Variation of strength and stiffness properties obtained from material extracted from different positions along the tree height

• Grant number: 24/01522-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Francisco Antonio Rocco Lahr
• Grantee: Maria Clara Cardoso
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated scholarship(s): 25/07021-0 - Analysis of crystallinity variation by X-ray diffraction in wood extracted from different positions along tree height, BE.EP.MS

Abstract

Wood is widely used in different fields, including civil construction, as it has high relation between mechanical resistance and density when compared to other materials usually applied to structures. Among the essential parameters in the design of wooden structural elements, it is worth mentioning: (i) CV (coefficient of variation of strength and stiffness properties) and (ii) ³w (coefficient of reduction of wood properties), which takes into account the factors: time taken to carry out tests to obtain estimates of the properties that will be required from wood after 20/25 years of use in a structural assembly; uncertainties related to the mathematical models that describe the failure modes of the specimens used in the tests to determine the aforementioned properties. In addition to these, one of the omitted aspects of influence concerns the eventual variation in the strength and stiffness properties obtained from material extracted from different positions, along the height of the tree. In the databases consulted, there are no studies available regarding this variation for wood from tropical species, an aspect that may affect the level of reliability in the design of structural elements. In this way, the present research will analyze four tropical species from native forests using non-destructive testing techniques and specimen tests carried out according to ABNT NBR 7190-3:2022, in order to verify the variation of these properties. If there is a significant statistical difference between the strength values obtained for beams taken from different heights, modifications to the CV and ³w values should be proposed to the members of the ABNT NBR 7190-2022 Revision Committee, with a view to their inclusion in future revisions of this normative document.