By Lt. Cdr. Avery Weston, P.E., PMP, M.SAME, USCG
For more than a century, Coast Guard Yard in Baltimore has built, repaired, and renovated ships for the U.S. Coast Guard. Today, it is the service’s sole shipyard and an essential part of the core industrial fleet support operations. Currently, the yard provides depot-level maintenance to nearly every cutter in the Coast Guard fleet. Dry-dock repairs are accomplished on the 62,000-ft² Land Based Transfer Platform, where vessels are lifted onto the landside platform through a Syncrolift (constructed in 1997) capable of lifting ships of up to 3,500-T and approximately 50-ft wide.
Demand for Coast Guard dry-dock repairs exceeds the yard’s capacity. To address this, a complex heavy construction project was carried out to expand the existing Land Based Transfer Platform to accommodate a new third rail, increasing shipyard dry-dock capacity by 30 percent. Once completed, the shiplift expansion will enable two 175-ft Keeper-class cutters to be serviced simultaneously with a clearance of 14-ft 10-in between vessels. Included in this expansion is a new steel sheet pile cut-off wall, tower crane, storm water treatment system, and industrial utilities to continue to build on the yard’s renowned reputation of quality and “Service to the Coast Guard Fleet.”
Delivering this critical project, however, required navigating ongoing base operations and adapting to changing circumstances.
SECURING A FOUNDATION
Coast Guard Yard’s waterfront was developed with man-placed fill. As a result, during the design stage a careful geotechnical analysis was conducted to identify the best support structure. At the site, there were three soil stratas: man-placed fill, Pleistocene age deposits (sandy silt), and Cretaceous age Potomac soils (clayey silt). To construct the new platform, auger pressure grouted piles were embedded down into the Potomac soils to achieve requisite bearing capacity. Piles 18-in in diameter were selected over displacement- type piles because of their ability to penetrate into the dense soils without jetting or hard driving. In total, 290 piles were installed to provide an allowable compressive load of 160-T to support the rail beams. The geotechnical data, coupled with the structural analysis, provided the foundation for the project to be successful.
As with all geotechnical operations, unforeseen site conditions emerged during excavation and groundbreaking. An abandoned septic system was unearthed that required environmental remediation and selective excavation. Additionally, there were numerous abandoned utility lines that were not depicted on as-built drawings and required workarounds. Fortunately, the unforeseen site conditions did not impact the critical path and there was no substantive time delay to the project completion.
With specific requirements for ship load distribution and levelness during dry-dock repairs, precise platform elevations and locations were essential. The total station survey was conducted during site preparations and directed the pile driving and concrete operations. However, a challenge emerged due to the inadvertent demolition of a benchmark reference station. Without this reference station, the triangulation was impacted and the measurements deviated, requiring a complete re-survey. This issue was overcome, but did cause the project to experience a loss of three work days.
During construction work, the most significant challenge encountered was the requirement for shipyard operations to continue. Separated by only a fenceline, heavy construction was often at odds with shipyard repairs, such as during demolition and excavation when the dust impacted paint operations on the dry dock platform. Due to both operations being subject to delay damages, Coast Guard Yard was between a rock and a hard place.
Communication was the key to navigating this conflict. The yard’s facilities engineer acted as liaison between the prime contractor and the production manager. By detailing precise time windows and additional protective measures for operations (such as water wet down during excavation and additional tarps for painting), progress was able to continue for both parties.
A further issue arose when Coast Guard operations required an emergency dry-dock to CGC VIGILANT, a 210-ft law enforcement cutter. This time sensitive dry-dock necessitated rail tie-in operations during December and January for ship movement on the loading platform. Persevering through freezing temperatures and weekly snow events, the contractor was able to complete the rail tie-in to enable the shipyard to conduct the emergency repairs. To achieve this, tents with space heaters were erected to keep the temperature above 40°-F. To prevent snow melt from infiltrating the rail pockets, the contractor utilized submersible pumps and spray foam to keep the work area dry for the rail tie-in. Although the rail-tie in was successful, the weather and additional measures delayed work progress and productivity.
Instead of continuing to battle the elements in January, the contractor decided to pause and continue the rail-tie ins when the weather was better. This meant that the strict scheduling timelines for dry-dock repairs were upended by the change in date for the rail-tie in. Through numerous scheduling meetings, impacts were mitigated by targeting specific rails that enabled critical ship movement. Concentrating on these areas overcame any significant impact to shipyard repair activity. Strategic, targeted work was critical toward mitigating adverse impacts.
Antiquated infrastructure at Coast Guard Yard posed another risk. Tie-ins to the existing utilities proved problematic, and the conditions at the connection points were deteriorated. As a result, additional linear feet needed to be demolished to find acceptable material for the tie-ins. Furthermore, existing steam line leaks caused a temporary water line to fail, leading to flooding on the job site. A swift response to secure the water and install a temporary steam vent quickly abated the issue with minimal damage.
From the facilities engineering perspective, the most rewarding portion of the project was the installation of a best practice stormwater treatment system. Removing and installing ship marine coatings requires robust environmental controls to minimize adverse effects to the environment. This project is upgrading the stormwater treatment system to institute cutting-edge technology and practices. The improvements will include a four-stage filtration system: the first stage is the storm basin inlet inserts with Fablite filter; the second stage is the Contech Jellyfish high-flow fabric filter directly downstream of the diversion structure; the third stage is the settling tank; and the fourth stage is the Contech StormFilter media cartridge filter before the water reaches the outfall.
This robust particulate filtration system is designed to significantly reduce total phosphorous, total nitrogen, and total suspended solids (namely copper and zinc) from the yard’s stormwater and fall significantly under the Maryland Department of Environment’s regulatory limit. The technologically advanced filtration system will ensure the installation is the most environmentally friendly shipyard in the nation.
All the planning in the world cannot prepare for the unexpected challenges encountered during a construction project. However, with a strong project management team able to problem solve and willing to work together with the shipyard, significant challenges were overcome. This heavy construction project remains on target for an on-time completion with minimal modification costs.
Lt. Cdr. Avery Weston, P.E., PMP, M.SAME, USCG, is Assistant Facility Engineer, Coast Guard Yard, Md.; email@example.com.
[This article first published in the May-June 2022 issue of The Military Engineer.]