WAN AWARDS 15 Concrete in Architecture

The design of the new Metro Transit Highway 610 & Noble Parkway Park & Ride Facility in Brooklyn Park, Minnesota fuses an abstraction of the surrounding landscape with a high performance, sustainable facility to create a striking statement along the Highway 610 corridor.

The vast prairie grass and snow swept landscape of this area was the genesis for the undulating precast façade panels. The subtle transformation of a standard precast panel typology was achieved by simply pulling two points along the panel’s surface. This strategy allowed us to meet the client’s budgetary and maintenance requirements while providing a dynamic façade that is in constant transformation as the sun travels along its articulated surface. The bold white precast panels emphasize the subtleties of light along the elevation and create a bold graphic statement against the flat black precast panels that enclose service areas and the speed ramp. Thus, users of the facility are greeted with an ever-changing experience that varies with season, time of day, and weather.

The two vertical circulation towers are pulled out from the ramp and create beacons along the western façade. They stand in contrast to the undulating panels and are simple cast in place concrete volumes with transparent curtain wall along the north and south. The cast in place concrete allowed us to maximize openings and minimize opaque structure. This transparency not only creates a beacon but addresses an underlying theme of security through surveillance.

Benches, native plantings and trees create a public plaza near the bus drop area for users to gather around the facility and soften the edges of the site. The overall site strategy utilizes native vegetation and onsite water filtration swales to filtering polluted surface runoff before releasing into the retaining pond on the south end of the site. Existing trees were preserved in the development of the site and a variety of native varieties where used throughout the surface parking area. Custom perforated screening at the surface parking prevents automobile light spill into the adjacent school and city park.

For the ramp structure, cast-in-place (CIP) was chosen for its relative durability in our northern climate, architectural flexibility and low cost of ownership. Nearly all levels of the facility are exterior surfaces, and when exposed to the elements in a facility such as this, the structure and concrete mix design can be calibrated specifically for parking deck use. There is also a wealth of construction expertise in our area in the use of post-tensioned CIP, increasing cost-efficiency and construction quality. CIP construction also allowed use of large flat floors without need for obtrusive shear walls, and malleability of form at stairs for design flexibility. Understanding these benefits, the designers were able to work with the trades to optimize structural systems, concrete mixtures, additives and construction methods to maximize value to the client.

The superstructure of the facility is composed of post-tensioned concrete. The compressive stress imposed by the post-tensioning provides unmatched crack control and protection from temperature change of the exposed structure. Specific, innovative detailing was utilized to drape continuous tendons at high-stress areas to provide enhanced crack control protection, and beam/column reinforcing detailing was designed to reduce congestion, facilitating efficient concrete placement. The concrete mixture was specifically designed to reduce shrinkage, resulting in a mixture expanding less than 0.04% at 28-days of drying. Further, fly ash was incorporated into the mixture at maximum amounts to reduce cement demand, lower permeability, increase strength, and decrease rate of deicer absorption into the structure. Finally, the superstructure mix received a corrosion-inhibiting admixture to delay on-set of deicer induced corrosion, providing a facility with robust deterioration resistance for generations.

To address the performance of the facility, a 40kw photovoltaic array will be the primary power supply for the facility and is Metro Transit’s first solar powered park and ride facility. Geothermal heating and cooling lower the overall building energy demand and the use of LED lighting with zoned sensor controls will reduce energy costs by 60% compared to a standard ramp design. Sustainable materials, building orientation, and solar shading will reduce energy load on the waiting area and circulation spaces of the facility.

Benches, native plantings and trees create a public plaza near the bus drop area for users to gather around the facility and soften the edges of the site. The overall site strategy utilizes native vegetation and onsite water filtration swales to filtering polluted surface runoff before releasing into the retaining pond on the south end of the site. Existing trees were preserved in the development of the site and a variety of native varieties where used throughout the surface parking area. Custom perforated screening at the surface parking prevents automobile light spill into the adjacent school and city park.