Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

In conjunction with the below-grade construction of a new office building at 1875 Pennsylvania Avenue in downtown Washington, D.C. an adjacent 11-story historic building was supported using a system of bracket piles, a transfer girder and flat jacks. Before Clark Foundations could begin work, an office building from the 1960’s was demolished. This paper will discuss the design, construction and performance of the 65-foot deep excavation support system for the new office building. Built at the turn of the century, the adjacent structure was first supported in 1960 by a series of bracket piles and a concrete grade beam. The new office building at 1875 Pennsylvania Avenue required subgrade to extend approximately 10 feet below the tip elevation of those original 1960’s bracket pile system. The Clark team installed a series of 25 additional bracket piles and a transfer girder between the existing bracket piles to support the older system. This system was preloaded using a series of flat jacks to minimize any additional settlement. Clark Foundations created a very unique two-tiered underpinning support system. This new system supports a 1960’s system, which in turn, supports the adjacent historic structure. Clark’s innovative approach created additional below-grade space gained for the law firm tenant while maintaining the integrity of a historic structure.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Sixth Conference

Publisher

Missouri University of Science and Technology

Publication Date

8-11-2008

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Case History of the Temporary Support of an 11-Story Historic Building in Downtown Washington, DC

Arlington, Virginia

In conjunction with the below-grade construction of a new office building at 1875 Pennsylvania Avenue in downtown Washington, D.C. an adjacent 11-story historic building was supported using a system of bracket piles, a transfer girder and flat jacks. Before Clark Foundations could begin work, an office building from the 1960’s was demolished. This paper will discuss the design, construction and performance of the 65-foot deep excavation support system for the new office building. Built at the turn of the century, the adjacent structure was first supported in 1960 by a series of bracket piles and a concrete grade beam. The new office building at 1875 Pennsylvania Avenue required subgrade to extend approximately 10 feet below the tip elevation of those original 1960’s bracket pile system. The Clark team installed a series of 25 additional bracket piles and a transfer girder between the existing bracket piles to support the older system. This system was preloaded using a series of flat jacks to minimize any additional settlement. Clark Foundations created a very unique two-tiered underpinning support system. This new system supports a 1960’s system, which in turn, supports the adjacent historic structure. Clark’s innovative approach created additional below-grade space gained for the law firm tenant while maintaining the integrity of a historic structure.