A Study of the Flexibility Response of Soil Elements on Uplifting Elastic Foundation During Seismic Motion

## A Study of the Flexibility Response of Soil Elements on Uplifting Elastic Foundation During Seismic Motion

© 2023 by IJETT Journal
Volume-71 Issue-12
Year of Publication : 2023
Author : Ugwu Juliet Nneka, Onyia Micheal Ebie, Okafor Fidelis Onyebuchi
DOI : 10.14445/22315381/IJETT-V71I12P214

How to Cite?

Ugwu Juliet Nneka, Onyia Micheal Ebie, Okafor Fidelis Onyebuchi, "A Study of the Flexibility Response of Soil Elements on Uplifting Elastic Foundation During Seismic Motion," International Journal of Engineering Trends and Technology, vol. 71, no. 12, pp. 133-143, 2023. Crossref, https://doi.org/10.14445/22315381/IJETT-V71I12P214

Abstract
This study investigated the influence of soil flexibility on the elastic foundation during uplifting from earthquake ground motion. Foundation flexibility and uplift are occurrences from ground motions that could cause significant changes to system responses, considering the Winkler Foundation with its limitations and the Filonenko-Borodich (F-B) foundation to overcome the limitations of the Winkler foundation. During uplift, the foundation becomes nonlinear as the soil elements yielding becomes more flexible, reducing the ductility of the soil structure system. El-Centro (1940) ground motion in the time domain was used, and differential equations describing motions of the system due to earthquake excitations were developed for the time history analysis with deformations outside the loaded part of the foundation considered. Analyses were performed using Newton's second law of motion, by dynamic equilibrium method like D'Alembert's principle and by applying equilibrium of moments for the equations of motion. The formulated differential equations were solved by applying the Duhamel integral and further solved using Simpson's numerical method. The resulting response effect of the F-B model was discussed in comparison with the Winkler model. The numerical case study was used to illustrate the effects of soil flexibility on elastic foundation and soil ductility during ground motion, which, when neglected, may lead to errors in predicting seismic actions. The structure's response during uplift may differ from the response before uplift, which might depend on the parameters of the structure foundation and intensity of excitation that might determine if structure uplift is beneficial.

Keywords
Earthquake, Elastic foundations, Natural frequency, Soil flexibility, Structure.

References
[1] N. Storgaard, “Earthquakes and Their Effects on Building,” Unpublished Thesis, VIA University College, 2010.
[2] Amir Hossein Jafarieh, and Mohammad Ali Ghannad, “Seismic Performance of Nonlinear Soil-Structure Systems Located on Soft Soil Considering Foundation Uplifting and Soil Yielding,” Structures, vol. 28, no. 1, pp. 973-982, 2020.
[3] Piotr Adam Bońkowski, Zbigniew Zembaty, and Maciej Yan Minch, “Engineering Analysis of Strong Ground Rocking and its Effect on Tall Structures,” Soil Dynamics and Earthquake Engineering, vol. 116, pp. 358-370, 2019.
[4] Jian Li et al., “Effect of Discrete Fiber Reinforcement on Soil Tensile Strength,” Journal of Rock Mechanics and Geotechnical Engineering, vol. 6, no. 2, pp. 133-137, 2014.
[5] Anil K. Chopra, and Solomon C.S. Yim, “Simplified Earthquake Analysis of Structures with Foundation Uplift,” Journal of Structural Engineering, vol. 111, no. 4, pp. 906–930, 1985.
[6] R. Thiers-Moggia, and C. Malaga-Chuquitaype, “Dynamic Response of Post-Tensioned Rocking Structures with Inerters,” International Journal of Mechanical Sciences, vol. 187, 2020.
[7] B.R. Jayalekshmi, Ansu Thomas, and R. Shivashankar, “Dynamic Soil-Structure Interaction Studies on 275m Tall Industrial Chimney with Openings,” Earthquakes and Structures, vol. 7, no. 2, pp. 233-250, 2014.
[8] Chik-Sing Yim, and Anil K. Chopra, “Earthquake Response of Structures with Partial Uplift on Winkler Foundation,” Journal of Earthquake Engineering & Structural Dynamics, vol. 12, no. 2, pp. 263–281, 1984.
[9] Xiaoyang Qin, and Nawawi Chouw, “Shake Table Test on Uplift Behaviour of a Shear Frame in Earthquake,” World Congress on Advances in Civil, Environmental and Materials Research, pp. 2061-2071, 2012.
[10] Ioannis N. Psycharis, and Paul C. Jennings, “Rocking of Slender Rigid Bodies Allowed to Uplift,” Earthquake Engineering and Structural Dynamics, vol. 11, no. 1, pp. 57-76, 1983.
[11] Shijun Ding et al., “Uplift Bearing Capacity of Transmission Tower Foundation in Reinforced Aeolian Sand Using Simplified Model Tests,” Advances in Civil Engineering, 2021.
[12] F. Zhou, M. Mori, and N. Fukuwa, “A New Uplift Foundation Analysis Model to Simulate Dynamic Nonlinear Soil-Structure Interaction,” 15WCEE, LISBOA, 2012.