scholarly journals Impact of initial stress field heterogeneity in dynamic soil–structure interaction

2021 ◽  
pp. 875529302110416
Author(s):  
Marc-Denis Rioux ◽  
Marie-José Nollet ◽  
Bertrand Galy
Keyword(s):  
Stress Field ◽  
Initial Stress ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Foundation Soil ◽  
Structure Interaction ◽  
Initial Stress Field ◽  
Geophysical Surveys ◽  
Field Heterogeneity ◽  
The Impact

This article covers the impact of soil initial stress field heterogeneity (ISFH) in wave-passage analysis and in prescribed structural acceleration in the context of dynamic soil–structure interaction (DSSI) analysis. ISFH is directly related to the natural behavior of soil where a significant increase in net effective confinement, as is the case in the foundation soil under a building, tends to increase the soil’s modulus and strain. This creates a heterogeneous stress field in the vicinity of the foundation elements, which results in a modification of the dynamic behavior of the soil–structure system. A simple method for considering the impact of ISFH on the value of the soil’s modulus and strain was developed using the direct DSSI approach. The method was used to analyze numerical artifacts and its impact on the surface acceleration values of a nonlinear two-dimensional (2D) numerical soil deposit under transient loading. This analysis was followed by a sample application for a three-story, three-bay concrete moment-resisting frame structure erected on a deep soil deposit. Floor acceleration and relative displacement were used for comparison. The soil deposit was modeled using the typical geotechnical properties of fine-grained, post-glacial soil samples obtained in Eastern Canada from in situ geotechnical borehole drilling, geophysical surveys, and laboratory testing. Ground motion was based on eastern calibrated seismic signals. The results of the soil deposit analysis show that ISFH had a significant impact on surface acceleration values. The effect was found to be period-dependent and to have a direct impact on prescribed acceleration values at the base of structure. Thus, failure to take the effects of ISFH into consideration can lead to errors in calculating prescribed structural accelerations (i.e. over- or underestimation).

Assessment of Spatial Property Variability of the Subsurface in SSI Studies of the Armenian Nuclear Power Plant

2004 ◽  
Author(s):  
Nicholas Simos ◽  
Paruyr Zadoyan ◽  
Pierre Labbe ◽  
Pierre Sollogoub ◽  
J.-Pierre Touret
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Soil Structure ◽  
Soil Layer ◽  
Soil Structure Interaction ◽  
Foundation Soil ◽  
Element Discretization ◽  
Structure Interaction ◽  
The Impact

This paper addresses issues surrounding soil property variability including uncertainties associated with “best estimate” values and searches for practical ways to assess the impact on the seismic response of a facility, such as a nuclear power plant, resting on it. Specifically, it attempts, using a parametric study, to formulate a probabilistic model that enables the enveloping of uncertainties associated with the soil-structure-interaction component of the seismic problem. The effects of most-likely sources of uncertainty, such as variability of “distinct” soil layer profile and variability of controlling soil properties, are to be addressed by generating a probabilistic profile in which randomization of key parameters that appear to have the most impact on the results of deterministic analyses is implemented. The use of stochastic finite elements and the introduction of correlation functions, in conjunction with finite element discretization of the foundation soil, are explored as means of achieving an enveloped structural response. The on-going evaluation of the Armenian nuclear plant site prompted this study. In order to stress the importance and relevance of the stated goal, the soil-structure-interaction of the nuclear power plant, subject to significant variation of the foundation soil, is examined. The conflicting results of two independent studies of the subsurface provide the basis for the variation range used in this study.

Soil-Structure Interaction in Buildings from Earthquake Records

1990 ◽  
Vol 6 (4) ◽  
pp. 641-655 ◽  
Author(s):  
Gregory L. Fenves ◽  
Giorgio Serino
Keyword(s):  
Soil Structure ◽  
Dynamic Properties ◽  
Strong Motion ◽  
Longitudinal Direction ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Foundation Soil ◽  
Soil System ◽  
Structure Interaction ◽  
Building Foundation

An evaluation of the response of a fourteen story reinforced concrete building to the 1 October 1987 Whittier earthquake and 4 October 1987 aftershock shows significant effects of soil-structure interaction. A mathematical model of the building-foundation-soil system provides response quantities not directly available from the records. The model is calibrated using the dynamic properties of the building as determined from the processed strong motion records. Soil-structure interaction reduces the base shear force in the longitudinal direction of the building compared with the typical assumption in which interaction is neglected. The reduction in base shear for this building and earthquake is approximately represented by proposed building code provisions for soil-structure interaction.

scholarly journals The Effect of Mass, Depth, and Properties of the Soil Below the Raft Foundation on the Seismic Performance of R.C. Plane Frames

2019 ◽  
Vol 9 (5) ◽  
pp. 4685-4688
Author(s):  
J. A. Alomari
Keyword(s):  
Modal Analysis ◽  
Modulus Of Elasticity ◽  
Soil Structure ◽  
Soil Mass ◽  
Seismic Excitation ◽  
Soil Structure Interaction ◽  
Foundation Soil ◽  
Structure Interaction ◽  
Raft Foundation ◽  
Soil Modulus

Soil structure interaction has been the subject of numerous studies. The foundation soil has a definite effect on the performance of structures during seismic excitation. Recent studies show that the effect of soil-structure interaction SSI may be detrimental to the structure during seismic excitation. In this study, the effect of consideration of the soil below foundation and its depth, and the soil modulus of elasticity on the response of structures is investigated. The number of mode shapes considered has an effect on the accuracy of the values of structure response. A structural model consisting of an 8-story reinforced concrete frame resting on raft foundation, and including the soil below the raft is analyzed. The frame is analyzed using SAP2000 software, and time history and modal analysis are carried out with varying values of both soil depth and soil modulus of elasticity. The soil below the foundation is connected to the raft elements by gap links. Gap element links are compression–only members with appropriate stiffness, which are active only in compression. Modal analysis results show that the periods of vibration decrease as the modulus of elasticity of the soil increases. Periods of vibration of the frame without the soil mass consideration are less than those when the soil mass below the raft is considered, and they increase with increased depth of foundation to a certain limit. The structures response in the form of columns shear forces and story displacements are also evaluated under the variable parameters considered.

Effect of Soil on the Seismic Response of Structures Taking Into Consideration Soil-Structure Interaction

2020 ◽  
Vol 11 (2) ◽  
pp. 72-90
Author(s):  
Radhwane Boulkhiout ◽  
Salah Messast
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Soil Structure ◽  
Shear Walls ◽  
Element Model ◽  
Soil Structure Interaction ◽  
Reinforced Concrete Frame ◽  
Structure Interaction ◽  
Model Soil ◽  
The Impact

The present study covers the influence of soil-structure interaction on the response of structures and civil engineering constructions under seismic excitation. The response of the structures being studied was evaluated, first, using a perfectly embedded structure at the base. Then, using two different models to model soil-structure contact, the finite element model and a rheological model (springs and dampers) in order to illustrate the impact of soil type behavior on structure response was considered based on periods, displacements, and stresses. On the other hand, the effect of superstructure type and its stiffness on the seismic response will be determined, first, using a reinforced concrete frame with shear walls and, second, using a girder bridge. Finally, in each model mentioned above, a parametric study was conducted to better understand the dynamic behavior of the analyzed structure. As for modelling by finite element method, the study was achieved using SAP2000 code.

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.

Performance of a raft foundation supporting a multistorey structure

1988 ◽  
Vol 25 (1) ◽  
pp. 138-149 ◽  
Author(s):  
A. O. Landva ◽  
A. J. Valsangkar ◽  
J. C. Alkins ◽  
P. D. Charalambous
Keyword(s):  
Soil Structure ◽  
Thick Layer ◽  
Field Testing ◽  
Soil Structure Interaction ◽  
Foundation Soil ◽  
Structure Interaction ◽  
Raft Foundation ◽  
Undisturbed Samples ◽  
Clayey Silt ◽  
Load Cells

A nine-storey structure was recently constructed on a raft founded on a 30 m thick layer of clayey silt at Fredericton, New Brunswick. Detailed soil investigations included conventional borings and self-boring pressuremeter, field vane, and flat dilatometer tests performed at the site. In addition to the field testing, undisturbed samples were obtained and tested in the laboratory to determine the compressibility and shear strength characteristics. To compare the performance of the foundation with the design assumptions, instrumentation consisting of piezometers, contact pressure load cells, and settlement points was installed. The instrumentation was monitored at regular intervals during the construction stage and at 6 month intervals following the completion of the building. This report presents (i) the results of the field and laboratory testing, (ii) the results of the field monitoring, and (iii) the results of a finite element computer analysis of the foundation-soil interaction. Key words: raft foundation, instrumentation, clayey silt, compressibility, soil tests, soil–structure interaction.

scholarly journals The ratio of response spectra from seismic-type free-field and building foundation vibrations: the influence of rockburst parameters and simple models of kinematic soil-structure interaction

2019 ◽  
Vol 18 (3) ◽  
pp. 907-924 ◽  
Author(s):  
Krystyna Kuzniar ◽  
Tadeusz Tatara
Keyword(s):  
Soil Structure ◽  
Epicentral Distance ◽  
Free Field ◽  
Response Spectra ◽  
Soil Structure Interaction ◽  
Ground Acceleration ◽  
Structure Interaction ◽  
Building Foundation ◽  
Mining Tremors ◽  
The Impact

Abstract Mining-related seismicity is a significant problem in regions with the exploitation in underground mines. Despite the fact that mining tremors result from human activity and are classified as so-called paraseismic shocks, as with earthquakes, they are random events. Moreover, these rockbursts could cause significant damage to surface structures, including buildings. This paper deals with the analysis of experimentally obtained results in terms of the differences between the mine-induced vibrations described by the response spectra from the free-field near a given building and the simultaneously recorded vibrations in the building foundations. The influences of epicentral distance, mining tremor energy and the value of peak ground acceleration on the curves of free-field—foundation response spectra ratio were studied. The impact of the type of building on the transmission of response spectra from the free-field vibrations to the building foundations was also analysed for three types of apartment buildings (low-rise, medium-rise, high-rise). The usefulness of the approximate models of the phenomenon of soil-structure interaction during earthquakes proposed in the literature is also estimated in this paper in specific instances of mining tremors. Furthermore, the study presents original, simple, empirical models for the evaluation of the differences in the response spectra originating from free-field and building foundation vibrations in the mining region.

Methodology for Assessing Shock Effect due to Aircraft Impact Considering the Nonlinear of Impact Zone and Soil-Structure Interaction

2017 ◽  
Author(s):  
Yugang Sun ◽  
Shujian Cheng ◽  
Honghui Ge ◽  
Xiaowen Wang ◽  
Fang Yuan ◽  
...  
Keyword(s):  
Linear Model ◽  
Soil Structure ◽  
Response Spectra ◽  
Material Nonlinearity ◽  
Soil Structure Interaction ◽  
Impact Zone ◽  
Structure Interaction ◽  
Shock Response ◽  
Two Factors ◽  
The Impact

Based on the shock damage propagation distances and the median fragility limit of the equipments, the NEI 07–13 employs the shock damage rules for determining the potential for affecting safe shutdown and fuel cooling equipments. However, the NEI 07–13 does not provide more detailed guidance for performing the shock damage assessments, because both the shock damage distances and the methodology for developing the median fragility limit are not provided in NEI 07–13. This paper discussed methodology developed for performing simplified assessments for shock effects considering the material nonlinearity of the impact zone and the soil-structure interaction. Three different models (i.e., linear model, nonlinear mode, and SSI model) were developed to calculate the in-structure shock response. The results of the linear model show the shock response due to aircraft impact would completely propagate from the center of initial impact zone and then along a structure pathway (e.g. wall, floor, basemat) to the in-structure without any energy dissipation. As a result, the in-structure shock response spectra are considerably higher than the spectra associated with the design-basis earthquake in the high frequency range. In order to reduce the shock effects on the in-structure safety-related systems and equipments, the material nonlinearity of the impact zone and the soil-structure interaction were incorporated in the dynamic analysis. The numerical results show that both the material nonlinearity and the soil-structure interaction would obviously absorb the energy of the shock waves, so the in-structure shock response spectra were reduced due to these two factors. Finally, the representative shock response spectra were compared with those used in the seismic margin assessment in order to assess specific equipment survival.

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