Recently, Arrowstreet’s internal housing group went on the first of two site visits to Ocean 650 in Revere to see how construction was coming along. Ocean 650 is a part of Arrowstreet’s Waterfront Square at Revere Beach masterplan—a transit-oriented, mixed use development adjacent to the Wonderland T station. The 230-unit high-rise building is podium construction—a three-hour fire rated horizontal assembly will separate the cast-in-place concrete parking garage from five levels of wood frame construction. This site visit focused on concrete elements, while the second will focus on the wood elements. After giving a site overview and looking at the masterplan, I explained the code for podium buildings, which allows for a concrete structure underneath the wood frame residential building. Technically a high-rise, Ocean 650 consists of two levels of concrete parking garage and amenity space, topped by five stories of wood residential, and a roof deck.
There are two particularly unique concrete elements within Ocean 650. Since the site’s clay and sand soil has a low bearing pressure, the footings sit on a Geopier ground support system, which strengthens the ground directly beneath the foundations. This system provides a higher bearing pressure, allows for smaller footings, and reduces settlement and soil export. The second interesting concrete element is the use of post-tension slabs, which are on levels 2 and 3. Tendon cables are located within the concrete pour and the cables are tensioned once the concrete cures to the optimal level. This method strengthens the slab, which can therefore be thinner, and eliminates the need for concrete beams. We also discussed strategies for utilizing concrete’s inherent strength for design applications. At Ocean 650, concrete was used to give depth and variation to the façade at a more economical cost than wood.
The Arrowstreet housing group is able to discuss industry related challenges and new materials together as a larger group on these site visits. We all gain insight into possible solutions by discussing them as a team. We’re looking forward to our next visit to Ocean 650 when we’ll be talking about the wood construction elements.