The problems facing Barton Malow and the architects of SHoP and Hamilton Anderson began with the lack of blueprints for a pre-World War II site. There was a previous Hudson’s building on the site that was completed in 1898 before the second one was built, which went through several undocumented renovations before it was demolished, including underground parking for its last owner, the city. Part of that parking structure includes a 5-ft concrete mat with double No. 9 rebar that will need to be cut through to place caissons for the new tower.

“We don’t know of anybody who had to cut through a 5-ft-thick concrete mat slab for a high-rise project like this to install deep foundations,” says Michael Schefka, senior project manager at Barton Malow. “The demolition process of removing the slab at each caisson has been discussed in detail.  Do you cut it on four sides and break out the concrete or core it? There’s a lot here to consider. Like any engineering problem at this stage of the project, especially anything that’s never been done, it’s a trial and error method.”

Digging Deeper Into a Concrete Mat

Barton Malow spent most of the first year—the development broke ground in November 2017—clearing the site and dismantling the basements and five-level underground parking structure, including all the steel and concrete beams. The parking structure was removed, but the retaining walls had to remain in place. The “bathtub” of brick retaining walls will allow Barton Malow to get down to the bedrock where they will install the new foundation, piles and piers.

“Part of our design strategy is to make sure there is proper testing, particularly in this case that the (old) brick walls from the existing structure are still sound,” says Lee Carter, senior project manager at Hamilton Anderson Associates, which is the local design partner.

Schefka says the process of cutting through the mat slab is going to be complicated because it will impact decisions about the caissons. While it’s a big site, it’s also highly congested, with the Michigan Dept. of Transportation’s QLINE butting up against it on Farmer Street and Gratiot Avenue, Library Street and Grand Avenue, and with all roads remaining open to traffic. The Shinola Hotel is under construction on the other side of Grand Avenue in this suddenly trendy neighborhood.

To date, 99% of the garage steel has been removed and Barton Malow is starting to remove the concrete rubble from the garage. Coating the existing perimeter tub walls with shotcrete began in early September and mat slab saw-cutting is scheduled to start by early October.

A Modern Downtown Destination?

Bedrock and owner Dan Gilbert are committed to building what will be Detroit’s tallest building by 2022, at 800 ft and 52 stories. An adjoining 12-story building will add more than 1 million sq ft of live-work-play space to a downtown experiencing a development renaissance. But the residents of today’s Detroit are not commuters and shoppers, and the days of going to Hudson’s to visit Santa Claus are over. The neighborhood is now full of restaurants and taverns and offices with millennial workers for Gilbert’s Quicken Loans business.

“There are all of these different layers of programming that happen from shopping and market, to a great event space that’s going to hold 1,300 to 1,500 people, an office destination, a technology exhibit, the residential component,” says James Witherspoon, director of architecture at Bedrock. “The density of different types of mixed-use programming really result in an exciting, dynamic, urban, experience that we’re trying to create. It’s all happening around this public promenade plaza space that goes between the tower building and what was the podium building next door.”

An earlier version of the design had a true podium, but that was replaced in SHoP and Hamilton Anderson’s second effort, which instead has a pedestrian way and an event area to open the space up for the gatherings that Witherspoon mentioned. What was, in the original design, a very forward-looking almost all steel and glass design has given way to a design that’s more modern, but that also looks back to what was there before.

“The design aesthetic is meant to hearken to the past,” Carter says. “On the ground floor [of the tower] there is a focus on traditional materials like brick and terra-cotta that speak to the historical buildings in the area. As you move up the building, there is a more modern feel. We see terra-cotta all over downtown Detroit. It can help localize a project when you focus on that material.”

One of the concerns with the first design, says Witherspoon, was it made the side facing Woodward Street very much the back of the building, whereas Bedrock wanted an experience that made the eventual development a valued part of the neighborhood on all its sides.

Live Work Play

“The retail experience along Woodward Avenue, all of these different shopping opportunities coming up and down Woodward. Really, the context has changed as we’ve drilled through this project, and we’re really trying to respond to those changes and really embrace the activity that’s happening in Detroit,” Witherspoon says. “We are all about how a building engages with the street.”

For the office portion of the development, Bedrock looked at some of the office spaces being built for tech companies to try to draw out best practices, then worked with design architect SHoP to create something that’s flexible and open and has an atrium in the middle. The atrium can go from a 1,300-seat auditorium that can be converted into various capacities, down to a 500-person event space and up to capacity for 1,500 with the second floor or third floor terraces opened up.

One thing that the development does not include is a lot of parking. Only 700 spaces are in the plan for all of the more than 1 million sq ft of office, retail, residential and event space. Witherspoon says the design studies for the space showed that, even in the Motor City, declining car ownership among young people would not require more than 700 spaces for the residential and office uses. The proximity to the QLINE was another factor that made both the city of Detroit and Bedrock feel confident that 700 would be enough.

“We actually were in Chicago talking with a few folks doing development there and there’s pretty strict rules around parking requirements based on the zoning and your location adjacent to transit and so forth and a lot of the conversations we had were, ‘Yeah, we built this many parking spaces but they’re unused because nobody wants to drive,’” Witherspoon says. “Nobody was maxed out.”

While the Hudson’s site is unique to Detroit, the problems facing the redevelopment of a large, pre-World War II downtown department store is sure to resonate with other Midwestern cities as well.