Observations From the Behaviour of Bolted Beam to Unstiffened Column Rigid Connections

A limit state design method is recommended for rigid beam-to-unstiffened-column extended endplate connections, with four high strength bolts, positioned symmetrically around the tension flange. The design procedure for the bolt size, endplate thickness, unstiffened column flange thickness, and slip, ensures that sufficient strength, stiffness and adequate rotation capacity are achieved. In a connection where the endplate thickness is not less than the unstiffened column flange and where the bolt diameter is not less than the endplate thickness, the design moment and rotation capacity of the joint are governed by both the strength and stiffness of the unstiffened flange. Simple equations to determine the size of the individual joint elements are recommended, which will ensure that rotations are within two or three times the relative rotation that would arise owing to elastic deformation in the adjoining structure. The recommended design method given in Appendix A is based on previously published experimental evidence and from the results of full-size specimens tested to failure by the author. The recommended design procedure is compared with design methods given by other investigators, and conclusions are made as to their suitability.

J. Graham