Dubuque Pipeline Replacement
A large natural gas distribution company required detailed engineering and design for a 30-inch, 8-mile pipeline replacement project located in northern Illinois.
The project posed a number of challenges. First, the pipeline was routed through an existing gas corridor in a heavily populated area. In addition, the existing 22” pipeline was replaced with a 30” pipeline, so a workaround had to be designed to accommodate this change.
Because the pipeline was in a heavily populated area, the team worked closely with the client’s real estate group to ensure all landowner concerns were mitigated prior to construction. Additionally, proposed pipeline installation methods were adjusted to place equipment in less populated areas. The proposed pipeline was to be installed mainly within the existing local gas distribution company’s easement.
To accommodate the new 30” pipeline, the design had to take into account the existing 22” pipeline that was required to stay in service throughout construction. The designers developed a way to locate the proposed 30” pipeline within the existing easement. The replacement required precision locating by the survey and subsurface utility consultants to ensure the existing pipeline was accurately located both horizontally and vertically. Once the designers received this information, locating the proposed 30” pipeline in the easement was crucial to maintain sufficient clearances between the existing 22” pipeline and other third party utilities, while still maintaining the construction limits within the existing easement. Every effort was made to obtain additional temporary workspace where available to allow the contractors flexibility in construction for safety and cost effectiveness. The challenging 6-month project was completed on time and on budget.