1. TopicDYNAMIC HORIZONTAL AND VERTICAL STIFFNESSES OF CAISSON FOUNDATIONS IN HOMOGENOUS SOIL ADVISOR: Prof. Dr. Shahid Ahmad Committee Member: Prof. Dr. Sabanayagam Thevanayagam

2. Objective To determine the horizontal and vertical stiffness and damping coefficients for caissons.

4. Diameter Range: 2-12 feet.

5. Depth to Dia ratio: 0.5-4Uses: Bridge foundation elements Foundation components of transmission towers Foundations at marine sites

6. D B Caisson Schematic Diagram of circular Caisson.

8. Varun et al. (2009) Lateral Response of Caissons, D/B=1-6.

10. S. Ahmad, A.K. Rupani (1999) Horizontal impedance of square foundation in layered soil

11. P. K. Pradhan et al (2004) presented vertical dynamic response of foundation using Cone Model

13. Artur Pais and Kausel (1988) Approximate formulas for dynamic stiffness’s of rigid foundations.

14. H. L. Wong and J. E. Luco (1985) Tables of impedance functions for square foundations on layered media.

16. Shear Wave Velocity, Vs=1

17. Radius of Caisson, B=1

19. . Surface Foundation Boundary Element Discretization (soil-foundation interface)

20. . Convergence study on free surface discretization for surface foundation

21. . Convergence study on free surface discretization for caisson, D/B=6

22. RESULTS, COMPARISON AND DISCUSSIONS Horizontal Static Stiffness of caissons.

23. . Vertical Static Stiffness of caissons

24. . Surface Foundation

25. . Embedded Foundation of D/B=1, Vertical stiffness

26. . Caissons vertical stiffness at different D/B ratio’s.

27. . Embedded Foundation, D/B=2.

28. . Caissons of D/B=4, Horizontal Stiffness.

29. . Caissons of D/B=6, Horizontal Stiffness.

30. . Caissons of D/B=8, Horizontal Stiffness.

31. Conclusion Results for vertical and horizontal stiffness and damping coefficients are available in layered and non-homogeneous media. The results were taken over homogeneous half-space and compared with available results. Thanks