Owner: New York City Economic Development Corporation
Total Size: 50,000 Square Feet (approximate)
Completion Date: 2018
Project Team:
Planner / Architect: SHoP Architects
Landscape Architect: Ken Smith Workshop
SMEP + Geotech Engineers: Arup (Joint Venture with HDR/Daniel Frankfurt)
Lighting Designer: Tillotson
General Contractor: Turner Construction
Mr. Dodge’s Role: Vibration Consultant
Improvements to the East River Waterfront have been planned as early as the 1990s. A huge undertaking, consisting of a new bike path, the rearrangement of traffic patterns, the rehabilitation of existing pier structures and the construction of new ones, and the construction of new public amenities, design work began in the early 2000s and construction in some areas has continued into the 2020s. As a partner in a joint venture comprised of a number of different design and construction firms, Arup was contracted to provide multidisciplinary engineering support for many different parts of the project.
Among Mr. Dodge’s roles in this project was the vibration analysis and structural steel design checking for the Pier 15 pavilion, a structure to be built atop a new hybrid precast/cast-in-place concrete pier provided by others. The structure was to enclose a maritime facility along with a bar/restaurant space at grade level, along with an elevated, landscaped park above. Access would be provided to the elevated park via a set of stairs and a system of decorative ramps.
The superstructure was comprised of a structural steel frame supporting cast-in-place concrete planters providing shelter above the enclosed spaces below, along with a wood deck at the surrounding pedestrian spaces that was built from black locust 2×2 lumber with half-inch gaps between to provide drainage through the structure via the similar wood soffit below.
Because of the lightweight, non-continuous nature of the decking and the overhanging form of the structure, vibrations were a major design consideration to ensure occupant comfort and pedestrian safety. Steel elements supporting the wood decking were analyzed via 3D models for their acceleration response to foot traffic and compared to experimentally-determined human tolerance limits. In many cases, vibration considerations controlled the design of the steel beams supporting the deck.
One area of particular design interest was a steel-framed stair with a clear run of nearly 40 feet from street level to the elevated deck above. Design of the stringer trusses for strength and deflection would have appeared adequate if vibrations were not considered, and may have resulted in a safety hazard for pedestrians if built without such consideration. Ultimately, the design of the stringers was controlled by a need to increase their first natural frequency to over 4 Hertz.
The structure was completed between 2011 and 2012, with no known complaints related to its vibration response.
