S - Kam Ng PhD Dissertation Final.pdf - Digital Repository of CCEE ...

120CHAPTER 3: PILE SETUP IN COHESIVE SOIL WITH EMPHASIS ONLRFD: AN EXPERIMENTAL INVESTIGATIONNg, K. W. 1 ; Roling, M. 1 ; AbdelSalam, S. S. 1 ; Suleiman, M. T. 2 ; and Sritharan, S. 3A paper to be submitted to the Journal of Geotechnical and Geoenvironmental Eng., ASCE3.1. AbstractSetup of piles driven in cohesive soils has been a known phenomenon for severaldecades. However, a systematic field investigation providing the needed data to developanalytical approaches for integrating pile setup into the design method rarely exists. Thispaper summarizes recently completed field investigation on five fully instrumented steel H-piles embedded in cohesive soils, while a companion paper discusses the development of thepile setup method and its incorporation into the Load and Resistance Factor Design (LRFD)approach. During the field investigation, detailed soil characterization, monitoring of soiltotal lateral stress and pore water pressure using push-in pressure cells, collection of piledynamic restrike data as a function of time, and vertical static load tests were completed.Restrike measurements confirm that pile setup occurs with a logarithmic increase followingthe end of driving and its development correlates well with the rate of dissipation of themeasured pore water pressure. The field data further concluded that only the skin frictioncomponent, not the end bearing, is largely contributes to the setup, which can be accuratelyestimated for practical purposes using soil properties, such as SPT N-value and coefficient ofconsolidation.CE Database Keywords: Pile Setup; Load tests; Cohesive soil; WEAP; CAPWAP;Coefficient of consolidation; SPT N-value; PI; Damping factor; Quake; LRFD._____________________________1 Research Assistants, Dept. of Civil, Construction and Environmental Engineering, Iowa State Univ.,Ames, IA 50011. E-mail: kwng@iastate.edu, roling@iastate.edu, and ssabdel@iastate.edu2 Assistant Professor, Dept. of Civil and Environmental Engineering, Lehigh University, Bethlehem,PA, 18015. E-mail: mts210@lehigh.edu3 Wilson Engineering Professor and Associate Chair, Dept. of Civil, Construction and EnvironmentalEngineering, Iowa State Univ., Ames, IA 50011. E-mail: sri@iastate.edu