The new Massachusetts Bay Transit Authority (MBTA) Salem Intermodal Commuter Rail Station, in Salem, Mass., is a testament to the versatility and high-performance characteristics that precast concrete can bring to the design and detailing of a project.
This rail station project had several major components, including excavation of the site, and construction of a five-level parking structure, a passenger waiting shelter, at-grade bus platform, taxi lane, drop-off/pick-up area, pedestrian sidewalks, and a pedestrian bridge, connecting a raised street to the second level of the structure. The owners originally wanted to use brick to fit in with the surrounding historic structures; however, they did not have the time or budget necessary for a traditional hand laid brick design. Maintaining a safe, accessible, and convenient environment for passengers during construction was also paramount.
Choosing a precast concrete design helped them achieve all of these goals. The use of precast concrete allowed the project architects and engineers to fast track the schedule with the use of early competitive bidding, and an efficient erection process, says Scott Brodsky, senior architect and associate principal of Fennick McCredie Architecture, the architect and prime consultant for the project. “The precast concrete pieces were fabricated while soil modification and foundations were being installed, then erected quickly,” he says. “This was critical to making the completion date required by the stakeholders.” Additionally, the use of embedded brick greatly reduced the need for future maintenance associated with traditionally laid brick. “Overall, the use of precast was preferred for the minimal maintenance and long-term durability demanded by the owner.”
The layout of the site featured one end at grade level for the train station with a covered lobby and a covered drop-off, which drove a desire to maximize open space to enhance sightlines and pedestrian movement. The precast concrete design was able to accommodate this goal through the use of lockup devices connecting double tees across the building joint between two segments of the garage, Clark says. “By transferring loads in this manner, shear walls in one direction were eliminated in one segment, providing the open space desired.”
Aesthetically, the use of precast concrete was also an attractive option to the design team. To acknowledge the historic significance of the former rail yard, which originally housed a locomotive roundhouse and turntable constructed in the late 1800’s, the designers incorporated patterned precast concrete spandrels on the facade to evoke images of steam locomotive wheels and drive bars. The design was accomplished through the use of sculpted, deeply ribbed formliners.
“We loved the ability to embed the special railroad and local history right in the facade of the building by exploiting the plasticity of precast concrete,” Clark says. “Unistress [the precast concrete producer] embraced the artistic aspect of this and took extra care in constructing handling and placing these unique elements.”