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

2014 ◽  
Vol 42 (4) ◽  
pp. 905-930
Author(s):  
Shehata E Abdel Raheem ◽  
Mohamed M. Ahmed ◽  
Tarek M.A. Alazrak
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Interaction Effects ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Raft Foundation

Seismic Response of Multistoried Building with Different Foundations Considering Interaction Effects

2018 ◽  
Vol 877 ◽  
pp. 276-281
Author(s):  
Shreya Sitakant Shetgaonkar ◽  
Purnanand Savoikar
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Response Spectrum ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Foundation Soil ◽  
Soil Medium ◽  
Structure Interaction ◽  
Raft Foundation ◽  
Fixed Base

Current seismic design practice assumes the base of the building to be fixed and does not consider the flexibility of foundation and soil. This assumption is realistic only when the structure is founded on solid rock or when the relative stiffness of the foundation soil compared to the superstructure is high. Whereas, in reality due to natural ability of soil to deform, supporting soil medium modifies the response of the structure during earthquake to some extent. In this work the effect of soil structure interaction on seismic response of building resting on different types of foundation was studied. Present work aims to study the effect of soil structure interaction on seismic response of building resting on fixed base, pile foundation, raft foundation and combined pile-raft foundation. G+9 RCC building is analyzed for earthquake loads considered in zone III by response spectrum method and storey displacement and base shear force of building by considering and without considering SSI effect is found out by using MIDAS GEN software.

Influence of Foundation Type on Seismic Performance of Buildings Considering Soil–Structure Interaction

2016 ◽  
Vol 16 (08) ◽  
pp. 1550043 ◽  
Author(s):  
Aslan S. Hokmabadi ◽  
Behzad Fatahi
Keyword(s):  
Seismic Response ◽  
Pile Foundation ◽  
Soil Structure ◽  
Soft Soil ◽  
Shallow Foundation ◽  
Shaking Table ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Raft Foundation ◽  
Different Types

In selecting the type of foundation best suited for mid-rise buildings in high risk seismic zones, design engineers may consider that a shallow foundation, a pile foundation, or a pile-raft foundation can best carry the static and dynamic loads. However, different types of foundations behave differently during earthquakes, depending on the soil–structure interaction (SSI) where the properties of the in situ soil and type of foundation change the dynamic characteristics (natural frequency and damping) of the soil–foundation–structure system. In order to investigate the different characteristics of SSI and its influence on the seismic response of building frames, a 3D numerical model of a 15-storey full-scale (prototype) structure was simulated with four different types of foundations: (i) A fixed-based structure that excludes the SSI, (ii) a structure supported by a shallow foundation, (iii) a structure supported by a pile-raft foundation in soft soil and (iv) a structure supported by a floating (frictional) pile foundation in soft soil. Finite difference analyzes with FLAC3D were then conducted using real earthquake records that incorporated material (soil and superstructure) and geometric (uplifting, gapping and [Formula: see text] effects) nonlinearities. The 3D numerical modeling procedure had previously been verified against experimental shaking table tests conducted by the authors. The results are then presented and compared in terms of soil amplification, shear force distribution and rocking of the superstructure, including its lateral deformation and drift. The results showed that the type of foundation is a major contributor to the seismic response of buildings with SSI and should therefore be given careful consideration in order to ensure a safe and cost effective design.

scholarly journals SOIL-RAFT FOUNDATION-STRUCTURE INTERACTION EFFECTS ON SEISMIC PERFORMANCE OF MULTI-STORY MRF BUILDINGS

2014 ◽  
Vol 6 (2) ◽  
pp. 43-61 ◽  
Author(s):  
Shehata E. Abdel Raheem ◽  
Mohamed M. Ahmed ◽  
Tarek M. A. Alazrak
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Response Spectrum ◽  
Design Procedure ◽  
Time History ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Fe Model ◽  
Structure Interaction ◽  
Raft Foundation

Recent studies show that the effects of Soil Structure Interaction (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. 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 Finite Element (FE) 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.

scholarly journals Seismic analysis of a highway bridge considering soil-structure interaction effects

1979 ◽  
Vol 12 (4) ◽  
pp. 305-313
Author(s):  
Toshio Iwasaki ◽  
Kazuhiko Kawashima
Keyword(s):  
Seismic Response ◽  
Natural Frequency ◽  
Soil Structure ◽  
Soft Soil ◽  
Ground Surface ◽  
Highway Bridges ◽  
Interaction Effects ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Fundamental Natural Frequency

In analyzing seismic behaviour of highway bridges constructed on soft soil deposits, it is important to take account of soil-structure interaction effects. In this paper, seismic response of a bridge pier-foundation is investigated based on earthquake acceleration records measured simultaneously on the pier crest and on the ground surface near that bridge. Four motions were used in the analysis, i.e., two were induced by two earthquakes with magnitudes of 7.5 and 6.6, respectively; and two by their aftershocks. In the former two earthquakes, the maximum accelerations were 186 and 438 gals on the ground surface, and 310 and 230 gals on the pier top, respectively. Analyses of frequency characteristics of the motions showed that the predominant frequencies of pier-foundation were always approximately identical with the fundamental natural frequency of the subsoil. Analyses of micro-tremors measured at the sites revealed that the natural frequency of the pier-foundation system is higher than the fundamental natural frequency of the subsoil. Analytical models were formulated to calculate the seismic response of the pier-foundation assuming the subsoil and pier-foundation to be a shear column model with an equivalent linear shear modulus and an elastically supported beam on the subsoil, respectively. Bedrock motions were computed from the measured ground surface motions and then applied to the bedrock of the analytical model. The seismic responses of pier-foundation were thus calculated and compared with the measured records giving a good agreement.

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