Evaluation of Buried Piping Restrained Against Thrust

Abstract

It is common practice to resist hydraulic thrusts in buried piping by the use of restrained joints. The most common design method currently in use for restraint design was proposed by Roger Carlsen and is currently incorporated in the 1996 American Water Works Association Manual of Water Supply Practices-M41. The writer reviewed the assumed soil distribution, which is essential to the validity of the Carlsen method, and found it to be incorrect. However, it was also found that the resistive forces that are incorporated in the method are ultraconservative. As a result, these hidden factors of safety compensate somewhat for the use of the improper pressure distribution.