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

162( ) (4.8)where f c = consolidation factor; and f r = remolding recovery factor, which are tabulated inFigure 4.6 for both the CAPWAP and WEAP-SA. Since pile setup is influenced by thesuperposition of soil consolidation and recovery of the surrounding remolded soils, the effectof soil consolidation is best described by the first term on the right ( ) and the effect ofrecovery of the remolded soils is best accounted for by the remolding recovery factor (f r ).The two distinct best fit lines shown in Figure 4.6 indicate that a larger C value will beestimated based on the factors (f c and f r ) calibrated for the WEAP-SA analyses. Thedifference in the two best fit lines was attributed to the larger initial pile resistances estimatedat EOD (R EOD ) using CAPWAP, which resulted in the smaller C values determined fromFigure 4.3. Furthermore, a better match was observed for CAPWAP, represented with ahigher coefficient of determination (R 2 ) of 0.95. In other words, Eq. (4.8) based onCAPWAP has a better accuracy than that based on WEAP-SA in predicting the C value.4.4.3. Proposed methodThe pile setup rate (C) has been successfully quantified using Eq. (4.8). SubstitutingEq. (4.8) into setup Eq. (4.1), the proposed pile setup equation is expressed as*( ) ( ) + ( ) (4.9)It is important to note that this proposed pile setup equation is developed from ISU field testsbased on one size steel H-piles embedded in cohesive soils. Although it needs to bevalidated for other piles sizes and types (discussed later), when compared with the existingpile setup methods discussed early, the proposed pile setup method in Eq. (4.9) provides thefollowing advantages and simplifications for designers:-1. Considering a reference pile resistance at EOD which can be conveniently estimatedusing either WEAP-SA or CAPWAP;