February 20, 2009

Red Mountain Freeway wins National Award

Design of the final link in the Red Mountain Freeway in Phoenix has received a National Honor Award from the American Council of Engineering Companies.

The project won this prestigious engineering excellence award based on originality, future value to the engineering profession and perception by the public, social, economic, and sustainable design considerations, complexity, and exceeding client needs.

The project qualified for the national competition by winning the Judges Choice Award in the 2008 Engineering Excellence Awards competition held by the American Council of Engineering Companies of Arizona.

Completion of the 4.8 mile segment of Red Mountain Freeway, deemed "The Golden Spike of our Regional Freeway System," provided the critical link that completes a Phoenix freeway loop 20 years in the making. The $195 million segment is one of ADOT’s largest single projects.

What is typically a two-year design effort was completed in nine months. The effort included development of multiple construction packages for advertisement and construction, and full team support of post design services during construction. Successful, timely delivery required innovation and quick problem solving to complete design of this new freeway segment over the vital CAP canal, over the Spook Hill Flood Retarding Structure (FRS), and through an established flood pool.

Components include 22 structures; 4 interchanges, 2 of which have modern roundabout ramp connections; 2 unique straddle substructure bridges; new freeway protection levee and flood alert system; existing dam rehabilitation; pump station; a vast drainage system; intricate utility relocation; and coordination of nearly 30 agencies and stakeholders.

It is uncommon to design a new freeway in an established flood pool. It alleviated disruption of neighborhoods but increased design complexity. Sound engineering proved it feasible that both could function correctly in all situations. Five million cubic yards of material were removed, a new earthen levee built, and dam rehabilitation completed to achieve the needed level of protection in the flood pool.

A unique straddle substructure using a combination of site-precast post-tensioned concrete and common precast/prestressed concrete girders made it possible to economically bridge an arterial roadway and the CAP canal at a difficult angle. Featured in Civil Engineering magazine, the bridge is the first of its kind in Arizona. The resulting cost savings allowed the inclusion of a fourth general use lane each way.

Recreational features were designed throughout the segment to allow connectivity to a future continuous trail system expected to eventually reach Tucson.

The project was delivered to the client under budget and to the traveling public ahead of schedule.