Confluence Bridge

Arvada, Colorado

2001

 

The bridge is a key component of the redevelopment of underused industrial land into park, parkway and recreational uses at the southeast edge of Arvada, an established smaller city within the Denver metropolitan area. Designed in collaboration with Range Engineering of Denver, the 450 foot long landmark structure will be a gateway into the city as well as the last link in a metropolitan wide bike path system unifying two trail systems at the confluence of Ralston Creek and Clear Creek..

Designed as a cable stayed span, the concrete and steel bridge is identified by it's 100 foot tall mast that supports 250 feet of its length with a series of tension cables. The physical geometry of the bridge is unique. The plan is configured into a gradually tightening arc while in section, the bridge dramatically changes elevation from one end to the other to resolve the differences between the pathways at the creek bank and the park, over 20 feet above.

 

The curve of the deck is enhanced by the placement of the vertical elements using the geometry of the structure to full advantage. The mast is offset to the inside radius of the deck to accommodate the curve.  This geometry creates a symmetrical cable array along the long curved axis and an asymmetrical cable configuration across the short section of the bridge. As the cable geometry resolves itself along both the inside and outside parallel radii of the deck, the inside cables and rail remain aligned with the perimeter beam while the cables along the outside appear to dance together with the undulating rail assembly. This visual point/counterpoint of rhythm provides interest as one moves along the bridge, either walking or on a bicycle.

 

The undulating composition exposes the primary and secondary deck beams from above and below allowing light and shadow to create visual interest and allowing the viewer to see how the bridge is constructed.

Completion: 2001

Structural and Bridge Engineering: Range Engineering