Chelsea Townhouse Pool & Elevator Shaft Retrofit.
Chelsea Townhouse Elevator Shaft & pool retrofit
While the project may seem simple, it involves a large amount of materials and work in a confined setting. The building is also landmarked by the historic preservation society of NYC and surrounded by several more landmark structured, leading to stringent performance criteria. Confined structures exceeded expectations of all project stakeholders (engineers, architects, construction manager and owner) in a fast paced project . Key features of the project are highlighted adjacent:
Underpinning
Project involved underpinning the existing building and neighboring building to allow for the excavation for new pool and elevator shaft. Underpinning was up to 11' deep and alternating piers were hydraulically jacked to prevent any settlement, intolerable for sensitive landmarked structures. Access agreements prevented underpinning of the west wall. The solution to this challenge was to build the west pool wass as a segmental retaining wall using an underpinning sequence.
Interior Excavation
Over 400 cubic yards were excavated from the rear yard and existing cub cellar once underpinning and shoring was installed,
Temporary Shoring & Bracing
Prior to demolishing the existing structural elements the first floor above required to be shored. Temporary footings were installed within sheeted pits below the proposed bottom of excavation. Lateral bracing was installed sequentially to brace the underpinning and segmental retaining walls against lateral earth pressures.
Structural Concrete.
Structiral concrete required 15' two faced & single faced concrete walls to form a new combined perimeter and elevator shaft wall at the buildings exterior. The pool construction required Segmental retaining walls, mat slab and single face retaining walls.
