Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

A 230,000 ft2 (21,367 m2) addition was planned for construction at the Plaza Bonita shopping mall in San Diego, CA. The soil profile at the site consisted of fill soils underlain by alluvial deposits followed by San Diego Formation. The saturated loose sand layers were liquefiable and would result in significant settlement under the site design earthquake. In addition, soft clay layers would undergo excessive settlement under heavy building column loads. The geotechnical contractor proposed soil treatment with vibro replacement stone columns to mitigate the site liquefaction and to reduce static settlement under building column loads. Building design changes were ongoing and when two floors were added, soil mix columns were proposed to supplement the stone columns to accommodate the heavy column loads. The geotechnical contractor installed 305 soil mix columns to depths up to 35 ft (10.6 m), and 4,085 stone columns to depths up to 50 ft (15.2 m), across the site between November 2006 and March 2007. These ground improvement techniques reduced the excessive settlements by densification and/or reinforcement of the soils. Extensive site investigation and post treatment verification was conducted. Fifty borings and nearly 100 CPTs were performed at the site. During the production work, the shopping mall design evolved from a single storey department store to a four-storey structure, including a theatre. The geotechnical contractor met the schedule, regulatory and technical requirements while keeping up with the constant design changes to the project. This paper focuses on the design, production work, as well as dynamic and static settlement analysis derived from post-treatment CPTs performed by the geotechnical contractor.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Vibro Replacement and Soil Mixing Ground Improvements at a Shopping Mall Site in San Diego, California, USA

San Diego, California

A 230,000 ft2 (21,367 m2) addition was planned for construction at the Plaza Bonita shopping mall in San Diego, CA. The soil profile at the site consisted of fill soils underlain by alluvial deposits followed by San Diego Formation. The saturated loose sand layers were liquefiable and would result in significant settlement under the site design earthquake. In addition, soft clay layers would undergo excessive settlement under heavy building column loads. The geotechnical contractor proposed soil treatment with vibro replacement stone columns to mitigate the site liquefaction and to reduce static settlement under building column loads. Building design changes were ongoing and when two floors were added, soil mix columns were proposed to supplement the stone columns to accommodate the heavy column loads. The geotechnical contractor installed 305 soil mix columns to depths up to 35 ft (10.6 m), and 4,085 stone columns to depths up to 50 ft (15.2 m), across the site between November 2006 and March 2007. These ground improvement techniques reduced the excessive settlements by densification and/or reinforcement of the soils. Extensive site investigation and post treatment verification was conducted. Fifty borings and nearly 100 CPTs were performed at the site. During the production work, the shopping mall design evolved from a single storey department store to a four-storey structure, including a theatre. The geotechnical contractor met the schedule, regulatory and technical requirements while keeping up with the constant design changes to the project. This paper focuses on the design, production work, as well as dynamic and static settlement analysis derived from post-treatment CPTs performed by the geotechnical contractor.