Reduction of Bending Moments on Hydraulic Structures in Seismic Areas

This paper addresses the benefits of adding flexible, yet restrained, grooved pipe couplings (subsequently referred to as flexible couplings) to above- and below-ground piping interfaces of hydraulic structures to promote seismic resilience at the area where pipes enter and exit reinforced concrete walls. To assess the efficacy of this approach, a piping stress study was conducted using CAESAR II software’s beam-style FEA analysis. The moments on an assumed fixed end (structure wall) were calculated with and without pairs of flexible couplings to show the benefit and reduction in bending moments and shear forces on the structure wall. The results indicated that adding flexible couplings to piping interfaces of hydraulic structures can reduce shear forces and moments on hydraulic structures by approximately 89%. Example calculations, modeling, and data are provided throughout this paper to help assess shear force and moment reduction on hydraulic structures.