Generalized Model for Lateral Load Slip of Nailed Joints

Abstract

An investigation is undertaken to develop a procedure for predicting the load‐slip curves of laterally loaded nailed wood joints. The resulting procedure makes possible the prediction of key parameters for a commonly used model over a wide domain of joint geometries. The prediction technique considers the effects of five basic joint characteristics: nail size, side‐member thickness, side‐member specific gravity, main‐member specific gravity, and interlayer gap. Utilizing earlier works by McLain and by Wilkinson, reference values of basic model parameters were calculated for standard joint configurations. Correction factors were then developed on the basis of the results of 342 load‐slip tests. These factors were used to modify reference values to account for the effects of different joint characteristics. In establishing the correction factors, three nail sizes, three side member (plywood) thicknesses, and a range of interlayer gaps between 0 and 0.035 in. were tested. Three types of alternate sheathing materials were also tested to determine the usefulness of the prediction technique with respect to these materials. In general, the prediction technique yields conservative values. On the average, predicted stiffness values for specimens having plywood side members were 6% less than experimental values. Seventy‐five percent of the predicted stiffness values were within 40% of the experimental values. For specimens with alternate sheathing materials, predicted stiffnesses were, on the average, 12% less than 4% greater than experimental values, depending on the type of sheathing.