Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
A Synthesis of Pile Performance Monitoring Projects in Downdrag Environments in Minnesota
The Minnesota Department of Transportation (MnDOT) has conducted several driven pile performance monitoring projects to investigate and assess the practical impact of the phenomenon of downdrag and the resulting dragload, often called “negative skin friction” on driven pile design and construction practice. While the current design guidance addressees downdrag and its associated dragload, there has been significant discussion by MnDOT personnel and the engineering community as to when negative skin friction can be expected, how to predict the magnitude of the dragload to be considered in design, and what scenarios, if any, exist when dragload may be safely ignored. This case history paper presents observations from five projects in Minnesota where driven piles were instrumented and monitored over periods of months to years, through construction and initial service, including lessons learned on those projects relative to the downdrag phenomenon. These projects have examined, among other things: the difference in behavior between standard pipe piles relative to Teflon-coated pipe piles; the impact of sleeves placed around stick-up lengths of piling in reducing dragload; the dragload distribution difference between subsurfaces composed of loose sands compared to soft clays; etc. While there is much to consider when dealing with negative skin friction and downdrag, a number of findings have allowed more knowledgeable decisions to be made, resulting in revisions to agency practice. Initial work proved that dragload existed, was measurable and permanent, and the behavior and observed magnitudes appeared consistent with predictions given geotechnical site conditions and structural loading.
A Synthesis of Pile Performance Monitoring Projects in Downdrag Environments in Minnesota
The Minnesota Department of Transportation (MnDOT) has conducted several driven pile performance monitoring projects to investigate and assess the practical impact of the phenomenon of downdrag and the resulting dragload, often called “negative skin friction” on driven pile design and construction practice. While the current design guidance addressees downdrag and its associated dragload, there has been significant discussion by MnDOT personnel and the engineering community as to when negative skin friction can be expected, how to predict the magnitude of the dragload to be considered in design, and what scenarios, if any, exist when dragload may be safely ignored. This case history paper presents observations from five projects in Minnesota where driven piles were instrumented and monitored over periods of months to years, through construction and initial service, including lessons learned on those projects relative to the downdrag phenomenon. These projects have examined, among other things: the difference in behavior between standard pipe piles relative to Teflon-coated pipe piles; the impact of sleeves placed around stick-up lengths of piling in reducing dragload; the dragload distribution difference between subsurfaces composed of loose sands compared to soft clays; etc. While there is much to consider when dealing with negative skin friction and downdrag, a number of findings have allowed more knowledgeable decisions to be made, resulting in revisions to agency practice. Initial work proved that dragload existed, was measurable and permanent, and the behavior and observed magnitudes appeared consistent with predictions given geotechnical site conditions and structural loading.
A Synthesis of Pile Performance Monitoring Projects in Downdrag Environments in Minnesota
Budge, A. S. (Autor:in) / Dasenbrock, D. D. (Autor:in) / Mattison, D. J. (Autor:in)
IFCEE 2015 ; 2015 ; San Antonio, Texas
IFCEE 2015 ; 457-471
17.03.2015
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
A SYNTHESIS OF PILE PERFORMANCE MONITORING PROJECTS IN DOWNDRAG ENVIRONMENTS IN MINNESOTA
| British Library Conference Proceedings | 2015
Analysis of downdrag on pile groups
| British Library Online Contents | 1995
Negative Friction 'Downdrag on a Pile'
| NTIS | 1978
Performance of Pile Foundations Subjected to Downdrag
| British Library Conference Proceedings | 1999