Nitsch Engineering’s site design created a platform on which a new public area could thrive.
The Boston Public Library’s Johnson Building renovation project won a 2018 Engineering Excellence Gold Award from the American Council of Engineering Companies of Massachusetts (ACEC/MA) and a 2018 Engineering Excellence National Recognition Award from the American Council of Engineering Companies (ACEC). The awards recognized Nitsch Engineering for solving a number of complex issues within a very small site – only 0.25 acres of usable space – while keeping the library open and accessible to the public.
In 2013, the Boston Public Library (BPL) began a three-year project to reinvigorate the library user’s experience at the 130,000-square-foot Johnson Building, the more modern half of the historic facility. The updated design focused on making space not just for books, but for people, by transitioning from an inward-facing fortress to an inviting public space.
To meet the needs of the community for a more accessible public space, and to help blur the line between the BPL’s interior and exterior, Nitsch Engineering applied innovative engineering techniques on a heavily-trafficked site on the corner of Boylston and Exeter Streets. Beyond the architectural improvements, the site was designed to invite people inside, by bringing the library outside. The new plaza resulted in an outdoor community space that is in constant use, and directly benefited the public by improving accessibility, respecting the historical building design, and supporting different modes of transportation.
As the civil engineer, Nitsch Engineering’s site design – completed on time and budget – created the platform on which a new public area that better serves the community could thrive. Their design addressed a number of critical infrastructure elements within only 0.25 acres of space outside of the building. This included highly traveled sidewalks and surrounding roadways, a 4,000-gallon underground oil tank that needed to be moved, large tree pits, foundations for catenary light poles and a community table, and the MBTA’s Green Line subway tunnel that runs under the site.
To protect nearby historic structures built atop wood piles, the site also needed to house a groundwater recharge system that recharged the first inch of rain from each storm into the ground, while keeping water away from the building’s foundation – which extends beyond the building’s walls – and the subway tunnel. Nitsch Engineering’s site design used slot drains, porous pavers, a system of underdrains, and tree pits to meet this groundwater recharge goal. The design reduced impervious sidewalk areas on site by 15%, and removes ~7,000 gallons of stormwater flows per storm from Boston’s combined sanitary sewers.
Nitsch Engineering CEO Lisa A. Brothers, PE, ENV SP, LEED AP BD+C, said, “The groundwater recharge system that our civil engineers designed within this small, complex, historic, urban site makes it clear that similar sustainable designs can be accomplished on all types of sites. This successful design shows that thoughtful engineering can improve sustainability in spite of site constraints.”
The project team included architects William Rawn Associates, landscape architects Reed Hilderbrand, contractors Consigli Construction Co., structural engineers LeMessurier Consultants, M/E/P engineers Cosentini Associates, code consultants R.W. Sullivan Engineering, cost estimators Faithful + Gould, graphics and wayfinding specialists Arrowstreet, lighting designers Lam Partners, and owner’s representatives PMA Consultants.