Plot 12
Boston
PROJECT OF THE YEAR FINALIST and BEST PROJECT, OFFICE/RETAIL/MIXED USE
Presented by Suffolk
Owner: Samuels & Associates
Main design company: Architects Elkus/Manfredi
General contractor: Suffolk
Civil Engineer: HBV
Structural Engineer: McNamara/Sage
Boston’s first mixed-use air-rights development above the Massachusetts Turnpike in more than four decades weaves the Back Bay and Fenway neighborhoods together again with a half-acre public park built directly over an active highway and MBTA rail lines. The project includes a 21-story office tower and a 14-story citizenM Hotel, which is Boston’s first fully electrified hotel, as well as 35,000 square meters of retail space.
In addition, Parcel 12 offers a reimagined MassPike access ramp, improvements to the Mass Ave Bridge, and a new entrance to the MBTA Hynes Station with improved pedestrian connectivity between neighborhoods. Plot 12 was also designed to accommodate future laboratory, office and retail tenants. It also incorporates MEP systems capable of supporting laboratory operations and nursery facilities.
Working on top of live infrastructure required careful coordination with state agencies, city stakeholders, and utility providers. Construction over the Mass Turnpike and active MBTA tracks made it one of the most logistically and technically complex construction projects in the city. The team had to meet strict MassDOT and MBTA standards not typically applied to private development, including 1/16-inch tolerances and enforcement of the MassDOT LRFD.
Photo by Vanderwarker, courtesy of Suffolk
Bridge Manual and AASHTO LRFD Bridge Design Specifications. Through early engagement, transparent coordination, and iterative reviews, the team established a workflow that met stakeholder demands.
Suffolk coordinated rolling road blocks with MassDOT to install 50-foot-long steel beams and precast panels above road traffic. The operations required minute-by-minute precision, and each pick had to be completed in 15-minute windows managed by the Massachusetts State Police.
A project-specific cantilever work platform over the freeway and rail played a critical role in maintaining safety while keeping the project on schedule by providing a stable, elevated work space for the installation of the building envelope. This platform eliminated fall hazards and the need for street closures and lane closures, allowing for safe installation over live traffic.
Photo by Vanderwarker, courtesy of Suffolk
Manufacturing constraints added another layer of complexity. The team resequenced the steel installation to allow vertical construction to continue while precast deck work progressed in parallel. Fire protection was previously applied to steel and precast concrete components outside the Vermont and Quebec facilities to save time.
As the project progressed, the construction program changed significantly, moving from standard offices to laboratory-ready facilities. The change in scope required wholesale upgrades to the mechanical, electrical and plumbing systems while construction was already underway. Suffolk maintained the schedule through collaborative pricing and pre-approvals with the customer, allowing changes to proceed without delay while costs were reviewed.
Photo courtesy of Suffolk
Built with post-tensioned concrete systems, the hotel features seamless curtain wall transitions
and detailed finishes. The office tower’s cast-in-place core and steel frame created open, flexible floor plates ready for laboratory conversion. Both structures required rigorous quality control in finishes, surrounds and construction systems.
Despite some supply chain issues related to the pandemic and working with live transit lines and active freeway, Suffolk remained committed to schedule milestones. As a result, plot 12
remained on track for tenant turnover and occupancy phases across all major components. The project was completed on budget and on schedule by December 2024.
