Annapolis City Dock Bulkhead Replacement, Phase 2 Outstanding Civil Engineering Achievement, Under $20 Million, 2017
City of Annapolis, Department of Public Works | Owner
EBA Engineering, Inc. | Consultants
Cianbro | Contractor
Located in the heart of Annapolis’ historic district, the Annapolis City Dock Bulkhead Design and Replacement project was a high-profile endeavor requiring careful and extensive coordination between the City of Annapolis, key organizations, businesses, and government agencies.
Phase 1, completed in 2008, involved replacing 1,100 linear feet of steel sheet pile bulkhead along the south section of City Dock, 850 linear feet of boardwalk, multiple piers, and associated utilities, as well as reconstruction of Susan Campbell Park. Phase 2 concluded the City Dock Bulkhead Replacement and was completed in Spring 2016. This phase focused on protecting the inner City Dock (north section) near Market Space and Compromise Street.
In all, Phase 2 involved constructing a 700-linear-foot cantilevered steel sheet pile bulkhead with concrete cap, replacing and widening the boardwalk, and installing new boat slips and timber mooring piles.
EBA Engineering, Inc. (EBA) provided engineering design and construction management services to the City of Annapolis for Phase 2 of the project. As the prime consulting firm, EBA’s services included a survey of the existing project site, geotechnical investigation and engineering, civil engineering site analysis and design, structural engineering design, design phase project management, construction management, and construction phase services including inspection and testing.
Cianbro was the project contractor. Three subconsultants, SRBR Engineers, Inc., Deborah M. Schwab Landscape Architecture, and Retrospect Architectural Research, LLC, also participated in this project.
The Annapolis City Dock was badly in need of bulkhead replacement and upgrades to preserve and enhance the high level of boater services. The bulkhead replacement addressed an ongoing issue of backfill loss through the deteriorating structure into the waters of Market Slip. The result was a slumping dock surface with areas of settlement adjacent to the transient slips. These conditions were hazardous to all users of the City Dock area. The loss of backfill also decreased available water depth in the slip area and was environmentally detrimental. The successful bulkhead replacement stopped this process and ensures that water depths in the slips will continue to be adequate.
The traditional configuration of a bulkhead of this size consists of sheet piles supported by steel tiebacks connected to a concrete deadman. This type of system requires a large excavation area behind the bulkhead. EBA proposed the use of an innovative cantilever bulkhead system that does not require tie-backs. This design choice greatly reduced the area disturbed by excavation, as well as the time required for construction, allowing the project to be constructed on time within a compressed schedule.
The cantilevered sheet piles are also a sustainable choice, as they provide the greatest range of options for future development of the area. Future replacement structures can be placed behind the existing structure due to the absence of a tie-back system connected to a deadman. This will allow excavation of the previous tie-back system without disruption to the functionality of the system that is currently in place. A future bulkhead could be installed landside of this bulkhead, widening the very narrow waterway that has been restricted with each subsequent bulkhead replacement that has traditionally been installed waterside of the existing bulkhead systems.
Throughout the design and construction processes, EBA worked closely with the City of Annapolis, stakeholders, and community members to ensure that each element of the project met the needs of the community. In addition to the functional improvements such as additional boat slips and updated electrical and water supplies, the project aimed to improve a community gathering place that has been central to the commercial and community life of Annapolis for over 300 years. Incorporating a bench seat in the new concrete pile cap, as well as installing a widened timber walkway along a portion of the new bulkhead, have created a space where residents and visitors feel welcome to stroll, linger, and enjoy the beauty of Annapolis.
The project also required careful and extensive coordination between the City of Annapolis, key organizations, businesses, and government agencies. The entire team (owner, contractor, designer, construction manager, stakeholders, etc.) started the project and proceeded throughout with common goals. Adding to the project’s complexity, all work had to be completed within an aggressive six-month timeframe, between the end of the Fall Boat Show in October 2015 and before the start of the Spring Boat Show in April 2016. With everyone working together diligently to achieve shared goals, the team met this demanding schedule.
The bulkhead replacement project also came in at $6.2 million, well under the $7.5 million budget. For both phases, in order to expedite the projects to meet the extremely demanding six-month schedule requirement, EBA recommended and assisted the City with employing two strategies: (1) developing a Request for Qualifications package to shortlist qualified contractors prior to releasing bid documents; and (2) through a separate and early bid package, procuring long-lead-time materials such as marine-grade steel sheet piles and custom mooring bitts. These two non-typical strategies allowed the City to secure a highly qualified and experienced contractor (Cianbro) before the notice to proceed and also have that same contractor ready, with all necessary materials, to begin construction the next day following the end of the Fall Boat Show.
In all, the team successfully managed a complex, severely time-constrained project, including a project site with 300 years of structural history. The team considered both sustainable development strategies and the needs of future generations in the project’s design.
The City Dock is the geographic, cultural, and commercial center of Annapolis. The city is an extremely active port, hosting fishing, recreational boating, sailing, boat shows, and racing fleets that are responsible for a vigorous maritime industry and a significant part of the local economy. Maintaining boating infrastructure is thus a key part of the City’s responsibility to the community.
Residents and visitors benefit from many aesthetic improvements and new amenities as a result of the project, such as a new seating area along the seawall, a wider wooden boardwalk along the Donner Parking Lot, and new boat slips with upgraded utilities including a fire protection system. Annapolis’ iconic City Dock has been given new life to the benefit of residents, visitors, local businesses, and the marine industry.