A SIMPLIFIED METHOD FOR QUALIFICATION OF SMALL BORE PIPING SUBJECTED TO SEISMIC LOADING

摘要

A simplified method for the qualification of small bore piping (2-inch diameter and smaller) subjected to gravity, pressure and seismic loads is presented. The method consists of evaluating stresses due to gravity and seismic loads based on uniformly loaded continuous span formulae, and adding stress due to internal pressure directly using code guidelines, instead of using the conventional estimates of 1/2 allowable stress. The procedure leads to a linear relationship between the frequency of pipe and spectral acceleration. Combining this with the spectral acceleration data from the earthquake gives an optimum span length for a given seismic loading. The method can be easily programmed to develop tables of allowable span lengths for different pipe sizes. The applicability of the technique is demonstrated with examples of practical interest, and by comparison with rigorous analysis.