Soil structure interaction

About: Soil structure interaction is a research topic. Over the lifetime, 3653 publications have been published within this topic receiving 48890 citations.

Influence of soil heterogeneity on load redistribution and settlement of a hyperstatic three-support frame

Abstract: Spatial and geometrical variability of mechanical soil properties can induce differential settlements and load redistribution in hyperstatic structures. Therefore damage prevention requires specific attention to be paid to the global mechanisms of soil–structure interaction. A reduced-scale model of a hyperstatic three-support frame (scale 1:100) is installed on the CEA-CESTA centrifuge, up to 100g. Various configurations are studied, with different loadings, different structural stiffnesses, and different geometries of the soil layer. Strain gauges are fixed at various points so as to enable the retro-analysis of all components of forces at free ends. Displacements are recorded at several points on the structure and on the free surface. A numerical model of the frame (based on beam theory with elastic supports) is calibrated, first to determine an equivalent support stiffness, and second to quantify the effect of variations of the structural stiffness/soil modulus ratio on the structural response. A prob...

Effects of nonlinear soil–structure interaction on the seismic response of structure-TMD systems subjected to near-field earthquakes

Abstract: The present investigation illustrates the performance of structure-Tuned Mass Damper (TMD) system to suppress the excessive vibration of structure buildings subjected to near-field ground motions involving the nonlinear effects of three dimensional soil–structure interaction (SSI). Accordingly, three medium-to-high-rise controlled structures based on a shallow mat foundation located on soft to very dense soil are examined. The ground motion database compiled for nonlinear time history (NTH) analyses of the soil–structure-TMD systems consists of an ensemble of 52 near-field ground motions. Comparisons are made in terms of maximum inter-story drift ratio as well as maximum inter-story acceleration ratio for the three possible conditions of the foundation: fixed-base structure, linear SSI (LSSI) and nonlinear SSI (NLSSI). The seismic responses of building structures are studied under the variation of key parameters such as peak ground velocity, factor of safety against vertical load bearing of the foundation (FS), non-dimensional frequency (a 0), ground motion characteristic and number of stories. On the one hand, the results indicate that the nonlinear effects of SSI significantly modify the structural responses in comparison with the LSSI counterpart. On the other hand, soil failure decreases the effectiveness of TMD. In a more precise view, it can be demonstrated that installing TMD can suppress the response of structures with linear SSI and without SSI (fixed-base structure) more significantly than that of structures considering NLSSI. Consequently, the responses would generally be underestimated if a linear behavior of the soil is assumed.

Static analysis of Timoshenko beam resting on elastic half-plane based on the coupling of locking-free finite elements and boundary integral

Abstract: Making use of a mixed variational formulation including the Green function of the soil and assuming as independent fields both the structure displacements and the contact pressure, a finite element (FE) model is derived for the static analysis of a foundation beam resting on elastic half-plane. Timoshenko beam model is adopted to describe structural foundations with low slenderness and to impose displacement compatibility between beam and half-plane without requiring the continuity of the first order derivative of the surface displacements enforced by Euler–Bernoulli beam. Numerical results are obtained by using locking-free Hermite polynomials for the Timoshenko beam and constant reaction over the soil. Foundation beams loaded by many load configurations illustrate accuracy and convergence properties of the proposed formulation. Moreover, the different behaviour of the Euler–Bernoulli and Timoshenko beam models is thoroughly discussed. Rectangular pipe loaded by a force in the upper beam exemplifies the straightforward coupling of the foundation FE with a structure described by usual FEs.

Effect of vertical component of an earthquake on steel frames considering soil-structure interaction

Abstract: The present study investigated the effects of vertical components of earthquakes on the responses of 5, 15, and 25 story steel frames by taking into account Soil-Structure Interaction (SSI). The frames were modeled on a fixed base and simulated using two shear waves velocities for the soil (100 and 250 m/s according to NEHERP soil code types E and D soils) using a cone model. The nonlinear behavior of the frames was investigated in the presence and absence of the vertical component of an earthquake and the effects of SSI were examined by comparing the results of the latter analysis with and without use of the cone model. The results showed that the vertical component and SSI can increase the axial force on columns by nearly 50%, the vertical displacement of the mid-point of the beams by nearly two-fold, drift of the stories by nearly 40%, and foundation rotation. Story shear was less affected. When soil type E and soil type D were compared, it was found that the effect of the vertical component of earthquakes on the dynamic response of the frames was generally significant.