STRESS DIAGNOSIS METHOD OF BENT PIPE BASED ON THE DIAMETER CHANGE SUBJECT TO BENDING

Abstract

If ground subsidence acts on piping that includes bent pipes, the highest stress often occurs not in a straight section but in a bent section. The author therefore has developed a method of estimating the stress generated by a change in diameter by adding an equation for the diameter change and bending moment to the bent pipe stress calculation equations proposed by Rodabaugh and George. To investigate the validity of this method, three kinds of bent pipe made using typical bent pipe manufacturing methods and having representative section wall thickness distributions were tested. As a result, it was confirmed that the stress estimated from the diameter change closely agrees with the measured value.