Evaluation of Dowel-Bearing Strength for Wood Dowel Using ‘Spring Theory’

Abstract

Dowel-bearing strength of wood base material is one of the important parameter to design the load carrying capacity of a timber joint. The information about the dowel-bearing strength using steel is available in National Design Standard (NDS, National Design Specification for Wood Construction Ameican Forest and Paper Association (AFPA) Washington DC, 2005). However none of these standards include dowel-bearing strength compressed using wood dowel. Very limited studies were published in determining the dowel-bearing strength of wood base material compressed with wood dowel. The ‘Spring Theory’ proposed by Schmidt and Daniels (Design Considerations for Mortise and Tenon Connections. Report for Timber Framers Guild. Becket. MA, 1999) was found reliable to be applied for European timber species. However, the capability of this theory in determining the dowel-bearing strength of wood based compressed with wood dowel has not be investigated for tropical timber. Therefore this study is aimed to investigate the capability of the ‘Spring Theory’ for 12.7 mm wood dowel. ‘Spring Theory’ is about the combination result of wood dowel compressed with steel block (WDCSB) and wood block compressed with the steel dowel (WBCSD). It was found that ‘Spring Theory’ value of Kempas is 34.81 Mpa. The value of the proportional, 5 % offset and maximum load of Kempas is 11.74, 18.12 and 50.64 kN respectively. The ‘Spring Theory’ was found capable and valid in determining the wood dowel of Kempas compressed with 12.7 mm wood dowel.