Saving Millions and Avoiding Disaster – TheO'Hare Hot Tap Project

The benefits of diverting flow from an active watermain to a bypass pipe without interruption of service are presented. The project was complex due to the type, size and location. The project purpose was to relocate a 5,000 foot, 90 plus inch pre-stressed concrete cylinder transmission main operating at 145 psi to enable construction of a new runway at Chicago's O'Hare airport. The owner of the main required no loss of service or operating pressure and O'Hare required no air service interruptions. Conventional construction methods were estimated to cost $80 million. An alternate proprietary STOPPLE® process was selected at an estimated cost of $6 million but required installation of bulkheads in two locations. These bulkheads would incur an estimated 1.5 million pounds of force as the flow was diverted into a 60-inch temporary by pass pipe. With challenges involving the site, service and weather constraints, two massive thrust restraint systems were successfully designed and built on schedule within the expected cost parameters.