Bending Stress and Deflection of the Cross Section of Buried Pipes

摘要

When designing cross sections of buried pipes, external forces such as earth pressure and pressures exerted by loaded vehicles are usually taken into consideration by applying the 'moment factors' prescribed by the Gas Utility Industry Law (GUIL) standard. For the design of buried pipes in general, the Iowa formula, proposed by Spangler, is widely used. However, the manner in which moment factors and the Iowa formula were derived is not well understood even by those using them. The present report, therefore, discusses them in detail, paying special attention to the processes by which they were established, and clarifies the physical concepts of design parameters (constants) used. In addition, it examines briefly basic concepts relating to changes in the cross section and to the 'flexibility' index. 7 refs., 15 figs., 8 tabs. (ERA citation 12:010888)