a building with a height of 5 to 7 m [46] and, since it has been proven not to affect the optimization results [34], a fixed value of 0.07 kN/m 2 was employed.…”

“…The possible dimensions (i.e., Hb, Hp, Wb, Wp, and angle) and arrangements (i.e., Sb, Sp) of beams and purlins were considered through specific values in their chromosomes. The evaluation of each design depended on the utilization rates determined within the structural calculation program developed in Matlab to verify the Eurocode 5 [43] criteria, that has been previously collected in [34] A limit value of l/300 for the final deflection (wfin)…”

“…Amid the less studied strength classes, it should be mentioned the investigation carried out by Jelušič [32], who proposed an optimization approach to variable cross-section beams of GL 30h timber, as well as the research performed on GL 32h timber by Šilih et al [33] for timber trusses and Simón-Portela [34] for an entire timber roof structure.…”

“…In this regard, there is an extensive literature on reducing material consumption in the design of steel and concrete structures; some examples could be found in [35][36][37]. Albeit more limited, optimization approaches have also been made for timber construction such as beams [17,32,34] and trusses [18,33,38,39].…”

“…Additionally, the consideration of the use of the strength classes could also result in advantages from a sustainability standpoint since a greater variety of wood species would be considered for construction purposes. It should be noted that besides their performance and classification within a strength class, the available tree species for selection would also be motivated by their intrinsic characteristics (e.g., climatic adaptation, growing rate [34], etc.) as well as the final acquisition cost of the material.…”