Seismic Upgrade of a Football and Soccer Stadium

The Rose Bowl Stadium is nestled in the foothills of the San Gabriel Mountains north of Los Angeles. California is located at the boundary between two huge tectonic plates, the so-called San Andreas fault. As the two plates slide past each other, earthquakes occur and for this reason, seismically retrofitting of the Rose Bowl Stadium was indispensable.

The stadium was originally designed in 1922 as a horseshoe stadium with the north, east and west sides built into an earthen berm. The first addition to the stadium was completed shortly thereafter in 1933 where the south end was closed, completing the elliptical stadium with poured in place concrete columns and bracing to support the concrete seating deck above. In 1948 an independent cantilevered structure was added, offering an additional eleven rows of seating to the top of the stadium, supported by a series of 1.00 m columns, with a 15 cm wide expansion joint between the two concrete structures.

As earthquake codes were developed and modified over the years, the Rose Bowl had already undergone a series of seismic strengthening programs in the past. In 1982 the south end was strengthened with concrete shear walls.

During the summer of 2005, the cantilevered structure built in 1948 was reinforced. Engineers at Brandow and Johnston Associates proposed a post-tensioned cabling system using DYWIDAG Multistrand Tendons to hold the 1948 addition to the 1933 concrete structure on the south side. DSI USA performed this latest strengthening.

DSI was contracted to:

  • Design special anchorages for DYWIDAG Multistrand Tendons and prepare the installation shop drawings.

  • Prepare and evaluate alternative reinforcement measures.

  • Supply and install DYWIDAG Multistrand Tendons with galvanized 0.5" strands.

DSI executed and completed the project in 3 months, a full month ahead of schedule, to the complete satisfaction of the client. Immediately after completion of the reinforcement work, sporting and other events took place in the Rose Bowl Stadium according to schedule.

SupplyInstallationTechnical supportDesignEngineering Consulting

City of Pasadena, California, USA


Rosebowl Resident Architect, Pasadena, California, USA

Brandow & Johnston, Assoc., Los Angeles, California, USA