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

2286.5. Construction Control Considerations6.5.1. IntroductionConstruction control involves procedures or methods for nondestructive verificationof designed pile resistances during pile driving. The Iowa DOT currently uses the Iowa BlueBook (originally written by Dirks and Kam, 1989) method to design piles and uses eitherWEAP or CAPWAP as a construction control method to verify the designed pile resistanceduring construction. If the desired pile resistance is not attained during construction, piledriving specifications will be adjusted accordingly, such as increasing pile length. Theadjustment may increase construction costs, delay construction schedule, and causecontractual challenges. The construction control method is also used to detect any piledamage and to check pile integrity. To improve the accuracy of pile resistance and costestimations during the design stage and to ensure an adequate pile performance, theconstruction control method using either WEAP or CAPWAP is integrated as part of thedesign procedure. To ensure consistent and practical pile designs, the Iowa Blue Book soilinput procedure used in WEAP was selected for the following construction controlevaluations and analyses. Databases from both PILOT and the recently completed field testswere selected for WEAP, while only the field tests were used for the CAPWAP evaluation.The total data points for WEAP in the clay, mixed, and sand profiles were 17, 12, and 13,respectively, and the total data points for CAPWAP in the clay, mixed, and sand profileswere 5, 2, and 2, respectively. The construction control evaluations were performed for threeresistance conditions—EOD, setup, and BOR. Referring to Table 6.8 for the constructioncontrol method using WEAP, construction control evaluations for EOD were performed forall three soil profiles, while evaluation for setup was only applied to clay. On the other hand,construction control evaluations for all three resistance conditions were performed for clay,and an evaluation for only BOR was applied to sand and mixed soil profiles.6.5.2. MethodologyConstruction control was accounted for by multiplying a construction control factor(ξ) for the respective resistance condition to the original resistance factor (φ) of the Blue