The Rion Antirion Bridge project involves constructing a 3 km long multi-cable stayed bridge across the Gulf of Corinth in western Greece. It will be one of the largest bridges of its type in the world. The project faces significant engineering challenges due to high seismic activity in the region, deep weak soil layers, and the potential for fault displacements. Sophisticated dynamic analyses and foundation designs were required to develop a structure that can withstand strong earthquakes while maintaining serviceability. The bridge design utilizes seismic isolation of the deck and innovative reinforced soil foundations to improve bearing capacity and control failure modes under high seismic loads.
The Rion-Antirion Bridge in Greece connects the Peloponnese peninsula to the western mainland via a 2252m long cable-stayed main bridge that spans the Corinth Strait. It was designed to withstand the severe seismic activity and possible fault movements in the area. The main bridge uses four pylons supported by large reinforced soil foundations to distribute seismic forces to the deep weak soil layers. Dynamic analysis showed that during major earthquakes, the reinforced soil and pylon foundations would yield and slide as designed to dissipate energy without compromising the structure. The continuous suspended deck acts as a flexible element that can accommodate displacements without damage. The bridge's innovative design allows all components to work together to resist earthquake forces through
The document summarizes the design and construction of the foundations for the Rion Antirion Bridge in Greece. Key points:
1) The foundations used an innovative design of large diameter gravity caissons resting on reinforced natural ground, with steel tubular inclusions and a gravel layer, to address weak soil conditions, seismic activity, and tectonic movements.
2) Subsurface investigations found deep alluvial deposits with low strength and shear wave velocities, posing challenges for the large bridge piers.
3) The foundation concept used capacity design principles, with the gravel layer absorbing inelastic deformations and inclusions providing overstrength to prevent deep failures, allowing sliding if design loads were exceeded.
Detailed Slope Stability Analysis and Assessment of the Original Carsington E...Dr.Costas Sachpazis
A 1225 m long, 35 m high zone earth filled embankment was being constructed from 1981 to 1984 from a British Regional Water Authority to regulate flows in the River Derwent in England. The Carsington Dam was planned to be one of the largest earth filled dams in Britain. Its reservoir capacity was 35 million m3 and the watertight element was Rolled Clay Core with an upstream extension of boot shaped and shoulders of compacted mudstone with horizontal drainage layers of crushed limestone about 4 metres apart and a cut-off grout curtain (Davey and Eccles, 1983).
The downstream slope was 1:2.5 and the upstream slope 1:3. Fill placing began in May 1982 and took three summers, with winter shutdowns. In August 1983 a small berm was placed at the upstream toe to compensate for a faster rate of construction. Earth filling restarted in April 1984 and was one metre below the final crest level on 4 June 1984 when the upstream slope slipped (Skempton, 1985). Observations of pore pressure and settlement were made during construction at four sections and horizontal displacements were observed from August 1983. The Carsington Dam was almost completed on 1984.
However, at the beginning of June 1984, a 400-m length of the upstream shoulder of the embankment dam slipped some 11 m and failed. At the time of the failure, embankment construction was virtually complete with the dam approaching its maximum height of 35 m. Horizontal drainage blankets were incorporated in both the upstream and the downstream shale fill shoulders. Piezometers had been installed and pore pressures were being monitored in the foundation, in the clay core, and in the shoulder fill. The failure surface passed through the boot shaped rolled clay core and a relatively thin layer of surface clay in the foundation of the dam. Investigation of the events at Carsington has made important contributions to the fundamental understanding of the behaviour of large earthworks of this type (Vaughan et al., 1989; Dounias et al., 1996).
The objective of this research is to evaluate a detailed slope stability assessment of the Carsington Earth Embankment Dam in the UK used to retain mine tailings.
By using and applying advanced geotechnical engineering analysis tools and modelling techniques the Carsington Earth Embankment Dam, which is considered a particular geotechnical structure, is analysed.
In the current detailed slope stability analyses the total and effective stress state soil properties / parameters were used, and the most critical slip circle centre according to Fellenius - Jumikis method was initially determined. Subsequently, the Carsington Earth Embankment Dam and its foundation was analysed and examined against failure by slope instability. Considerations of loading conditions which may result to instability for all likely combinations of reservoir and tailwater levels, seepage conditions, both after and during construction were made, and hence three construction and / or loading condit
The document discusses various types of loads and pressures that act on underground tunnels, including:
1) Earth/rock pressures and water pressure are the most important potential loads. Live loads from surface traffic can usually be neglected.
2) Dimensions of tunnel sections must account for overburden weight (geostatic pressure) or loosening pressure (weight of loosened rock zone).
3) Lateral pressures, bottom pressures, and rock pressures are discussed. Several theories for estimating vertical and lateral loads are presented, including those by Bierbaumer, Terzaghi, and Tsimbaryevitch.
4) Rock pressures depend on factors like the quality of rock, stresses/strains around the
The document discusses various geological factors that must be considered when constructing tunnels, including: conducting subsurface exploration using pits, adits, drilling, and pilot tunnels; using core drilling and geophysical investigations to interpret geological features; addressing issues related to joint orientation, weathering, faults, rock bursts, and more. Pilot tunnels can help explore critical geological conditions ahead of main excavation and drain rock. The ideal tunnel cross-section depends on the type of rock and purpose of the tunnel.
Challenges of Tunneling-- A Peep Into The Exciting World of TunnellingIEI GSC
By Shri Manoj Verman, President, Indian National Group of ISRM
President, International Commission on Hard Rock Excavation
Vice President, Indian Society of Engineering Geology
at 31st National Convention of Civil Engineering
organised by
Gujarat State Center, The Institution of Engineers (India)
at Ahmedabad
parametric study of effect of column shapes on earthquake resistance of build...Solcon Technologies LLP
This document summarizes a study on the effect of column shapes on the earthquake resistance of reinforced concrete framed buildings. The study analyzed 10-story buildings with square and rectangular plans containing rectangular, square, and circular cross-section columns under seismic loads. It was found that using square or circular columns rather than rectangular columns resulted in a 7-8% reduction in required steel reinforcement and a cost savings of around Rs. 100,000. The study concluded that non-rectangular column shapes can improve a building's seismic performance while reducing costs.
- The document provides information about tunnels and tunneling, including background on some of the earliest tunnels constructed by ancient Egyptians and Babylonians.
- Tunnels can be classified based on their purpose, geological location/condition, and cross-sectional shape. Examples of different tunnel types and shapes are given.
- Key geological conditions that influence tunnel planning and construction are discussed, including rock properties, groundwater conditions, and fault zones. The importance of site investigations is emphasized.
- Methods of tunnel construction in soft ground, dealing with water and gases in tunnels, and controlling temperature are outlined. Excavation methods like cut-and-cover, sequential excavation (drill-and-blast), and tunnel boring
The Rion-Antirion Bridge in Greece connects the Peloponnese peninsula to the western mainland via a 2252m long cable-stayed main bridge that spans the Corinth Strait. It was designed to withstand the severe seismic activity and possible fault movements in the area. The main bridge uses four pylons supported by large reinforced soil foundations to distribute seismic forces to the deep weak soil layers. Dynamic analysis showed that during major earthquakes, the reinforced soil and pylon foundations would yield and slide as designed to dissipate energy without compromising the structure. The continuous suspended deck acts as a flexible element that can accommodate displacements without damage. The bridge's innovative design allows all components to work together to resist earthquake forces through
The document summarizes the design and construction of the foundations for the Rion Antirion Bridge in Greece. Key points:
1) The foundations used an innovative design of large diameter gravity caissons resting on reinforced natural ground, with steel tubular inclusions and a gravel layer, to address weak soil conditions, seismic activity, and tectonic movements.
2) Subsurface investigations found deep alluvial deposits with low strength and shear wave velocities, posing challenges for the large bridge piers.
3) The foundation concept used capacity design principles, with the gravel layer absorbing inelastic deformations and inclusions providing overstrength to prevent deep failures, allowing sliding if design loads were exceeded.
Detailed Slope Stability Analysis and Assessment of the Original Carsington E...Dr.Costas Sachpazis
A 1225 m long, 35 m high zone earth filled embankment was being constructed from 1981 to 1984 from a British Regional Water Authority to regulate flows in the River Derwent in England. The Carsington Dam was planned to be one of the largest earth filled dams in Britain. Its reservoir capacity was 35 million m3 and the watertight element was Rolled Clay Core with an upstream extension of boot shaped and shoulders of compacted mudstone with horizontal drainage layers of crushed limestone about 4 metres apart and a cut-off grout curtain (Davey and Eccles, 1983).
The downstream slope was 1:2.5 and the upstream slope 1:3. Fill placing began in May 1982 and took three summers, with winter shutdowns. In August 1983 a small berm was placed at the upstream toe to compensate for a faster rate of construction. Earth filling restarted in April 1984 and was one metre below the final crest level on 4 June 1984 when the upstream slope slipped (Skempton, 1985). Observations of pore pressure and settlement were made during construction at four sections and horizontal displacements were observed from August 1983. The Carsington Dam was almost completed on 1984.
However, at the beginning of June 1984, a 400-m length of the upstream shoulder of the embankment dam slipped some 11 m and failed. At the time of the failure, embankment construction was virtually complete with the dam approaching its maximum height of 35 m. Horizontal drainage blankets were incorporated in both the upstream and the downstream shale fill shoulders. Piezometers had been installed and pore pressures were being monitored in the foundation, in the clay core, and in the shoulder fill. The failure surface passed through the boot shaped rolled clay core and a relatively thin layer of surface clay in the foundation of the dam. Investigation of the events at Carsington has made important contributions to the fundamental understanding of the behaviour of large earthworks of this type (Vaughan et al., 1989; Dounias et al., 1996).
The objective of this research is to evaluate a detailed slope stability assessment of the Carsington Earth Embankment Dam in the UK used to retain mine tailings.
By using and applying advanced geotechnical engineering analysis tools and modelling techniques the Carsington Earth Embankment Dam, which is considered a particular geotechnical structure, is analysed.
In the current detailed slope stability analyses the total and effective stress state soil properties / parameters were used, and the most critical slip circle centre according to Fellenius - Jumikis method was initially determined. Subsequently, the Carsington Earth Embankment Dam and its foundation was analysed and examined against failure by slope instability. Considerations of loading conditions which may result to instability for all likely combinations of reservoir and tailwater levels, seepage conditions, both after and during construction were made, and hence three construction and / or loading condit
The document discusses various types of loads and pressures that act on underground tunnels, including:
1) Earth/rock pressures and water pressure are the most important potential loads. Live loads from surface traffic can usually be neglected.
2) Dimensions of tunnel sections must account for overburden weight (geostatic pressure) or loosening pressure (weight of loosened rock zone).
3) Lateral pressures, bottom pressures, and rock pressures are discussed. Several theories for estimating vertical and lateral loads are presented, including those by Bierbaumer, Terzaghi, and Tsimbaryevitch.
4) Rock pressures depend on factors like the quality of rock, stresses/strains around the
The document discusses various geological factors that must be considered when constructing tunnels, including: conducting subsurface exploration using pits, adits, drilling, and pilot tunnels; using core drilling and geophysical investigations to interpret geological features; addressing issues related to joint orientation, weathering, faults, rock bursts, and more. Pilot tunnels can help explore critical geological conditions ahead of main excavation and drain rock. The ideal tunnel cross-section depends on the type of rock and purpose of the tunnel.
Challenges of Tunneling-- A Peep Into The Exciting World of TunnellingIEI GSC
By Shri Manoj Verman, President, Indian National Group of ISRM
President, International Commission on Hard Rock Excavation
Vice President, Indian Society of Engineering Geology
at 31st National Convention of Civil Engineering
organised by
Gujarat State Center, The Institution of Engineers (India)
at Ahmedabad
parametric study of effect of column shapes on earthquake resistance of build...Solcon Technologies LLP
This document summarizes a study on the effect of column shapes on the earthquake resistance of reinforced concrete framed buildings. The study analyzed 10-story buildings with square and rectangular plans containing rectangular, square, and circular cross-section columns under seismic loads. It was found that using square or circular columns rather than rectangular columns resulted in a 7-8% reduction in required steel reinforcement and a cost savings of around Rs. 100,000. The study concluded that non-rectangular column shapes can improve a building's seismic performance while reducing costs.
- The document provides information about tunnels and tunneling, including background on some of the earliest tunnels constructed by ancient Egyptians and Babylonians.
- Tunnels can be classified based on their purpose, geological location/condition, and cross-sectional shape. Examples of different tunnel types and shapes are given.
- Key geological conditions that influence tunnel planning and construction are discussed, including rock properties, groundwater conditions, and fault zones. The importance of site investigations is emphasized.
- Methods of tunnel construction in soft ground, dealing with water and gases in tunnels, and controlling temperature are outlined. Excavation methods like cut-and-cover, sequential excavation (drill-and-blast), and tunnel boring
Practices in Planning, Design and Construction of Head Race Tunnel of a Hydro...Mohit Shukla
This paper has been selected for oral presentation as well as inclusion in the conference proceedings of the ICCCGE 2016 : 18th International Conference on Civil,Construction and Geological Engineering held in Toronto, Canada during June,
13-14, 2016. This paper was also able to find a position in the international conference of Dams and Hydropower held at Laos in May 2016.
The Rion-Antirion Bridge in Greece connects the Peloponnese peninsula and western Greece over the Gulf of Corinth. It presents significant engineering challenges due to deep and weak soil, large water depths of up to 65 meters, and high seismic activity. The innovative design features 90 meter diameter foundations reinforced with steel inclusions resting on soil and a 2,252 meter continuous cable-stayed deck fully suspended from pylons. Unconventional construction methods were required such as building foundation components in a dry dock and using a tension-leg barge for underwater work.
Structural design including disaster (wind & cyclone land slide_eq_ resistan...RAJESH JAIN
The document summarizes key aspects of structural design as outlined in Part 6 of the National Building Code of India, with a focus on loads, forces, and earthquake resistance. It discusses the sections and standards covered in Part 6, including loads from wind, seismic activity, imposed loads, and more. Methods of calculating design wind speed and pressure are presented. Seismic zoning maps and factors are shown, along with equations for determining design lateral force based on seismic weight and acceleration spectra. Types of structural irregularities are defined.
1) A magnitude 7.6 earthquake struck Gujarat, India in 2001 near the city of Bachau, causing widespread damage.
2) Two embankment dams, Chang Dam and Fatehgadh Dam, within 150 km of the epicenter were examined. Chang Dam experienced almost a complete collapse likely due to liquefaction of its shallow foundation soils, while Fatehgadh Dam experienced less severe but still significant damage.
3) Analysis of the foundation soils beneath the dams found they were susceptible to liquefaction when saturated, which likely contributed to the observed damage during the earthquake when reservoir levels were low but foundation soils remained saturated.
This document discusses rock tunnel engineering. It introduces different types of tunnels and their purposes. Tunnels can have various cross-sectional shapes and be located underground in different ground types. Tunnels are constructed using methods like cut-and-cover, drilling and blasting, or mechanized boring machines. Geotechnical investigations for tunnels are challenging due to uncertainties in ground conditions. Rock mass classification systems help characterize rock strength. The principles of tunnel stabilization and design aim to control ground movements rather than carry ground loads by mobilizing the strength of the surrounding ground.
This document provides an overview of tunneling, including the purposes of tunnels, effects of tunneling on the ground, tunnel lining, economic aspects, geological considerations, overbreak, and examples of important tunnels. Tunnels are used for transportation, utilities, and protection from hazards. They affect the surrounding ground and require lining for structural integrity and waterproofing. Cost, time, and construction method are economic factors to consider. Geological conditions like rock type influence tunnel design and construction challenges like overbreak. The Pir Panjal Railway Tunnel in India is highlighted as a significant tunnel project.
The pattern of Slopes Pattern in Rock Media
By: Omitogun Solomon T.
Student(MSc. Geology-Engineering Geology/Hydrogeology-2018/2019 set) University of Lagos, Nigeria
solotosin6@gmail.com
The document summarizes seismic damages from the 2001 Bhuj earthquake in India. It killed over 13,000 people and destroyed nearly 400,000 homes. Common failures of reinforced concrete structures included soft stories, floating columns, strong column weak beam configurations, mass and plan irregularities, poor construction materials and techniques, and pounding between adjacent buildings. Soft story failures occurred particularly in buildings with large ground floor openings. Floating columns and strong column weak beam designs led to column failures. Masonry structures commonly experienced out-of-plane wall failures, in-plane shear failures, connection failures between walls and floors, diaphragm failures, and failures around wall openings.
Earthquake structural damage lecture notes 2015Ahmad T.
The document discusses different types of damage caused by earthquakes, including structural and non-structural damage. It describes several types of structural damage such as soft story failure, short column failure, torsional failure, pounding between buildings, column failure, beam failure, beam-column joint failure, and shear wall failure. Specific examples are provided to illustrate different damage types. Non-structural damage is also briefly mentioned.
Importance of geological considerations while choosing tunnel sites and align...Buddharatna godboley
This document discusses the importance of geological considerations when selecting sites and alignments for tunnels. It notes that geological investigations are essential for choosing the best route, determining the excavation method, designing the tunnel, assessing costs and stability, and evaluating environmental hazards. The document provides details on how different rock types and geological structures like folding and faulting can impact tunnel construction and design. It emphasizes that understanding the area's geology is crucial for planning tunnels and minimizing risks.
The document discusses failure of foundations due to earthquakes. It describes how earthquakes can cause damage to different types of foundations like shallow foundations, mat/raft foundations, and pile foundations. Shallow foundations see a decrease in bearing capacity during earthquakes due to horizontal loads and rocking moments. Pile foundations are affected by both kinematic interaction, where piles move sideways, and inertial interaction from forces on the pile cap from the structure. The document examines how earthquakes can impact various types of structures that rely on foundations, like buildings, dams, and bridges.
Analysis and Design Aspects of Support Measures of Main Caverns of Karuma Hyd...IOSRJMCE
The Power house complex of Karuma Hydropower project comprises three main caverns i.e Power house, Transformer Hall and Tailrace surge gallery set at a depth of about 80m in mainly granitic gneiss rock medium. The cavern has been oriented in a N141° direction based on engineering considerations. The principle stress direction is also found nearly parallel to the axis of the caverns and thus the present orientation satisfies both engineering and geotechnical criteria. The support by way of rock anchors and SFRS/ Plain shotcrete has been provided based on analysis using phase 2 software. The underground caverns lie in low geostress field and therefore numerical simulation of excavation of these caverns were done to understand the rock mass behavior during excavation and thus help in design of excavation sequence and rock support. The excavation of all three caverns has since been completed and concrete works are in progress. This paper sums up the 3D simulation analysis of the rock medium and the proposed rock support system for the three caverns.
This document summarizes tunnelling projects and experiences in Greece from the early 1990s to present. It discusses the Athens Metro and use of microtunnelling and jet grouting to construct underground stations. It also describes the Egnatia Motorway project and challenges with Tunnel S3. Specifically, it examined over 100km of railway tunnels and nearly 350km of motorway and railway tunnels constructed. Lessons included using a Geological Strength Index and Tunnel Stability Factor to assess tunnel conditions. Jet grouting was used to improve weak rock and prevent face collapses during the Athens Metro project.
The document describes the key features of a river diversion arrangement and roller compacted concrete dam for the Jamrani Dam Multipurpose Project. The river diversion includes upstream and downstream cofferdams and a 6.5m diameter tunnel. The 150.6m high RCC dam has a 9km long reservoir and is designed to withstand a probable maximum flood of 8472 cumecs. Stability analyses were conducted considering loads such as earthquake, uplift, and hydrostatic forces, and stresses were found to have adequate factors of safety under all loading conditions.
Behavior of rc structure under earthquake loadingBinay Shrestha
The document discusses reasons why reinforced concrete (RC) structures fail during earthquakes and measures to improve their performance. Key points include:
1) RC buildings often fail due to design deficiencies like ignoring concepts of strong columns-weak beams or having soft stories, or construction defects like weak joints or improper reinforcement detailing.
2) Measures to improve performance include following design concepts of strong columns-weak beams and designing soft story elements to withstand higher forces, as well as improving construction quality of joints and reinforcement details.
3) Other factors that can lead to failure are short column effects, torsional forces from asymmetric shapes, and disturbance of the load path through the structure.
This document discusses seismic response prediction of concrete arch dams. It begins with an introduction to arch dams, describing their curved shape and suitability for narrow valleys. It then discusses various classifications of arch dams based on thickness ratios and structural heights. The document reviews literature on dynamic analysis of arch dams, noting factors like reservoir boundaries, water compressibility, and dam-foundation interaction. It provides an example of the Idukki Dam in Kerala, India, the first arch dam built in the country. Finite element modeling is mentioned as a tool for seismic response prediction of concrete arch dams.
Presentation on earthquake resistance massonary structureRadhey Verma
This presentation discusses how to make masonry structures more resistant to earthquakes. It defines earthquake resistant masonry structures as those built from brick, stone or other masonry materials combined with containment reinforcement. It describes stresses in masonry walls during quakes and modeling of walls, then discusses techniques to strengthen buildings like adding flexibility, reinforcing walls and foundations, and containment reinforcement around walls. Shock table testing was also used to evaluate different earthquake resistant building features in masonry models.
This document summarizes the design of a retaining structure to stabilize a section of highway affected by slope failures. A combination system using soldier piles, rock anchors, and ground improvement piles was developed to support the road formation and account for varying bedrock depths. Soldier piles were used where bedrock was shallow, and were anchored with rock anchors where overburden was thicker. Ground improvement piles were used where bedrock was deepest. The detailed design specified pile sizes and spacing based on bedrock depth, and rock anchors were installed through soldier piles below road level. This hybrid system provided stabilization while accommodating site conditions in a cost-effective manner.
The document provides an overview of the "Cut-and-Cover" and "Cover-and-Cut" tunnel construction techniques. The "Cut-and-Cover" method involves excavating a trench and constructing the tunnel structure within it, then refilling the trench. The "Cover-and-Cut" method first constructs a retaining concrete shell, then excavates underneath it for tunnel construction. Both methods are used for highway and railway tunnels where shallow depths or unstable ground conditions require extra support during construction. The document discusses the design process and construction steps for each method.
(2010) - Yates M, Krzeminski M, Berthier D, Hamidi B - The Application of Jet...Michal Krzeminski
Jet grouting was used to construct the Runway End Safety Area for Sydney International Airport. It was needed to bridge over existing structures in a way that stabilized the ground, provided bearing capacity, and created an impermeable barrier. A complex design of jet grout columns with varying diameters, lengths, and reinforcement was implemented based on detailed modeling. Over 1,600 jet grout columns totaling over 13,000 meters in length and 5,100 cubic meters in volume were constructed using a double fluid system to meet the project's geotechnical requirements.
El documento presenta los planos y la idea general de un proyecto que incluye residencias, un centro deportivo, un centro de interpretación, un centro de convenciones, una galería de arte, casas, una escuela, y áreas verdes. Propone dos ejes que dividen las áreas públicas de las privadas. Incluye un recorrido peatonal que conecta las diferentes actividades y atracciones.
Este documento resume las preguntas frecuentes sobre la herramienta de presentaciones en línea Prezi. Explica que los archivos se pueden guardar gratuitamente pero existen riesgos de robo, que permite trabajar en línea de forma gratuita pero con opciones de pago para proteger trabajos, y que la interfaz ha recibido críticas por producir nauseas. Identifica a los creadores de Prezi y dice que está disponible en inglés y español.
Practices in Planning, Design and Construction of Head Race Tunnel of a Hydro...Mohit Shukla
This paper has been selected for oral presentation as well as inclusion in the conference proceedings of the ICCCGE 2016 : 18th International Conference on Civil,Construction and Geological Engineering held in Toronto, Canada during June,
13-14, 2016. This paper was also able to find a position in the international conference of Dams and Hydropower held at Laos in May 2016.
The Rion-Antirion Bridge in Greece connects the Peloponnese peninsula and western Greece over the Gulf of Corinth. It presents significant engineering challenges due to deep and weak soil, large water depths of up to 65 meters, and high seismic activity. The innovative design features 90 meter diameter foundations reinforced with steel inclusions resting on soil and a 2,252 meter continuous cable-stayed deck fully suspended from pylons. Unconventional construction methods were required such as building foundation components in a dry dock and using a tension-leg barge for underwater work.
Structural design including disaster (wind & cyclone land slide_eq_ resistan...RAJESH JAIN
The document summarizes key aspects of structural design as outlined in Part 6 of the National Building Code of India, with a focus on loads, forces, and earthquake resistance. It discusses the sections and standards covered in Part 6, including loads from wind, seismic activity, imposed loads, and more. Methods of calculating design wind speed and pressure are presented. Seismic zoning maps and factors are shown, along with equations for determining design lateral force based on seismic weight and acceleration spectra. Types of structural irregularities are defined.
1) A magnitude 7.6 earthquake struck Gujarat, India in 2001 near the city of Bachau, causing widespread damage.
2) Two embankment dams, Chang Dam and Fatehgadh Dam, within 150 km of the epicenter were examined. Chang Dam experienced almost a complete collapse likely due to liquefaction of its shallow foundation soils, while Fatehgadh Dam experienced less severe but still significant damage.
3) Analysis of the foundation soils beneath the dams found they were susceptible to liquefaction when saturated, which likely contributed to the observed damage during the earthquake when reservoir levels were low but foundation soils remained saturated.
This document discusses rock tunnel engineering. It introduces different types of tunnels and their purposes. Tunnels can have various cross-sectional shapes and be located underground in different ground types. Tunnels are constructed using methods like cut-and-cover, drilling and blasting, or mechanized boring machines. Geotechnical investigations for tunnels are challenging due to uncertainties in ground conditions. Rock mass classification systems help characterize rock strength. The principles of tunnel stabilization and design aim to control ground movements rather than carry ground loads by mobilizing the strength of the surrounding ground.
This document provides an overview of tunneling, including the purposes of tunnels, effects of tunneling on the ground, tunnel lining, economic aspects, geological considerations, overbreak, and examples of important tunnels. Tunnels are used for transportation, utilities, and protection from hazards. They affect the surrounding ground and require lining for structural integrity and waterproofing. Cost, time, and construction method are economic factors to consider. Geological conditions like rock type influence tunnel design and construction challenges like overbreak. The Pir Panjal Railway Tunnel in India is highlighted as a significant tunnel project.
The pattern of Slopes Pattern in Rock Media
By: Omitogun Solomon T.
Student(MSc. Geology-Engineering Geology/Hydrogeology-2018/2019 set) University of Lagos, Nigeria
solotosin6@gmail.com
The document summarizes seismic damages from the 2001 Bhuj earthquake in India. It killed over 13,000 people and destroyed nearly 400,000 homes. Common failures of reinforced concrete structures included soft stories, floating columns, strong column weak beam configurations, mass and plan irregularities, poor construction materials and techniques, and pounding between adjacent buildings. Soft story failures occurred particularly in buildings with large ground floor openings. Floating columns and strong column weak beam designs led to column failures. Masonry structures commonly experienced out-of-plane wall failures, in-plane shear failures, connection failures between walls and floors, diaphragm failures, and failures around wall openings.
Earthquake structural damage lecture notes 2015Ahmad T.
The document discusses different types of damage caused by earthquakes, including structural and non-structural damage. It describes several types of structural damage such as soft story failure, short column failure, torsional failure, pounding between buildings, column failure, beam failure, beam-column joint failure, and shear wall failure. Specific examples are provided to illustrate different damage types. Non-structural damage is also briefly mentioned.
Importance of geological considerations while choosing tunnel sites and align...Buddharatna godboley
This document discusses the importance of geological considerations when selecting sites and alignments for tunnels. It notes that geological investigations are essential for choosing the best route, determining the excavation method, designing the tunnel, assessing costs and stability, and evaluating environmental hazards. The document provides details on how different rock types and geological structures like folding and faulting can impact tunnel construction and design. It emphasizes that understanding the area's geology is crucial for planning tunnels and minimizing risks.
The document discusses failure of foundations due to earthquakes. It describes how earthquakes can cause damage to different types of foundations like shallow foundations, mat/raft foundations, and pile foundations. Shallow foundations see a decrease in bearing capacity during earthquakes due to horizontal loads and rocking moments. Pile foundations are affected by both kinematic interaction, where piles move sideways, and inertial interaction from forces on the pile cap from the structure. The document examines how earthquakes can impact various types of structures that rely on foundations, like buildings, dams, and bridges.
Analysis and Design Aspects of Support Measures of Main Caverns of Karuma Hyd...IOSRJMCE
The Power house complex of Karuma Hydropower project comprises three main caverns i.e Power house, Transformer Hall and Tailrace surge gallery set at a depth of about 80m in mainly granitic gneiss rock medium. The cavern has been oriented in a N141° direction based on engineering considerations. The principle stress direction is also found nearly parallel to the axis of the caverns and thus the present orientation satisfies both engineering and geotechnical criteria. The support by way of rock anchors and SFRS/ Plain shotcrete has been provided based on analysis using phase 2 software. The underground caverns lie in low geostress field and therefore numerical simulation of excavation of these caverns were done to understand the rock mass behavior during excavation and thus help in design of excavation sequence and rock support. The excavation of all three caverns has since been completed and concrete works are in progress. This paper sums up the 3D simulation analysis of the rock medium and the proposed rock support system for the three caverns.
This document summarizes tunnelling projects and experiences in Greece from the early 1990s to present. It discusses the Athens Metro and use of microtunnelling and jet grouting to construct underground stations. It also describes the Egnatia Motorway project and challenges with Tunnel S3. Specifically, it examined over 100km of railway tunnels and nearly 350km of motorway and railway tunnels constructed. Lessons included using a Geological Strength Index and Tunnel Stability Factor to assess tunnel conditions. Jet grouting was used to improve weak rock and prevent face collapses during the Athens Metro project.
The document describes the key features of a river diversion arrangement and roller compacted concrete dam for the Jamrani Dam Multipurpose Project. The river diversion includes upstream and downstream cofferdams and a 6.5m diameter tunnel. The 150.6m high RCC dam has a 9km long reservoir and is designed to withstand a probable maximum flood of 8472 cumecs. Stability analyses were conducted considering loads such as earthquake, uplift, and hydrostatic forces, and stresses were found to have adequate factors of safety under all loading conditions.
Behavior of rc structure under earthquake loadingBinay Shrestha
The document discusses reasons why reinforced concrete (RC) structures fail during earthquakes and measures to improve their performance. Key points include:
1) RC buildings often fail due to design deficiencies like ignoring concepts of strong columns-weak beams or having soft stories, or construction defects like weak joints or improper reinforcement detailing.
2) Measures to improve performance include following design concepts of strong columns-weak beams and designing soft story elements to withstand higher forces, as well as improving construction quality of joints and reinforcement details.
3) Other factors that can lead to failure are short column effects, torsional forces from asymmetric shapes, and disturbance of the load path through the structure.
This document discusses seismic response prediction of concrete arch dams. It begins with an introduction to arch dams, describing their curved shape and suitability for narrow valleys. It then discusses various classifications of arch dams based on thickness ratios and structural heights. The document reviews literature on dynamic analysis of arch dams, noting factors like reservoir boundaries, water compressibility, and dam-foundation interaction. It provides an example of the Idukki Dam in Kerala, India, the first arch dam built in the country. Finite element modeling is mentioned as a tool for seismic response prediction of concrete arch dams.
Presentation on earthquake resistance massonary structureRadhey Verma
This presentation discusses how to make masonry structures more resistant to earthquakes. It defines earthquake resistant masonry structures as those built from brick, stone or other masonry materials combined with containment reinforcement. It describes stresses in masonry walls during quakes and modeling of walls, then discusses techniques to strengthen buildings like adding flexibility, reinforcing walls and foundations, and containment reinforcement around walls. Shock table testing was also used to evaluate different earthquake resistant building features in masonry models.
This document summarizes the design of a retaining structure to stabilize a section of highway affected by slope failures. A combination system using soldier piles, rock anchors, and ground improvement piles was developed to support the road formation and account for varying bedrock depths. Soldier piles were used where bedrock was shallow, and were anchored with rock anchors where overburden was thicker. Ground improvement piles were used where bedrock was deepest. The detailed design specified pile sizes and spacing based on bedrock depth, and rock anchors were installed through soldier piles below road level. This hybrid system provided stabilization while accommodating site conditions in a cost-effective manner.
The document provides an overview of the "Cut-and-Cover" and "Cover-and-Cut" tunnel construction techniques. The "Cut-and-Cover" method involves excavating a trench and constructing the tunnel structure within it, then refilling the trench. The "Cover-and-Cut" method first constructs a retaining concrete shell, then excavates underneath it for tunnel construction. Both methods are used for highway and railway tunnels where shallow depths or unstable ground conditions require extra support during construction. The document discusses the design process and construction steps for each method.
(2010) - Yates M, Krzeminski M, Berthier D, Hamidi B - The Application of Jet...Michal Krzeminski
Jet grouting was used to construct the Runway End Safety Area for Sydney International Airport. It was needed to bridge over existing structures in a way that stabilized the ground, provided bearing capacity, and created an impermeable barrier. A complex design of jet grout columns with varying diameters, lengths, and reinforcement was implemented based on detailed modeling. Over 1,600 jet grout columns totaling over 13,000 meters in length and 5,100 cubic meters in volume were constructed using a double fluid system to meet the project's geotechnical requirements.
El documento presenta los planos y la idea general de un proyecto que incluye residencias, un centro deportivo, un centro de interpretación, un centro de convenciones, una galería de arte, casas, una escuela, y áreas verdes. Propone dos ejes que dividen las áreas públicas de las privadas. Incluye un recorrido peatonal que conecta las diferentes actividades y atracciones.
Este documento resume las preguntas frecuentes sobre la herramienta de presentaciones en línea Prezi. Explica que los archivos se pueden guardar gratuitamente pero existen riesgos de robo, que permite trabajar en línea de forma gratuita pero con opciones de pago para proteger trabajos, y que la interfaz ha recibido críticas por producir nauseas. Identifica a los creadores de Prezi y dice que está disponible en inglés y español.
Prezi es una herramienta en línea para crear presentaciones con animaciones y zoom. Ofrece una cuenta gratuita de 100 MB sin necesidad de instalación. También hay una cuenta paga de 500 MB por $159 al año. Se requiere Adobe Flash Player 10 o superior, 1 GB de memoria y un mouse con rueda para usar Prezi a través de navegadores como Chrome, Firefox y Safari. Para crear una cuenta, se debe hacer clic en "Registrarse" e ingresar nombre, apellidos, correo electrónico y contraseña.
El documento describe el Plan Lara Saludable, cuyo objetivo es ajustar el sistema regional de salud a las necesidades de la población de Lara. Se propone mejorar la infraestructura hospitalaria mediante la construcción, ampliación y modernización de hospitales y centros de salud. También se promoverá un estilo de vida saludable a través de programas de nutrición, deporte, vacunación y atención médica móvil. Se detallan las inversiones realizadas y planificadas en varios hospitales de la región.
Este documento presenta una introducción a la negociación y mediación de conflictos impartida por Wilson López López. Incluye definiciones de conflicto, contextos donde ocurren, tácticas para afrontarlos y formas de resolución como la negociación y mediación. Explica quiénes participan en estos procesos como las partes involucradas, terceros, facilitadores, mediadores, entre otros.
This document lists various films, artworks, and locations that depict environments and externalities. It mentions Paul Citroen's 1923 painting Metropolis, William Hodges' 1776 painting Oaitepeha Bay, the Olympic Dam copper and uranium mine in South Australia, and the films Lord Jim from 1965, Greed from 1923, Some Like It Hot from 1959, and locations in Buenos Aires. All of these examples are connected through their portrayal of enclosures, environments, and externalities.
Frédéric Chopin was a Polish composer and virtuoso pianist who is considered one of the greatest Romantic composers. He began composing at age 7 and performing at age 8. Chopin came from a musically talented family, with both his father and mother playing instruments. By age 15, he had enthralled audiences in Warsaw with his skill at the piano. Later in life, Chopin moved to Paris and had a successful concert career, composing many mazurkas, études, preludes, waltzes, and sonatas during his time there. However, his career was cut short when he passed away in 1849 at the young age of 39.
The document summarizes the design and construction of the foundations for the Rion Antirion Bridge in Greece. An innovative foundation concept was adopted using steel tubular piles driven into the seabed to reinforce the soil, with a gravel layer between the piles and the concrete caisson foundation. This concept provided seismic capacity and minimized differential settlement risks. Close cooperation between designers, contractors, and reviewers was essential to developing and implementing this challenging foundation solution.
The Rion Antirion bridge in Greece connects the Peloponnese peninsula to the mainland across the Gulf of Corinth. Its foundations had to withstand severe environmental conditions including weak soils, earthquakes up to magnitude 7.0, and long-term tectonic movements. The innovative foundation concept adopted reinforced the natural ground with steel tubular piles and included a gravel layer between the piles and foundation raft. This provided capacity to resist the large seismic forces while minimizing differential settlement hazards. Extensive site investigations characterized the poor soil properties to ensure compatible design of seismic demand and foundation capacity.
The document summarizes the design and construction of the foundations for the Rion Antirion Bridge in Greece. Key points:
- The foundations had to withstand severe environmental conditions like weak soil, earthquakes, and tectonic movements. An innovative concept was adopted using large diameter caissons resting on reinforced natural ground with steel pipe inclusions.
- Under each caisson, 150-200 steel pipe inclusions 2m in diameter were driven into the soil in a 7m grid to reinforce it. A 2.8m thick gravel layer separated the caisson from the inclusions.
- This concept provided capacity design by allowing sliding at the gravel interface during large seismic forces, limiting forces on the super
This document discusses the seismic design of foundations for the Rion Antirion Bridge in Greece. It describes the challenging soil and seismic conditions at the site, which required innovative foundation design. The foundations consist of large diameter caissons resting on top of reinforced natural ground, with steel tubular inclusions driven into the soil to increase its strength. Three of the four bridge piers use this reinforced foundation solution, while the fourth pier's caisson rests directly on a thick gravel layer without inclusions. The document outlines the design process and considerations, which aimed to ensure the foundations could adequately resist the large earthquake and ship impact loads expected at the seismically active site with poor soil conditions.
This document discusses the foundation design processes for two major bridge projects - the Vasco da Gama Bridge in Lisbon, Portugal and the Rion-Antirion Bridge in Greece. For the Vasco da Gama Bridge, the foundations consisted of vertical large diameter bored concrete piles due to favorable soil conditions and design requirements. For the Rion-Antirion Bridge, the soil conditions were less favorable so an innovative foundation concept was developed and implemented, which allowed for some permanent displacement under seismic loading. The additional time for design of the Rion-Antirion Bridge was crucial to developing and validating this new foundation solution.
A gravity dam is a solid structure, made of concrete or masonry, constructed across a river to create a reservoir on its
upstream. The section of the gravity dam is approximately triangular in shape, with its apex at its top and maximum width at bottom.
The section is so proportioned that it resists the various forces acting on it by its own weight. Most of the gravity dams are solid, so that
no bending stress is introduced at any point and hence, they are sometimes known as solid gravity dams to distinguish them from hollow
gravity dams in those hollow spaces are kept to reduce the weight. Early gravity dams were built of masonry, but now-a-days with
improved methods of construction, quality control and curing, concrete is most commonly used for the construction of modern gravity
dams.
Post tensioned concrete walls & frames for seismic resistanceĐỗ Hữu Linh
This case study describes the innovative use of post-tensioned concrete in the construction of the David Brower Center in Berkeley, California. The building uses a hybrid system of post-tensioned concrete walls and frames to provide improved seismic performance and self-centering behavior after earthquakes. This allows the building to avoid permanent damage and remain functional. The post-tensioning reduces the amount of conventional reinforcement needed, making the building more compact and efficient to construct while also lowering its carbon footprint through the use of slag cement. Non-linear simulations were used to verify the design of this unique structural system.
This document describes a 4-storey reinforced concrete test building with unreinforced masonry infill walls that will be used to test different seismic retrofit schemes. An analysis found the building has weak columns that are susceptible to sidesway collapse. The masonry infill provides much more shear strength than the bare concrete frame but at a smaller drift. Three retrofit schemes are proposed: 1) Replace masonry with damped bracing, 2) Jacket columns and some masonry with composite material to improve ductility, 3) Strengthen columns and add steel bracing. The effectiveness of each scheme will be tested using full-scale dynamic tests.
Abstract: Geo-technical engineering as a subject has developed considerably in the past four decades. There
has been remarkable development in the fields of design, research and construction of dam. India is capable of
designing and constructing a dam that would withstand a seismic jolt. The country needs water and electricity
to provide its people good living standards. Hydropower is the solution to the country's requirements, and this
can be achieved by storing water in dams.
In the past, earthquake effects may have been treated too lightly in dam design. Are such dams safe,
and how have they fared in previous earthquakes, this Paper will be limited to the some of finding about one
concrete types.
What will happen to dams during severe earthquake shaking? It is obvious that at present engineers
cannot answer this question with any certainty. But we are very much aware of the threat of disastrous losses of
life and damage to property if dams should fail, and we are making great effort to increase our under standing
of this complex topic.
This Paper deals with the case study of totaladoh Dam Situated in Vidarbha Region of Maharashtra
for Seismic Analysis by I.S.Code method (Simple Beam Analysis method). This also includes future scope of
analyzing the same dam for Seismic safety by very accurate method i.e. finite element method.
Keywords: Earthquake, The finite element method, Indian Standard codes(I.S.Code), horizontal
seismic coefficient (αh ),Hydrostatic pressure, Seismic analysis,
This presentation consists of information about earthquake and techniques used in the low cost earthquake resistant structures. There is complete description about the earthquake as well as the techniques related to the eq resistant techniques
A STUDY ON THE SEISMIC RESPONSE OF ELEVATED WATER TANKIRJET Journal
- The document discusses analyzing the seismic response of an elevated water tank considering soil-structure interaction and sloshing effects.
- A 3m x 3m x 3m reinforced concrete water tank supported by a 6m tall staging is modeled and analyzed using SAP2000 software.
- Fixed base analysis is performed considering empty and full tank conditions for different soil types in seismic zones II and III. Flexible base analysis accounting for soil-structure interaction is also conducted.
- Parameters such as base shear, base moment, displacements, modal periods, and frequencies are calculated and compared between the different analysis methods and soil/tank conditions.
The document discusses piles and their application in building tall structures like the Burj Khalifa. It describes how 192 piles that were 47 meters long supported the Burj Khalifa's foundation. The piles transmitted loads to hard rock 50 meters below through friction and end bearing. Challenges included weak soil and groundwater, which required using a polymer slurry during excavation to keep boreholes open until concrete was pumped in.
Research study on Soil Structure Interaction of Integrated Earth Retaining Wa...IRJET Journal
This document summarizes research on soil-structure interaction of integrated earth retaining walls. It discusses how precast concrete retaining walls can be constructed more quickly and cost effectively using interlocking blocks with mortar-less joints. The research aims to analyze such integrated retaining walls and evaluate their strength and deformation under lateral soil pressures through modeling in ANSYS software. Prior studies on precast retaining walls, soil-structure interaction, and use of relief shelves to increase wall stability are also reviewed.
This document discusses when a rock engineering design can be considered acceptable. It notes that there are no universal rules and that each design is unique based on the site conditions, loads, and intended use. Acceptability is based on engineering judgment guided by analyses and studies. Tables provide examples of typical problems, parameters, analysis methods, and acceptability criteria for different rock structures. Case histories are also discussed to illustrate the factors considered and criteria used to determine acceptability, including ensuring stability and reducing deformation. One case examines slope drainage works to improve stability of landslides in a reservoir area. Another evaluates deformation control for a power tunnel by locating a replacement in a zone of small movements.
This document proposes an alternative design for constructing the foundations of a new pedestrian bridge across a harbour. It suggests using a temporary sheet pile wall cofferdam that would allow workers to build the pile group and pile cap at the riverbed level, avoiding the need for divers. The cofferdam design is sized at 10x10m and embedded 10m deep. Calculations are presented to check for piping, heaving, and structural failure. A finite element model is also used. It is determined that drains will be needed to reduce water pressures and piping risks. The design of the internal bracing structure and construction sequence are also considered. The cofferdam is concluded to be a feasible alternative construction method for the bridge
Construction Of A Viaduct/Bridge: An OverviewSourav Goswami
This document is a submission by Sourav Goswami describing his 7-day internship project focused on the construction of a metro rail bridge. The project was conducted under Rail Vikas Nigam Limited and Gammon India Limited. Sourav thanks the project guides and staff who provided guidance and knowledge about bridge construction activities including piling, pile caps, piers, bearings and segments.
The document summarizes the planning, analysis, and design of a prestressed concrete bridge. It includes the design of various components like the deck slab, beams, piers, footings, and pile foundations. The bridge is a single span of 30 meters made of M40-M45 grade concrete and high strength steel tendons. The design considers aspects like dead and live loads, shear forces, bending moments, reinforcement requirements, and stress limits to construct the different elements of the prestressed concrete bridge according to code specifications.
The document discusses literature related to longwall mining geo-technical studies conducted at Ramagundam region in SCCL, India. It summarizes the key findings from 9 completed longwall panels at GDK.10A incline mine including production trends, geological conditions, equipment specifications, and analyses of caving behavior and periodic weighting distances for different panel lengths. Face length was found to influence main and periodic fall spans, with main fall varying between 63-78m for face lengths from 90-170m.
IRJET- Design and Analysis of Floating ResidenceIRJET Journal
This document describes the design and analysis of a floating residential building. The objectives were to design a floating structure using a pontoon system and expanded polystyrene (EPS) for buoyancy, and to analyze the structure using ANSYS software. Load calculations were performed to determine design loads on the structure from self-weight, live loads, wind loads, and wave loads. The floating base was designed with a draught of 2.8 meters to provide buoyancy equal to the weight of the superstructure. Stability analysis determined the center of gravity and metacentric height to ensure the structure would be stable under loading.
The document discusses a case study on designing aseismic structures in Earthquake Zone 5. It provides background on earthquakes and their effects. India is divided into 4 earthquake zones, with Zone 5 having the highest risk of earthquakes of MSK IX intensity or greater. The case study aims to design buildings with less expense to prevent total collapse and minimize damage in Zone 5. Literature on previous earthquake-resistant design studies is reviewed. The objectives are to compare shear forces and displacements in buildings of different shapes and with seismic irregularities, and to minimize expenses without compromising safety.
La Unión Europea ha acordado un embargo petrolero contra Rusia en respuesta a su invasión de Ucrania. El embargo prohibirá la mayoría de las importaciones de petróleo ruso a la UE y se implementará de manera gradual durante los próximos seis meses. La medida es la sanción económica más dura contra Rusia hasta la fecha y tiene como objetivo aumentar la presión sobre el gobierno de Putin para que ponga fin a la guerra.
The Rion-Antirion Bridge connects Greece across a strait prone to earthquakes. Its 2,252 meter long deck is suspended from four pylons by stay cables. To protect the bridge from seismic events, innovative energy dissipation systems were used, including viscous dampers and fuse restraints. Extensive testing of full-scale prototypes confirmed the design assumptions and behavior of the seismic protection system. The dampers and restraints limit deck movement during earthquakes while dissipating seismic energy. The fuse restraints fail under strong quakes, allowing the dampers to control deck oscillations. Similar systems isolate the approach viaducts from ground motions.
This document discusses ground reinforcement in seismic areas to improve the bearing capacity of shallow foundations. It presents the yield design theory framework for evaluating seismic bearing capacity, which defines a bounding surface delimiting allowable load combinations. This framework has been extended to a new design concept using soil reinforcement with inclusions to significantly improve foundation seismic bearing capacity. Numerical studies and experiments have validated this concept and the theoretical tools.
Patras 4th congress on steel structuresgefyra-rion
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
This document summarizes wind tunnel experiments investigating rain-wind induced vibration of inclined bridge stays. Key findings include:
1) Vibration occurred over a narrow wind speed range and was dependent on the presence of a thin water film on the stay surface.
2) Pressure and water thickness sensors on a model stay measured lift forces and water movement correlated with vibration. Lift force peaks preceded increases in vibration amplitude.
3) A physical model was developed explaining how small changes in water film thickness could alter boundary layer flow and pressure fields, driving vibration.
4) Tests on two larger stay diameters validated the model, showing vibration control through surface texturing that disrupted water flow without drag penalties.
This document discusses centrifuge tests that were conducted to validate an innovative foundation concept for the Rion Antirion bridge in Greece. The tests were conducted at a scale of 1/100 to simulate the behavior of the foundation system under various loading conditions. The tests validated the theoretical predictions of the foundation's bearing capacity and identified its failure mechanism under combined shear and overturning loads. Key results showed the development of pore pressures and bending moments in the foundation inclusions under cyclic loading, as well as a critical shear force of around 45 MN where bending moments increased rapidly. The centrifuge tests proved the validity of the innovative foundation concept and the design tools used.
On January 27, 2005, a lightning strike caused a fire on a stay cable of a cable-stayed bridge, leading to the failure of the cable. Tests and investigations were conducted to understand the failure mechanism and develop protection solutions. It was found that the lightning struck near a metallic collar, igniting a small fire that did not self-extinguish due to wind and rain. To prevent future failures, stretch wires were installed above stay cables to intercept strikes, and pylon protection was enhanced according to new standards to reduce direct strikes to cables.
The Rion-Antirion bridge in Greece experienced vibrations in its lightning protection cables after their installation. Wind tunnel testing revealed that the vibrations were due to galloping caused by the compact arrangement of the three stainless steel ropes. Reconfiguring the ropes with spacers to separate them was found to suppress the galloping without additional damping. Alternative solutions like adding viscous dampers would only work if a high level of damping could be achieved. It was decided to change the rope arrangement with spacers to provide both separation and additional damping to resolve the vibration issues.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
The document describes the seismic protection systems for the Rion-Antirion Bridge in Greece, which crosses an active seismic strait. The main bridge's continuous deck is suspended from four tall pylons and protected using fluid viscous dampers and fuse restraints connecting the deck to pylons. The dampers dissipate energy during earthquakes after the restraints fail at a predetermined force. Similar dampers and elastomeric isolators protect the approach viaducts. Full-scale tests on prototype dampers and restraints were conducted at laboratories in Italy and the US to verify the devices could withstand accelerations up to 0.48g as designed.
Fib2010 article269 june 2008 eq case study_rev_agefyra-rion
The Rion-Antirion Bridge in Greece withstood the 2008 Mw 6.5 Achaia-Ilia earthquake without structural damage. The bridge's seismic design included energy dissipation devices and sacrificial fuses that were activated during the quake as intended. Post-earthquake inspections confirmed yielding of all lateral fuses while minor non-structural damage occurred. Data from the bridge's monitoring system was analyzed to evaluate the bridge's response and performance of the seismic design elements during the strong shaking event.
1) The concrete durability strategy for the Rion-Antirion Bridge project focused on controlling corrosion of embedded steel by reducing chloride penetration through proper definition of exposure zones, concrete covers, and characterization of concrete mixes.
2) Specific tests were performed on concrete mixes to evaluate durability parameters such as rapid chloride penetration, water penetration, chloride diffusion coefficient, and oxygen permeability.
3) Strict quality assurance/quality control procedures were followed during construction to ensure the in-situ concrete quality matched specifications and laboratory results.
leewayhertz.com-AI in predictive maintenance Use cases technologies benefits ...alexjohnson7307
Predictive maintenance is a proactive approach that anticipates equipment failures before they happen. At the forefront of this innovative strategy is Artificial Intelligence (AI), which brings unprecedented precision and efficiency. AI in predictive maintenance is transforming industries by reducing downtime, minimizing costs, and enhancing productivity.
Your One-Stop Shop for Python Success: Top 10 US Python Development Providersakankshawande
Simplify your search for a reliable Python development partner! This list presents the top 10 trusted US providers offering comprehensive Python development services, ensuring your project's success from conception to completion.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Generating privacy-protected synthetic data using Secludy and MilvusZilliz
During this demo, the founders of Secludy will demonstrate how their system utilizes Milvus to store and manipulate embeddings for generating privacy-protected synthetic data. Their approach not only maintains the confidentiality of the original data but also enhances the utility and scalability of LLMs under privacy constraints. Attendees, including machine learning engineers, data scientists, and data managers, will witness first-hand how Secludy's integration with Milvus empowers organizations to harness the power of LLMs securely and efficiently.
Trusted Execution Environment for Decentralized Process MiningLucaBarbaro3
Presentation of the paper "Trusted Execution Environment for Decentralized Process Mining" given during the CAiSE 2024 Conference in Cyprus on June 7, 2024.
Nunit vs XUnit vs MSTest Differences Between These Unit Testing Frameworks.pdfflufftailshop
When it comes to unit testing in the .NET ecosystem, developers have a wide range of options available. Among the most popular choices are NUnit, XUnit, and MSTest. These unit testing frameworks provide essential tools and features to help ensure the quality and reliability of code. However, understanding the differences between these frameworks is crucial for selecting the most suitable one for your projects.
Introduction of Cybersecurity with OSS at Code Europe 2024Hiroshi SHIBATA
I develop the Ruby programming language, RubyGems, and Bundler, which are package managers for Ruby. Today, I will introduce how to enhance the security of your application using open-source software (OSS) examples from Ruby and RubyGems.
The first topic is CVE (Common Vulnerabilities and Exposures). I have published CVEs many times. But what exactly is a CVE? I'll provide a basic understanding of CVEs and explain how to detect and handle vulnerabilities in OSS.
Next, let's discuss package managers. Package managers play a critical role in the OSS ecosystem. I'll explain how to manage library dependencies in your application.
I'll share insights into how the Ruby and RubyGems core team works to keep our ecosystem safe. By the end of this talk, you'll have a better understanding of how to safeguard your code.
A Comprehensive Guide to DeFi Development Services in 2024Intelisync
DeFi represents a paradigm shift in the financial industry. Instead of relying on traditional, centralized institutions like banks, DeFi leverages blockchain technology to create a decentralized network of financial services. This means that financial transactions can occur directly between parties, without intermediaries, using smart contracts on platforms like Ethereum.
In 2024, we are witnessing an explosion of new DeFi projects and protocols, each pushing the boundaries of what’s possible in finance.
In summary, DeFi in 2024 is not just a trend; it’s a revolution that democratizes finance, enhances security and transparency, and fosters continuous innovation. As we proceed through this presentation, we'll explore the various components and services of DeFi in detail, shedding light on how they are transforming the financial landscape.
At Intelisync, we specialize in providing comprehensive DeFi development services tailored to meet the unique needs of our clients. From smart contract development to dApp creation and security audits, we ensure that your DeFi project is built with innovation, security, and scalability in mind. Trust Intelisync to guide you through the intricate landscape of decentralized finance and unlock the full potential of blockchain technology.
Ready to take your DeFi project to the next level? Partner with Intelisync for expert DeFi development services today!
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
Boost your website's visibility with proven SEO techniques! Our latest blog dives into essential strategies to enhance your online presence, increase traffic, and rank higher on search engines. From keyword optimization to quality content creation, learn how to make your site stand out in the crowded digital landscape. Discover actionable tips and expert insights to elevate your SEO game.
Skybuffer SAM4U tool for SAP license adoptionTatiana Kojar
Manage and optimize your license adoption and consumption with SAM4U, an SAP free customer software asset management tool.
SAM4U, an SAP complimentary software asset management tool for customers, delivers a detailed and well-structured overview of license inventory and usage with a user-friendly interface. We offer a hosted, cost-effective, and performance-optimized SAM4U setup in the Skybuffer Cloud environment. You retain ownership of the system and data, while we manage the ABAP 7.58 infrastructure, ensuring fixed Total Cost of Ownership (TCO) and exceptional services through the SAP Fiori interface.
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
Letter and Document Automation for Bonterra Impact Management (fka Social Sol...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on automated letter generation for Bonterra Impact Management using Google Workspace or Microsoft 365.
Interested in deploying letter generation automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
Digital Marketing Trends in 2024 | Guide for Staying AheadWask
https://www.wask.co/ebooks/digital-marketing-trends-in-2024
Feeling lost in the digital marketing whirlwind of 2024? Technology is changing, consumer habits are evolving, and staying ahead of the curve feels like a never-ending pursuit. This e-book is your compass. Dive into actionable insights to handle the complexities of modern marketing. From hyper-personalization to the power of user-generated content, learn how to build long-term relationships with your audience and unlock the secrets to success in the ever-shifting digital landscape.
5th LF Energy Power Grid Model Meet-up SlidesDanBrown980551
5th Power Grid Model Meet-up
It is with great pleasure that we extend to you an invitation to the 5th Power Grid Model Meet-up, scheduled for 6th June 2024. This event will adopt a hybrid format, allowing participants to join us either through an online Mircosoft Teams session or in person at TU/e located at Den Dolech 2, Eindhoven, Netherlands. The meet-up will be hosted by Eindhoven University of Technology (TU/e), a research university specializing in engineering science & technology.
Power Grid Model
The global energy transition is placing new and unprecedented demands on Distribution System Operators (DSOs). Alongside upgrades to grid capacity, processes such as digitization, capacity optimization, and congestion management are becoming vital for delivering reliable services.
Power Grid Model is an open source project from Linux Foundation Energy and provides a calculation engine that is increasingly essential for DSOs. It offers a standards-based foundation enabling real-time power systems analysis, simulations of electrical power grids, and sophisticated what-if analysis. In addition, it enables in-depth studies and analysis of the electrical power grid’s behavior and performance. This comprehensive model incorporates essential factors such as power generation capacity, electrical losses, voltage levels, power flows, and system stability.
Power Grid Model is currently being applied in a wide variety of use cases, including grid planning, expansion, reliability, and congestion studies. It can also help in analyzing the impact of renewable energy integration, assessing the effects of disturbances or faults, and developing strategies for grid control and optimization.
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-An opportunity to connect with fellow Power Grid Model enthusiasts and users.
1. 1609
1
DUMEZ-GTM, Nanterre, France
2
Kinopraxia Gefyra, Rion-Antirion Bridge Site, Greece
3
Géodynamique et Structure, Bagneux, France
STRUCTURAL RESPONSE OF THE RION-ANTIRION BRIDGE
Jacques COMBAULT1
, Pierre MORAND2
And Alain PECKER3
SUMMARY
The Rion Antirion Bridge will cross the Gulf of Corinth near Patras, in western Greece. It consists
mainly of a very impressive multi cable-stayed span bridge, about 3 kilometres long, which will be
the most important bridge of this type in the world (Refer to the article “The Rion-Antirion Bridge
– Design and Construction” by Jean-Paul Teyssandier, in these proceedings).
An exceptional combination of physical conditions makes the project quite unusual : high water
depth, deep strata of weak soil, strong seismic activity and fault displacements.
The structure is designed in view of challenging the earthquakes and ensuring the every day
serviceability of the link as well. Unusual techniques have been developed to solve the critical
problem of high degree seismicity in conjunction with a weak soil.
As the in-situ soil had to be improved with stiff and closely spaced inclusions, the yield design
theory, used for the evaluation of the bearing capacity of shallow foundations, has been extended
to an innovative foundation concept.
As the bridge deck is suspended on its full length, and therefore isolated as much as it can be,
sophisticated dynamic calculations have been implemented with the objectives of adjusting the
main parameters of the structure, evaluating the behaviour of the bridge under a strong seismic
event and taking into account the variability of the input motion.
Finally, as the pylons are one of the most critical part of the structure, several push-over analyses
were carried out to evaluate their structural response and have an over view of their behaviour.
INTRODUCTION
The Rion Antirion crossing consists of a main bridge, 2252 m long and 27.20 m wide, connected to the land by
two approaches, respectively 392 m and 239 m long, on each side of the gulf.
The main bridge is located in an exceptional environment which consists of a high water depth, a deep soil strata
of weak alluvions (the bedrock being approximately 800 m below the sea bed level) and finally a strong seismic
activity with possible slow but important tectonic movements.
If all these difficulties could be considered separately, there would be no unusual conceptual problem. But, the
conjunction of all these unfavourable conditions leads to a tough design. As the seismic activity is severe, the
soil structure interaction is the centre of high forces. As high forces are generated in the weak top layers of the
soil, they have to be reinforced and such reinforcement is not an easy task under 60 m of water.
2. 16092
DESIGN FEATURES
The seismic conditions to be taken into account are given by
the response spectrum at the sea bed level which
corresponds to a 2000 year return period (figure 1). The
peak ground acceleration is 0.5 g and the maximum spectral
acceleration is equal to 1.2 g on a rather large period range.
As previously mentioned the bridge also has to
accommodate possible fault movements which could lead to
a 2 m vertical and horizontal displacement of one part of the
main bridge with regard to the other part, the pylons being
simultaneously the subject of small inclinations due to the
corresponding rearrangement of the sea bed below the
foundations.
0
0,2
0,4
0,6
0,8
1
1,2
1,4
0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0
Period [s]
pseudoacceleration[g]
Fig. 1 - Design Spectrum
MAIN BRIDGE CONCEPT
This range of possible disasters lead to reduce as much as
possible the number of pylons in the strait and, therefore to
an exceptional multi-cable stayed span bridge made of 3
central spans 560 m in length and 2 side spans 286 m long
(figure 2).
The corresponding 4 pylons rest on the sea bed through a
large concrete substructure foundation, 90 m in diameter, 65
m high, which distribute all the forces to the soil.
Below this substructure, the heterogeneous and weak soil is
improved by means of inclusions which consist of 20 mm
thick steel pipes, 25 to 30 m long and 2 m in diameter,
driven at a regular spacing equal to or more than 7 m.
Fig. 2 - Main Bridge Concept - General view
The top of the steel pipes is covered by a calibrated gravel
layer which provides a transition between the structure and
the reinforced soil.
The huge foundations support, through octagonal pylon
shafts, pyramidal capitals which are the base of 4 concrete
legs converging at the top of the pylons and giving them the
appropriate rigidity.
The deck is a composite steel-concrete structure 27.20 m
wide (figure 3).
It is made of a concrete slab connected to twin longitudinal
steel I girders, 2.20 m high, braced every 4 meters by
transverse cross beams.
Fig. 3 - Composite Deck Concept
Careful analyses of the behaviour of the reinforced soil and improvements of this innovative concept lead to the
design of a continuous deck fully suspended and therefore isolated as much as it can be.
This made also possible to reduce the height of the deck girders and therefore to reduce the wind effects on the
bridge.
3. 16093
DESIGN
According to the previous general presentation of the Project, it is clear that the design of the Main Bridge is
mainly governed by the capability of the whole structure to resist the major seismic events including a possible
fault movement.
But both of these actions are generated by the motion of the ground and the corresponding displacements of the
foundations which implies the flexibility of the whole structure, the motion due to the earthquake being
temporary when the displacement due to the fault movement is a new permanent action.
As a matter of fact, substantial progress has been made with time in the seismic design approach. Meanwhile, it
does not allow the engineers to make a clear differentiation of the various steps of the design process to be
adopted in that case and it is not always easy to keep in mind that the structure has first to fit for purpose.
Actually, as long as the force-based design is definitely considered to be not appropriate from most of the world
experts, several design philosophies, including Capacity Design, Performance-based Design, Displacement-
based Design, appeared in many publications and could generate confusion in the design teams.
Indeed these design philosophies cover the same fundamental aspect of the problem which is that more flexible
is the structure, better will be its behaviour.
This means that the structure has first to be designed to resist what will be the main actions during its span life,
i.e. for the classical Serviceability Limit States and the corresponding Ultimate Limit States. This is the only
process which will produce the most flexible structure and will lead to the most favourable concept from a
seismic behaviour point of view. Then, the main components of the structure will be adjusted to the demand
during a given design earthquake in terms of acceptable damage.
Seismic Evaluation of the Foundations
The foundations are a typical example of a major part
of a structure where the Performance of the concept
has to be evaluated through the Capacity of the Soil,
to resist the Soil-Structure Interaction during the
Earthquake event, and the ability of the structure to
be the subject of exceptional displacements
(generated by the ground motion) with a controlled
Damage considered as acceptable.
In the case of the Rion-Antirion Main Bridge, the
foundations of the structure (figure 4) consist of two
separate parts :
• the reinforced soil, which is a clay-steel
composite 3D volume Fig. 4 - Reinforced Soil and Foundation Concept
• the pylon bases, which are rigid bodies not subject to any strength problems
These parts are made partially independent through the gravel layer which is designed to transfer a range of
horizontal forces compatible with both the strength of the reinforced soil and the global stability and acceptable
permanent displacements of the pylons.
Although the foundation looks like a piled foundation, it does not at all behave as such : no connection exists
between the inclusions and the raft. The foundation is therefore allowed to uplift or to slide with respect to the
reinforced soil.
The capacity design philosophy, introduced in foundation engineering for the evaluation of the seismic bearing
capacity of shallow foundations through the yield design theory, had then to be extended to this innovative
foundation concept in seismic areas.
4. 16094
Using extensively the yield design theory, through
a set of appropriate kinematic mechanisms
(figure 5), it was possible to derive an upper
bound estimation of the global bearing capacity of
the reinforced soil (figure 6).
For this purpose the reinforced soil was modeled
as a two-dimensional continuum appropriately
connected to beams simulating the stiff
inclusions.
Consequently, the calculations included the
contribution of the inclusions to the overall
resistance of this new concept
Fig. 5 - Kinematic Mechanism
.The simplicity of such calculations allowed to
optimize the size and the spacing of the
inclusions.
A set of centrifuge tests was run to validate the
concept and the theoretical approaches.
Then, non-linear finite element analyses could be
carried out. They lead to the constitutive laws of
the reinforced soil which are used in the general
calculations of the structure.
All these calculations, adequately combined with
a global dynamic analysis, allowed to check that
the effect of the coupled gravel layer and soil
reinforcement was to improve the bearing
capacity of the whole foundation system while
controlling the failure mode:
0
5000
10000
15000
20000
25000
30000
35000
0 100 200 300 400 500 600 700 800
Horizontal shear force at foundation level (MN)
Overturningmoment(MN-m)
W= 900 MN
W= 700 MN
W= 500 MN F.E Analysis
Results
Fig. 6 - Reinforced Soil Interaction Diagram
• The fuse provided by the gravel layer
limits the maximum shear force at the
interface, dissipates energy by sliding
and forces the foundation “to fail”
according to a mode which is compatible
with an acceptable behaviour of the
structure.
• The stiff inclusion reinforcement
increases the strength capacity of the soil
in order to eliminate undesirable failures
modes, like rotational failure which
would compromise dangerously the
global stability of the structure, and
dissipates an important amount of energy
as it could be anticipated from the Force-
Displacement Diagram (figure 7).
-1500
-1000
-500
0
500
1000
1500
-1,0 -0,8 -0,6 -0,4 -0,2 0,0 0,2 0,4 0,6 0,8 1,0
Fig. 7 - Soil Horizontal Force-Displacement Diagram
General Calculation of the Bridge (Dynamic Analyses)
All the previous calculations and results are used to carry out detailed and careful 3D dynamic analyses of the
whole structure.
5. 16095
Thanks to the development of a certain number of calculation tools on the basis of an existing powerful
computer software, the following very important properties are taken into account :
• non linear hysteretic behaviour of the reinforced soil
• possible sliding of the pylon bases on the gravel beds precisely adjusted to the accompanying vertical
force
• non linear behaviour of the reinforced concrete of the pylon legs (including cracking and stiffening of
concrete due to confinement)
• non linear behaviour of the cable-stays
• non linear behaviour of the composite bridge deck (including yielding of steel and cracking of the
reinforced concrete slab)
• and second order effects (or large displacements if any)
Twelve sets of independent artificial accelerograms conforming to the seismic design spectrum for the
3 components of the ground motion (the vertical one being scaled to 70 %) are used.
From these calculations, the way the reinforced soil behaves and the bases slide can be carefully checked.
Behaviour of the Pylons
The general calculation of the Bridge confirms the very good behaviour of the fully suspended deck which is
isolated as much as it can be. The relative displacement of the pylon bases with respect to the gravel layer
evidences some sliding which remains nevertheless acceptable and if, for any reason, this sliding could not occur
it has been checked that this was not a major point of concern.
Because the stability of the fully suspended multi cable-stayed span deck is secured by the stiffness of the pylons
which consist therefore of four legs converging at mid height of the anchorage zone, the pylons are the most
critical parts of the structure.
The dynamic analyses evidence that pylons and shortest cable-stays are indeed heavily loaded during the
earthquake event.
Clearly, from this point of view, there is a contradiction between what is required for the normal operation of
the bridge and the demand when a severe earthquake occurs. Indeed, the pylons are too stiff and the shortest
cables as designed for serviceability are not flexible enough.
Dynamic calculations show that the extreme shakes generate various crack patterns, distributed along the legs,
coming from both bending and tension. On the one hand, it can be observed that this cracking is favourable as it
generates the necessary flexibility of the legs without leading to unacceptable strains in the materials (i.e non
acceptable damages). On the other hand, it is not an easy task to get a global view of the behaviour of the pylon
as the information produced by a sophisticated analysis is too impressive. Time steps being 0.02 s - i.e
2500 steps for a 50 second event – the number of cross-sections in the model of one pylon leg being 13 – this
means that there would be 130.000 configurations of reinforced concrete cross-sections to be checked for each
pylon in order to evaluate the global behaviour of the structure at any time.
To face this voluminous quantity of information, the option is to check for the duration of the earthquake that the
strains of the materials (concrete and steel) in each cross-section are not exceeding the acceptable limits which
guarantee a controlled damage of the pylons while the general consistency of these sophisticated calculations
through the corresponding deflection shapes of the legs, axial shear forces and bending moments generated in
each cross-section, can be verified for time history peak values of those parameters.
6. 16096
Push-Over Analyses of the Pylons
Under these conditions, it makes sense to carry out a push-over analysis of the pylons to evaluate their global
behaviour and compare their performance to the demand, in terms of displacements, during the extreme seismic
event.
It can be pointed out that such a push-over analysis has become usual. Moreover it is extremely simple for a high
pier of a bridge which behaves as a single degree of freedom system and is therefore loaded by a shear force
acting at the level of the centre of gravity of the bridge deck.
It is not that simple anymore when the pier has become a pylon group made of four legs converging in a zone
where a large number of cables are generating many forces at various levels.
In this case, one way of performing such
a push-over analysis consists in
reproducing the state of equilibrium at a
stage of the dynamic analysis which can
be considered as the most unfavourable
situation during the 50 second event –
i.e. when forces, bending and
displacements are the most severe.
This approach allows to assess the
displacement demand on the pylon as
well as its displacement capacity as
estimated from the 3D dynamic analysis.
In a static analysis on a precise model of
the pylon, inertial forces coming from
the deck through the cables and from the
pylon concrete mass acceleration are
gradually increased by a magnification
factor while gravity or initially applied
forces (permanent loads) are not.
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
u=36cm
Fig. 8 – Displacement at top of pylon legs / Magnification factor
The diagram showing the displacement D at the top of the pylon legs versus the magnification factor A (figure 8)
allows to make a clear differentiation of the various steps characterising the behaviour of a whole pylon group.
As the displacement is mainly diagonal, these steps are as follows :
• Step 1 (0 < A < 0.4) - Elastic behaviour 0 < D < 0.10 m
• Step 2 (0.4 < A < 1.2) - Axial Cracking in the tension leg, hinges forming at the top of this leg then at
the top of the middle legs. (0,10 m < D < 0.45 m)
• Step 3 (1.2 < A < 1.4) - Yielding of steel in the tension leg (0,45 m < D < 0.60 m)
• Step 4 (1.4 < A < 1.6) – Hinge forming at the top of the compression leg (0,60 m < D < 0.90 m)
Such a push-over analysis shows that the displacement demand (D = 0.36 m for A = 1) is far under the
displacement capacity of the pylon legs which is of the order of 0.90 m at maximum and, therefore, either that
the damage should be limited in case of an extreme event and also that any deviation with regard to the input
motion should not have any bad consequences.
Another way to assess a realistic push-over analysis consists in using the classical approach and evaluating the
stucture’s modal response as proposed by the Independent Checker team (Buckland and Taylor and Seismic
Experts N. Priestley, F. Seible and M. Calvi).
7. 16097
Fig. 9 - Typical Deflection Shape of the Pylons
Such an approach could seem to be a priori unpracticable, the question being
how to simplify enough the loading of the pylon to model it by an horizontal
pushing force and where to push. Nevertheless, it can be shown from a
modal analysis of the structure that the deflection shape of a pylon for a
certain number of significant modes always involves simultaneously
bending moments and axial loads (either tension or compression) in the
various legs (figure 9).
This is indeed a consequence of the fact that the vertex of the legs has been
initially designed to be at the centre of gravity of the horizontal forces
generated by the cable-stays in the pylon heads in order to reach the
maximum stiffness under unfavourable live loads (traffic).
In addition to that it could be pointed out that the relative horizontal
displacement between the deck and the pylons due to the horizontal motion
of the ground should generate an extra tension of the longest stay cables
which should then reduce the action of the bending moments in the legs.
But it happens that the conjunction of all the characteristics of the fully
suspended bridge deck systematically leads to a modal deflection shape of
the deck which tends to generate a detention of the longest cable-stays which
should be over-stressed by the pylon deck relative displacement. In other
words, the favourable effects of the bending moments in the legs are
amplified by the favourable action of the cable-stays and this is a very
important result as far as the seismic evaluation of these stiff pylons is
concerned.
It can be therefore anticipated that a force F has to be applied step by step at
a distance d below the vertex (figure 10) which was finally considered to be
10.5 m after due consideration of the forces and bending moments generated
at the bottom of the pylon legs.
Fig. 10 - Push-Over Principles
Comparison of results from both push-over approaches with the results of the non linear full structural model
time-history approach reveals a very good consistency and then show the reliability and accuracy of this last
approach which, by the way, gives many other fruitful results for all parts of the structure the other approaches
cannot give.
Meanwhile, it must be emphasised that the second approach allows evaluating the seismic behaviour and
performing sensitivity analyses of an unusual reinforced concrete structure in a simple way. Used in an
appropriate manner, it gives a force-deflection curve similar to the one obtained from the peak time-history
results and can be run quickly to study the influence of the most significant pylon parameters (axial load and
steel reinforcement ratios).
8. 16098
CONCLUSION
It appears that permanent displacements of the reinforced soil are not significant when the sliding of the pylon
bases is of the order of 10 cm only.
Although the horizontal force is limited by this sliding, the pylons can globally rotate and the permanent rotation
of the reinforced soil can lead to a displacement of 85 cm of the pylon top.
All these displacements are acceptable as long as provision has been made for the whole structure to be
adaptable even if some adjustment has to be done after the major seismic event.
During the earthquake, the dynamic analysis shows that three of the four legs of the pylons are under tension. In
this case the maximum axial load ratio in the leg under compression is 0.40 and the maximum strains in the
materials are respectively 2.5 %o for the concrete (under combined compression and bending) and 6 %o for the
steel reinforcement. These values are therefore in a range which should guarantee that no uncontrolled damage
may happen.
In addition to that the pylon behaviour has been checked through a Push-Over Analysis which evidences a safety
factor of 1.6 with regard to the maximum effects generated by the design seismic event.
Finally, if the number of strands in most of the shortest cable stays is governed by the forces generated during
the earthquake it has to be pointed out that the deck is flexible enough to behave normally without any damage.
REFERENCES
[1] Combault J.and Morand P., The exceptional structure of the Rio-Antirion Bridge in Greece, Proceedings of
the IABSE Symposium in Kobe, Japan, September 1998.
[2] Pecker A., Capacity Design Principles for shallow foundations in Seismic Areas, 11th
European Conference
in Earthquake Engineering, Key Note Lecture, Paris la Defense, September 1998.
[3] Teyssandier J.P., The Rion-Antirion Bridge, Proceedings of the International Conference on New
Technologies in Civil Engineering, Lisbon, July 1997