Assessment of structural computer code implementation of PVRC recommended piping damping values

A task group of the Pressure Vessel Research Committee of the Welding Research Council has recommended that structural damping for seismic analyses of piping systmes be modified from the present constant damping to allow higher damping values at low response frequencies. This Technical Development Program project evaluates the implementation of the proposed change on the INEL structural computer codes. For response spectrum analyses and time history modal superposition analyses, the most commonly used seismic techniques, the proposed changes can be easily carried out. Appropriate methods are described in this report. For the time history direct integration method of solution, exact implementation is impossible, and choosing the appropriate Rayleigh constants in order to avoid excessive over- or underconservatism in damping values will be difficult. However, this type of solution method is rarely used in seismic structural analyses