Soil-Structure Interaction Effects on Seismic Response of multi-story Buildings on Raft Foundation

Abstract

The investigation on the energy transfer mechanism from soils to buildings during earthquakes is critical for the design of earthquake resistant structures and for upgrading existing structures. Thus the need for research into Soil-Structure Interaction (SSI) problems is greater than ever. Moreover, recent studies show that the effects of SSI may be detrimental to the seismic response of structure and neglecting SSI in analysis may lead to un-conservative design. Despite this, the conventional design procedure usually involves assumption of fixity at the base of foundation neglecting the flexibility of the foundation, the compressibility of soil mass and consequently the effect of foundation settlement on further redistribution of bending moment and shear force demands. Hence the soil-structure interaction analysis of multi-story buildings is the main focus of this study; the effects of SSI are analyzed for typical multi-story building resting on raft foundation. Three methods of analysis are used for seismic demands evaluation of the target moment resistant frame buildings: equivalent static load (ESL); response spectrum (RS) methods and nonlinear time history (TH) analysis with suit of nine time history records. Three-dimensional FEM model is constructed to analyze the effects of different soil conditions and number of stories on the vibration characteristics and seismic response demands of building structures. Numerical results obtained using soil structure interaction model conditions are compared to those corresponding to fixed-base support conditions. The peak responses of story shear, story moment, story displacement, story drift, moments at beam ends, as well as force of inner columns are analyzed. The analysis results of different approaches are used to evaluate the advantages, limitations, and ease of application of each approach for seismic analysis.

The Effect of Soil-Structure Interaction (SSI) on Structural Stability and Sustainability of RC Structures

“…Owners and insurance companies are very concerned about earthquake-related losses because large earthquakes cause a lot of social disruption and death [44]. Another significant phenomenon that was the subject of numerous research analyses has been the SSI impact on the seismic reaction of structures [45]. Building foundations frequently rely on soil, making them flexible bases.…”

Análisis comparativo en la respuesta lineal de sistemas estructurales muro-pórtico representativos de Bucaramanga incorporando interacción suelo estructura

“…Al considerar la flexibilidad de la base en los sistemas estructurales ED1 -ED9, se observó un aumento en los periodos fundamentales, como se ha encontrado en estudios similares [41]. Así mismo, estos periodos superaron los valores máximos recomendados por la norma (NSR-10 [5]), con la excepción del modelo ED7 (12 pisos sobre suelo C), como se muestra en la Figura 6.…”