DESIGN OF FOUNDATIONS WITH MODULUS OF SUBGRADE REACTION
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2015
Thesis Language: Turkish
Student: BURHAN AVCI
Supervisor: Ayhan Gürbüz
Open Archive Collection: AVESIS Open Access Collection
Abstract:
To perform foundation design with structural analysis programs currently used, modulus of subgrade reaction is required. In our country and in the world, to determine the modulus of subgrade reaction, literature studies and plate loading test results are utilized. In the scope of literature studies, modulus of subgrade reaction values are tabulated with respect to the type of soil and exhibit variance within a wide range. It is important to be careful while using this method due to the fact that the modulus of subgrade reaction values are found for a very wide range. Since the plate load test has extremely shallow impact depth, the modulus of subgrade reaction obtained through this method should be merely used for the design of shallow foundations. Furthermore, the modulus of subgrade reaction values found using the plate loading tests should be corrected depending upon the dimensions of the foundation. In this study, data obtained through measured plate loading tests is compared to the load – displacement curves found by means of finite elements method and thereafter, reverse analysis is conducted by modifying the modulus of elasticity to capture curves which provides the best results. As a result of such reverse analyses, it is observed that the soils with same friction angles may possess variable modulus of elasticity. Accordingly, it is concluded, in terms of the modulus of subgrade reaction which tends to decrease depending on the displacement, that it will be more efficient approach to use correlations developed on the basis of foundation depth, internal friction angle of the soil, and modulus of elasticity of the soil, while designing the foundation.
Key Words : Subgrade reaction, plate load test, foundation load tes