Major issues to be considered for the successful application of unreinforced and steel fiber reinforced concrete (SFRC) tunnel final linings concepts include:
1) Application limits related to the geotechnical environment, seismic regime, and topography that must be determined based on safety and serviceability requirements.
2) Existing design codes and recommendations provide frameworks for evaluating the safety and serviceability of these lining concepts.
3) Case studies demonstrate that unreinforced and SFRC tunnel linings have been successfully used in tunnels up to 8km and 4.8km respectively, in various ground conditions.
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.
1. The document examines the use of Tunnel Stability Factor (TSF) to estimate convergence and face stability in weak rock tunnels. TSF considers rock mass strength, overburden height, and tunnel size.
2. Parametric numerical analyses were conducted on 74 tunnels varying in size, depth, and rock mass quality. Dimensionless plots of plastic zone radius and convergence vs TSF showed good correlation despite varying conditions.
3. Guidelines for criticality of stability were developed based on convergence-to-radius ratio ranges associated with TSF levels, indicating severe squeezing for TSF < 0.2 and increased risk of collapse below 0.3 without support.
This document discusses the challenges of tunnel design and construction in the GCC (Gulf Cooperation Council) region. It outlines several ongoing and future major tunneling projects in GCC countries like Qatar, Saudi Arabia, and Oman. Key challenges include weak rock formations, karstic features, high groundwater, and tight project timelines. Solutions proposed include using closed-face TBMs, detailed risk analysis to estimate machine advance rates, grouting programs for karst, and steel fiber-reinforced concrete tunnel linings to resist aggressive groundwater. Overall, the large scale of projects in challenging geotechnical conditions requires innovative design and construction approaches.
Back analysis of high tunnel convergences in clayey marlsSYSTRA
Ganntas Tunnel is part of the modernization project of the
railway between Alger and Oran, in Algeria. In order to double
and rectify the existing line between El Affroun and Khémis
Miliana, the alignment foresees the excavation of a 7km-long
twin tunnel. The excavation works started in June 2011 with
the contractor CCECC, under the supervision of SYSTRA.
Excavation is driven in conventional method by hydraulic
hammer simultaneously on 8 different faces since excavation
was started also from a junction window towards the middle
of the tunnel. The minimum longitudinal distance to be
respected between two contiguous tunnel faces has been set
to 30m. The tunnel cross-section is a 70m² oval shaped profile,
temporary support consists of shotcrete, bolts and steel ribs.
A 30 to 50cm thick cast in situ concrete final lining is provided
as well.
When the tunnel reached a fault zone in soft clayey marls,
extreme squeezing occurred, works were stopped, and reprofiling
operations were carried out along more than 100m
tunnel length. To date, works proceed at slow rate since high
convergences are still monitored and completion of works is
not expected before December 2016.
Written by SYSTRA tunnel experts : MISANO Edoardo, COUBRAY Jean-Louis,
ESPINOZA CARMONA Fabiola
Separating underground metro lines under operation in BakuSYSTRA
The document discusses a project to separate the existing Green and Red underground metro lines in Baku, Azerbaijan. This is a complex project due to constraints like limited surface access, unstable soil conditions with artesian water, and the need to complete the work within a 5 week shutdown period to minimize metro disruptions. The chosen design solution involves installing a steel pipe jacking frame to excavate two large caverns and separate the existing lines while constructing new tunnels, with soil treatment to control geotechnical risks and impacts on existing structures.
Assessing the interaction between the excavation of a large cavern and existi...SYSTRA
The Laboratoire Souterrain de Modane (LSM)
is an underground research laboratory located
in the Western Alps on the French – Italian
border. It is located in the middle of the
13km long Fréjus highway tunnel that links
Modane (France) to Bardonecchia (Italy) in
correspondence of the highest overburden
of 1800m. The LSM current activity is
mainly based on the investigations about
the dark matter and requires very sensitive
instrumentation which shall be protected from
cosmic rays. To comply with the new legislation
about safety in tunnels, the highway tunnels
2 owners agreed in 2007 the construction of
a parallel safety tunnel, at an average distance
of 50m from the existing tunnel and the
laboratory owner CNRS (Centre National de
recherche scientifique) also decided to extend
the existing laboratory with the construction of
a new 17000m3 cavern allowing the installation
of wider and more powerful instruments that
could increase chances of success of research.
Written by SYSTRA tunnel experts : SEMERARO Martino, MISANO Edoardo, SCHIVRE Magali, BOCHON Alain
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 document describes the cut and cover construction method used to build sections of a tunnel. It discusses (1) the reception area and sections built using diaphragm walls, soil nailing, and shotcrete; (2) the challenges of relocating utilities for the cut and cover sections; and (3) the process of excavating trenches, installing diaphragm walls, pouring concrete tunnel segments, and waterproofing. Cut and cover allows shallow tunnel sections to be constructed by excavating an open trench, installing structural supports, and then casting the tunnel structure.
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.
1. The document examines the use of Tunnel Stability Factor (TSF) to estimate convergence and face stability in weak rock tunnels. TSF considers rock mass strength, overburden height, and tunnel size.
2. Parametric numerical analyses were conducted on 74 tunnels varying in size, depth, and rock mass quality. Dimensionless plots of plastic zone radius and convergence vs TSF showed good correlation despite varying conditions.
3. Guidelines for criticality of stability were developed based on convergence-to-radius ratio ranges associated with TSF levels, indicating severe squeezing for TSF < 0.2 and increased risk of collapse below 0.3 without support.
This document discusses the challenges of tunnel design and construction in the GCC (Gulf Cooperation Council) region. It outlines several ongoing and future major tunneling projects in GCC countries like Qatar, Saudi Arabia, and Oman. Key challenges include weak rock formations, karstic features, high groundwater, and tight project timelines. Solutions proposed include using closed-face TBMs, detailed risk analysis to estimate machine advance rates, grouting programs for karst, and steel fiber-reinforced concrete tunnel linings to resist aggressive groundwater. Overall, the large scale of projects in challenging geotechnical conditions requires innovative design and construction approaches.
Back analysis of high tunnel convergences in clayey marlsSYSTRA
Ganntas Tunnel is part of the modernization project of the
railway between Alger and Oran, in Algeria. In order to double
and rectify the existing line between El Affroun and Khémis
Miliana, the alignment foresees the excavation of a 7km-long
twin tunnel. The excavation works started in June 2011 with
the contractor CCECC, under the supervision of SYSTRA.
Excavation is driven in conventional method by hydraulic
hammer simultaneously on 8 different faces since excavation
was started also from a junction window towards the middle
of the tunnel. The minimum longitudinal distance to be
respected between two contiguous tunnel faces has been set
to 30m. The tunnel cross-section is a 70m² oval shaped profile,
temporary support consists of shotcrete, bolts and steel ribs.
A 30 to 50cm thick cast in situ concrete final lining is provided
as well.
When the tunnel reached a fault zone in soft clayey marls,
extreme squeezing occurred, works were stopped, and reprofiling
operations were carried out along more than 100m
tunnel length. To date, works proceed at slow rate since high
convergences are still monitored and completion of works is
not expected before December 2016.
Written by SYSTRA tunnel experts : MISANO Edoardo, COUBRAY Jean-Louis,
ESPINOZA CARMONA Fabiola
Separating underground metro lines under operation in BakuSYSTRA
The document discusses a project to separate the existing Green and Red underground metro lines in Baku, Azerbaijan. This is a complex project due to constraints like limited surface access, unstable soil conditions with artesian water, and the need to complete the work within a 5 week shutdown period to minimize metro disruptions. The chosen design solution involves installing a steel pipe jacking frame to excavate two large caverns and separate the existing lines while constructing new tunnels, with soil treatment to control geotechnical risks and impacts on existing structures.
Assessing the interaction between the excavation of a large cavern and existi...SYSTRA
The Laboratoire Souterrain de Modane (LSM)
is an underground research laboratory located
in the Western Alps on the French – Italian
border. It is located in the middle of the
13km long Fréjus highway tunnel that links
Modane (France) to Bardonecchia (Italy) in
correspondence of the highest overburden
of 1800m. The LSM current activity is
mainly based on the investigations about
the dark matter and requires very sensitive
instrumentation which shall be protected from
cosmic rays. To comply with the new legislation
about safety in tunnels, the highway tunnels
2 owners agreed in 2007 the construction of
a parallel safety tunnel, at an average distance
of 50m from the existing tunnel and the
laboratory owner CNRS (Centre National de
recherche scientifique) also decided to extend
the existing laboratory with the construction of
a new 17000m3 cavern allowing the installation
of wider and more powerful instruments that
could increase chances of success of research.
Written by SYSTRA tunnel experts : SEMERARO Martino, MISANO Edoardo, SCHIVRE Magali, BOCHON Alain
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 document describes the cut and cover construction method used to build sections of a tunnel. It discusses (1) the reception area and sections built using diaphragm walls, soil nailing, and shotcrete; (2) the challenges of relocating utilities for the cut and cover sections; and (3) the process of excavating trenches, installing diaphragm walls, pouring concrete tunnel segments, and waterproofing. Cut and cover allows shallow tunnel sections to be constructed by excavating an open trench, installing structural supports, and then casting the tunnel structure.
The document discusses the design and construction challenges of the Deh Cho Bridge in the Northwest Territories of Canada. Some key points:
- The bridge crosses the Mackenzie River and connects Yellowknife to Highway 1, replacing a ferry. Its remote northern location and extreme winter conditions of -40°C posed challenges.
- An innovative extradosed bridge design was used with a 1045m continuous superstructure and expansion joints only at the abutments.
- Construction methods like incremental launching and extensive prefabrication were employed to minimize field work during the short construction season.
- Rigorous shop trial assembly and quality control processes were required given the remote site and need to minimize repairs.
Effect of underground tunnelling by (TBM) on foundations of existing structuresKishor Ade
This document discusses a dissertation on the effect of underground tunnelling by tunnel boring machine (TBM) on existing structures' foundations. It introduces the topic, provides a literature review on previous related studies, and outlines the methodology, which involves finite element modeling and analysis of shallow and raft foundations at different tunnel depths using Midas GTS NX software. The results found that tunnelling was suitable for raft and shallow foundations on hard and soft murrum soils when the tunnel crown depth was 20-25m below foundations, as displacements did not exceed code limits. Tunnelling was not suitable under shadu soil foundations.
Procedure and construction of road under bridge by box pushing methodeSAT Journals
Abstract The intersection of railway track and the road at the same level is referred to a level crossing. In the urban areas the level crossing are generally monitored by qualified railway personnel who monitor the train movement and close the level crossing gate to stop the interfering road traffic but such closing of gates leads to congestion in road traffic and also causes loss of time to road users. Road under bridge and road over bridge are considered as solutions for avoiding level crossings of roads and railway track. There are 3 main methods in construction of road under bridge. Box pushing method, Cut and cover method, Rolling technique using RH girder. In this we discuss about the implements, soil friction, effects required, capacity of jacks and there uses, skew angles and at square angles. Keywords: Road Under Bridge, Level Crossing, Box Pushing Method and RUB etc
The document discusses various aspects of tunnel engineering. It begins by introducing tunnels and their uses for transportation. It then discusses the Thames Tunnel in London as an example. The document outlines several advantages of tunneling over other methods. It also discusses considerations for selecting tunnel routes and economies of tunneling. The remainder of the document describes various tunneling methods through both rock and soft ground, as well as tunnel drainage, lighting, ventilation, lining, and maintenance.
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.
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.
Lyapichev Yury - Innovation structures of very lean RCC dams (Journal of Stru...Yury Lyapichev
This document discusses innovations in the structural design of roller compacted concrete (RCC) dams to reduce cement consumption and expand their use on non-rock foundations. It analyzes the static and seismic stress-strain states of symmetrical RCC dams with very lean concrete cores. It finds that for rock and dense sandy-gravel foundations, symmetrical RCC dams with slopes of 0.5-0.7 and outer zones of conventional concrete and central zones of cement-strengthened rockfill are the most economical option. These dams can be built up to 200m high on rock foundations and up to 100m high on dense sandy gravel foundations. They have greater seismic resistance and technical/economic efficiency than conventional RCC dams.
Construction Challenges For Bridges In Hilly AreasShantanu Patil
Hilly region pose unique problem for bridge construction. In a restricted hilly area itself climatic condition, Geographical features and hydrological parameters affect considerably. Keeping in view the bridge site and various constraints, type of bridges and method of construction are to be selected carefully for safe, economical and successful completion of bridges construction.
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.
Lyapichev. Analysis, design & behavior of CFRDsYury Lyapichev
This document provides information on the analysis, design, behavior, and seismic resistance of concrete face rockfill dams (CFRDs). It discusses numerical modeling of CFRDs, stresses in the concrete face and underlying transition zones, and the effects of high compressibility of rockfill materials. It also summarizes general recommendations for dynamic analysis and design of high CFRDs in seismic regions, including use of roller compacted concrete to reduce concrete face deformation. A new design for the 275m high Kambarata-1 CFRD in Kyrgyzstan incorporates this technique to improve seismic safety.
The document provides details on the design of the third phase of the Thannermukkom salt water barrier bridge. It includes the design of the following bridge components:
1) Deck slab using Pigeaud's curves to calculate bending moments from dead and live loads.
2) Cantilever slab, longitudinal girders, cross girders, bearings, pedestals, operating platform, pier, pier cap, pile, pile cap and apron designed based on codes and previous project details.
3) Pier design carried out using STAAD Pro software. Reinforced concrete grade M30 and steel grade Fe415 are used.
The preliminary dimensions and design loads as per IRC codes are
tunnelling scope, construction techniques and necessityShashank Gaurav
This document discusses tunnel construction methods and planning. It describes the main types of tunnels based on application and construction method. The key construction methods covered are cut-and-cover, pipe jacking, shield tunneling, New Austrian tunneling method, and immersed tube tunneling. For each method, the document outlines the construction sequence, advantages, and disadvantages. Proper planning stages including investigations and alignment selection are also emphasized.
The document discusses the Torino Metro Line 1 project in Italy. It describes the general characteristics of the metro line including the tunnel dimensions, length, and stations. It then discusses several key aspects that had to be managed for the project, including the contract type, procurement of a tunnel boring machine, complex design process due to the urban environment, public opinion, legislative conditions, and environmental requirements. The geology of the tunnel route consisting of quaternary deposits is also summarized.
Lyapichev. New RCC dams (Inter. Conf. on RCC, 2003)Yury Lyapichev
Seismic analyses of stress-strain state of new type of composed faced symmetrical hardfill dams with central zone of rockfill enriched with cement mortar of different heights & slopes are performed & compared with the traditional gravity RCC dams
This document contains a question bank for the subject Design of Bridges taught in the second semester at Valliammai Engineering College. It includes questions divided into parts A, B and C covering two units - short span bridges and design principles of long span RC bridges. The questions test different cognitive levels ranging from remember to evaluate and cover topics such as types of bridges, loading standards, design of slab bridges, box girder bridges, balanced cantilever bridges, arch bridges and box culverts. Design problems related to the analysis and design of bridges under different loadings are also included.
This document discusses the problem of differential settlement at bridge approaches in flexible pavements, which can cause bumps and reduce safety. It presents a 3D finite element model developed in ANSYS to analyze the response of different pavement structures at the bridge approach under static loads. The model evaluates the interface between the bridge abutment and flexible pavement. Results for varying base material properties and compaction levels are compared to a linear elastic model. Addressing differential settlement at bridge approaches is important for maintaining safety and comfort for road users.
Evaluating the application limits of Unreinforced & Steel Fiber Reinforced Co...MECandPMV
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of tunnel linings
7. Conclusions
The document provides an overview of reinforced concrete structures and discusses key concepts. It introduces reinforced concrete, describing it as a composite material made of concrete and steel reinforcement that works together. It then outlines the chapters that will be covered in the course, including generalities of reinforced concrete, evolution of standards, material properties, durability, beams under bending, and tension members. Selected references are also provided.
TINCE2016 - Steel Concrete Modules in Civil Work design of future Nuclear Pow...Gildas POTIN
Design of reinforced concrete structures ongoing nuclear power plant projects frequently faces issues related to more stringent design codes requirements that make necessary to take into account at design stage severe accident design loads which, in turn, lead to very large steel reinforcement demand. Subsequently design of these RC structures become very complex and, at construction stage, constructability often raises problems linked to actual installation of large densities of rebars which becomes in itself a complex task, expensive and time consuming. As a consequence, a trend in nuclear civil work design is emerging which consists in substituting, when very dense steel reinforcement ratios are expected from plain steel reinforcement bars design, typical reinforced concrete structural elements by Steel Concrete (SC) structures.
We will successively develop in this paper the technical issues that can arises when using this design process, try and identify the advantages and possible drawbacks that could be linked when using such Steel Concrete modules in project where the overall design is based on Euronorms.
Finally will be quickly presented computational methodologies which may be used for their design and describe some examples of structures for which this construction approach has been retained.
The document discusses the design and construction challenges of the Deh Cho Bridge in the Northwest Territories of Canada. Some key points:
- The bridge crosses the Mackenzie River and connects Yellowknife to Highway 1, replacing a ferry. Its remote northern location and extreme winter conditions of -40°C posed challenges.
- An innovative extradosed bridge design was used with a 1045m continuous superstructure and expansion joints only at the abutments.
- Construction methods like incremental launching and extensive prefabrication were employed to minimize field work during the short construction season.
- Rigorous shop trial assembly and quality control processes were required given the remote site and need to minimize repairs.
Effect of underground tunnelling by (TBM) on foundations of existing structuresKishor Ade
This document discusses a dissertation on the effect of underground tunnelling by tunnel boring machine (TBM) on existing structures' foundations. It introduces the topic, provides a literature review on previous related studies, and outlines the methodology, which involves finite element modeling and analysis of shallow and raft foundations at different tunnel depths using Midas GTS NX software. The results found that tunnelling was suitable for raft and shallow foundations on hard and soft murrum soils when the tunnel crown depth was 20-25m below foundations, as displacements did not exceed code limits. Tunnelling was not suitable under shadu soil foundations.
Procedure and construction of road under bridge by box pushing methodeSAT Journals
Abstract The intersection of railway track and the road at the same level is referred to a level crossing. In the urban areas the level crossing are generally monitored by qualified railway personnel who monitor the train movement and close the level crossing gate to stop the interfering road traffic but such closing of gates leads to congestion in road traffic and also causes loss of time to road users. Road under bridge and road over bridge are considered as solutions for avoiding level crossings of roads and railway track. There are 3 main methods in construction of road under bridge. Box pushing method, Cut and cover method, Rolling technique using RH girder. In this we discuss about the implements, soil friction, effects required, capacity of jacks and there uses, skew angles and at square angles. Keywords: Road Under Bridge, Level Crossing, Box Pushing Method and RUB etc
The document discusses various aspects of tunnel engineering. It begins by introducing tunnels and their uses for transportation. It then discusses the Thames Tunnel in London as an example. The document outlines several advantages of tunneling over other methods. It also discusses considerations for selecting tunnel routes and economies of tunneling. The remainder of the document describes various tunneling methods through both rock and soft ground, as well as tunnel drainage, lighting, ventilation, lining, and maintenance.
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.
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.
Lyapichev Yury - Innovation structures of very lean RCC dams (Journal of Stru...Yury Lyapichev
This document discusses innovations in the structural design of roller compacted concrete (RCC) dams to reduce cement consumption and expand their use on non-rock foundations. It analyzes the static and seismic stress-strain states of symmetrical RCC dams with very lean concrete cores. It finds that for rock and dense sandy-gravel foundations, symmetrical RCC dams with slopes of 0.5-0.7 and outer zones of conventional concrete and central zones of cement-strengthened rockfill are the most economical option. These dams can be built up to 200m high on rock foundations and up to 100m high on dense sandy gravel foundations. They have greater seismic resistance and technical/economic efficiency than conventional RCC dams.
Construction Challenges For Bridges In Hilly AreasShantanu Patil
Hilly region pose unique problem for bridge construction. In a restricted hilly area itself climatic condition, Geographical features and hydrological parameters affect considerably. Keeping in view the bridge site and various constraints, type of bridges and method of construction are to be selected carefully for safe, economical and successful completion of bridges construction.
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.
Lyapichev. Analysis, design & behavior of CFRDsYury Lyapichev
This document provides information on the analysis, design, behavior, and seismic resistance of concrete face rockfill dams (CFRDs). It discusses numerical modeling of CFRDs, stresses in the concrete face and underlying transition zones, and the effects of high compressibility of rockfill materials. It also summarizes general recommendations for dynamic analysis and design of high CFRDs in seismic regions, including use of roller compacted concrete to reduce concrete face deformation. A new design for the 275m high Kambarata-1 CFRD in Kyrgyzstan incorporates this technique to improve seismic safety.
The document provides details on the design of the third phase of the Thannermukkom salt water barrier bridge. It includes the design of the following bridge components:
1) Deck slab using Pigeaud's curves to calculate bending moments from dead and live loads.
2) Cantilever slab, longitudinal girders, cross girders, bearings, pedestals, operating platform, pier, pier cap, pile, pile cap and apron designed based on codes and previous project details.
3) Pier design carried out using STAAD Pro software. Reinforced concrete grade M30 and steel grade Fe415 are used.
The preliminary dimensions and design loads as per IRC codes are
tunnelling scope, construction techniques and necessityShashank Gaurav
This document discusses tunnel construction methods and planning. It describes the main types of tunnels based on application and construction method. The key construction methods covered are cut-and-cover, pipe jacking, shield tunneling, New Austrian tunneling method, and immersed tube tunneling. For each method, the document outlines the construction sequence, advantages, and disadvantages. Proper planning stages including investigations and alignment selection are also emphasized.
The document discusses the Torino Metro Line 1 project in Italy. It describes the general characteristics of the metro line including the tunnel dimensions, length, and stations. It then discusses several key aspects that had to be managed for the project, including the contract type, procurement of a tunnel boring machine, complex design process due to the urban environment, public opinion, legislative conditions, and environmental requirements. The geology of the tunnel route consisting of quaternary deposits is also summarized.
Lyapichev. New RCC dams (Inter. Conf. on RCC, 2003)Yury Lyapichev
Seismic analyses of stress-strain state of new type of composed faced symmetrical hardfill dams with central zone of rockfill enriched with cement mortar of different heights & slopes are performed & compared with the traditional gravity RCC dams
This document contains a question bank for the subject Design of Bridges taught in the second semester at Valliammai Engineering College. It includes questions divided into parts A, B and C covering two units - short span bridges and design principles of long span RC bridges. The questions test different cognitive levels ranging from remember to evaluate and cover topics such as types of bridges, loading standards, design of slab bridges, box girder bridges, balanced cantilever bridges, arch bridges and box culverts. Design problems related to the analysis and design of bridges under different loadings are also included.
This document discusses the problem of differential settlement at bridge approaches in flexible pavements, which can cause bumps and reduce safety. It presents a 3D finite element model developed in ANSYS to analyze the response of different pavement structures at the bridge approach under static loads. The model evaluates the interface between the bridge abutment and flexible pavement. Results for varying base material properties and compaction levels are compared to a linear elastic model. Addressing differential settlement at bridge approaches is important for maintaining safety and comfort for road users.
Evaluating the application limits of Unreinforced & Steel Fiber Reinforced Co...MECandPMV
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of tunnel linings
7. Conclusions
The document provides an overview of reinforced concrete structures and discusses key concepts. It introduces reinforced concrete, describing it as a composite material made of concrete and steel reinforcement that works together. It then outlines the chapters that will be covered in the course, including generalities of reinforced concrete, evolution of standards, material properties, durability, beams under bending, and tension members. Selected references are also provided.
TINCE2016 - Steel Concrete Modules in Civil Work design of future Nuclear Pow...Gildas POTIN
Design of reinforced concrete structures ongoing nuclear power plant projects frequently faces issues related to more stringent design codes requirements that make necessary to take into account at design stage severe accident design loads which, in turn, lead to very large steel reinforcement demand. Subsequently design of these RC structures become very complex and, at construction stage, constructability often raises problems linked to actual installation of large densities of rebars which becomes in itself a complex task, expensive and time consuming. As a consequence, a trend in nuclear civil work design is emerging which consists in substituting, when very dense steel reinforcement ratios are expected from plain steel reinforcement bars design, typical reinforced concrete structural elements by Steel Concrete (SC) structures.
We will successively develop in this paper the technical issues that can arises when using this design process, try and identify the advantages and possible drawbacks that could be linked when using such Steel Concrete modules in project where the overall design is based on Euronorms.
Finally will be quickly presented computational methodologies which may be used for their design and describe some examples of structures for which this construction approach has been retained.
this slides is about the technologies like using HPC, SCC, high performance steel, prefabricated deck panels, spot welding system,GSSI bridge scan system used in construction of bridges
This document provides details about innovative technologies used in the construction of special bridge structures. It summarizes the construction of a cable-stayed bridge in Bardhaman, India. Some key points:
- The bridge has a main span of 124 meters and uses precast concrete segments, steel pylons, and parallel strand cable-stay system for support.
- Advanced modeling software and wind tunnel testing were used in the design. Precast concrete slabs were used to avoid scaffolding.
- Construction involved erecting the steel pylons and deck segments, installing and stressing the 180 tons of stay cables to provide support.
- Monitoring sensors were installed to track the bridge's performance over its 100
This document provides an overview of slab track systems for high-speed railways. It examines in depth various slab track designs that are being used around the world. At least 34 different ballastless systems have been recorded. The most significant slab track systems are analyzed in detail and compared based on their structural characteristics, technical performance, economic factors, and advantages over conventional ballasted tracks. Finite element modeling is used to demonstrate the improved stability and durability of slab tracks under traffic loading.
There was a Bridge 2018 Conference on Innovative Technologies of Bridges organised by IIBE at Lucknow. During the conference held on 25.05.18 this paper was presented by Rajesh Prasad, ED Metro RVNL.
This document discusses the development of eco-friendly high-performance concretes for use in the structural design of record-long suspension bridge towers along the E39 highway in Norway. The concretes were designed with low water-to-binder ratios of 0.35 or 0.30 and supplementary cementitious materials to reduce CO2 emissions. Testing showed strength development and durability suitable for the large bridge towers. Structural analysis and optimization methods were used to dimension the towers, resulting in up to 32% less concrete and 15% less reinforcement for a 2,050m main span bridge, reducing CO2 emissions by up to 60%. These concretes and design approaches could enable the construction of even longer suspension bridges.
Pt slab design philosophy with slides and pictures showing benefitPerwez Ahmad
This document summarizes the history and development of post-tensioned flat slab construction. It began with early research and development of prestressing in Europe in the 1920s-1930s to allow for longer bridge spans. Prestressing was later applied to other structures like aircraft hangars and then to flat slab construction in the 1950s. Post-tensioned flat slabs provide benefits over reinforced concrete flat slabs like reduced cracking, thinner slabs, and increased spans. The document discusses materials, design codes, comparisons to reinforced concrete, and examples of ongoing post-tensioned flat slab projects in Oman.
Types of pavement construction procedureBhavik A Shah
The document discusses different types of pavement construction procedures, including continuously reinforced concrete pavement (CRCP), prestressed pavement, steel fibre reinforced concrete pavement, and specifications from organizations like the Indian Road Congress (IRC) and American Concrete Institute (ACI). It provides details on the characteristics, advantages, and construction issues of CRCP and prestressed pavement. It also outlines properties and specifications for steel fibre reinforced concrete and various IRC specifications for pavement construction.
Sustainable Solution for Shoring Method of Cross-Creek Bridge in Ankeng MRT S...Dr. Amarjeet Singh
In the Ankeng Light Rail MRT system (ALRMS) project, the U7 box girder passes crossing the Erbads creek and needs a temporary supporting system for the construction work. In this study, three temporary shoring system options were proposed to be the construction method. The D-B Contractor, New Asia construction and Development Corporation, evaluated and selected the optimal choice, The Steel truss frame with supporting beams, to serve as the temporary supporting system. Compare the deflection of Δmax and Δactual, which are 1.609 cm and 1.59 cm, respectively. This result presented that the shoring system composed of the H912*302*18*37 supporting beams and steel truss frame had achieved outstanding performance and work to construct the U7 box girder. This paper presents how the three options are evaluated and the detailed construction processes along with the survey verification for the method.
The document discusses concrete filled steel tube (CFST) columns under axial compressive loads. It summarizes that CFST columns have higher load capacity than hollow steel tubes due to the composite action between steel and concrete. Experimental tests were conducted on circular and square CFST columns with varying concrete grades and heights. The results showed that square CFST columns had higher load capacity than circular columns. Ultimate load also increased with higher concrete grade. Failure modes included local and overall buckling. CFST columns provide advantages like increased strength, reduced construction costs, and improved fire resistance compared to reinforced concrete columns.
This document discusses optimizing the design of road bridges to minimize environmental impact and cost. It proposes an automated design and optimization procedure that covers gaps between theoretical studies and practical application. The procedure is demonstrated for optimizing three bridge types: (1) reinforced concrete beam bridges, (2) reinforced concrete overhang bridge slabs, and (3) composite bridge decks. For each application, the procedure determines optimal structural configurations and cross-sectional dimensions to minimize investment cost and environmental impact from materials. Case studies show the optimized solutions reduce costs by 4-13% compared to traditional designs while remaining constructible. Recommendations include using more durable materials like GFRP reinforcement and minimizing reinforcement.
My publication Tunnels and Tunnelling magazineFilipe Mello
The document summarizes the construction of a crossover tunnel at the Fisher Street site for the Crossrail project in London. Key details include:
- The crossover tunnel allows trains to switch between the main eastbound and westbound running tunnels for maintenance or emergencies.
- Construction involved sprayed concrete lining (SCL) for the primary lining and cast-in-situ concrete for the secondary lining of the crossover tunnel and tunnel enlargements.
- Logistics were challenging due to the small site footprint in central London. Concrete delivery used boreholes from an adjacent disused tram tunnel to supply the tunnels.
- The secondary lining construction involved spraying a regulating layer, installing dowels and sprayed
We apply state-of-the-art technology to obtain the most efficient design for geotechnical and tunnelling projects. We are specialist in the field of applications of 2D and 3D Finite Element Method for tackling complex soil-structure interaction problems.
We have experience of more than 35 years in the field of geotechnical and tunnel engineering, leading design teams for major challenging projects in The UK, Europe and Middle East.
IRJET - Analysis and Design of Steel Box Girder Bridge using Tekla StructuresIRJET Journal
This document presents the analysis and design of a steel box girder bridge with four different cross-sectional models using Tekla Structures software. The models include a single cell, double cell, triple cell, and multi-cell steel box girder bridge. The bridges are designed for a highway loading according to IRC specifications and codes. The models are analyzed under dead loads, live loads, and other load combinations. Results show that bending moments and stresses increase with more cells in the cross-section. The single cell box girder results in the lowest bending moment, requiring less steel and providing the most economical cross-section compared to the other multi-cell options when loading and support conditions are kept the same.
This document summarizes the design of a steel frame structure for an indoor sports facility in Portugal according to Eurocode standards. It describes the architectural design of a dual-pitch roof and choice of structural steel components including planar truss rafters. It also outlines the modeling approach in SAP2000 including definition of loads such as self-weight, live, wind and thermal loads according to Eurocode standards. Load combinations are defined for the ultimate limit state structural/geometric verification of members.
Modern fastening systems in tunnel constructionStefan Lammert
This document discusses fastening systems used in tunnel construction. It begins by providing examples of fixing failures in tunnels that resulted in accidents and deaths. It then discusses various fastening systems, focusing on cast-in channels. Cast-in channels are categorized as a cast-in-place anchor system. The document outlines key considerations for selecting fastening systems, including corrosion protection, the anchoring base (concrete properties), and installation. It emphasizes the importance of selecting systems suitable for the intended service life and environment of the tunnel. Cast-in channels are presented as a preferred alternative to traditional post-installed anchors, as they allow for simpler installation and compensation of tolerances.
This document discusses the analysis of cable-stayed bridges. It begins with an introduction to cable-stayed bridges, noting that they usually span 200 to 800 meters and have towers from which cables support the bridge deck. It then discusses the various components of cable-stayed bridges such as the pylons, cables, and deck. The document also summarizes the different modeling, analysis methods like linear and non-linear, and software that can be used to analyze cable-stayed bridges. It concludes by stating that cable-stayed bridges are more economical than suspension bridges and that area object modeling is more accurate than spine modeling.
Similar to Ilias Michalis PMV Workshop Dubai 2014 (20)
1. Evaluating the application limits of Unreinforced &
Steel Fiber Reinforced Concrete (SFRC) for tunnel final linings
Ilias Michalis, MSc, DIC
Technical Manager Underground Works, Qatar Rail
Dr. Petros Fortsakis
Tunnel Expert, Qatar Rail
Konstantinos Seferoglou, MSc
Geotechnical Expert, Qatar Rail
Dr. Zheng Huang
Tunnel Expert, Qatar Rail
https://www.db-international.de
2. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
3. The existing design and construction
experiences in tunnelling worldwide
gives the answer:
NO
1. ARE THE CONCEPTS OF
THE UNREINFORCED &
STEEL FIBER REINFORCED
CONCRETE TUNNEL FINAL
LININGS PROHIBITIVE
ONES?
https://www.db-international.de
4. https://www.db-international.de
Tunnel Country Type of
tunnel
Completion
time
Length
(km)
Tunnel
section
(m2)
Final lining
thickness
(cm)
Brief
geology
Tradenberg Switzerland Motorway 2009 2 126 40 Mudstones,
Sandstones,
Clay marls
Grouft Tunnel Luxembourg Motorway 2010 3 96 Marls,
Sandstones
Gotthard -
Base Tunnel
Switzerland Railway On going 25 65 30 - 40 Gneiss
Loetschberg
Tunnel
Switzerland Railway 2008 35
Schwarzer berg
Tunnel
Germany Motorway 2004 1 102 30 - 40 Gypsum
CTRL 104 North
Downs Tunnel
U.K. Railway 2002 3 103 35 - 40 Chalk
RECENT TUNNELS WITH UNREINFORCED CONCRETE
TUNNEL FINAL LININGS
5. https://www.db-international.de
Tunnel Country Type of
tunnel
Completion
time
Length
(km)
Tunnel
section
(m2)
Final lining
thickness
(cm)
Brief
geology
Aesch Tunnel Switzerland Motorway 2.3 135 35 - 40 Molasse rocks
Rennsteigtunnel Germany Motorway 2001 8 80 - 120 30 Sandstones,
Siltstones,
Conglomerates
Tempi Tunnel T1 Greece Motorway 2014 1.8 120 45 Marbles and
Amphobolites
Tempi Tunnel T2 Greece Motorway 2014 6 120 45 Amphibolites
Marbles with
phyllites
intercalations
Panagopoula
Tunnel T26
Greece Motorway On going 4 100 40 Limestones,
Cherts and
Conglomerates
RECENT TUNNELS WITH UNREINFORCED CONCRETE
TUNNEL FINAL LININGS
6. https://www.db-international.de
Tunnel Country Type of
tunnel
Completion
time
Length
(km)
Tunnel
section
(m2)
Final lining
thickness
(cm)
Brief
geology
CTRL
(Connection to
St. Pancras Station)
U.K. Railway 2004 2 40.2 35 London Clay
Oenzberg Tunnel Switzerland Railway 2003 3.16 102.7 40 Molasse
Hofoldinger Stollen tunnel Germany Hydraulic 2004 17.5 8.6 18 Hard
Conglomerates
STEP
(Strategic Tunnel
enhancement Programme)
U.A.E (Abu
Dhabi)
Hydraulic 2012 15.6 31.2 28 Claystones &
Mudstones
Siltstones
Gypsum
Barcelona Metro
(Line 9) - Can Zam stretch
Spain Railway 2003 3.9 93.3 35 Granodiorites
RECENT TUNNELS WITH STEEL FIBER REINFORCED CONCRETE
TUNNEL FINAL LININGS
7. https://www.db-international.de
Tunnel Country Type of
tunnel
Completion
time
Length
(km)
Tunnel
section
(m2)
Final lining
thickness
(cm)
Brief
geology
Sao Paulo Metro (Line 4) Brazil Railway 2009 1.2 55.4 35 Weathered
Gneiss
Clem Jones Tunnel Australia Motorway 2010 4.8 102 40 Volcanic Ash
Metamorphic
rocks
Gold Coast
Desalination Tunnels
Australia Hydraulic 2008 (planned) 4.2 9.1 30 Sandstones &
Mudstones
RECENT TUNNELS WITH STEEL REINFORCED CONCRETE
TUNNEL FINAL LININGS
8. https://www.db-international.de
Unreinforced concrete tunnel linings were
successfully constructed for tunnels of large
cross sections and in different ground conditions.
Rennsteig tunnel presently is the longest
Motorway tunnel in Germany (length ~ 8km).
Tempi Tunnel T2 presently is the longest
Motorway tunnel in the Balkans region (length ~
6km).
In CTRL 104 North Downs Tunnel, the
unreinforced lining is considered as a real “value
engineering” solution resulted to £10m savings in
the budget and completion time 5 months ahead
of the Project’s schedule.
9. https://www.db-international.de
Steel fiber reinforced concrete tunnel final linings
have been successfully constructed mainly in
railway tunnels of cross sections between 40m2
to 90m2.
Thickness of the Steel fiber reinforced concrete
tunnel final linings in railway tunnels varied
between 35cm 45cm.
Barcelona Line 9. “Mixed” concept of steel fibers
and traditional steel reinforcement was applied.
Clem Jones Tunnel currently is the longest
motorway tunnel in Australia (4.8 km).
STEP is the first application of the steel
reinforced concrete concept in segmental linings
in the GCC countries.
10. Major issues to be considered for the successful application of the concepts:
Application limits of the concepts must be derived.
These Application limits are related to:
• The geotechnical environment (e.g. ground stiffness & acting overburden geostatic load)
• The seismic / tectonic regime
• The topography
of every tunnel location
The Application limits are related to well determined safety and serviceability
requirements of the unreinforced & steel reinforced concrete tunnel final lining behaviors.
The Design and Construction must fulfill these requirements.
https://www.db-international.de
11. Major issues to be considered for the successful application of the concepts:
The Safety and Serviceability Requirements of the unreinforced and SFRC
tunnel final linings behaviors are described in existing Design Codes and
Design Recommendations.
Realistic cost-effective in situ concrete construction solutions, which
prevent from the formation of the initial cracking, caused during the
temperature cycle: “Dissipation of the hydration heat and subsequent
shrinkage”.
https://www.db-international.de
12. Main advantages and material properties of steel fiber reinforced concrete:
Ductility in tension and in compression
Impact resistance
High resistance against spalling
Increased Durability
Low crack widths under service conditions
Flexural strength in all three directions
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13. Applications & Effectiveness of steel fiber reinforced concrete in segmental linings
Steel fiber reinforced concrete segmental linings can be used for loading
cases, which result to high compressive forces and relatively low bending
moments.
There are no costs from the provision and storage of reinforcement cages.
No reinforcement works is necessary, thus the working process is
accelerated.
In case of cracking, load transfer across the crack is assured. Load bearing
capacity of steel fiber reinforced concrete segmental lining is ensured.
The increased ductility of the steel fiber reinforced concrete in segmental
linings results to lower “absorbed” forces.
https://www.db-international.de
14. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
15. Relevant Codes, Standards, Guidelines & Recommendations
Eurocode 2 EN 1992 - 1 / Section 12: Plain and lightly reinforced concrete
structures
AFTES Recommendations in respect of the use of plain concrete in tunnels
(e.g. crack depth and loads eccentricity limits)
Rudolf Pottler publication: “The unreinforced inner lining of rock tunnels -
stability analysis and deformation of the crack area” (e.g. crack width
estimation)
DAUB Recommendations for executing and application of unreinforced tunnel
inner linings
FIB Model Code for Concrete Structures 2010
https://www.db-international.de
17. https://www.db-international.de
Eurocode 2 EN 1992 - 1 / Section 12:
Plain (unreinforced) and lightly reinforced concrete structures
Concrete additional design assumptions (Clause 12.3.1):
1. Design compressive strength: fcd = acc,pl(fck/γc)
2. Design tensile strength: fcd = acc,pl(fctk,005/γc)
where: acc,pl & act,pl = 0.8, due to the less ductile properties of plain concrete
fck is the characteristic compressive strength of concrete
fctk,0.05 is the characteristic axial tensile strength of concrete and
γc =1.50 for persistent and transient actions, 1.20 for accidental actions
18. https://www.db-international.de
Eurocode 2 EN 1992 - 1 / Section 12:
Plain (unreinforced) and lightly reinforced concrete structures
Concrete additional design assumptions
(Clause 12.3.1):
3. Tensile stresses can be considered in
the design, by extending linearly the
stress- strain diagram of concrete into
the tensile region, up to the design
tensile strength fctd
19. https://www.db-international.de
Eurocode 2 EN 1992 - 1 / Section 12:
Plain (unreinforced) and lightly reinforced concrete structures
Verification Criteria at the Ultimate Limit States are described in Clause 12.6:
Clause 12.6.1 describes the design resistance to bending and axial force:
Computed axial force N < NRd = fcd × b × hw × (1-2e/hw)
fcd is the concrete design compressive strength
NRd is the ultimate axial force,
b is the overall width of the lining section
hw is the overall thickness of the lining section and
e is the load eccentricity
No limit to acceptable
crack depth
20. https://www.db-international.de
Eurocode 2 EN 1992 - 1 / Section 12:
Plain (unreinforced) and lightly reinforced concrete structures
Verification Criteria at the Ultimate Limit States are described in Clause 12.6:
Clause 12.6.3 describes the design resistance to shear:
For a tunnel lining section subjected to a shear force V and an axial force N,
acting over a compressive area Acc, then:
the shear component of design stress τcp = 1.5(V/Acc) ≤ fcvd
where fcvd is the concrete design strength in shear and compression
21. https://www.db-international.de
AFTES Recommendations in respect to the use of plain concrete in tunnels
Verification Criteria at the Ultimate Limit State (based on Eurocode 2):
Design resistance to bending and axial force.
If the computed axial forces N < NRd0 = 0.027(fck × b × hw), NO particular
check is needed.
fck is the characteristic compressive strength of concrete, b is the overall width
of the lining section and hw is the overall thickness of the tunnel lining section
22. https://www.db-international.de
Verification Criteria at the Ultimate Limit States (based on Eurocode 2)
Design resistance to bending and axial force.
If the computed axial forces N>NRd (ultimate axial force), then Reinforcement
MUST be provided or Redesign of the section is NECESSARY
NRd = 0.57 × fck × b × hw (1-2e/hw) (basic ULS)
NRd = 0.74 × fck × b × hw (1-2e/hw) (accidental ULS)
Load eccentricity e = (M / N), M is the computed bending moment
AFTES Recommendations in respect to the use of plain concrete in tunnels
23. https://www.db-international.de
Verification Criteria at the Ultimate Limit State (based on Eurocode 2)
Design resistance to bending and axial force.
If the computed axial forces NRd0 < N<NRd then:
Load eccentricity e=M/N > 0.3 × hw
Load eccentricity e=M/N < 0.3 × hw
AFTES recommends the limitation of the load eccentricity: e< 0.3xhw and imposes
the crack depth limitation to the ½ of the unreinforced tunnel lining thickness (major
serviceability criterion for the unreinforced concrete tunnel final linings)
Unreinforced: UNACCEPTABLE
Unreinforced: ACCEPTABLE
AFTES Recommendations in respect to the use of plain concrete in tunnels
25. https://www.db-international.de
DAUB - German Recommendations for executing and application of
unreinforced Tunnel final (inner) linings
DAUB attempts to restrict the application fields of unreinforced tunnel final
linings, due to high possibility of cracking, as an effect of their low tensile
strength.
According to DAUB, unreinforced tunnel final linings are suitable for blocks
of standard geometry in road tunnels, provided that these are located in
solid rocks and not in excessive depths.
26. https://www.db-international.de
DAUB - German Recommendations for executing and application of
unreinforced Tunnel final (inner) linings
DAUB proposes:
Unreinforced tunnel linings can be executed at maximum block lengths of
12m to 12.5m.
For road and railway tunnels, the minimum thickness of unreinforced
tunnel linings is 30cm. Smaller thicknesses are possible for relative
smaller tunnel sections.
27. https://www.db-international.de
DAUB - German Recommendations for executing and application of
unreinforced Tunnel final (inner) linings
DAUB proposes:
Suitable concrete mixes, which restrict the maximum temperature during
the setting process, but result to short stripping periods.
• Cement / fly ash combinations are advantageous.
• The addition of hard coal fly ash reduces the hydration heat effect,
improves processability, diminishes the danger of demixing and caters
for a denser concrete texture.
28. https://www.db-international.de
FIB Model Code for Concrete Structures 2010
Significant relevant clause for FRC: Clause 5.6
“……Structural design of FRC elements is based on the post-cracking
residual strength provided by fibre reinforcement….Fibres can be used to
improve the behavior at SLS since they can reduce crack spacing and
crack width, thereby improving durability. Fibres can be used to improve
the behavior at ULS where they can partially or totally substitute
conventional reinforcement……”
Fiber reinforced concrete structures
30. https://www.db-international.de
Behavior in tension
Nominal values of the material properties can be determined by performing a
three-point bending test on a notched beam according to EN 14651.
Fiber reinforced concrete structures
Fj[N]: load corresponding to CMOD = CMODj
CMOD: crack mouth opening displacement
31. https://www.db-international.de
Behavior in tension
Nominal values of the material properties can be determined by performing a
three-point bending test on a notched beam according to EN 14651.
Fiber reinforced concrete structures
Fj[N]: load corresponding to CMOD = CMODj
CMOD: crack mouth opening displacement
fR1
fR3
32. https://www.db-international.de
Classification
• Characteristic flexural strength, serviceability conditions: fR1k
• Characteristic flexural strength, ultimate conditions: fR3k
• Example of FRC class: 4c
The first number “4” defines the minimum value fR1k: 4MPa
The letter “c” defines the ratio the range of the ratio fR3k/fR1k
Fiber reinforced concrete structures
a: 0.5 < fR3k/fR1k < 0.7
b: 0.7 ≤ fR3k/fR1k < 0.9
c: 0.9 ≤ fR3k/fR1k < 1.1
d: 1.1 ≤ fR3k/fR1k < 1.3
e: 1.3 ≤ fR3k/fR1k
Limit of Proportionality:
33. https://www.db-international.de
Classification
• Characteristic flexural strength, serviceability conditions: fR1k
• Characteristic flexural strength, ultimate conditions: fR3k
• Example of FRC class: 4c
The first number “4” defines the minimum value fR1k: 4MPa
The letter “c” defines the ratio the range of the ratio fR3k/fR1k
• Fibre reinforcement can substitute (also partially)
conventional reinforcement at ultimate limit state, if the
following relationships are fulfilled: fR1k/fLk>0.4, fR3k/fR1k>0.5.
Fiber reinforced concrete structures
35. https://www.db-international.de
The design of FRC structures is a challenging procedure since some of
the design parameters are not determined via the relevant codes, but
using results of laboratory tests.
It is critical to choose the concrete mix and carry out the laboratory tests in
the initial stages of the design to calculate / verify all the design strength
values.
In tunnelling it is useful to carry out a sensitivity analysis for anticipated
range of the geotechnical parameters to determine the limitations of this
design approach.
Fiber reinforced concrete structures
36. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
37. https://www.db-international.de
Located in North Greece
Two bore NATM tunnel with cross section
120m2. Length = 6km
Geological conditions: Marbles and
Amphibolites (mostly competent rock mass
conditions)
38. https://www.db-international.de
Numerical parametric analyses – Static conditions
Eurocode Part1-1/Section 12 and AFTES
recommendations for plain concrete were
adopted
3-D non-linear Finite Element code was used
Willam & Warnke constitutive model to
simulate concrete response (cracking and
crushing) was adopted
Basic Ultimate Limit States (for different load
cases and lining types) were calculated
The numerical parametric analyses examined
the effect of the in-situ rockmass properties on
to the linings response
39. https://www.db-international.de
Willam & Warnke Unreinforced concrete
constitutive model (1975)
Major advantages of the model:
Simulate concrete non-linear stress-strain
response, as well as concrete
cracking/crushing in three-dimensions.
Adopts different strength values in
compression and in tension.
Accounts directly lining stiffness degradation
due to cracking.
However it requires very fine 3D finite
element mesh (element size ≈0.05m).
octahedral
plane
σx=σy=σz
r1
r2
r2
r2
r1
r1 n
σz
fcd
σx
fcd
σy
fcd
49. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
50. https://www.db-international.de
Eurocode Part1-1/Section 12 and AFTES
recommendations for plain concrete were
adopted. Seismic actions resulting in low
axial forces did not require an eccentricity
check (no restrictions in crack depth).
Eurocode 8 EN-1998 was used to
determine seismic actions, concrete
properties, factors of safety for the
accidental load case etc.
Competent limestone conditions E = 1GPa
and irregular topography were examined.
Ch. 106+040
LEFT BORE
GU - III (L)
52. https://www.db-international.de
2-D Dynamic numerical analyses
Eccenticity check according to AFTES (Erockmass = 1GPa)
0 1 2 3 4 5 6
0
400
800
1200
1600
2000
axialforce(kN)
NRdo
0 1 2 3 4 5 6
-20
-10
0
10
20
bendingmoment(kNm)
0 1 2 3 4 5 6
time (sec)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
eccentricity(m)
e=0.3hw
N>NRdo zone
excitation: Aigio
orientation: (-)
location: A1-IVbResults in critical points along
the tunnel cross-section
Zone of high axial force requirement for low
eccentricity (crack control)
Conclusion: In competent rock
mass conditions (E=1GPa), an
unreinforced lining may be
sufficient, even in areas of high
seismicity
53. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
60. https://www.db-international.de
Load assumption 1 “+” Application of grouting pressure
Maximum overburden height for SFRC concept vs Eground and Ko
For Erockmass < 1GPa, the grouting
pressure is beneficial, since the
overburden height (for which SRFC
concept is applicable) increases
For Erockmass ≥1GPa, the grouting
pressure has no benefit
61. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
62. https://www.db-international.de
The ground load applied on the tunnel lining is not a “property” of the ground -
as it is assumed by the empirical methods - but depends very significantly on
the construction procedure and the applied support measures.
The parameters that must be taken into account for the calculation of the
tunnel load are:
• Rock mass strength and stiffness parameters
• Tunnel depth
• Dimensions and shape of the tunnel section
• Construction procedure (full face, sequential excavation etc.)
• Support stiffness and distance of the support from the tunnel face
• Face pressure or face treatment measures (forepolling, fiberglass nails etc.)
• Rock mass creep
63. https://www.db-international.de
The role of the geotechnical conditions (Fortsakis 2012)
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00
TLF = (σc/po)0.3 (ED/Eshdsh)0.7
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
Μέσηπίεση/Μέσηγεωστατικήτάση
pm/po,m
Άνω όριο
Κάτω όριο
m
1.80 1.80
0.30 0.70o,m
c
o sh sh
p 1.40 p 1.40
p 0.50(1 K)γΗ(0.5TLF 1.85)
σ ED
0.5 1.85
p E d
Conventional method
Hoek-Brown materials
Fortsakis (2012)
Averagetunnelload/meangeostaticstress
TLF = ( σc / po )0.3 ( ED / Eshdsh )0.7
64. 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
σc / po,m
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
1.20
pFL,m/psh,m
dsh = 20cm, dFL = 60cm
dsh = 40cm, dFL = 40cm
https://www.db-international.de
Load transfer from temporary support to final lining (NATM method)
po,m=0.5(1+K)γΗ
σc=2∙c∙tan(45+φ/2)
pFL,m: Final lining average load
psh,m: Shotcrete average load
Fortsakis et al. (2014)
65. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
66. https://www.db-international.de
The use of F.E. analysis has become widespread and popular in tunnelling, as
means of controlling and optimizing design tasks
F.E method is extremely powerful in stress - strain predictions
The quality of any stress - strain prediction (with F.E methods) depends on the
adequate model being adopted (rockmass constitutive model)
More realistic prediction of rockmass movements requires the adoption of a
non-linear stress - strain relation, before reaching the ultimate state
Non-linear elasticity, characterized by strong variations of rockmass stiffness,
which depend on the magnitude of strain levels occurring during construction
stages
67. https://www.db-international.de
In tunnelling design, pre-failure rockmass stiffness plays a crucial role in
predicting the complete behavior of tunnels and their surrounding rockmass in
Serviceability Conditions
Characteristic Rockmass stiffness (G) vs shear strain curves must be derived
These curves can be determined on the basis of reliable and accurate in-situ
testing and conventional laboratory testing
In situ testing methods: Seismic & Geophysical methods, Dilatometer
tests(DMT), Pressuremeter tests (PMT)
Conventional laboratory testing: UCS with stiffness measurement
69. Proposed Rock mass stiffness value
measured in dilatometer tests and in
the initial loading cycles of
pressuremeter tests.
Proposed Rock mass stiffness value
at the range of shear strain: 0.5x10-3
to 10-3.
ROCK MASS
STIFFNESS FOR
TUNNEL DESIGN
IN SERVICEABILITY
CONDITIONS
https://www.db-international.de
70. https://www.db-international.de
OUTLINE OF THE PRESENTATION
1. Recent tunnel cases with unreinforced and Steel Fiber Reinforced Concrete
tunnel linings
2. Existing Design Codes and Design Recommendations framework
3. Numerical analyses of the unreinforced concrete tunnel linings under static
and seismic loading conditions. T1 & T2 tunnels of Maliakos - Kleidi Motorway
and T26 tunnel of Athens - Patras Motorway in Greece.
4. Numerical analyses of SFRC tunnel linings under static loading conditions.
5. Some critical thoughts about the geostatic loads on to the tunnel final linings.
6. Some critical thoughts about the ground elastic modulus for the design of
tunnel linings
7. Conclusions
71. https://www.db-international.de
CONCLUSIONS
The concepts of the unreinforced and steel fiber reinforced concrete tunnel
final linings are not prohibitive
During the recent years, a significant number of motorway and railway tunnels
with unreinforced and steel fiber reinforced concrete tunnel final linings have
been constructed successfully
Eurocode 2, EN 1992-1 / Section 12 and AFTES Recommendations, provide
the necessary design code framework for the design of unreinforced concrete
tunnel final linings
Fib Model 2010 (Design Code since November 2013) can be used for the
design of steel reinforced concrete tunnel final linings
72. https://www.db-international.de
CONCLUSIONS
The structural integrity of the unreinforced concrete tunnel linings has been
verified for the case of competent rock masses with Em > 800MPa - 1000MPa,
even in areas of high seismicity and irregular topography
Unreinforced concrete tunnel linings in rock masses with 300MPa < Em ≤
800MPa may exhibit significant cracking, in combination with spalling.
Unreinforced concrete tunnel linings of typical thickness 30cm to 40cm in rock
masses with Em ≤ 300 MPa are characterized by high risk of concrete
crushing. Must be avoided
At tunnel portals, as well as in areas of nearby or crossing active faults, the
unreinforced concrete tunnel linings must be avoided
73. https://www.db-international.de
CONCLUSIONS
The design of FRC structures is a challenging procedure since some of the
design parameters are not determined via the relevant codes, but using
results of laboratory tests.
It is critical to choose the concrete mix and carry out the laboratory tests in the
initial stages of the design to calculate / verify all the design strength values.
In tunnelling it is useful to carry out a sensitivity analysis for anticipated range
of the geotechnical parameters to determine the limitations of this design
approach.
74. https://www.db-international.de
CONCLUSIONS
Steel fiber reinforced concrete tunnel final linings of typical thickness between
30cm to 35cm in rock masses with Em ≥ 800 MPa can be safely applied, even
with the consideration of full geostatic load for overburden heights ≤ 30m.
Steel fiber reinforced concrete tunnel final linings in rock masses with
500MPa< Em< 800 MPa can be safely applied, even with the consideration of
full geostatic load for overburden heights ≤ 20m.
In rock masses, which are characterized by high shear strength and stiffness,
tunnel final lining loading conditions are significant lower than the ones of the
initial geostatic stress field.
75. https://www.db-international.de
CONCLUSIONS
The use of face treatment measures or the application of face pressure may
lead to increase of the final lining loads due to the decrease of the
deconfinement.
In conventional tunnelling the load transfer from the temporary support to final
lining depends on the stiffness of the support systems and the geotechnical
conditions.
The interaction between twin tunnels may lead to increase of the applied loads
and to an unsymmetrical load distribution.
Rock mass stiffness value at the range of shear strain: 0.5x10-3 to 10-3 (from
in-situ dilatometer and pressuremeter testing results).
76. https://www.db-international.de
ACKNOWLEDGEMENTS
Qatar Rail and specifically Mr. Daniel Leckel, Chief of Program Delivery
Dr. George Kouretzis, University of Newcastle in Australia
Deutsche Bahn International and specifically Mr. Michael Ahlgrimm, Executive
Director of Doha branch
Mr. Carsten Schulte of Hochtief Offshore Development Solutions GmBH
Dr. Isavella Vassilopoulou, Civil Engineer N.T.U.A.
77. THANK YOU FOR
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