Structural performance evaluation of connections for steel-timber composite members using high-strength bolts and oteel ripes

Details of connections are developed for steel-timber hybrid structural members, which are economical and take advantage of the beneficial properties of each material, such as the strength of steel and ease of construction of wood. In a hybrid member, a steel plate is sandwiched with timber on both sides. The steel and timber are connected with high-strength bolts, which penetrate through doubly placed steel pipes. The outer pipe, which is slightly (1mm) longer than the inner pipe, is designed to buckle under compression when the bolt is tightened. The outer pipe expands radially as it deforms inelastically and fills the gap in the timber hole, thereby enhancing the initial bearing stiffness of the connection. The inner pipe prevents the outer pipe from shortening more than 1mm. The bearing performance of the connections was investigated experimentally and analytically.