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Investigating the Performance of Wood Portal Frames as Alternative Bracing Systems in Light-Frame Wood BuildingsAl Mamun, Abdullah 07 August 2012 (has links)
Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.
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Investigating the Performance of Wood Portal Frames as Alternative Bracing Systems in Light-Frame Wood BuildingsAl Mamun, Abdullah 07 August 2012 (has links)
Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.
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Investigating the Performance of Wood Portal Frames as Alternative Bracing Systems in Light-Frame Wood BuildingsAl Mamun, Abdullah January 2012 (has links)
Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.
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Development of an Innovative Resilient Steel Braced Frame with BellevilleDisk and Shape Memory Alloy AssembliesAsgari Hadad, Alireza 11 June 2021 (has links)
No description available.
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Distribution of Lateral Forces on Reinforced Masonry Bracing Elements Considering Inelastic Material Behavior - Deformation-Based Matrix Method -Michel, Kenan 15 June 2021 (has links)
The main goal of CIC-BREL project (Cracked and Inelastic Calculation of BRacing Elements) is to develop an analytical method to distribute horizontal forces on bracing elements, in this case reinforced masonry shear walls, of a building considering the cracked and inelastic state of material.
The moment curvature curve of the wall section is created first depending on the section geometry and material properties of both the masonry units and steel reinforcement. This curve will start with an elastic material behavior, then continue in inelastic material behavior where the masonry crushes and the steel start to yield, until the maximum bending moment M_p is reached. Due to reinforced masonry wall ductility, post maximum capacity is also considered assuming a maximum curvature of 0.1%. From the moment curvature curve, the force displacement curve could be extracted depending on the wall height and wall boundary conditions.
Matrix formulation has been developed for both elastic and damaged stiffness matrix, considering different boundary conditions. Fixed-fixed boundary condition which usually exists at the middle stories or last story with strong top diaphragm, fixed-pinned which is the case of the last story that has a relatively soft top diaphragm, and pinned-fixed in the first story case. Other boundary conditions could be considered depending on the degree of fixation on the wall both ends at the top and the bottom.
The matrix formulation combined with the force-displacement curve which considers different material stages (elastic, inelastic, ductile post peak force) is used to define forces in each bracing element even after elastic behavior. After elastic phase of each wall the stiffness of the element will degrade leading to a less portion of the total lateral force; other elastic walls, i.e., stronger walls, will receive more portion of the total force leading to a redistribution of the total force. This process will be iterated until the total force is distributed on each bracing element depending on the wall section state: elastic, inelastic and ductile post-peak capacity. Flowcharts clearly will show this process. Finally, a Fortran code is developed to show examples using this method.
The developed analytical method will be verified by the results of shake table tests held at the University of California in San Diego, USA. Last test performed in the year 2018 uses T-section reinforced masonry walls, subjected to shakings with increased intensity. The total applied force for each shaking could be defined depending on the structural weight and shaking intensity (acceleration). The damage and displacement at each intensity has been recorded and evaluated. Depending on these test results, the results of the analytically developed method will be compared and evaluated. Total system displacement at different lateral load values has been compared for analytical calculations and shake table tests; furthermore, each wall state at increased load has been compared, good agreement could be noticed.:Acknowledgement 5
1. Introduction 7
1.1. State of the Art 9
1.2. Elastic Formulae 9
1.3. Example, Elastic Calculation 12
1.3.1. Stiffnesses of the System 13
1.3.2. Torsion due to Eccentric Lateral Loading 14
1.3.3. Distribution of the Lateral Load on Wall “j” and Floor “i” 15
2. Force Displacement Curve of RM Shear Wall 19
2.1. Introduction 19
2.2. Cantilever Wall 19
2.2.1. Cantilever Elastic Wall 19
2.2.2. Cantilever Inelastic Wall 21
2.2.3. Cantilever Post-Peak Wall 22
2.3. Fixed-Fixed Wall 23
2.3.1. Fixed-Fixed Elastic Wall 23
2.3.2. Fixed-Fixed Inelastic Wall 24
2.3.3. Fixed-Fixed Post-Peak Wall 26
2.4. Moment – Curvature Analysis 26
2.5. Example, Rectangle Cross Section, Cantilever 29
a) Moment Curvature Curve 29
b) Force Displacement Curve 32
2.6. Example, Rectangle Cross Section, Fixed-Fixed 33
a) Moment Curvature Curve 33
b) Force Displacement Curve 33
2.7. Example, T Cross Section, Cantilever 35
a) Moment Curvature Curve 35
b) Force Displacement Curve 41
2.8. Example, T Cross Section, Fixed-Fixed 43
a) Moment Curvature Curve 43
b) Force Displacement Curve 43
3. Matrix Formulation 47
3.1. Procedure 47
3.2. Structure Discretization 47
3.3. Element, i.e.; Wall, Local Stiffness Matrix 48
3.4. Stiffness Matrix of Fixed-Pinned Beam 52
3.4.1. Elastic 52
3.4.2. Pre-Peak Inelastic 54
3.4.3. Post-Peak Inelastic 55
3.4.4. Normal Force Part in the Stiffness Matrix 56
3.5. Stiffness Matrix of Pinned-Fixed Beam 57
3.5.1. Elastic 57
3.5.2. Post-Peak Inelastic 57
3.6. Stiffness Matrix of Fixed-Fixed Beam 58
3.6.1. Elastic 58
3.6.2. Post-Peak Inelastic 60
3.7. Summary of Stiffness Matrices 61
3.7.1. Fixed-Fixed 61
3.7.2. Fixed-Pinned 62
3.7.3. Pinned-Fixed 63
3.8. Transformation Matrix 63
3.9. Assemble the Structure Stiffness Matrix 65
3.10. Assemble the Structure Nodal Vector 66
3.11. Solve, Get Nodal Displacements and Forces 66
4. Matrix Formulation and Deformation Based Method 69
4.1. Elastic Method in Distributing Lateral Force 69
4.2. Elastic and Inelastic Method in Distributing Lateral Force 70
5. Shake Table Tests 73
5.1. Introduction 73
5.2. Design of Test Structure 73
5.3. Material Properties 75
5.4. Tests and Observations 75
5.4.1. Tests up to Mul-90% 76
5.4.2. Tests with Mul-120% 76
5.4.3. Tests with Mul-133% 76
5.5. Deformations 77
6. Verification 81
6.1. T Cross Section, Dimensions, Reinforcement and Materials 81
6.2. Moment Curvature Curve 82
6.3. Force Displacement Curve 85
6.4. Force Displacement Curve of the Structure 88
7. Conclusions and Suggestions 91
8. References 93
Appendix 1, Timoshenko Beam 95
• Fixed-Fixed 95
• Fixed-Pinned 95
• Pinned-Fixed 96
Appendix 2, Bernoulli Beam 97
• Fixed-Fixed 97
• Fixed-Pinned 97
• Pinned-Fixed 98
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Ocelová konstrukce vícepodlažní administrativní budovy / Steel structure of a multi-storey administrative buildingCejpek, Martin January 2018 (has links)
The main target is to design and asses the steel structure of a administartive multi-storey building. The steel structure is T shaped, with 30m span and 42m length. An analysis of two solutions of the supporting structure was performed. The first variant is consists of rigid bracing system. Trusses bracing in the second variant is an alternative solution. Both variants were compared and the amount of steel was found. The selected option was developed in greater details with static calculation, drawings and material report of steel.
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Performance Based Seismic Design of Lateral Force Resisting SystemMichel, Kenan 06 October 2020 (has links)
Das seitliche Kraftwiderstandssystem, in diesem Fall Stahlbetonkernwände eines 10-stöckigen Gebäudes, das aus Schwerkraftstützen und Scherwänden besteht, wurde linear (unter der Annahme eines linearen elastischen Materialverhaltens von Beton) und nichtlinear gerissen (unter Berücksichtigung des Materialverhaltens von Beton) unter seismische Belastung analysiert. Erst wurde die grundlegenden Methode der äquivalenten Seitenkraft zur Schätzung der seismischen Belastungen benutzt, später wurde die aktuelle Methode The Performance Based Seismic Design verwendet, bei der reale seismische Aufzeichnungen verwendet werden und die Beschleunigungen mithilfe der Software ETABS auf das Gebäude angewendet werden. Nach dem Anwenden der Beschleunigungen wurden die maximal resultierenden Kräfte und Verformungen bewertet. Das Gebäude wurde dann für die maximal resultierenden Kräfte ausgelegt.Der Inhalt des Hauptberichts ist:
- Allgemeine Beschreibung des Gebäudes, seismische Standortinformationen, Standortantwortspektren, Belastung und seismische Kräfte einschließlich Analyse des modalen Antwortspektrums.
- Lineares Design des Modells für Schwerkraft und seismische Belastungen, P-M-Wechselwirkungsdiagramme für den U-Querschnitt aus Stahlbeton, Entwurf einer Längs- und Schubbewehrung der Scherwände und des Koppelbalkens.
- Zwei Varianten des nichtlinearen Modells, bei denen die Kernwand (Scherwände) gemäß jeder Variante entworfen wird, wobei der Einfluss des Dämpfungsmodells auf das nichtlineare dynamische Verhalten sowie der Einfluss des Kopplungsstrahlmodells auf das nichtlineare dynamische Verhalten untersucht werden.
- Entwurfsüberprüfung, erst mit der Definition der Leistungsobjekte und Modell für die Zeitverlaufsanalyse. Es wurden zwei Leistungsziele untersucht: Vollbetriebs- und Lebenssicherheitsprüfungen.
- In zwei Fällen wurde eine zusätzliche Studie zur Reaktion von nicht strukturellen Elementen aufgrund seismischer Belastung durchgeführt: Überprüfung des Vollbetriebs und der Lebenssicherheit.
- Die Durchsetzungszeichnungen wurden fertiggestellt und dem Bericht beigefügt. Schlussfolgerung und Empfehlungen waren am Ende des Berichts. Dies ist wichtig für die Gesellschaft, da die verwendete Methode für die seismische Planung jedes Gebäudes verwendet werden kann. Es könnte ein Holzbau oder ein Mauerwerk sein. Die Gestaltung eines Mauerwerksgehäuses wird Gegenstand eines zukünftigen Forschungsprojekts sein.
Allgemeine Ziele: Lineare und nichtlineare seismische Bemessung von Stahlbetongebäuden unter Verwendung der 'seismischen Bemessung der Leistungsgrundlagen:Acknowledgement 4
PART I: General Information, Site and Loading 5
1. General Information About the Building 5
1.1. Specified Material Properties: 6
1.2. Site Information: 6
1.3. Geometry (Figure I.1): 7
2. Site Seismicity and Design Coefficients 7
2.1. USGS Results 7
2.2. Site Response Spectra 8
2.3. Design Coefficients And Factors For Seismic Force-Resisting Systems 8
3. Loading 9
3.1. Determination Of Seismic Forces 9
3.2. Modal Response Spectrum Analysis 9
3.3. Seismic Load Effects And Combinations 11
PART II: Core Wall Design - Linear Model 12
4. Model of ETABS 12
4.1. Geometry 12
4.2. Gravity Loads 13
4.3. Seismic Loads 15
4.4. Tabulated Selected Results From ETABS Analysis 16
5. P-M Interaction Diagrams 17
5.1. N-S Direction 17
5.2. E-W Direction 19
6. Lateral Force Resisting System, Linear 20
6.1. Longitudinal Reinforcement 20
6.2. Shear Reinforcement 22
6.3. Boundary Elements 24
6.3.1. Transverse Reinforcement Of Boundary Elements 26
6.4. Coupling Beams 27
7. Detailing 30
PART III: Site Response Spectra and Input Ground Motions 31
8. Performance Levels 31
8.1. ASCE 7-16 Target Spectra 31
8.2. Site Response Spectra 34
8.2.1. Ground Motion Conditioning 34
8.2.2. Amplitude Scaling 37
8.2.3. Pseudo Acceleration and Displacement Response Spectra 38
PART IV: Non-Linear Model 40
9. Variant 1 of Non-Linear Model 40
9.1. Complete Core Wall Design for Combined Axial-Flexure 40
9.2. Modal Analysis 43
9.3. Influence of the Damping Model on the Nonlinear Dynamic Response 49
10. Variant 2 of Non-Linear Model 57
10.1. Influence of the Coupling Beam Model on the Nonlinear Dynamic Response 57
10.2. Estimated Roof Displacement 68
PART V: Design Verification 70
11. General 70
11.1. Performance Objectives 70
11.2. Model For Time-History Analyses 71
11.3. Performance Level Verification 71
11.4. Fully Operational Performance Level Verification 71
11.5. Life Safety Performance Level Verification 78
PART VI: Capacity Design of Force Controlled Elements and Regions and Design of Acceleration-Sensitive Nonstructural Elements 87
12. General 87
12.1. Design Verification 87
12.1.1. Full Occupancy Case 87
12.1.2. Life Safety Case 91
12.1.3. Observations on Plots 93
12.2. Acceleration response spectra at roof level 94
12.2.1. Observations on Plots 95
12.3. Core Wall 97
12.4. Design Detail Comparison 103
12.5. Detailed Drawing 103
12.6. Diaphragm 104
12.7. Fire Sprinkler System 117
12.8. Overhanging Projector 119
PART VII: Conclusion 122 / Lateral Force Resisting System, in this case reinforced concrete core walls of a 10 story building consists of gravity columns and shear walls, has been analyzed in linear (assuming linear elastic material behavior of concrete) and nonlinear cracked (considering plastic material behavior of concrete) case, for seismic loading. Starting with the basic method of equivalent lateral force to estimate the seismic loads, then using the up to date method, The Performance Based Seismic Design, which uses real seismic records and apply the accelerations on the building using the software ETABS. After applying the accelerations, maximum resulted forces and deformations have been evaluated. The building then have been designed for the maximum resulted forces.
The contents of the main report are:
- General description of the building, site seismic information, site response spectra, loading and seismic forces including modal response spectrum analysis.
- Linear design of the model for gravity and seismic loads, P-M interaction diagrams developed for U cross section from reinforced concrete, designing longitudinal and shear reinforcement of the shear walls and coupling beam.
- Two variants of Nonlinear model, designing the core wall (shear walls) according to each variant, studying the influence of damping model on the nonlinear dynamic response, as well as the influence of the coupling beam model on the nonlinear dynamic response.
- Design verification, starting with defining the performance objects, and model for time history analysis. Two performance objectives have been studied: Fully operational and Life safety level verifications.
- Additional study was performed for the response of non-structural elements due to seismic loading in two cases: Fully operational and Life safety level verifications.
- Reinforcement Drawings have been finalized and attached to the report.
- Conclusion and recommendations was at the end of the report.
It is important for the society, because the used method could be used for the seismic design of any building. It could be wood building or masonry building. Designing a masonry building case will be the subject of future research project.
Overall objectives: Linear and Nonlinear seismic design of reinforced concrete building using the performance bases seismic design.:Acknowledgement 4
PART I: General Information, Site and Loading 5
1. General Information About the Building 5
1.1. Specified Material Properties: 6
1.2. Site Information: 6
1.3. Geometry (Figure I.1): 7
2. Site Seismicity and Design Coefficients 7
2.1. USGS Results 7
2.2. Site Response Spectra 8
2.3. Design Coefficients And Factors For Seismic Force-Resisting Systems 8
3. Loading 9
3.1. Determination Of Seismic Forces 9
3.2. Modal Response Spectrum Analysis 9
3.3. Seismic Load Effects And Combinations 11
PART II: Core Wall Design - Linear Model 12
4. Model of ETABS 12
4.1. Geometry 12
4.2. Gravity Loads 13
4.3. Seismic Loads 15
4.4. Tabulated Selected Results From ETABS Analysis 16
5. P-M Interaction Diagrams 17
5.1. N-S Direction 17
5.2. E-W Direction 19
6. Lateral Force Resisting System, Linear 20
6.1. Longitudinal Reinforcement 20
6.2. Shear Reinforcement 22
6.3. Boundary Elements 24
6.3.1. Transverse Reinforcement Of Boundary Elements 26
6.4. Coupling Beams 27
7. Detailing 30
PART III: Site Response Spectra and Input Ground Motions 31
8. Performance Levels 31
8.1. ASCE 7-16 Target Spectra 31
8.2. Site Response Spectra 34
8.2.1. Ground Motion Conditioning 34
8.2.2. Amplitude Scaling 37
8.2.3. Pseudo Acceleration and Displacement Response Spectra 38
PART IV: Non-Linear Model 40
9. Variant 1 of Non-Linear Model 40
9.1. Complete Core Wall Design for Combined Axial-Flexure 40
9.2. Modal Analysis 43
9.3. Influence of the Damping Model on the Nonlinear Dynamic Response 49
10. Variant 2 of Non-Linear Model 57
10.1. Influence of the Coupling Beam Model on the Nonlinear Dynamic Response 57
10.2. Estimated Roof Displacement 68
PART V: Design Verification 70
11. General 70
11.1. Performance Objectives 70
11.2. Model For Time-History Analyses 71
11.3. Performance Level Verification 71
11.4. Fully Operational Performance Level Verification 71
11.5. Life Safety Performance Level Verification 78
PART VI: Capacity Design of Force Controlled Elements and Regions and Design of Acceleration-Sensitive Nonstructural Elements 87
12. General 87
12.1. Design Verification 87
12.1.1. Full Occupancy Case 87
12.1.2. Life Safety Case 91
12.1.3. Observations on Plots 93
12.2. Acceleration response spectra at roof level 94
12.2.1. Observations on Plots 95
12.3. Core Wall 97
12.4. Design Detail Comparison 103
12.5. Detailed Drawing 103
12.6. Diaphragm 104
12.7. Fire Sprinkler System 117
12.8. Overhanging Projector 119
PART VII: Conclusion 122
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[en] MULTI-OBJECTIVE OPTIMIZATION OF STEEL FRAMES CONSIDERING THE BRACING SYSTEM AS A DESIGN VARIABLE / [pt] OTIMIZAÇÃO MULTIOBJETIVO DE PÓRTICOS DE AÇO CONSIDERANDO A CONFIGURAÇÃO DO SISTEMA DE CONTRAVENTAMENTO COMO VARIÁVEL DE PROJETOCLAUDIO HORTA BARBOSA DE RESENDE 04 November 2024 (has links)
[pt] Os pórticos espaciais de aço são amplamente utilizados na engenharia civil,
desempenhando um papel essencial em diversas construções, como centros comerciais, residências e estádios. Apesar de suas vantagens em resistência e leveza,
o aumento da altura dessas estruturas apresenta desafios significativos, tais como
deslocamentos devido ao vento e comprometimento do comportamento dinâmico.
Para lidar com tais questões, sistemas de contraventamento são empregados, sendo
essenciais para garantir também a estabilidade estrutural. A presente tese propõe
uma abordagem abrangente para otimizar pórticos espaciais de aço, com o objetivo
de equilibrar custo e desempenho. Além da minimização de custos, os objetivos
incluem maximizar a frequência natural de vibração, o fator de carga crítica relacionado à flambagem global, bem como reduzir o máximo deslocamento no topo,
o número de perfis distintos e o peso total da estrutura. A metodologia adotada envolve a aplicação de quatro algoritmos evolutivos baseados em evolução diferencial
e uma análise multicritério de tomada de decisões para a extração das soluções das
frentes de Pareto, considerando diferentes cenários de estudo. Destaca-se como aspecto inovador a consideração conjunta de variáveis de projeto, como o sistema de
contraventamento, o conjunto de orientações dos eixos principais de inércia dos pilares e perfis comerciais, permitindo a avaliação simultânea de até quatro funções
objetivo, além da inclusão de restrições adicionais. Os experimentos numéricos realizados demonstram a eficácia das metodologias propostas, fornecendo soluções
viáveis para diferentes cenários com objetivos diversos. Também é explorada a automatização do agrupamento de pilares nos experimentos numéricos, através da
formulação multiobjetivo, bem como a consideração de efeitos de segunda ordem
na análise estrutural. Os resultados obtidos oferecem informações valiosas aos projetistas, permitindo a extração de soluções da frente de Pareto que balanceiam os
objetivos conflitantes, resultando em estruturas mais eficientes, econômicas e sustentáveis. / [en] Steel space frames are widely used in various civil engineering projects such
as shopping centers, residences, and stadiums. Despite their strength and lightness,
increasing their height poses challenges like wind-induced displacements and compromised dynamic behavior. To address these issues, bracing systems are employed
to also ensure the structural stability. This thesis presents a comprehensive approach
to optimizing steel space frames, aiming to balance cost and performance. Alongside cost reduction, objectives include maximizing natural frequency of vibration,
the critical load factor for global buckling, and minimizing maximum displacement
at the top, the number of distinct profiles, and total weight of the structure. The
methodology involves using four evolutionary algorithms based on differential evolution and a multi-criteria decision-making analysis to extract solutions from the
Pareto front for different study scenarios. An innovative aspect is the integrated
assessment of design variables, including the bracing system configuration, orientations of the principal inertia axes of the columns, and commercial profiles. This
allows simultaneous evaluation of up to four objective functions, along with additional design constraints. Numerical experiments demonstrate the effectiveness
of the proposed methodologies, offering feasible solutions for various scenarios
with different objectives. The automation of column grouping and consideration
of second-order effects in structural analysis are also explored. The results provide
valuable insights to designers, enabling them to extract solutions from the Pareto
front that balance conflicting objectives, resulting in more efficient, economical,
and sustainable structures.
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Montovaná konstrukce haly / Assembled structure of hallBartosch, Václav January 2017 (has links)
Master´s thesis describes the design and static calculating of selected elements of prefabricated reinforced concrete hall with bulit-in office, elaboration of basic drawings of the project documentation, shape and reinforcemenet drawings of these selected structural prefabricated elements. The work also includes technical report, details of selected element´s contacts, drawing of plates and study of the behavior of reinforced buildings. Calculation was performed by using a computer program AxisVm, Microsoft Excel a IDEA StatiCa
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