Silman, A TYLin Company, provided comprehensive structural engineering services for the renovation and expansion of Smith College’s Neilson Library in Northampton, Massachusetts.
Originally opened in 1909, the main library structure had undergone numerous unsystematic alterations over the years. Silman’s first task was the careful excision of two eras of additions, followed by renovations to the main building interior. This preliminary work paved the way for restoring the original design and creating more inviting central library spaces.
Because the project’s large-scale modifications triggered a seismic lateral system retrofit, Silman designed a new system of steel braced frames located just inside the existing masonry bearing walls. These new frames are supported on a new foundation system of pile caps and grade beams.
The new construction consists of two “jewel box” wings located to the north and south of the original H-shaped library. The south wing holds special collections, archives, and rare books; the north wing includes learning spaces, a café, and a digital media hub. The jewel boxes comprise steel frame and composite slab construction with continuous curved steel ring beams supporting a series of reinforced concrete walls to define the window openings.
Due to clay soils and a high water table, the site required creative foundation solutions. Instead of dewatering or excavating the existing clay layer, which would have significantly impacted the overall project schedule and costs, the project team installed new pile foundations at the south basement by locally drilling through the existing mat slab and using the new pile caps to help resist hydrostatic uplift.
Despite the increase in overall interior floor area, the project team managed to decrease the building’s footprint by about 25%, returning lost green space to the adjacent grounds in alignment with Frederick Law Olmsted’s original 1893 design.
- Scope of work included the design and detailing of two feature stairs.
- Silman designed the steel framing for the “jewel box” wings to accommodate over 800 mechanical, electrical, and plumbing (MEP) penetrations.
- The foundation work also replaced the basement roof slab and part of the top of the foundation wall with new landscaping and a basement roof structure buried below grade.
- The Neilson Library renovation project, designed to achieve LEED Gold certification, is part of a larger Smith College campus library master plan.
Image Credit: Nic Lehoux