Depth Effect of Tropical Heavy Hardwood of Kekatong Species Towards EC5 using Weibull’s Theory

Abstract

The design practice has shifted from permissible stress design to limit state design using Eurocode 5 (EC5), which introduces design strength optimization. However, the adoption of EC5 in Malaysia cannot be done directly due to the absence of design strength data for Malaysian timber species. This paper presents a study that evaluates the bending strength properties, moisture content, and density of kekatong (Cynometra malaccensis) timber specimens using the Weibull theory to produce 1/k values for the local timber species. The depth impact adjustment factors for kekatong timber had a value of 0.23, which is not far from the well-established 1/k value of 0.2 for softwood and temperate hardwood with characteristic densities below 700 kg/m³ in EC5. The study shows that the bending strength of local timber is affected by its volume, and the variation of bending strength at several probabilities is in close agreement with theoretical predictions. Overall, the study provides important insights for the design of timber structures using Malaysian timber species, which can be used to improve the safety and sustainability of timber structures.