Accuracy evaluation of API P-Y model for Offshore Piles in Clays

Piles are widely used as foundation structures supporting offshore wind turbines, with the p-y curve method commonly recommended for analysis of pile-soil interactions by current mainstream design specifications. Among these methods, the p-y curve model developed by the American Petroleum Institute...

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Main Authors: Peiyuan Lin, Xun Yuan, Tong Liu, Haoyi Li, Xiangwei Yu
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590123025028397
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author Peiyuan Lin
Xun Yuan
Tong Liu
Haoyi Li
Xiangwei Yu
author_facet Peiyuan Lin
Xun Yuan
Tong Liu
Haoyi Li
Xiangwei Yu
author_sort Peiyuan Lin
collection DOAJ
description Piles are widely used as foundation structures supporting offshore wind turbines, with the p-y curve method commonly recommended for analysis of pile-soil interactions by current mainstream design specifications. Among these methods, the p-y curve model developed by the American Petroleum Institute (API) has gained extensive applications and been the key reference for development of analogous models in numerous countries and regions. Nevertheless, the accuracy of the API-specified p-y curve model remains to be quantitatively evaluated. This study first collected 402 sets of pile p-y curves from multiple offshore wind turbine projects in clays to establish a field-measured p-y curve database. The database was then used to statistically evaluate the prediction accuracy of the p-y curve model for clays recommended by the API specification. The model accuracy is represented by a model factor defined as the ratio of measured to predicted values of soil resistance around the pile. Results showed that the API p-y model underestimates the true soil resistance by about 50 % on average. The dispersions in prediction accuracy are high. Calibration terms considering statistic and physical information are introduced to calibrate the current API p-y model. The calibrated API model exhibits unbiased average prediction accuracy and have a significant reduction in dispersion of prediction accuracy. Finally, Gaussian functions were employed to fit the probability density functions of the API p-y curve model factors before and after calibration, respectively. The research outcomes of this study is of help towards reliability-based design of offshore piles.
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issn 2590-1230
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spelling doaj-art-bf207f2a9769496aba7626c184436e212025-08-20T05:07:40ZengElsevierResults in Engineering2590-12302025-09-012710677410.1016/j.rineng.2025.106774Accuracy evaluation of API P-Y model for Offshore Piles in ClaysPeiyuan Lin0Xun Yuan1Tong Liu2Haoyi Li3Xiangwei Yu4State Key Laboratory for Tunnel Engineering, Guangzhou, 510275, China; School of Civil Engineering, Sun Yat-Sen University; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai). Zhuhai, Guangdong, 519082, China; Corresponding author.School of Civil Engineering, Sun Yat-Sen University, Zhuhai, Guangdong, 519082, ChinaSchool of Civil Engineering, Sun Yat-Sen University, Zhuhai, Guangdong, 519082, ChinaSchool of Civil Engineering, Sun Yat-Sen University, Zhuhai, Guangdong, 519082, ChinaSchool of Civil Engineering, Sun Yat-Sen University, Zhuhai, Guangdong, 519082, ChinaPiles are widely used as foundation structures supporting offshore wind turbines, with the p-y curve method commonly recommended for analysis of pile-soil interactions by current mainstream design specifications. Among these methods, the p-y curve model developed by the American Petroleum Institute (API) has gained extensive applications and been the key reference for development of analogous models in numerous countries and regions. Nevertheless, the accuracy of the API-specified p-y curve model remains to be quantitatively evaluated. This study first collected 402 sets of pile p-y curves from multiple offshore wind turbine projects in clays to establish a field-measured p-y curve database. The database was then used to statistically evaluate the prediction accuracy of the p-y curve model for clays recommended by the API specification. The model accuracy is represented by a model factor defined as the ratio of measured to predicted values of soil resistance around the pile. Results showed that the API p-y model underestimates the true soil resistance by about 50 % on average. The dispersions in prediction accuracy are high. Calibration terms considering statistic and physical information are introduced to calibrate the current API p-y model. The calibrated API model exhibits unbiased average prediction accuracy and have a significant reduction in dispersion of prediction accuracy. Finally, Gaussian functions were employed to fit the probability density functions of the API p-y curve model factors before and after calibration, respectively. The research outcomes of this study is of help towards reliability-based design of offshore piles.http://www.sciencedirect.com/science/article/pii/S2590123025028397Pile foundationP-y curveAPI specificationOffshore wind turbineModel uncertaintyModel calibration
spellingShingle Peiyuan Lin
Xun Yuan
Tong Liu
Haoyi Li
Xiangwei Yu
Accuracy evaluation of API P-Y model for Offshore Piles in Clays
Results in Engineering
Pile foundation
P-y curve
API specification
Offshore wind turbine
Model uncertainty
Model calibration
title Accuracy evaluation of API P-Y model for Offshore Piles in Clays
title_full Accuracy evaluation of API P-Y model for Offshore Piles in Clays
title_fullStr Accuracy evaluation of API P-Y model for Offshore Piles in Clays
title_full_unstemmed Accuracy evaluation of API P-Y model for Offshore Piles in Clays
title_short Accuracy evaluation of API P-Y model for Offshore Piles in Clays
title_sort accuracy evaluation of api p y model for offshore piles in clays
topic Pile foundation
P-y curve
API specification
Offshore wind turbine
Model uncertainty
Model calibration
url http://www.sciencedirect.com/science/article/pii/S2590123025028397
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AT tongliu accuracyevaluationofapipymodelforoffshorepilesinclays
AT haoyili accuracyevaluationofapipymodelforoffshorepilesinclays
AT xiangweiyu accuracyevaluationofapipymodelforoffshorepilesinclays