kth.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Numerical modelling considerations for analysis of concrete hydraulic structures subjected to high-frequency seismic loads
KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
2023 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Concrete hydraulic structures are of great importance in today's society. When situated in areas with hard bedrock, these structures may become extra vulnerable to seismic excitations as these here are dominated by high-frequency vibrations which can have disastrous consequences for slender structures. The aim of this thesis was to investigate special considerations that must be made when conducting analyses of such hydraulic structures during high-frequency excitations. Underground and on the ground structures were investigated separately. Underground concrete pipelines and concrete buttress dams were selected for the study because their behaviour when exposed to seismic excitations is dominated by their stiffness. The most effective models and modelling methods for the seismic analyses of such structures were implemented and evaluated. Two-dimensional finite element (FE) models were developed for the dynamic analysis of underground concrete pipelines loaded by seismic waves propagating from bedrock through soil. The interaction between the bedrock and the surrounding soil was investigated with respect to rock geometry and soil properties. The surface of dam foundations is commonly irregular, resulting in nonuniform motions at the dam-foundation interface. The free-field modelling methods for concrete dam foundations were adapted in order to accurately describe the propagation of earthquake vibrations from the source to the ground surface. The implementation of a threedimensional FE model for concrete buttress dams was investigated. Two different methods for free-field modelling are presented, which can be implemented independently of the software used. The seismic loads are applied as effective earthquake forces at non-reflecting boundaries. In the first method, the free-field motions at the non-reflecting boundaries are determined by the so-called domain reduction method using the direct FE calculation. In the second method, the free-field motions are analytically determined based on the onedimensional wave propagation theory. The results are also compared with the massless foundation modelling approach, in which the topographical amplifications are neglected. It was demonstrated that a two-dimensional model can effectively account for pipeline behaviour. The most important aspect of the models is the ability to capture bending deformations, as segmented structures such as pipelines are vulnerable in this respect. Nonuniform bedrock reduces the safety of concrete pipeline, especially because of bending deformations in the pipe and joints. The massless method gave unreliable results for analyses of dams, especially for high-frequency excitations. The analytical method was also unreliable in estimating the non-linear behaviour of the dams. But, a new time domain deconvolution method was developed to transform the earthquake motion from the foundation surface to the corresponding input motion at depth. It wasfound that free-field modelling of foundations using the direct FE method can accurately capture the topographic amplifications of the seismic excitations. It was shown that a three-dimensional model is required for seismic evaluation of concrete buttress dams. The topographic amplification of high-frequency waves at the surface of canyons had a significant effect on the response of this type of dam. 

Abstract [sv]

Betongkonstruktioner för vattenkraft och vattenförsörjning är av stor betydelse för dagens samhällen. I områden med hård berggrund kan dessa konstruktioner vara särskilt känsliga för seismiska händelser då de domineras av höga frekvenser, vilket kan leda till katastrofala konsekvenser för slanka konstruktioner. Syftet med föreliggande avhandling var att undersöka överväganden och antaganden som måste göras vid analyser av sådana strukturer för vattenkraft och vattenförsörjning vid excitationer med högre frekvenser. Strukturer under jord och på markytan undersöktes separat. Underjordiska rörledningar och lamelldammar av betong valdes till studien eftersom de vid seismiska excitationer domineras av deras styvhet. De mest effektiva modellerna och modelleringsmetoderna för de seismiska analyserna av sådana strukturer implementerades och utvärderades. Tvådimensionella finita element (FE) modeller utvecklades för dynamisk analys av underjordiska rörledningar av betong utsatta för seismiska vågor som utbreder sig från berggrunden och genom jordlager. Samspelet mellan berggrunden och den omgivande marken undersöktes med avseende på bergets geometri och markegenskaperna. Bergytan hos dammfundament är vanligtvis oregelbunden, vilket resulterar i ojämna rörelser vid gränsytan mellan damm och grundläggning. Modelleringsmetoderna med fria fält för betongdammars berggrundläggning har här anpassats för att korrekt beskriva utbredningen av jordbävningsvibrationer frånvibrationscentrum till markytan. Implementeringen av en tredimensionell FE-modell för betonglamelldammar undersöktes. Två olika metoder för frifältsmodellering presenteras, vilka kan användas oberoende av aktuell programvara. De seismiska belastningarna appliceras som effektiva jordbävningskrafter vid icke-reflekterande materialgränser. Med den första metoden bestäms de fria fältens rörelser vid de icke-reflekterande gränserna genom den så kallade domänreduktionsmetoden, med direkt FE-beräkning. I den andra metoden bestäms frifältsrörelserna analytiskt utifrån teorin om endimensionell vågutbredning. Resultaten jämförs också med metoden för modellering med antagen masslös undergrund, där de topografiska förstärkningarna försummas. Det visades att en tvådimensionell modell effektivt kan redogöra för rörledningarnas beteende. Den viktigaste aspekten av modellerna är förmågan att beskriva böjdeformationer, eftersom segmenterade strukturer såsom rörledningar är sårbara i detta avseende. Ojämn berggrund minskar säkerheten för betongrörledningar, särskilt på grund av böjdeformationer i rör och fogar. Metoden som ej beaktade undergrundens massa gav opålitliga resultat vid analys av dammar, speciellt vid högfrekventa excitationer. Den analytiska metoden var också opålitlig när det gäller att uppskatta dammars icke-linjära beteende. Men, en ny metod med konvolution i tidsdomänen utvecklades för att omvandla jordbävningens rörelse från grundläggningsytan till motsvarande rörelse på djupet. Det framkom att modellering av fria fält för grundläggningen med den direkta FE-metoden exakt kan beskriva de topografiska förstärkningarna av de seismiska excitationerna. Det visades att en tredimensionell modell krävs för seismisk utvärdering av betonglamelldammar. Den topografiska förstärkningen av högfrekventa vågor vid markytan hos dalgångar hade en betydande effekt på responsen hos denna typ av damm. 

Place, publisher, year, edition, pages
Stockholm: Kungliga Tekniska högskolan, 2023. , p. 115
Series
TRITA-ABE-DLT ; 231
National Category
Civil Engineering
Research subject
Civil and Architectural Engineering, Concrete Structures
Identifiers
URN: urn:nbn:se:kth:diva-323972ISBN: 978-91-8040-447-1 (print)OAI: oai:DiVA.org:kth-323972DiVA, id: diva2:1737539
Public defence
2023-04-06, Kollegiesalen, Brinellvägen 8, KTH Campus, https://kth-se.zoom.us/j/67698390917, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC230224

Available from: 2023-02-24 Created: 2023-02-17 Last updated: 2023-02-24Bibliographically approved
List of papers
1. Analysis of shallowly buried reinforced concrete pipelines subjected to earthquake loads
Open this publication in new window or tab >>Analysis of shallowly buried reinforced concrete pipelines subjected to earthquake loads
2014 (English)In: Nordic Concrete Research, ISSN 0800-6377, no 51, p. 111-130Article in journal (Refereed) Published
Abstract [en]

Buried reinforced concrete pipelines are widelyused in e.g. water and wastewater systems. Failure of these infrastructures mayresult in drastic effects and recently they have been brought into focus asvital components in safety systems for nuclear power installations. The highlevel of safety has here lead to a demand for reliable earthquake risk analyses.In this paper, methods are compared and the use of seismic design loadsdemonstrated. FE analysis in 2D of soil-pipe interaction under seismic wavepropagation is performed. The performance of concrete pipes subjected toseismic waves with different frequency content is evaluated with respect todifferent soil condition but also water mass effect.

National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-159224 (URN)
Note

QC 20150128

Available from: 2015-01-26 Created: 2015-01-26 Last updated: 2024-03-15Bibliographically approved
2. Seismic response of large diameter buried concrete pipelines subjected to high frequency earthquake excitations
Open this publication in new window or tab >>Seismic response of large diameter buried concrete pipelines subjected to high frequency earthquake excitations
2020 (English)In: Int. J. Structural Engineering, ISSN 1758-7328, Vol. 10, no 4, p. 307-329Article in journal (Refereed) Published
Abstract [en]

Buried pipelines are tubular structures that cross large areas with different geological conditions. During an earthquake, imposed loads from soil deformations on pipelines may cause drastic damages. In this study two dimensional finite element models of pipelines and surrounding soils are usedfor simulation of seismic waves that propagate from the bedrock through thesoil. The models describe both longitudinal and transverse cross-sections ofpipelines and the soil-pipe interaction is described as a nonlinear behaviour.The effects of uniform ground with different burial depth and soil layer thickness, soil stiffness and non-uniform ground on the seismic response of reinforced concrete pipelines is studied. Two earthquakes, with high and low frequency contents, are employed for the dynamic analysis. The results show asignificant effect on the response due to non-uniform ground caused by inclined bedrock, especially for high frequency earthquake excitations.

Keywords
buried pipelines; high frequency; finite element; seismic analysis; non-uniform ground; soil stiffness
National Category
Infrastructure Engineering
Identifiers
urn:nbn:se:kth:diva-282856 (URN)10.1504/IJSTRUCTE.2020.109854 (DOI)000937868000002 ()2-s2.0-85092276421 (Scopus ID)
Note

QC 20201019

Available from: 2020-10-01 Created: 2020-10-01 Last updated: 2023-09-21Bibliographically approved
3. Implementation of free-field modelling of foundations for large dam structures exposed to high-frequency vibrations
Open this publication in new window or tab >>Implementation of free-field modelling of foundations for large dam structures exposed to high-frequency vibrations
(English)In: Article in journal (Refereed) Submitted
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-323971 (URN)
Note

QC 20230221

Available from: 2023-02-17 Created: 2023-02-17 Last updated: 2023-02-21Bibliographically approved
4. Non-linear Behavior of a Concrete Gravity Dam During Seismic Excitation: A Case Study of the Pine Flat Dam
Open this publication in new window or tab >>Non-linear Behavior of a Concrete Gravity Dam During Seismic Excitation: A Case Study of the Pine Flat Dam
2021 (English)In: Numerical Analysis of Dams: Proceedings of the 15th ICOLD International Benchmark Workshop, Springer Nature , 2021, p. 99-112Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, seismic analyses of Pine Flat Concrete dam performed as part of theme A in the 15th benchmark workshop are presented. The results presented focuses on differences between mass and massless foundation and the influence from non-linear material behavior. The analyses performed with mass foundation using analytical free field input records and infinite boundary elements corresponded with the expected free surface results, for lower frequencies. For higher frequencies some discrepancies caused by the influence from the dam and the reservoir as expected. The corresponding analyses with massless foundation showed significantly higher accelerations but good agreement with the expected free surface displacement at the dam toe. To consider the influence from nonlinear material behavior, a dynamic push-over analysis (endurance time acceleration function, ETAF) was performed. It was possible to perform the analysis for the full duration of the record, despite significant non-linear material behavior. The initial damage occurred at the upstream toe and then showed significant induced damage as the level of excitation successively increased. In the end of the analysis, the top of the dam is cracked through which would cause an instability failure of the top of the dam.

Place, publisher, year, edition, pages
Springer Nature, 2021
Series
Lecture Notes in Civil Engineering, ISSN 2366-2557 ; 91
Keywords
Concrete dam, Cracking, Free field boundary conditions, Non-linear analyses, Seismic analyses, Concrete dams, Concretes, Gravity dams, Numerical analysis, Seismology, Concrete gravity dams, Higher frequencies, Infinite boundary element, Lower frequencies, Nonlinear behavior, Nonlinear material behavior, Push-over analysis, Seismic excitations, Reservoirs (water)
National Category
Geotechnical Engineering
Identifiers
urn:nbn:se:kth:diva-291372 (URN)10.1007/978-3-030-51085-5_2 (DOI)2-s2.0-85096565004 (Scopus ID)
Conference
ICOLD International Benchmark Workshop on Numerical Analysis of Dams, ICOLD-BW, 9-11 September, Milan, Italy
Note

QC 20210409

Available from: 2021-04-09 Created: 2021-04-09 Last updated: 2023-02-17Bibliographically approved
5. Nonlinear Behaviour of Concrete Buttress Dams under High-Frequency Excitations Taking into Account Topographical Amplifications
Open this publication in new window or tab >>Nonlinear Behaviour of Concrete Buttress Dams under High-Frequency Excitations Taking into Account Topographical Amplifications
2021 (English)In: Shock and Vibration, ISSN 1070-9622, E-ISSN 1875-9203, Vol. 2021, p. 1-22Article in journal (Refereed) Published
Abstract [en]

Concrete buttress dams could potentially be susceptible to high-frequency vibrations, especially in the cross-stream direction, due to their slender design. Previous studies have mainly focused on low-frequency vibrations in stream direction using a simplified foundation model with the massless method, which does not consider topographic amplifications. This paper therefore investigates the nonlinear behaviour of concrete buttress dams subjected to high-frequency excitations, considering cross-stream vibrations. For comparison, the effect of low-frequency excitations is also investigated. The influence of the irregular topography of the foundation surface on the amplification of seismic waves at the foundation surface and thus in the dam is considered by a rigorous method based on the domain-reduction method using the direct finite element method. The sensitivity of the calculated response of the dam to the free-field modelling approach is investigated by comparing the result with analyses using an analytical method based on one-dimensional wave propagation theory and a massless approach. Available deconvolution software is based on the one-dimensional shear wave propagation to transform the earthquake motion from the foundation surface to the corresponding input motion at depth. Here, a new deconvolution method for both shear and pressure wave propagation is developed based on an iterative time-domain procedure using a one-dimensional finite element column. The examples presented showed that topographic amplifications of high-frequency excitations have a significant impact on the response of this type of dam. Cross-stream vibrations reduced the safety of the dam due to the opening of the joints and the increasing stresses. The foundation modelling approach had a significant impact on the calculated response of the dam. The massless method produced unreliable results, especially for high-frequency excitations. The free-field modelling with the analytical method led to unreliable joint openings. It is therefore recommended to use an accurate approach for foundation modelling, especially in cases where nonlinearity is considered.

Place, publisher, year, edition, pages
Hindawi Limited, 2021
National Category
Infrastructure Engineering
Research subject
Civil and Architectural Engineering, Concrete Structures
Identifiers
urn:nbn:se:kth:diva-307532 (URN)10.1155/2021/4944682 (DOI)000781908400006 ()2-s2.0-85119926651 (Scopus ID)
Note

QC 20220502

Available from: 2022-01-28 Created: 2022-01-28 Last updated: 2023-02-17Bibliographically approved

Open Access in DiVA

fulltext(6059 kB)852 downloads
File information
File name FULLTEXT01.pdfFile size 6059 kBChecksum SHA-512
e477943ba016ef727b38d40bf08bcded5d0ed0fb69235881e45a0711ba0c1c9ee55e567a77a0c8eeb30cd23ecc6764cfa7bcc6c5d5f999d3589d6676354fed66
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Abbasiverki, Roghayeh
By organisation
Concrete Structures
Civil Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 858 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1502 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf