STRUCTURAL ENGINEERS ASSOCIATION OF ARIZONA
Central Chapter Dinner Meeting:
Design and Construction of Drilled Shaft Foundations for the Phoenix Sky Train Project
The PHX Sky Train is a 5-mile long automated people mover system located at Phoenix Sky Harbor International Airport. Stage 1 of the PHX Sky Train included the design and construction of 227 drilled shafts supporting three stations and approximately 9,000 feet of elevated guideway. Stage 1A consists of a ¾-mile long above-grade and below-grade people mover guideway between existing airport Terminals 3 and 4. Stage 2 is currently in the final design phase and will be approximately 11,500 feet long and includes elevated, at-grade and below-grade guideway which will connect Terminal 3 to the Rental Car Center. The design of the large diameter drilled shafts supporting the elevated guideway was complicated by space constraints, due to the elevated guideway alignment being situated adjacent to existing buildings, retaining walls, a baggage cart tunnel, and between an existing retaining wall and an existing high-pressure jet fuel line, all of which had to remain in service during construction. The foundation system supports relatively high axial loads, lateral loads and moments due to the height of the guideway above the ground surface, where it needs to pass over existing concourse walkways, bridges, a taxiway and buildings. The extreme design requirements, together with difficult ground conditions at the site, resulted in several challenges in the design of the deep foundation system. Results from full-scale axial and lateral load tests were used to reduce the size of the drilled shafts. This presentation will provide an overall description of the PHX Sky Train project, a summary of the ground conditions, design requirements, numerical modeling, load test results and construction methods used to successfully install the drilled shafts for this project.
John Niedzielski is a Principal Geotechnical Engineer for the Phoenix, Arizona office of Gannett Fleming. Gannett Fleming is a global infrastructure design firm that provides planning, design, technology and construction services for a diverse range of disciplines and markets. John performs geotechnical investigation and design services for highway, transit, dam, building, and power projects. John received his Bachelors degree from the University of Toledo and attended graduate school at the Ohio State University. John has 33 years of experience as a consulting geotechnical engineer - 15 years in Arizona and 18 years in Michigan. He is registered as a professional engineer in Arizona and California. John is a member of ASCE and DFI (Deep Foundations Institute), and has previously published papers for ASCE and DFI conferences, and ASCE’s Civil Engineering magazine.
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