Analysis of Bolted Butt Joints

A general theoretical solution for the load partition in double-lap butt joints is developed. The solution is applicable to both the elastic and inelastic regions of bearing-type connections. The solution was aided by the development of analytical expressions for the stress-strain relationship of plates with holes and for the shear-deformation relationship of high-strength bolts. A digital computer program was developed to make the solution practical. The theoretical solution was compared with test results of large bolted connections and showed good agreement with the greatest difference between test and theory of approximately 4%. The solution is used to study the influence varying the relative proportions of the bolt shear area and the net tensile area. This study showed that an increase in net plate area increased the average shear strength of the fasteners in the longer joints. Supplemental tests are shown to verify this behavior.