Bending strength distributions and LRFD code conversion of Korean softwood species: Bending strength distributions and LRFD code conversion

The aim of this study was to check the load resistance factored design (LRFD) codes for Korean softwood species. Three representative structural timber Lazix Kaempferi, Pinus koraiensis, and Pinus densiflora, in the northeastern South Korea were selected. For evaluating the bending strength, a full-sized specimen was used. In the test results, it seemed that the KFRI grading rule was suitable for grading the three species due to the high percentage of grade 1 or 2. However, in terms of modulus of rupture, the grading rule had a problem due to the large coefficient of variation in the grade class. Moreover, in case of Pinus densiflora, it is difficult to use LRFD design values by format conversion since the reference resistance values were much lower than the values. For greater reliability, the accumulation of additional data is necessary and further studies should be performed.