HDD Crossing of Lake Austin Generates Data and New Model for Calculating Pull Force for Ductile Iron Pipe

摘要

April 23, 2009 saw the successful completion of a new ductile iron pipe (DIP) water supply by horizontal directional drilling in Austin, Texas. This project required an engineered prediction of pull loads that could be applied to the pipe for this installation as the pipe was longer than previous DIP installations. The requirements of the owner were very specific, the District wanted DIP with a low profile, flexible restrained joint for HDD. The issue was that construction required a large drill rig to make the bore though the tough rock therefore; the rig pull capacity significantly exceeded the strength of the pipe. The owner was concerned about damaging the product pipe during the pull. Though the risk was on the contractor, the owner required engineering calculations to assess the possibility of exceeding the allowable pulling load for the pipe. This paper describes the project, DIP characteristics, the new DIP pull load calculation method developed specifically for this project, and includes an assessment of the new calculation method against available data.