Abstract
Soil structure interaction can significantly affect the behavior of buildings subjected to seismic attacks, wind excitation, and other dynamic loading types. Different researches were developed in the last decade demonstrating the importance of taking account of soil properties and its effect in changing the behavior of the structures. It is common practice to analyze the structures assuming a fixed base, but this approach is not appropriate for the reason that neglecting the soil parameters such as the stiffness and the damping affect the behavior of the structure. Therefore, the nonlinear static approach provided the nonlinear response behavior of a structure for different types of soil. In this chapter, the authors will discuss some proposed methods in taking account of soil-structure interaction that must be considered from the very beginning of the design process and its impact on the structural behavior optimization by adding springs and dashpots to reproduce the soil behavior.
TopModelization Of Soil Structure Interaction
Understanding of SSI principles varies widely across both the structural and geotechnical engineering disciplines. Most structural engineers can appreciate that SSI effects are more pronounced in soft soils, and many are aware that foundation input motions can differ from free-field ground motions.
Current methods of SSI analysis can be classified according to the choice of surface surrounding the basement in the soil that divides the soil-structure model into two parts: the external part and the internal part.
Nowadays, there exist two main methods for SSI problems: Direct and Substructure approaches, and to understand them, let us start with basic definitions.
Key Terms in this Chapter
Capacity Curve: Curves generated by exposing a detailed structural model to one or more lateral load patterns and then increasing the magnitude of the total load to generate a nonlinear inelastic force-deformation relationship for the structure at a global level.
Dashpot: Is a mechanical device, a damper that resists motion via viscous friction.
Free Field Ground Motion: Motions that are not affected by structural vibrations or the scattering of waves at and around the foundation.
Fixed Base: A combination of rigid foundation elements on a rigid base.
Soil-Structure Interaction: Is a term that describes the effect and the stress exchanging between the soil and the structure.
Radiation Damping: Damping associated with wave propagation into the ground away from the foundation.
Impedance Functions: Represents the frequency dependent stiffness and damping characteristics of soil foundation interaction.