Showing 3 results for Centrifuge
Hamid Reza Khodaei, Majid Moradi, Abbas Ghalandarzadeh,
Volume 11, Issue 22 (3-2016)
Abstract
One of the most common methods to analyze and design monopiles under lateral load is load-displacement curves, particularly the p-y curves, at different locations of the structure. Thus, in order to investigate the soil-monopile behavior and interaction under lateral load is physically modeled and tested by utilizing the Geotechnical Centrifuge of Tehran University in the Ng space. In this study, five modeling tests are designed by considering the following two parameters with changes in their values and ratios: the penetration depth of the pile in soil (L) and the free length of the pile (e). The existing p-y curves in API are extracted and compared to experimental curves to observe differences and make the necessary modifications.
Mahdi Shahidikhah, Majid Moradi, Alireza Khamseh,
Volume 15, Issue 29 (4-2019)
Abstract
Monopiles are the most common type of foundation for offshore wind turbines (OWT). Monopiles have been used in more than 80% of the offshore wind turbines. A monopile will be affected by millions of lateral load cycles during the operating period, which will cause its rotation and lateral deformation. The rotation and the deformation are dependent on the soil properties, monopile specification, and lateral loading characteristics. Current methods are only for the design of piles with less than 1meter in diameter. Due to this fact that monopiles are hollow cylindrical steel tubes with a diameter of 2 to 8 meters, in this research the behavior of these structures due to monotonic and cyclic lateral loads in sandy soils has been studied by physical modeling in a geotechnical centrifuge. One monotonic test and six cyclic tests were designed and implemented to investigate the effect of lateral load characteristics. According to the results of 7 tests, the effect of different loading parameters on monopile cumulative displacement and soil stiffness is discussed.
In all tests, the monopile deflection is a rigid body, and the cumulative displacement of the monopile head is increasing with power functions. Also, the monopile stiffness in terms of the number of cycles is ascending, and the rate of the increase is decreasing.
Shahriar Shirazi, Majid Moradi,
Volume 19, Issue 38 (4-2023)
Abstract
In this research paper, five centrifuge lateral loading tests of long piles with a considerable load eccentricity were carried out in the sand to investigate the impacts of the load eccentricity and pile length changes on the lateral behavior of a flexible pile beside the determination of experimental p-y curves.
Comparing experimental test results with the recommended API (American Petroleum Institute) curves clarifies what is nowadays identified as the difference between the behaviors of monopiles and flexible piles how far can be affected by the load eccentricity. Additionally, the efficiency and accuracy of the available equipment at the University of Tehran have also been investigated. Results show that although the load eccentricity affects p-y curves, the current design approach can lead to a proper design even at high load eccentricities. In most tests, the initial stiffness in p-y curves is lower than that of the guidelines. Also, the hyperbolic model shows a closer estimation to the experimental test results.
