image for 121 Seaport Tops Off
121 Seaport Tops Off
March 2017

On March 10, 2017, CBT celebrated the topping off of 121 Seaport  a 17-story, 400,000-square-foot, Class-A office building targeting LEED Platinum certification at a ceremony hosted by the project’s developer and contractor, Skanska USA, marking the completion of the building’s unique elliptical steel frame. When complete in early 2018, 121 Seaport’s distinctive design will enhance the area’s artistic architectural landscape, maximize the skyline visible from Seaport Square Green, and reduce solar heat gain. 
 
121 Seaport is situated in the heart of Boston’s booming Seaport District, across from District Hall and Seaport Square Green. Its three-story lobby faces Boston Harbor and opens onto Harbor Way, an expansive 70-foot-wide pedestrian retail promenade that will be located between 101 and 121 Seaport with 20,000 square feet of tree-lined open space. 

To achieve this significant milestone, a team of nearly 200 construction professionals dedicated more than 35,000 hours of work to:
- Employ a 500-ton crane to set four plate girders, each weighing roughly 120,000 pounds and measuring 76 feet long, to support the structure above the Silver Line Tunnel 
- Install approximately 3,400 tons of steel 
- Secure roughly 63,000 fastners in place
- Employ up-down construction, an unconventional technique that requires the project’s steel and concrete contractors to build the building’s foundation and frame simultaneously.