23 October 2002
Rector Street Pedestrian Bridge opens at Ground Zero
In New York a new pedestrian bridge connecting the residents of Battery Park City and the various businesses of the World Financial Center to the rest of Lower Manhattan has opened to foot traffic. The 70m bridge spans from the East Side of West Street (at Rector) to Battery Park City, directly south of Ground Zero. The project is a collaborative effort among Buro Happold consulting engineers, Sharples, Holden and Pasquarelli (SHoP) Architects PC, the Battery Park City Authority, the New York State Department of Transportation, and the Sam Schwartz Company. The project was funded by FEMA (The Federal Emergency Management Agency).
In order to meet a fast-track schedule, a pre-fabricated galvanized steel box truss system (supplied by Mabey Bridge) was specified for the bridge super-structure. The project brief was to provide safe passage for up to 4000 people per hour, while providing shelter from weather and offering occasional views to the surrounding areas. To accomplish this, a steel roof truss system was mounted to the prefabricated structure, allowing for a roof and partial cladding of the exterior walls.
The partial cladding enables the penetration of sunlight during the day and light to emanate from the apertures at night from 1.5m long light planks in the bridge floor. To guide pedestrians safely across the bridge, use of apertures in the elevation and the light planks in the floor and stair riser emphasize the direction of flow of pedestrian traffic and light the passageway.
The bridge is a series of welded steel tube frames bolted to the prefabricated structure with frames located at approximately 2.4m centres along the entire length of the bridge. The frames are connected with a 7.5cm steel deck screwed directly to the frames, providing bracing for the frames. The frames are stabilized with tension rods at 8 locations along their length.
Speed was of the essence in conceptual design and subsequent fabrication where the archtitectural team was pushing for a complex form, but a simple solution. While frames for each side of the bridge vary in vertical dimension, the design team was able to capitalise on repetitive use of the complex frame section geometry which sped up critical ship time for the fabricators. Single tube sizes were used for all the frames to simplify welding and other connections.
To design and verify the roof structure, Buro Happold used QSE computer program to analyze the aluminium frame stubs and connections. Both big and small frame types were considered. Each frame was modelled using pin support conditions at the connection to the bridge structure. Buro Happold’s computer model obtained maximum strengths under both a uniform dead load and snow load applied horizontally at the top elements.
The roof structure is considered a permanent structure and no reductions were taken for temporary construction.
Credit list
Project: Rector Street Pedestrian Bridge
Client: New York State Department of Transportation and The Battery Park City Authority
Design: SHoP Architects, PC
Structural Engineers: Buro Happold
Urban Design/Planning: The Sam Schwartz Company
Construction Manager: LiRo-Kassner, Inc.
Civil Engineers: Edwards and Kelcey
General Contractors: Tully Construction, Inc.
Fabricators: MABEY Bridge and Shore, Inc.
Press Office and Practice information at www.burohappold.com
Buro Happold is a multi-disciplinary international practice of consulting engineers established in 1976 offering civil and structural engineering, mechanical and electrical engineering, quantity surveying, building services and environmental engineering, health and safety management, infrastructure and traffic engineering, ground engineering, façade engineering, fire engineering, computational fluid dynamics analysis, disability design consultancy, project management, urban design and a range of specialist CAD services.
ShoP/Sharples Holden Pasquarelli is an emerging design firm with five partners whose education and experience encompass architecture, fine arts, structural engineering, and finance and business management. Founded in 1996, SHoP was recently awarded the 2001 Academy Award in Architecture by the Architectural League of New York and the 2001 Academy Award in Architecture from the American Academy of Arts and Letters. Their broad range of recent projects includes a university academic building, a civic park, two public art installations, a museum, retail shops and two mid-rise apartment buildings. With each new design problem the office uses a combination of digital expertise, in the form of three-dimensional computer form generation and rapid prototyping, and model building in their in-house shop, to arrive at an original and buildable solution that only that particular project could have inspired. SHoP’s reputation as architects who can link emerging concepts and theories of the digital age with the tactile fundamentals of design and construction is what sets us apart from other design practices. We have a proven track record of bringing cutting edge design to a project while using the computer to maintain, or often reduce, construction budgets. Concepts of value engineering are inherent in the logic based design strategies we employ and the result is a dynamic, exciting building with a budget comparable to that of standard predictable construction.
For more information and images, please contact
