DOWNTOWN BRIDGE AAT REAFFIRMS AESTHETIC DESIGN PREFERENCES AT JULY MEETING
August 2006 – In July, the Downtown Bridge design team and its Area Advisory Team (AAT) reached an important milestone in what has been a very productive working partnership.
The Downtown Bridge AAT, which began the Bridge Type Selection Process in 2005, came together July 11 to review the recommended three alternatives for Step 4 of the Bridge Type Selection process. Team members echoed many of the same opinions that have helped design engineers narrow the field of design options to three.
AAT members reviewed scale models of each of the three alternatives, followed by a brief presentation. The Downtown Bridge design team showed each bridge type from a wide range of views and simulated driver and aerial perspectives. The ensuing discussion produced comments reflective of the aesthetic preferences noted in past meetings. The three proposed bridge types are:
Single-tower Cable-stayed: This alternative’s distinctive single "A"-shaped tower offers a visually prominent feature with the distinctive, diagonally shaped support cables typical of a cable-stayed bridge fanning out from either side of the tower. Support cables attach to the outside of the deck superstructure.
Three-tower Cable-stayed: This cable-stayed alternative features three low-height towers and cables that are arranged in a simple harp formation. The support cables attach to the outside of the deck superstructure. The middle tower is slightly higher than the two on the outside.
Three-span Thru Arch: The three-span arch has three sets of vertical arch ribs connected by horizontal bracing. A unique feature of this design is the arch form, which extends down to water level. The vertical support hangers attach to the outside of the deck superstructure.
In general, the group appeared to favor the “openness” of the two cable-stayed designs. One attendee pointed to the thru-arch alternative’s compatibility with the nearby Kennedy Bridge. However, many were concerned by the “obtrusiveness” of the thru-arch’s thrust-block support element, which seemed to violate the team’s general preference for an aesthetic bridge that blends in with the parks.
Most members believed the Downtown Bridge should feature a “grand” design, something unique that accentuates and complements the local landscape. Utility also remained a concern, leading to discussion of the pedestrian/bikeway. One attendee asked that the final design provide sufficient separation between traffic and the accompanying lane, which will enable people to walk and bike between Louisville and Jeffersonville.
“Our AAT members have done the Bridges Project an invaluable service by telling us what they want, and don’t want, to see in the bridge type,” said J.B. Williams, project design manager for the Downtown Bridge. “They’ve been very frank and open with us, and our entire community will reap the benefits of that honesty.”
Step Four of the Bridge Type Selection Process entails narrowing the list of alternatives to three final bridge types. The design teams will develop a comprehensive assessment of each of the final bridge types and present all of the input received from the AAT/RAC committees and the public to the Executive Bridge Selection Committee (EBSC), made up of representatives from Indiana and Kentucky. The EBSC, which will decide the final bridge types for the Downtown and East End bridges, will also consider feedback from other public interest groups as well as safety issues, Coast Guard parameters, historic context, budget, life-cycle costs and constructability.