Hawthorne EcoVillage

Due to unexpected poor soil quality in the area where the townhome buildings were to be constructed, a new approach to the foundation systems had to be devised late into construction. BKBM’s structural and civil team worked with the architectural team, construction team, and geotechnical engineer to come up with options to avoid expensive soil corrections that would disrupt an actively used alleyway. The team was able to shift the locations of the buildings to reduce the impact and decided to use helical piles and grade beams to avoid deep soil corrections that were needed for one of the townhome buildings. The quick re-design of the townhomes from all parties allowed the construction to continue with minimal disruption to the construction timeline.

The project is located on an approximately 1.24-acre site in northwest Minneapolis. The site, though an open grassy lot, presented several challenges.  There was a significant elevation change across the site, in the range of 10-feet.  This limited accessible routes, walk up units, and connections to public walkways/streets.  BKBM worked with the architect to locate doorways and sidewalks to provide safe and easy access by the residents to the public right-of-way.  Second, the native sandy soils were in a densely compacted state.  This provides good structural stability but restricts the site for infiltration of stormwater.  Due to the owner seeking grant funding for stormwater management purposes, alternate methods were needed.  BKBM designed a linear system that exceeded local standards.  The system included a re-use irrigation system, filtration tanks, cascading rain gardens and permeable pavements.  The system flowed from west to east across the site and gradually increased the amount of stormwater volume treated.     
The project consists of an L-shaped main apartment building and two adjacent detached townhome buildings each containing two townhomes, along with a central courtyard between the townhomes and apartments. The main building features one level of below grade parking, 71 affordable units, a large fitness room, bike storage, and community room. The structural system consists of a slab on grade at the lowest level, a precast podium with masonry perimeter walls, and four levels of conventional wood framing for the west side of the building and three levels of conventional wood framing on the north side of the building. Both areas have flat roofs with the three-story roof being designed to support a green roof system and solar arrays.