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

250CHAPTER 7: AN IMPROVED CAPWAP MATCHING PROCEDUREFOR THE QUANTIFICATION OF DYNAMIC SOIL PARAMETERSNg, K. W. 1 ; Sritharan, S. 2 ; and Suleiman, M. T. 3A paper to be submitted to the Computers and Geotechnics Journal7.1. AbstractAlthough dynamic analysis methods have been widely used in estimating axial pileresistance, the accuracy of these methods is highly dependent upon the appropriate selectionof dynamic soil parameters, such as damping factor and quake value. Due to the high degreeof scatter found during correlation studies and the limitation with the current defaultCAPWAP matching procedure from which constant parameters are assumed over an entiresoil profile, these parameters have not been successfully quantified from any standardgeotechnical in-situ or laboratory soil test results. To improve the prediction of theseparameters, a systematic CAPWAP matching procedure is proposed, based on variable soilparameters along the pile length. The proposed CAPWAP matching procedure improved thematch quality between measured and estimated pile responses to as high as 20%. Correlationstudies showed a good relationship between the SPT N-value and shaft dynamic soilparameters at the EOD condition for both cohesive and cohesionless soils. Empiricalequations were established with relative high coefficient of determination. Also, the analysespresented herein revealed the influences of pile setup and pile installation on the estimationof the parameters. The application of these parameters was validated based on anindependent CAPWAP analysis performed on a recently tested steel H-pile embedded in amixed soil profile with a 19% match quality improvement._____________________________1 Ph.D. Candidate, Dept. of Civil, Construction and Environmental Engineering, Iowa State Univ.,Ames, IA 50011. E-mail: kwng@iastate.edu2 Wilson Engineering Professor and Associate Chair, Dept. of Civil, Construction and EnvironmentalEngineering, Iowa State Univ., Ames, IA 50011. E-mail: sri@iastate.edu3 Assistant Professor, Dept. of Civil and Environmental Engineering, Lehigh University, Bethlehem,PA, 18015. E-mail: mts210@lehigh.edu