Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-4-2013

Abstract

During the last decade, a series of ports are being built along the Thi Vai River in the Mekong delta approximately 80 km southeast of Ho Chi Minh City, Vietnam. The ports are built on reclaimed ground over an about 30 to 40 m thick deposit of soft, normally consolidated, compressible clay deposited on dense to compact sand The deep foundation system typically used for buildings in this region consists of pretensioned spun high strength concrete piles driven to significant toe bearing in dense soils. Because of the anticipated significant costs of this solution, a more economical alternative foundation system was essential, and the alternative of a shaft bearing pile, a precast concrete pile, was proposed for Cai Mep Container Port. To reduce settlements, a soil improvement scheme was imposed, consisting of wick drains installed through the clay to the sand and placing an up to 8 m thick surcharge over the area. After removal of the surcharge, piled-raft foundations were constructed for the Port building, incorporating 400 mm square, precast concrete piles, which were driven to depths of 18 m. Settlement monitoring showed that the area and the piles continued to settle after the removal of the surcharge, indicating that consolidation settlement had not been completed despite the about 18 months long surcharge period. It became clear that the long-term settlements, primarily due to downdrag, would exceed the limit of maximum 400 mm over a 20-year period. In order to remedy the situation, the piles were lengthened to a total length of 44 m to ensure that the neutral plane was located in the sand, where no long-term settlement would occur. The problem and its solution were analyzed by means of the Unified Design Method. The remedial solution added about US$2 million to the project and caused a 12-month delay.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Seventh Conference

Publisher

Missouri University of Science and Technology

Publication Date

4-29-2013

Document Version

Final Version

Rights

© 2013 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 29th, 12:00 AM May 4th, 12:00 AM

Analysis of Piled-Raft Foundation for CAI MEP Container Port, Vietnam

Chicago, Illinois

During the last decade, a series of ports are being built along the Thi Vai River in the Mekong delta approximately 80 km southeast of Ho Chi Minh City, Vietnam. The ports are built on reclaimed ground over an about 30 to 40 m thick deposit of soft, normally consolidated, compressible clay deposited on dense to compact sand The deep foundation system typically used for buildings in this region consists of pretensioned spun high strength concrete piles driven to significant toe bearing in dense soils. Because of the anticipated significant costs of this solution, a more economical alternative foundation system was essential, and the alternative of a shaft bearing pile, a precast concrete pile, was proposed for Cai Mep Container Port. To reduce settlements, a soil improvement scheme was imposed, consisting of wick drains installed through the clay to the sand and placing an up to 8 m thick surcharge over the area. After removal of the surcharge, piled-raft foundations were constructed for the Port building, incorporating 400 mm square, precast concrete piles, which were driven to depths of 18 m. Settlement monitoring showed that the area and the piles continued to settle after the removal of the surcharge, indicating that consolidation settlement had not been completed despite the about 18 months long surcharge period. It became clear that the long-term settlements, primarily due to downdrag, would exceed the limit of maximum 400 mm over a 20-year period. In order to remedy the situation, the piles were lengthened to a total length of 44 m to ensure that the neutral plane was located in the sand, where no long-term settlement would occur. The problem and its solution were analyzed by means of the Unified Design Method. The remedial solution added about US$2 million to the project and caused a 12-month delay.