Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-13-2013

Abstract

Adoption of new technologies and a push for money-saving value engineering designs may produce unpredictable and unwanted results. Particularly with shrinking budgets, proposals that reduce initial costs become more appealing. However, without careful consideration and implementation, cost-reducing measures can become more expensive in the end. This paper presents a case study of geostructural forensic analysis related to the failure of a helical anchor tie-down system selected to support an Olympic size swimming pool against hydrostatic uplift forces. The selection of helical anchors over a more expensive traditional anchorage system appeared to be a smart value engineering decision for the project’s design-build construction team. However, structural failure occurred soon after construction. A review of design and construction documents revealed a myriad of mistakes leading to the failure and very costly repair of the pool’s bottom slab. The demolition and consequent restoration of the slab triggered the forensic study. The geostructural forensic analysis initially focused on the tension capacity of the anchorage system. However, review of design data indicated several critical mistakes at the anchor-to-concrete slab connections. Moreover, issues with final installation elevation, which were overlooked in the original design and construction, necessitated the need for field modification of the connection. A step-by-step summary of the forensic analysis of the tie-down support system failure is presented herein.

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 13th, 12:00 AM

Failure Investigation of a Helical Anchor Tie-Down System Supporting an Olympic Size Swimming Pool

Chicago, Illinois

Adoption of new technologies and a push for money-saving value engineering designs may produce unpredictable and unwanted results. Particularly with shrinking budgets, proposals that reduce initial costs become more appealing. However, without careful consideration and implementation, cost-reducing measures can become more expensive in the end. This paper presents a case study of geostructural forensic analysis related to the failure of a helical anchor tie-down system selected to support an Olympic size swimming pool against hydrostatic uplift forces. The selection of helical anchors over a more expensive traditional anchorage system appeared to be a smart value engineering decision for the project’s design-build construction team. However, structural failure occurred soon after construction. A review of design and construction documents revealed a myriad of mistakes leading to the failure and very costly repair of the pool’s bottom slab. The demolition and consequent restoration of the slab triggered the forensic study. The geostructural forensic analysis initially focused on the tension capacity of the anchorage system. However, review of design data indicated several critical mistakes at the anchor-to-concrete slab connections. Moreover, issues with final installation elevation, which were overlooked in the original design and construction, necessitated the need for field modification of the connection. A step-by-step summary of the forensic analysis of the tie-down support system failure is presented herein.