Enhanced seismic performance of non-standard bolted flange joints for petrochemical piping systems

• Two non-standard seismically enhanced bolted flange joints were designed.
• Performance of proposed joints was evaluated through bending and axial tests.
• The joints showed favourable ductility, energy dissipation and leakage capacity.
• Experimental leakage and yield loads of joints were above allowable design loads.
• Joint capacities were far above seismic demands obtained from a Case Study.

This paper presents an experimental test campaign carried out on a number of seismically enhanced Bolted Flange Joints. In particular, two non-standard Bolted Flange Joints, comparatively thinner than standard ones, were designed and their performance was evaluated through several monotonic and cyclic tests. Experimental results exhibited a favourable performance of the examined joints under bending and axial loading and moderate internal pressure; a good capacity in terms of strength, ductility, energy dissipation and leakage was observed. A comparison between experimental results and Code-based design loads proved the usability of the proposed joints during and after Operating Basis Earthquake ground motions. Finally, a comparison between capacity and seismic demands of these joints adopted in a piping system of a realistic Case Study suggested their suitability for seismic applications as well as some building code deficiency with respect to response modification factors.