The Farley Post Office Building in Manhattan, adjacent to Penn Station, was one of the very first buildings landmarked under NYC preservation laws—which were instituted after the demolition of its sister structure, the original Penn Station. In 2020, a $1.6 Billion revitalization project was underway to convert the old post office into a train hall to serve as an extension to the nearby Penn Station. The new train hall maintained the historic fabric of the building façade but adapted and updated the building interior to encompass 700,000 square feet of commercial, retail, and dining spaces in addition to the train hall.
WDP was engaged on multiple occasions to provide consulting services and construction sequencing support. For the first project, our staff was engaged as a specialty consultant to assess the structural capacity of an original bridge for construction loads. This bridge acted as a critical access point to move equipment and materials in and out of the construction area, but was important to the historic fabric of the building and had to be preserved. The bridge was originally constructed in 1932 with a concrete deck supported on steel framing. WDP evaluated the structural capacity of the bridge for the construction load including the load applied by a 2500-lb telescopic forklift. WDP reviewed the original construction documents and performed a visual condition and corrosion survey of the steel sub-structure and evaluated the concrete super-structure. The condition of the concrete deck was studied using a Surface Penetration Radar (SPR) and testing of the core samples to obtain more information about the reinforcement and strength. The condition of the steel was evaluated with calipers to determine the degree of corrosion. Using the field data, structural analysis was performed to evaluate the bridge’s structural capacity, and a subsequent report was provided with our recommendations.
Once construction further progressed, WDP was contacted to perform an emergency structural evaluation of a brick masonry façade for one of the inner courtyards of the train hall. During construction, a large amount of masonry near the base of the wall had been removed. Due to the loss of support, the face brick of the three upper floors visibly deflected as much as ¼ inch. WDP had to mobilize quickly to evaluate the immediate life-safety hazards associated with the conditions and develop an emergency masonry shoring design that included needle beams to arrest further displacement and stabilize the unsupported masonry.
A new domed skylight was planned to enclose the courtyard, but the existing historic courtyard masonry façade was to remain visible as an essential component of the original architecture. Following the emergency stabilization, WDP performed a more thorough investigation of the face brick engagement with the backup masonry to ensure that the original engagement was sufficient, and that the recent displacement had not further compromised the lateral support. WDP developed recommendations for methods to secure the masonry as required for the long-term renovation project. We also assisted in designing construction sequencing to address the complexity in maintaining adequate veneer support.
ServicesForensic Structural Engineering
Benjamin Townsend, P.E., Senior Engineer, New York Division Manager
New York State | Deerpath Construction
New York, NY