AN EXPERIENCE IN THE EVALUATION OF THE SLIP COEFFICIENT OF FRICTION BOLTED JOINTS NOT PROTECTED

Bolted joints could be designed to transmit shear forces by means of shear strength of bolts or by taking into account the friction established between the plates surfaces by bolts tightening. In the second case, relative displacements of the connection are avoided and a more homogeneous contribution of each bolt to the global behaviour of the system is guarantee. In this framework, an important parameter for the calculation of the required number of bolts of the connection and for the correspondence of the design approach with respect to the actual behaviour of the joint is the slip coefficient; it depends significantly from the surface treatment of the adjacent plates in the connection. Present paper describes the results of experimental tests regarding the evaluation of slip coefficient for sandblasted not protected surfaces; experimental evidences suggest the adoption in the calculation of a more accurate slip coefficient with respect to the Codes provisions, with a reduction of bolt\u2019s number in the connection