Unified Approach to Thrust Restraint Design

The design of thrust blocks for water pipelines and sewer force mains vary from one pipe material or standard to another just like the design of pipe wall thickness. This creates tremendous confusion among consulting engineers and owners of projects. The designers and the owners have to look up Design Manual M9 for concrete pipe, Design Manual M11 for welded steel pipe, Design Manual M41 for ductile iron pipe, and Design Manual M45 for fiberglass pipe. The marketing philosophy of the pipe vendors is that the more that these design manuals are in print the more confusion they create that the pipeline asset owners and the designers have to turn to the pipe suppliers for the design and development of the specifications. This results in an undesirable situation where the pipe manufacturers are designing and writing specifications they know they will have to meet when the projects are bid on behalf of the public. In other countries most water pipeline materials are required to meet a common standard, where design equations are kept the same while material properties vary from one pipe material to another. The purpose of this paper is to start from the fundamental principles of fluid mechanics and geotechnical engineering and build the engineering know-how needed to apply the same design methodology for all pipe materials and applications. A step-by-step design methodology is presented.