Utility coordination at FLL: abandoned underground lines

Thomas M. Wilcox, P.E., Senior Project Manager (retired), HDR Engineering, Inc., Sarasota, Florida, and member of the combined Construction Practices & GIROW Subcommittee of the APWA UPROW Committee

e are currently in the midst of designing an apron expansion for the new Terminal 4/Concourse G project at the Ft. Lauderdale – Hollywood International Airport (FLL), Florida. Some interesting utility coordination work has been required and it highlighted a common problem—what do you do with abandoned underground utility lines and the resulting congestion of utilities?

Included in the project scope is the modification of the existing airport terminal (Figure 1) and its underground utility infrastructure including apron and airside infrastructure and impacted landside utilities.

The existing Terminal 4 Pier Gate layout and aircraft parking positions include 10 gates assigned to Concourse “H.”

The new Terminal 4 Project along with the Expansion of Runway 9R-27L Project will require modification of the terminal building and apron area as shown in Figure 2 with 14 gates in a linear layout. Our project elements include the following:

On the Airside – New apron and modifications to the existing apron as required for the build-out of the new concourse and demolition of the existing Concourse H; also needed are some new utilities and relocation of affected utilities under the T-4 apron area.

On the Landside – Construct a new Florida Power and Light duct bank and manhole system, construct multiple duct bank branches with at least one new manhole from the main AT&T duct bank ring network (under Terminal Drive) tie the Communications Centers for Terminal 4 and Terminal 3 together.

Existing underground utilities in the landside and airside areas affected include:

• 4-inch natural gas line supplying

Terminals-2, 3 and 4; • 8-inch sanitary sewer system providing collection for

Concourse “H”; • Lift Station and 8-inch sanitary force main discharging effluent from Terminals 3 and 4; • Stormwater sewer collection system – varies in size from 18” to 96” diameter; • 8-inch water main supplying potable water and fire protection water to the T-4 area; • 16-inch water main supplying the terminal core;

Figure 2: T-4 Gate Relocation – Apron Area

• 12-inch and 14-inch jet fuel hydrant system; • FPL power cable duct banks running along Perimeter Road,

South Service Road and Terminal

Drive; and • Communications cable duct banks running along Perimeter

Road, South Service Road and

Terminal Drive.

As you can see, much of the work involved working with utilities. The goals for the proposed T-4 Civil Work included the following tasks:

Airside

• Complete minor modifications to the existing T-4 apron in support of phased gate openings prior to the replacement of the entire apron; • Replace the existing apron to accommodate the reconfigured aircraft parking, taxiways, taxilanes and Remain Overnight (RON) aircraft parking areas in coordination with the construction of the new

Concourse; • Revise the stormwater drainage to meet the requirements of the proposed apron work; • Complete the hydrant fueling system modifications (installation of the eastern expansion primary loop, secondary supply loops and fueling hydrant pits); • Reroute and modify sanitary sewer and potable water systems as required to support the T-4

Gate Relocation Project; • Install an underground emergency fuel storage tank and piping adjacent to the emergency Diesel

Generator Room; • Reroute the TECO 4 inch Gas Line to Terminal 4; and • Reroute and resize the airside potable water pipe segment around Terminal 4.

Landside

• Construct a new FPL power duct bank branch between the Terminal Drive Power duct bank ring and the new FPL vault in Terminal 4;

• Construct new Communications duct bank branches between the main Terminal Drive

AT&T duct bank ring and the existing communications closet in Terminal 4, the new

Communications closet in

Terminal 4 expansion and the existing Communications center in Terminal 3;

• Construct a parking lot south of Terminal Drive and north of the apron fence line, just east of

Terminal 4; and

• Install temporary and permanent

AOA fences along the edge of the new apron.

As in nearly every retrofit project there are choke-points, locations where you need to put ten pounds of utilities in a five pound bag, so to speak. Along with the larger Terminal building comes the need for additional infrastructure to serve more passengers, planes, luggage, food, water, restrooms, fuel, etc.

Figure 3: An open grassy area tends to be a magnet for attracting every utility in the area.

Figure 4: In this blow-up more than 10 utility lines can be counted in the very narrow grassy space between a multi-story parking garage on the right and busy Terminal Drive on the left.

Utility needs often pose conflicts with competing users such as roads, toll plazas, parking garages, and each other. Most utilities don’t want their lines to be placed under a 15½”-thick Portland Cement Concrete slab or a busy terminal drive as it makes getting to them rather difficult, especially in an emergency repair situation. Therefore an open grassy area tends to be a magnet for attracting every utility in the area. One can be seen in Figure 3.

In Figure 4 you can count over 10 utility lines in the very narrow grassy space between a multi-story parking garage on the right and busy Terminal Drive on the left.

This situation is not found only at airports as shown in this photo of an intersection (Figure 5). Public rights-of-way are viewed as the “open areas” by the utilities in zero-lot line conditions. Think about how you would run a new utility line through this area. Wonder how many of these lines have been abandoned over the years but are still taking up valuable space because they weren’t removed? What happens when a utility line is abandoned? Generally it just becomes part of the underground puzzle. Underground utility congestion isn’t a new problem, as shown in this photo from 1917 (Figure 6). It’s a good bet that many of these lines have outlived their useful lives and have been replaced over the years. There is an equally good chance that any abandoned line(s) were abandoned-in-place. How would you be able to remove a failed line? Even today the common treatment for abandoned lines is emptying them of any product they might contain and filling the line with flowable fill (abandonment grout) or perhaps just cutting and capping of the mains and services. This does not free up space for future utilities. In some cases the abandoned lines are mistakenly identified by the locators as a live line, which an excavator exposes then protects and afterward starts digging with abandon (pun intended) and hits the real line nearby. Who pays for the costs associated with this?

What does an excavator do when he finds an unknown or unexpected utility line? He stops. Why? Every

Figure 5: Public rights-of-way are viewed as the “open areas” by the utilities in zero-lot line conditions. Figure 6: Underground utility congestion isn’t a new problem, as this 1917 photo shows.

line must be treated as if it is in use, unless it is known for sure that it is abandoned. The contractor should have the locator (1-Call system, USIC or the Utility owner) verify that the line is abandoned and safe to excavate around or through. Nobody wants to be “The King of Unintentional Underground Locates.” That leads to safety hazards, possible loss of life, injuries, property damage, releases of product into the environment, cost to correct and, of course, company liability.

However, a work stoppage may require revised design drawings when the improvements have to be relocated or if the unexpected utility line has to be moved, which translates to lost production and may generate claims for delay by the contractor. Any claims will ultimately result in finger pointing and additional cost to all involved. Who was at fault—the engineer, the utility locator, the contractor or subcontractor/excavator, inspector, project owner, utility owner? What about the disruption and/or economic loss to those served by the utility line while it was out of service, i.e., a restaurant that can’t prepare or serve food, a building on fire that doesn’t have fire flow available to extinguish the blaze; and perhaps additional losses even after it is repaired, i.e., a water line with a boil order while waiting for the results of the bacterial tests.

A few years ago the answer to utility congestion was to go deeper. Jack and bore, directional boring or horizontal directional drilling was the answer and they are still going strong; however, we are beginning to realize that sometimes we just moved the problem from a shallow area to a deeper area. It’s not uncommon now for the directional borings to encounter previously installed (directional bored) utilities sometimes rupturing them. Many of these were not properly tracked, marked nor put on as-builts accurately and consequently cannot be located before construction commences. Therefore, “The King of Unintentional Underground Locates” finds them as a surprise and work stops while a new solution is worked on. Additionally finding an area clear of underground lines and large enough for the starting pit and the exit pit is another problem in small congested corridors.

With their CSA S250 Standard, “Mapping of Underground Utility Infrastructure,” Canada has started a “Standard” for reliability and accuracy of mapping records including both the horizontal and vertical position of the utility, and uniform descriptions, symbols, line style, color and data structure to identify the different types of infrastructure on as-built survey plans.

Companies are now marketing RFID-enabled electronic utility markers to address the broad range of permanent marking needs. RFID markers locate specific underground facilities precisely and efficiently. The new markers are designed for both shallow markings two feet (0.6 m) below the surface and deeply buried applications at eight feet (2.4 m). Both are available as active (programmable) or passive (nonprogrammable). Read more: http://tdworld.com/ projects_in_progress/construction_ equipment/electronic-utilitymarkers/#ixzz1wz081CQg

The United States and Canada have many associations that are involved with pieces of this problem, but I think it is time that we come together and establish a standard dealing with abandoned utility lines—and perhaps APWA should take the lead. Shouldn’t there be a uniform way to plan for, construct, and at the end of their service life remove underground utilities?

The problem of abandoned utilities is an issue that, at this point in time, doesn’t have a clear-cut answer. Different owners/agencies/utilities approach the problem in different ways: mandate that all abandoned facilities in ROW must be removed; mandate that all abandoned facilities must be mapped; remove when encountered during construction; etc.

Should the utility owner be responsible for all costs associated with the maintenance or removal of its abandoned or idled lines within the ROW or public easement? Should the utility have to post a bond that would serve as financial protection against damages from spills and for removal of the line if it is abandoned someday? Should the utility company pay rent for every line they have within the ROW or public easement until it is removed or reused by another utility?

Singapore is now considering underground space as a strategic resource. In some areas today we have aerial easements for scenic views and sunshine (solar energy); someday we may have underground easements, and who knows what depth of soil under your property comes with your warranty deed?

Please let me know what your thoughts are on how to handle underground utility congestion and abandoned utility lines. Isn’t it time a regulation was developed for this? As with many unsolved issues it probably boils down to money. How do we fund the necessary work?

Thomas M. Wilcox can be reached at Tom4883@gmail.com.