Finite Element Based Investigation of Belled Piers in Expansive Soils
| dc.contributor.advisor | Henok, Fikre (PhD) | |
| dc.contributor.author | Gideon, Amha | |
| dc.date.accessioned | 2020-06-15T08:58:34Z | |
| dc.date.accessioned | 2023-11-11T12:51:18Z | |
| dc.date.available | 2020-06-15T08:58:34Z | |
| dc.date.available | 2023-11-11T12:51:18Z | |
| dc.date.issued | 2017-04 | |
| dc.description.abstract | Expansive soils are a worldwide challenge. Straight shaft drilled pier foundation and the belled drilled pier foundation are rational and reliable solutions to combat the problem of expansive soils. The belled drilled pier foundation is especially preferred when deep depths of the swelling zone exist and large uplift forces have to be resisted. Various investigations have studied the behavior of straight shaft drilled pier foundations when they are employed in expansive soils, while very few investigations exist for belled drilled pier foundations employed in expansive soils. The only in-depth investigation concerned with the study of the behavior of belled piers in expansive soils is the elastic pier approach. Yet, this approach has limitations and is majorly focused on straight shaft piers. Concerning the design of belled piers in expansive soils, the rigid pier design method is commonly used. However, this method has limitations as well. To address the limitations of the elastic pier approach and the rigid pier design, a nite element based investigation of the behavior of belled piers in expansive soils is conducted using the nite element software Abaqus. The nite element model was validated using several mechanisms. The e ect of various parameters a ecting belled pier behavior in expansive soils was investigated. A cost comparison among di erent types of piers was conducted. Finally, trend lines that can serve as design charts were developed. The parametric investigations indicated that when designing belled piers in expansive soils increasing the shaft diameter is preferred to increasing the length or the bell size; the limiting diameter for belled piers is much higher than that for straight shaft piers; most belled piers in expansive soils in Ethiopia do not need tensile reinforcement and the applied load needed to fully eliminate tensile stresses in belled piers is less than that needed in straight shaft piers. The cost comparison indicated that for smaller values of the swelling pressure and the depth of the swelling zone, straight shaft piers are more cost e ective; while for medium to large values of the swelling pressure and the depth of the swelling zone, large bell size belled piers are more cost e ective. The trend lines indicated that in Ethiopia belled piers with the minimum possible values of the shaft diameter, base to shaft diameter ratio and length can be used. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/21590 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Expansive soils | en_US |
| dc.subject | Belled piers | en_US |
| dc.subject | Elastic pier approach | en_US |
| dc.subject | Rigid pier design | en_US |
| dc.subject | Finite element model | en_US |
| dc.subject | Parametric investigation | en_US |
| dc.subject | Cost comparison | en_US |
| dc.subject | Trend lines | en_US |
| dc.title | Finite Element Based Investigation of Belled Piers in Expansive Soils | en_US |
| dc.type | Thesis | en_US |