Seismic Performance of Bolted Flange Joints in Piping Systems for Oil and Gas Industries

Recent seismic events showed a quite high vulnerability of industrial piping systems and components, where damage ranges from simple failure of joints to failure of supporting structures. The performance of the whole piping system strictly depends on the functionality of its individual components. Moreover, the behaviour of bolted joints is complex and critical under seismic actions. Therefore, they need special attention and deep investigation. In addition even for refinery industries, it is also important to know the leakage behaviour of typical flanged joints. Currently, both American and European codes are available to design flanged joints under static loading. Nonetheless, there is no code available to take into account seismic loading effects on these joints. Along these lines, we intend to present in this paper the results of a test campaign on two different types of flanged joints carried out at the University of Trento(Italy), by means of bending and axial loading, respectively. Test results were favourable and were analysed and compared with: 1) the demand provided by piping systems connected to a typical support structure, 2) allowable, yielding and ultimate design values provided by available codes.