San Diego State University Tunnel and Station

Constructed under and through the San Diego State University campus, the 4,000-ft.-long San Diego State University Tunnel and Station connects to the Green Line, a 5.9-mi., $496-million extension of the Mission Valley East trolley line.

Parking at the SDSU campus is extremely limited. The San Diego Trolley system now offers a cost-effective viable solution to the parking/traffic problems that have plagued the campus community.

The $103-million San Diego Tunnel and Station consist of four main areas:

• The west box, approximately 900-ft. of open-cut and cover-box culvert construction
  
• The tunnel, approximately 1,070 ft. of sequentially mined and constructed New Austrian Tunneling Method tunnel
  
• The station, approximately 670 ft. of open cut and cover box support of excavation to provide for the construction of the main station and
  
• The east box, approximately 1,000 ft. of open cut and cover box culvert construction.

Clark Construction's subsidiary, Atkinson Construction, excavated the tunnel utilizing NATM mining, making it the second-largest diameter tunnel in the U.S. The transit tunnels are of a twin-box construction separating east and west bound trolleys.

The trolley station platform is a 50,000-sq.-ft. "soaring" space, highlighted with a serpentine brick paving pattern and multiple other artistic elements including sculptures in the station and etched botanical images.

Construction of a .75-mi. transit tunnel through and below the most active locations on SDSU's campus proved to be the main project challenge. Coordination was vital to work efficiently in a 35,000-student campus with a full calendar year schedule of classes. On-site representatives met on a daily and weekly basis, formally and informally, to discuss project events and work schedules to coordinate with the university's operations.

After four years of construction, the project was closed out without any disputes or litigation.

Owner's Comments:

"The tunnel and underground trolley station...required a true partnership between the [general] contractor and MTS/SANDAG to be successful. Clark Construction was an excellent partner. Even with its expanded scope, Clark delivered this project on time...I was also impressed how they controlled costs and came to the table to negotiate changes." -Jim Linthicum, director of engineering and construction, SANDAG

Project Team:

Owner: San Diego Association of Governments
Architect: Zimmer Gunsul Frasca Partnership
Construction manager: Washington Infrastructure Services
General contractor: Clark Construction Group California
Engineer: URS
Key subcontractors:
A.O. Reed
Burtech Pipeline
Clark Steel
F.J. Willert
J.F. Tejeda
Malcolm Drilling
Morley Construction
Pacific Southwest Structures
T.B. Penick

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