Pseudo-static low cycle test on the mechanical behavior of PHC pipe piles with consideration of soil-pile interaction

• Published in: Engineering structures Vol. 171; pp. 992 - 1006
• Main Authors: Huang, Fu-yun, Wu, Sui-wen, Luo, Xiao-ye, Chen, Bao-chun, Lin, Youwei
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.09.2018; Elsevier BV
• Subjects: Bridge abutments; Bridge foundations; Concrete; Concrete pipes; Deformation; Deformation effects; Design; Ductile-brittle transition; Ductility; Earthquake damage; Earthquakes; Energy dissipation; Failure modes; Force distribution; High strength concretes; Instrumentation; Low-cyclic pseudo-static test; Materials elasticity; Mechanical behavior; Mechanical properties; PHC pipe-pile; Pile foundation of IAJB; Pile foundations; Pipe piles; Pipes; Plastics; Prestressed concrete; Sandy soils; Seismic activity; Seismic design; Seismic engineering; Seismic response; Soil mechanics; Soil strength; Soil stresses; Soil-pile interaction; Soil-structure interaction; Static electricity; Static tests; Stress concentration; Temperature effects; Low-cyclic pseudo-static test; Mechanical behavior; PHC pipe-pile; Pile foundation of IAJB; Soil-pile interaction
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2018.01.060

Pre-stressed high-strength concrete (PHC) pipe piles have been widely used in the pile foundations of buildings and bridges which are usually designed elastic based on the capacity design principle. However, when the PHC pipe pile comes to the foundations of Integral Abutment Jointless Bridges (IAJBs), limited ductility might apply in order to accommodate the relatively large deformation demand under the effect of temperature fluctuations or earthquake. The conventional design methods for PHC pipe piles remain in doubt. This paper focuses on low cycle pseudo-static tests on 4 PHC pipe-pile models with various pre-stress levels to gain insight into their mechanical behaviors with consideration of soil-pile interaction. Medium sand was employed in the tests. The details of the experiments are introduced, including design of the models, instrumentation and loading scheme. The testing results indicate that the damages of the PHC pipe piles are mainly concentrated at 4D to 8D of embedded depths. Moreover, the pre-stress level and reinforcement ratio have a significant influence on the failure mode of PHC pipe piles, especially on the distribution of internal force and moment along piles. It is found that the interaction effect of pile-soil strengthens with the pre-stress level which is beneficial to the seismic performance. Furthermore, the backbone of the PHC pipe piles model has four stages: elastic, elastic-plastic, plastic hardening, and failure. It is concluded that PHC pipe piles perform favorably plastic and ductile behavior, and their failure modes are flexural (bending) not brittle (shear). Finally, the PHC pipe pile has an appreciable energy dissipation and deformation capacity, and hence can be used for pile foundations in IAJBs.