Jeff Stephenson, P.E., is the Team Leader of [...]
When you’re looking at designing (or redesigning) a roadway, you need to think first about the impact that project will have on the utilities surrounding the road. If you don’t, you’ll likely find yourself grinding to a halt when you encounter a utilities-related roadblock in your project.
Utilities are the lines, wires, and pipes that carry utility service to customers (either residential or commercial). Typical utilities you’ll encounter on roadway projects are power, telephone, cable, fiber optic, water, gas, and sanitary sewer.
Utilities can be a tricky component in your roadway design. Several utilities are located underground and are shown on surveys in an estimated location. The estimated location is obtained either by a utility locator spray painting a mark on top of the ground or by a review of the utility map. Vertical locations are estimated based on typical depths (generally 24 to 36 inches) based on input from the owner of the utility. Since the utility locations are estimated, not exact, evaluating direct conflicts can sometimes be difficult; therefore, due diligence with utility companies is recommended during the planning stage to assess whether a conflict actually exists, the cost of potential relocations, and the impact the relocation(s) will have on the overall project.
When we start the design of a roadway, we prepare a concept drawing of the horizontal and vertical components of the roadway and can assess the possible utility conflicts. If a conflict is possible, we do more investigation into the size of utility, clearances required by the utility owner, and exact location of the utility. Potholing of the utility or a subsurface utility exploration may be needed to aid in evaluating the exact location of the utilities. We’ve had several projects in which the utilities in direct conflict have been large and relocation was not feasible, which could mean they are vaults, main transmission lines, etc. In those instances, we may have to re-design the roadway and/or drainage to avoid a conflict.
Utility relocations can add additional time to the overall construction schedule and they need to be planned in advance. We are currently working on a project that has needed several relocations to accommodate the roadway widening. This particular widening project requires a large rock cut on one side of the road. The existing utility poles and lines cannot be relocated until the rock cut is performed, so we must stage construction for a portion of the grading to be completed first, followed by the utility relocations and then the final grading and paving can be finished. The utility pole and line relocations will take approximately two months, which means we have a two-month gap in the middle of the roadway grading activities.
Utility relocations can be costly. If you are tasked with preparing estimates of cost for your roadway project, utility relocations should be considered as they can be significant cost adds to the overall construction cost. We have seen entire projects be dropped by the project sponsor because the cost of the utility relocations made the project unfeasible. A good rule of thumb is to question how the utility relocation will be funded; either it’s paid by the utility owner or by the roadway sponsor. Several factors, such as type of funding, type of project, type of utility, etc. play into who funds the relocation.
Make sure you’re considering all the utilities located in and around your construction project, or you could find yourself stalled unexpectedly for several months and surprised by the cost to your clients.
Sain Associates, Inc., is headquartered in Birmingham, Alabama, with offices in Pulaski, Tennessee and Mandeville, Louisiana. Sain is a site engineering, traffic/transportation engineering and planning and land surveying firm with experience in more than thirty states.