Salas O’Brien Takes Top CFSEI ‘Non-Building’ Award for Colorado Springs Pedestrian Bridge

Featured image: The Park Union Bridge in Colorado Springs, Colorado (City of Colorado Springs photo). Project profile provided courtesy of CFSEI. All photos courtesy of Salas O’Brien, except where indicated. 

The Park Union Bridge — a 250-foot-long, 550-ton “bridge of the future” for pedestrians — connects the United States Olympic & Paralympic Museum™ with America the Beautiful Park in Colorado Springs, Colorado.

The unique, hybrid steel structure combines an arch and a truss into two interlocking, twisting loops to form an oculus in the middle span. The bridge’s oculus frames gorgeous views of Pikes Peak and downtown Colorado Springs for pedestrians.

Dana Hennis (left), P.E., S.E. and CFSEI vice chair presents the first place award to Daniel Stadig, P.E., of Salas O’Brien.

Salas O’Brien, a Denver-based structural engineering team, has been recognized by the Cold-Formed Steel Engineers Institute (CFSEI) with the 2023 CFSEI Design Excellence Award — first place in the competition’s non-building application award category.

Ryan Nelson of Salas O’Brien submitted the Park Union Bridge project to the CFSE Awards competition. Daniel Stadig, P.E., of Salas O’Brien accepted the award for the firm’s work on the bridge at the 2023 CFSEI Expo held recently in New Orleans.

CFS Studs Support Twisting Wall Panels

Salas O’Brien was tasked with designing the cold-formed steel (CFS) framing supporting the canted wall panels that wrapped the inside of the twisting oculus at the center of the span. 

The light-gauge metal framing curved gradually. The CFS framing varied in height on each end of the bridge and above and below the oculus. 

The biggest challenge presented by the CFS design was dealing with the three-dimensional and rotational movement of the steel structure as it induced thermal, wind, seismic and live loads. 

The 250-foot-long, 550-ton pedestrian “bridge of the future” connects a park (left) the U.S. Olympic and Paralympic Museum (right) in Colorado Springs, Colorado.

Cold-formed Steel (CFS) framing curves within panels that create a central oculus on the bridge.

SL Clips Fasten Studs to the Structure

To accommodate the complex movements in the bridge superstructure, each stud was rigidly fastened to the varying upper steel structure, while the base was fastened to the concrete bridge with SL clips. 

• The base connection to the SL clips uses two screws 
• This allows the connection to handle rotational demands and vertical movements of the bridge

The design took several iterations and meetings with the engineer of record, panel manufacturer and contractor to secure final approval. Each element required an allowable tolerance of movement so that the panels could achieve their flawless smooth appearance.

Salas O’Brien received the CFSEI 2023 first place award (non-building category) for its work on the bridge.

SL clips attach cold-formed steel (CFS) studs and bases respectively to the upper steel structure and to concrete to accommodate complex movements.

The pedestrian bridge was fabricated in Houston, Texas in six separate sections, which were transported to Colorado Springs for assembly on site. The completed project is impressive and appreciated by visitors.

Read more about Salas O’Brien’s CFS details for the Park Union Bridge in Colorado Springs, and see more diagrams of the bridge, here.

Additional Resources

• Cold-Formed Steel Helps Olympic Museum Rise and Twist
• Cold-Formed Steel Engineers Institute to Hold the 2024 CFSEI Expo in Tucson, Arizona (May 20-22, 2024)
• McClure Wins CFSEI Award for Church’s Multiple Cold-Formed Steel Domes