TY - GEN

T1 - Capacity Degradation Method for Driven Steel Piles Under Cyclic Axial Loading

AU - Achmus, Martin

AU - Abdel-Rahman, Khalid

AU - Schaefer, Dominik

AU - Kuo, Yu Shu

AU - Chung, Chih Yin

AU - Tseng, Yu Hsiu

N1 - Funding Information: This study was carried out as part of the research project “GIGAWIND-life” funded by the Federal Ministry for Economic Affairs and Energy (BMWi) of Germany. This research was also supported by the Ministry of Science and Technology of Taiwan, MOST 106-3113-E-006-008 -CC2. The support is gratefully acknowledged. Publisher Copyright: Copyright © 2017 by the International Society of Offshore and Polar Engineers (ISOPE). Copyright: Copyright 2017 Elsevier B.V., All rights reserved.

PY - 2017/6/25

Y1 - 2017/6/25

N2 - The piles used for jacket type foundation for an offshore wind turbine are subjected to highly cyclic tension and compressive loading. The pile capacity under cyclic axial loading decreases with number of loading cycles due to the reduction of pile shaft resistance. A numerical simulation scheme is presented, which allows the calculation of pile capacity degradation (CDM) due to cyclic loading for driven steel piles. The volume compaction of soil near pile surface during the cyclic loading is determined from cyclic simple shear test results and is then applied to the pile-soil system. From the limited number of tests available, interaction diagrams have been developed, which give the number of load cycles leading to failure dependent on the mean load and the amplitude of the cyclic load portion, both related to the static pile capacity. However, such diagrams cannot account for different soil conditions or pile geometry and pile stiffness. The calculation results for piles with three different embedded lengths in sandy soil under cyclic loading in tension are presented and compared with the existing interaction diagrams. Finally, recommendations regarding necessary further investigations and improvements of the method are given.

AB - The piles used for jacket type foundation for an offshore wind turbine are subjected to highly cyclic tension and compressive loading. The pile capacity under cyclic axial loading decreases with number of loading cycles due to the reduction of pile shaft resistance. A numerical simulation scheme is presented, which allows the calculation of pile capacity degradation (CDM) due to cyclic loading for driven steel piles. The volume compaction of soil near pile surface during the cyclic loading is determined from cyclic simple shear test results and is then applied to the pile-soil system. From the limited number of tests available, interaction diagrams have been developed, which give the number of load cycles leading to failure dependent on the mean load and the amplitude of the cyclic load portion, both related to the static pile capacity. However, such diagrams cannot account for different soil conditions or pile geometry and pile stiffness. The calculation results for piles with three different embedded lengths in sandy soil under cyclic loading in tension are presented and compared with the existing interaction diagrams. Finally, recommendations regarding necessary further investigations and improvements of the method are given.

KW - Axial load

KW - Capacity degradation method (CDM)

KW - Jacket type foundation

KW - Offshore wind

UR - http://www.scopus.com/inward/record.url?scp=85038942619&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85038942619

T3 - Proceedings of the International Offshore and Polar Engineering Conference

BT - Proceedings of the 27th International Ocean and Polar Engineering Conference, ISOPE 2017

PB - Society of Petroleum Engineers (SPE)

T2 - 27th International Ocean and Polar Engineering Conference, ISOPE 2017

Y2 - 25 June 2017 through 30 June 2017

ER -