This ongoing project is for the selective demolition of platforms along several Washington Metro. Area Transit Authority platforms. Every platform includes the demolition of the tile and concrete surfaces of the platforms themselves as well as surrounding walkways and curbs plus removal and storage of amenities like signage, lighting fixtures, and handrails. Each individual platform also presents its own unique challenges. Several platforms are in built-up areas with overhead cover and adjacent structures that require substantial logistical planning to move equipment, personnel, and waste onto and off-site. Additionally, because of differences in construction and location many platforms had significant sewage and utilities sections directly beneath areas requiring excavation. This created an additional layer of care and precision at every stage of work.
ACECO’s scope included large-scale demolition of the VA Tunnel owned by CSX Transportation, Inc. This incorporated a section of the rail line covering approximately 7,000 linear feet divided into fifteen sections, each having different requirements. Several sections required the existing North wall of the tunnel to remain intact to prepare for new construction, while others included the entire tunnel (walls, roof, and track foundations) to be demolished. This necessitated a complex system of shoring and bracing to protect existing structure and ensure safety during the demolition, and a carefully-designed demolition plan to be followed meticulously throughout the 17-month project.
This job entailed the demolition of Building J, a part of the Alexandria Renew Enterprises complex, as well as selective demolition of specific areas of adjacent buildings G/1 and G/2. Included in the scope of work was a significant asbestos abatement requirement, which was fulfilled through subcontractor Progress Environmental, LLC, a long-time working partner of ACECO. The project presented unique challenges, as Building J was to be razed down to an elevation of 17.33’ with all deck slab and structural columns left intact. There were also strict vibration limits which could not be exceeded, necessitating the use of hydraulic processors and a crushing plant mobilized to the site by ACECO.
ACECO was hired by the Clark-Christman Joint Venture to provide demolition, shoring, abatement, and excavation services in the efforts to renovate the Cannon House Office Building (CHOB) which is controlled by The Architect of the Capitol. Located on Capitol Hill, The CHOB is the oldest Congressional office building besides the Capitol Building. This is a 4-phase renewal project in which ACECO has had and will have the pleasure of working on all phases as well as the preparatory phase 0.
The current Phase 3 focuses on the East wing along First Street. The East Wing requires selective interior demolition of the ground floor through 4th floor, structural demolition of the 5th floor and roof, and asbestos abatement. Historical preservation and design changes are the biggest challenges on this project. With the careful efforts of both our day and night shift crews and ACECO’s historic appreciation, we have been able to navigate the demolition activities safely while preserving the history of the building. Built in 1908, the building has seen many minor renovations and changes to design. With the assistance of the Clark-Christman Joint Venture, ACECO has tackled any design changes while maintaining the schedule and production.
ACECO was contracted to perform the design and installation of the structural support, demolition of the foundation wall, interior demolition, and excavation, all while protecting the historic facade above. To support the existing building wall and facade, a detailed steel support system was installed utilizing the existing interior building columns as the main load bearing elements. Beams, tube steel, needle beams, diagonal braces, and knife plates were installed to support the building wall and exterior facade. This complex support allowed the foundation wall to be demolished under strict vibration and movement thresholds, creating the illusion of a “floating” building until the new addition is constructed, while meeting the aggressive project schedule.