Behavior of Timber Joints with Multiple Nails

Abstract

An attempt was made to study the effect of the number of nails on the stiffness of laterally‐loaded timber joints with interface friction, fabricated with 2–8 nails in a row. A mathematical model was developed to predict the load‐slip behavior of the joints. An experimental program investigated the effect of the number of nails, and some 140 joint tests were conducted, in total, in the present research. The current design concept that a joint fastened together with multiple nails in a row carries a lateral load equal to the product of the lateral capacity of single nail joint, and the number of nails in a row of the joint is somewhat of an overestimation of the overall capacity of the joint. Modification factors are developed to account for the effect of the number of nails in a row on the stiffness of joints with multiple nails. Experiments were also conducted to determine the parameters required for the application of the theoretical model. Frictional forces between the constituent members of joints were observed to be constant for joints with 3–8 nails in a row. The load‐slip curves of tested joints and the corresponding curves obtained from the theoretical model are compared with each other to verify the extent of the validity of the model. The theoretical predictions yield an upper bound solution for all types of joints—seven different types—tested in this research.