Factor of Safety for Dowelled-Double Shear Kempas and Kapur Connections

Abstract

Load-carrying capacity, strength and stiffness properties are critical properties in determining the factor of safety for structural timber joint designs. The capability of joint in form of double shear is the guided method and based guidelines information in analyzing other modern and traditional joints design. The dowelled timber-to-timber strength capacity were used in this study to determine the performance and capability of the EYM theoretical equations to predict the load-carrying of mortise and tenon joints when it is dowelled with steel, GFRP or wood dowel. When the factor of safety is taken as the average of both species, the higher safety factor values is presented. The safety factor for joints dowelled with steel, GFRP and wood with references to the 5 % offset load is 2.7, 2.8 and 1.8 and ultimate values to the predicted values is 2.8, 2.9 and 2.5 respectively. As a conclusion, even though the safety factors is confirmed acceptable and the EYM is evidently suitable for predicting the GFRP and steel dowelled joints but not that accurate to predict the wood dowelled joint. In the case of wood dowels, though EYM are adequate to soundly predict the failure mode of the joints with wood dowel to an acceptable accuracy, modifications to the EYM equations are evidently necessary to predict the load-carrying capacity with a sufficient margin of safety for the design purposes.