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A platform for research: civil engineering, architecture and urbanism
High Capacity Micropiles in Wissahickon Schist Bedrock
Urban construction frequently dictates that new foundations are capable of supporting very high structural loads within project sites of a limited footprint. In the interest of limiting pile diameters for constructability, the structural loads per unit cross-section have increased significantly in recent years. This paper details a case history of high capacity micropiles founded in Wissahickon Mica Schist bedrock in Philadelphia, Pennsylvania. Sixty production piles were installed at the project site to carry the load of a new 10-story building addition with heavy new foundation loads on a cramped site. The structural loading demands on these rock-socketed micropiles necessitated an aggressive approach to design. A heavily instrumented compression load test was conducted to confirm the pile performance. Observed strain compatibility between the structural elements of the pile and the high degree of confinement validated the use of high-strength steel reinforcement and high allowable stresses. The load distribution in the bond zone was found to be nonlinear and concentrated in the upper 1/4 to 1/2 of the socket length, and mobilized bond stresses were shown to be higher than reliable, published values for similar geologic materials and environments.
High Capacity Micropiles in Wissahickon Schist Bedrock
Urban construction frequently dictates that new foundations are capable of supporting very high structural loads within project sites of a limited footprint. In the interest of limiting pile diameters for constructability, the structural loads per unit cross-section have increased significantly in recent years. This paper details a case history of high capacity micropiles founded in Wissahickon Mica Schist bedrock in Philadelphia, Pennsylvania. Sixty production piles were installed at the project site to carry the load of a new 10-story building addition with heavy new foundation loads on a cramped site. The structural loading demands on these rock-socketed micropiles necessitated an aggressive approach to design. A heavily instrumented compression load test was conducted to confirm the pile performance. Observed strain compatibility between the structural elements of the pile and the high degree of confinement validated the use of high-strength steel reinforcement and high allowable stresses. The load distribution in the bond zone was found to be nonlinear and concentrated in the upper 1/4 to 1/2 of the socket length, and mobilized bond stresses were shown to be higher than reliable, published values for similar geologic materials and environments.
High Capacity Micropiles in Wissahickon Schist Bedrock
Holman, Terence P. (author)
International Foundation Congress and Equipment Expo 2009 ; 2009 ; Orlando, Florida, United States
Contemporary Topics in Deep Foundations ; 359-366
2009-03-10
Conference paper
Electronic Resource
English
High Capacity Micropiles in Wissahickon Schist Bedrock
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