Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

A soft soil site, located near Vancouver, BC, presented a unique challenge for the Owner and geotechnical engineer. The relatively narrow but long site was covered by a variable thickness of silty sand and gravel fill overlying about 3 m of peat, organic silt to 12 m depth and very soft, sensitive clay to about 35 m depth. A three/two-story, 27 by 200 m, concrete tilt-up warehouse type structure was proposed for the site. The two foundation options initially considered included the full structure and slab supported on piles driven down to refusal at about 40m depth or conventional spread foundations after preloading the site with up to 6 m of fill for at least one year. An alternative and chosen design was to use a thick mat of Lightweight Cellular Concrete (LCC) to offset building and fill loads as well as to provide a method of redistributing foundation stresses to reduce potentially adverse differential movements. Because of a history of variable fill thicknesses placed over the property, with resulting variable magnitude of preconsolidation of the soft soils, it was necessary to design a variable thickness for the LCC along the length of the building and provide a nominal preload for three months prior to building construction. The project was completed on budget and has performed as predicted over the past four years since construction. This paper presents the results of settlement monitoring of the preload and warehouse, and provides a summary of building performance.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Unique Foundation Solution for Organic Soil Site

New York, New York

A soft soil site, located near Vancouver, BC, presented a unique challenge for the Owner and geotechnical engineer. The relatively narrow but long site was covered by a variable thickness of silty sand and gravel fill overlying about 3 m of peat, organic silt to 12 m depth and very soft, sensitive clay to about 35 m depth. A three/two-story, 27 by 200 m, concrete tilt-up warehouse type structure was proposed for the site. The two foundation options initially considered included the full structure and slab supported on piles driven down to refusal at about 40m depth or conventional spread foundations after preloading the site with up to 6 m of fill for at least one year. An alternative and chosen design was to use a thick mat of Lightweight Cellular Concrete (LCC) to offset building and fill loads as well as to provide a method of redistributing foundation stresses to reduce potentially adverse differential movements. Because of a history of variable fill thicknesses placed over the property, with resulting variable magnitude of preconsolidation of the soft soils, it was necessary to design a variable thickness for the LCC along the length of the building and provide a nominal preload for three months prior to building construction. The project was completed on budget and has performed as predicted over the past four years since construction. This paper presents the results of settlement monitoring of the preload and warehouse, and provides a summary of building performance.