The design practice of timber structures in Malaysia is still based on permissible stress codes as stated in Malaysian Standard (MS) 544: Part 2 and MS 544: Part 3, which was adopted from the British Standard (BS) 5268. The British Standard was later completely replaced by Eurocode 5 (EC5) in 2009. Therefore, to preserve the continuity of design concepts specified in the British code of practice, local designers should adopt an EC5 limit state design to generate safe and economical designs. However, new strength data based on characteristic values which comply with EC5 for Malaysian tropical hardwoods are still lacking. The aim of this study was to investigate the compressive strength properties of nine structural-sized Malaysian tropical hardwood species namely Balau, Kempas, Kelat, Resak, Kapur, Keruing, Mengkulang, Light Red Meranti and Geronggang tested according to European Standard (EN) 408. A compression test was performed to measure the compressive strength and modulus of elasticity of the timbers and were used to derive characteristic values. The equation for determining characteristic compressive strength given in EN 384 was also assessed to verify that whether it is suitable for high density Malaysian hardwoods, as this equation was derived from softwood and European hardwoods. The results revealed that the derived characteristic values are higher than the values given in EN 338 for the relevant strength classes, particularly for heavy and medium hardwood with densities greater than 700 kg/m³. A verification of the equation used in EN 384 to determine compressive strength characteristic value yields a different equation, $f_{c,0,k}=2.2 {\left(f_{m,k}\right)}^{0.7}$. This shows that the EN 384 equation is not suitable to be used with hardwood timber with a density more than 700 kg/m³, since it will underestimate the strength value.

The adoption of limit state design according to Eurocode 5 (EC5) has brought about design strength optimisation in design practices worldwide. However, the implementation of EC5 may not be suitable for Malaysian tropical timber species as the design strength data in European Standard (EN) 338:2016 is based on softwood and temperate hardwood species. EC5 has a well-established 1/k value of 0.2 for softwood and temperate hardwood with characteristic densities below 700 kg/m³. The value of 0.2 is still uncertain for tropical hardwood timber and it is predicted that the 1⁄k value for characteristic density above 700kg/m³ will be different. Therefore, in this study, the application of Weibull's theory is being used to determine the 1/k value for selected species namely, Balau (Shorea spp.), Kempas (Koompassia malaccensis), Kapur (Dryobalanops spp.), Keruing (Dipterocarpus spp.), Geronggang (Cratoxylon arborescens), and Light Red Meranti (Shorea spp.) with density ranges from 300 kg/m³ to 1000 kg/m³. Experimental bending data from previous researchers were analysed and verified using this theory. From the theoretical prediction, the calculated 1/k value for the selected species ranges from 0.158 to 0.204 which is close to the established value of 0.2. This study provides the actual k value as well as the true depth modification factors for tropical hardwood which important for safe and economical structural timber design.