An Award Winning Transformation Project of Calgary Underpass

Calgary created its CP Railway underpasses so pedestrians could move safely between the Beltline and downtown along its busiest streets. But over the years, these passageways have felt dark and at times threatening, becoming spaces to be endured rather than experienced. 


Entering 4th Street SW Underpass from Downtown Photo credit: Bruce Edward Statham/yellowcamera

In 2015, Marc Boutin and his team were entrusted with an unusual task, that of revitalizing an important urban passageway, the 4th Street SW Underpass. MBAC has been at the forefront of Calgary's recent transformation, with inspiring urban projects such as Memorial Drive, Poppy Plaza, and C-Square. Internationally known artist Krzysztof Wodiczko joined the team as well as Boston-based studio INVIVIA. Four years later, long-time design champion and city councilor, Druh Farrell, described the transformed infrastructure as “a place of delight and wonder." 


View towards Downtown Photo credit: Bruce Edward Statham/yellowcamera

MBAC recently received a National Urban Design Award from the Royal Architectural Institute of Canada for its work on this project. The design was highly recognized as having the potential to turn a negative pedestrian experience into something positive.

The use of dynamic lighting to reflect the movement of pedestrians is a highlight of the design. The lighting is as much an art feature as a security and amenity enhancement.

RAIC Urban Fragments Category Jury

MBAC’s proposal for the 4th Street SW Underpass was founded on the notion of reclaiming a ‘space of removal’ and turning it into a ‘space for conversation.’ Their design responded to a narrative they developed for this two-block long underpass, which goes under the Canadian Pacific Railway (CPR) rail corridor and 9th Avenue.


View towards CPR rail corridor Photo credit: Bruce Edward Statham/yellowcamera

As pedestrians walk down towards the first segment of the underpass, they go through a ‘Space of Anticipation,’ followed by a ‘Space of Reflection.’ The middle section, open to the sky above, becomes the ‘Space of Conversation.’ The introduction of animated light and color effects, responding to the flow of people going through the double underpass, was meant to create an evocative and timeless experience.

The effects are produced by thousands of LED lights, located along the 87-meter walls on either side of the underpass. A sophisticated custom detection technology software, which generates an abstract representation of passersby’s movements, was developed by Boston-based INVIVIA consultants. Cameras sense pedestrians, as they enter the underpass, and project their shadows diagonally across, on the facing wall. According to artist Krzysztof Wodiczko, “this interactive light installation creates an impression of seeing ourselves the way we are seen by others when observed from across the underpass.”


Translucent resin veil, detail Photo credit: Bruce Edward Statham/yellowcamera

Materials were selected for their ability to reflect, diffuse, and ‘catch’ light. The envelope designed to house the interactive lighting installation includes a reflective aluminum ‘exoskeleton,’ on the public side, an 8mm layer of tempered, laminated safety glass with a translucent interlayer for light diffusion, a thermoformed, translucent polycarbonate panel, and a supporting subframe of galvanized steel, hung from the existing concrete infrastructure.


Axonometric study showing wall assembly and walkway Photo credit: mbac

Particular attention was paid to ensure that this public art installation would be performative not only at night but also during daytime. The lighting system’s components are located within the new envelope, behind the protective surfaces. The wall itself is designed as a series of panels so that each individual LED fixture can be accessed, serviced, or replaced.


Night view Photo credit: Bruce Edward Statham/yellowcamera

Citizens were given various opportunities to participate in the creative process, identifying issues within the existing site, finding collective solutions, and influencing the project as it progressed. Models and mock-ups served as key tools for coordinating with consultants and suppliers, as well as for communicating the project’s feasibility to the City of Calgary’s internal stakeholders.

About MBAC

Founded by architect and professor Marc Boutin in 1997, the marc boutin architectural collaborative (MBAC) is a medium-size Alberta firm focused on interdisciplinary design excellence. The firm is well known for its projects, public and private, which convey multifaceted and pluralistic readings of the built environment. Over the past 10 years, MBAC’s built work has raised a lot of interest. Projects such as Calgary's Poppy Plaza and C-Square as well as the Edmonton Valley Zoo Children's Precinct have received numerous architecture and urban design awards. MBAC has distinguished itself with public realm projects responding to more mundane urban contexts, among them the 1st Street SW Underpass enhancement project and the 3rd Street streetscape improvements.