Investigation of the Seismic Risk of Industrial Pipe Rack - Piping Systems Accounting for Soil-Structure Interaction

2019 ◽  
Author(s):  
George Karagiannakis ◽  
Luigi Di Sarno
Keyword(s):  
Soil Structure ◽  
Soil Structure Interaction ◽  
Design Parameters ◽  
Soil Conditions ◽  
Piping System ◽  
Seismic Action ◽  
Alluvial Deposits ◽  
Nonstructural Components ◽  
Structure Interaction ◽  
Piping Systems

Abstract Earthquake events have shown that industrial pipe racks lack of a completed design framework that encompasses contemporarily a number of uncertainties such as modelling, seismic action, design and analysis procedures as well as soil conditions. That being said, the seismic behaviour of piping systems has not been assessed up to par recognizing the potential effects of nonbuilding – nonstructural components interaction as well as soil conditions that constitute a decisive parameter particularly for structures that lie on alluvial deposits. In the present work, after reviewing European and American standards and technical literature upon design parameters, the seismic reliability analysis of two pipe rack – piping systems in decoupled and coupled case considering near- and far-field records as well as soil deformability is addressed. As it is illustrated, the classic nonlinear static analysis may overestimate the resistance of racks, common limit states of interstorey drift ratio cannot be applied and the behaviour factor selection may be unjustifiable. Also, soil-structure interaction affects detrimentally the response both of rack and piping system as depicted by the fragility functions.

A Study on the Embedment Effect in the Soil-Structure Interaction Analysis of the APR1400

2002 ◽  
Author(s):  
Young-Sun Jang ◽  
Kwang-Ho Joo ◽  
Chong-Hak Kim
Keyword(s):  
Nuclear Power ◽  
Soil Structure ◽  
Interaction Analysis ◽  
Response Spectra ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Structure Interaction ◽  
Structure Response ◽  
Parametric Analyses ◽  
Volume Method

The SSI (Soil-Structure Interaction) analyses are being performed for the APR1400 (Advanced Power Reactor 1400MWe, Old name - KNGR ; Korean Next Generation Reactor) design, because the APR1400 is developed as a Standard Nuclear Power Plant concept enveloping suitable soil conditions. For the SSI analyses, SASSI program which adopts the Flexible Volume Method is used. In the SSI analyses, there can be uncertainties by Bond and De-bond problem between the structure and lateral soil elements. According to ASCE Standard 4, one method to address this concern is to assume no connectivity between structure and lateral soil over the upper half of the embedment of 20ft (6m), whichever is less. This study is performed as a part of the parametric analyses for the APR1400 seismic analyses to address the concern of the potential embedment effect on the in-structure response spectra due to connectivity between structure and lateral soil. In this study, 4 model cases are analyzed to check the potential embedment effect — Full connection, 20ft no connectivity which is defined as a minimum De-bond depth of the soil in ASCE Standard 4 and 26.5ft no connectivity between structure and lateral soil over the upper half of the embedment. Last one is full no connection for only reference. The in-structure response spectra are compared with the response spectra without considering the embedment effect.

scholarly journals Effect of Soil-Structure Interaction on the Seismic Response of Existing Low and Mid-Rise RC Buildings

2020 ◽  
Vol 10 (23) ◽  
pp. 8357
Author(s):  
Ibrahim Oz ◽  
Sevket Murat Senel ◽  
Mehmet Palanci ◽  
Ali Kalkan
Keyword(s):  
Seismic Response ◽  
Seismic Performance ◽  
Soil Structure ◽  
Soft Soil ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Existing Buildings ◽  
Structure Interaction ◽  
Fixed Base ◽  
New Buildings

Reconnaissance studies performed after destructive earthquakes have shown that seismic performance of existing buildings, especially constructed on weak soils, is significantly low. This situation implies the negative effects of soil-structure interaction on the seismic performance of buildings. In order to investigate these effects, 40 existing buildings from Turkey were selected and nonlinear models were constructed by considering fixed-base and stiff, moderate and soft soil conditions. Buildings designed before and after Turkish Earthquake code of 1998 were grouped as old and new buildings, respectively. Different soil conditions classified according to shear wave velocities were reflected by using substructure method. Inelastic deformation demands were obtained by using nonlinear time history analysis and 20 real acceleration records selected from major earthquakes were used. The results have shown that soil-structure interaction, especially in soft soil cases, significantly affects the seismic response of old buildings. The most significant increase in drift demands occurred in first stories and the results corresponding to fixed-base, stiff and moderate cases are closer to each other with respect to soft soil cases. Distribution of results has indicated that effect of soil-structure interaction on the seismic performance of new buildings is limited with respect to old buildings.

scholarly journals Soil-structure interaction effects on modal parameters of office buildings with different number of stories

2018 ◽  
Vol 219 ◽  
pp. 03001 ◽  
Author(s):  
Natalia Lasowicz ◽  
Tomasz Falborski
Keyword(s):  
Soil Structure ◽  
Interaction Effects ◽  
Office Buildings ◽  
Soil Structure Interaction ◽  
Modal Parameters ◽  
Soil Conditions ◽  
Fundamental Vibration ◽  
Shear Moduli ◽  
Structure Interaction ◽  
Soil Foundation

The paper summarizes the results of a numerical investigation designed to study the soil-structure interaction effects on modal parameters of three office buildings. The reinforced-concrete 4-storey, 8-storey, and 12-storey office buildings, each with additional two levels of embedded basements, represent low, medium, and high-rise structures, respectively. In order to conduct this research, detailed finite-element structure models were prepared. Soil-foundation flexibility was represented with the use of spring-based solutions, incorporating foundation springs and dashpots. The influence of diverse soil conditions (represented by their average effective profile velocities and shear moduli) on the dynamic characteristics of the analyzed three office buildings (e.g. fundamental vibration periods) was investigated and discussed.

Case Study: Effect of Soil-Structure Interaction and Ground Motion Incoherency on Nuclear Power Plant Structures

2009 ◽  
Author(s):  
Jim Xu ◽  
Sujit Samaddar
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Seismic Response ◽  
Ground Motion ◽  
Nuclear Power ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Structure Interaction

The soil-structure interaction (SSI) has a significant impact on nuclear power plant (NPP) structures, especially for massive and rigid structures founded on soils, such as containments. The U.S. Nuclear Regulatory Commission’s (NRC) Standard Review Plan (SRP) provides the requirement and acceptance criteria for incorporating the SSI effect in the seismic design and analyses of NPP structures. The NRC staff uses the SRP for safety review of license applications. Recent studies have indicated that ground motions in recorded real earthquake events have exhibited spatial incoherency in high-frequency contents. Several techniques have been developed to incorporate the incoherency effect in the seismic response analyses. Section 3.7.2 of Revision 3 of the SRP also provided guidance for use in the safety evaluation of seismic analyses considering ground motion spatial incoherency effect. This paper describes a case study of the SSI and incoherency effects on seismic response analyses of NPP structures. The study selected a typical containment structure. The SSI model is generated based on the typical industry practice for SSI computation of containment structures. Specifically, a commercial version of SASSI was used for the study, which considered a surface-founded structure. The SSI model includes the foundation, represented with brick elements, and the superstructure, represented using lumped mass and beams. The study considered various soil conditions and ground motion coherency functions to investigate the effect of the range of soil stiffness and the ground motion incoherency effect on SSI in determining the seismic response of the structures. This paper describes the SSI model development and presents the analysis results as well as insights into the manner in which the SSI and incoherency effects are related to different soil conditions.

Numerical Analysis of a Gravity Substructure for 5MW Offshore Wind Turbines due to Soil Conditions

2015 ◽  
Author(s):  
Min-Su Park ◽  
Youn-Ju Jeong ◽  
Young-Jun You ◽  
Du-Ho Lee ◽  
Byeong-Cheol Kim
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Soil Structure ◽  
Offshore Wind ◽  
Soil Structure Interaction ◽  
Structural Safety ◽  
Soil Conditions ◽  
Wave Forces ◽  
Offshore Wind Turbines ◽  
Structure Interaction

In order to increase the gross generation of wind turbines, the size of a tower and a rotor-nacelle becomes larger. In other words, the substructure for offshore wind turbines is strongly influenced by the effect of wave forces as the size of substructure increases. In addition, since a large offshore wind turbine has a heavy dead load, the reaction forces on the substructure become severe, thus very firm foundations should be required. Therefore, the dynamic soil-structure interaction has to be fully considered and the wave acting on substructure accurately calculated. In the present study ANSYS AQWA is used to evaluate the wave forces. The wave forces and wave run up on the substructure are presented for various wave conditions. Moreover, the substructure method is applied to evaluate the effect of soil-structure interaction. Using the wave forces and stiffness and damping matrices obtained from this study, the structural analysis of the gravity substructure is carried out through ANSYS mechanical. The structural behaviors of the strength and deformation are evaluated to investigate an ultimate structural safety and serviceability of gravity substructure for various soil conditions. Also, the modal analysis is carried out to investigate the resonance between the wind turbine and the gravity substructure.

scholarly journals Beneficial and Detrimental Effects of Soil-Structure Interaction on Probabilistic Seismic Hazard and Risk of Nuclear Power Plant

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Shinyoung Kwag ◽  
BuSeog Ju ◽  
Wooyoung Jung
Keyword(s):  
Seismic Hazard ◽  
Failure Mode ◽  
Soil Structure ◽  
Failure Modes ◽  
Soil Structure Interaction ◽  
Seismic Fragility ◽  
Soil Conditions ◽  
Response Analysis ◽  
Structure Interaction ◽  
Overall Risk

The purpose of this study is to investigate the soil-structure interaction (SSI) effect on the overall risk of a PWR containment building structure with respect to two failure modes: strength and displacement. The precise quantification of the risk within the seismic probabilistic risk assessment framework depends considerably on an accurate treatment of the seismic response analysis. The SSI effect is one of the critical factors to consider when accurately predicting structural responses in the event of an earthquake. Previous studies have been conducted by focusing more on the positive side of the SSI effects and the effects mainly on the seismic fragility result. Therefore, this paper presents the results of a study of the SSI effect on the overall risk. Also, the study relies on an emphasis on revealing a beneficial and a detrimental effect of the SSI by utilizing an example of the containment structure in three soil conditions and two main failure modes. As a result, the consideration of SSI shows a complete conflicting effect on the seismic fragility and risk results depending on two failure modes considered in this study. This has a positive effect regarding the strength failure mode, but this brings a negative effect regarding the displacement failure mode. The risk fluctuation width is particularly noticeable in the site having a considerable change in seismic hazard information such as Los Angeles on the western site of the US. Such results can be expected to be utilized in a future study for investigating the pros and cons of the SSI effect associated with various failure modes in diverse conditions.

scholarly journals Analysis of the Second Order Effect of the SSI on the Building during a Seismic Load

2021 ◽  
Vol 6 (2) ◽  
pp. 20
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Abdelhay El Omari ◽  
Mohamed Rougui ◽  
Mimoun Chourak ◽  
...  
Keyword(s):  
Soil Structure ◽  
Cohesive Soil ◽  
Order Effect ◽  
Second Order ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Seismic Load ◽  
Structure Interaction ◽  
Story Drift

The type and the properties of the soil can potentially intensify the internal forces on buildings during seismic loads. To predict the effects of the soil parameters on the soil–structure interaction of buildings, it is necessary to consider the soil–structure interaction (SSI) in the modeling process. Therefore, this document aims to evaluate the seismic effect on the maximal displacement and inter-story drift, and evaluate the behavior of buildings under the second-order effect known in the literature as the P-delta effect. For this purpose, three cases of buildings with 5, 10 and 15 stories were modelled using a FLAC 2D finite-difference element calculation software with infinite soil conditions, including five types of base with four types of soil (one cohesive soil and three non-cohesive soils) considering the soil–structure interaction and a fixed base (without soil–structure interaction). According to the results for the above-mentioned boundary, as the height of the building increases and due to the weak properties of the soil, we notice that the maximal displacements and inter-story drift increase considerably. To that purpose, we recommend considering the second-order effect in seismic design, especially for non-cohesive soil.

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.

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