1. The document discusses applying the convergence-confinement approach to analyze rock-lining interaction in tunnels using the Shimizu Tunnel case study.
2. It constructs ground reaction and support characteristic curves for different support systems - steel ribs, shotcrete, and rock bolts used in Shimizu Tunnel.
3. By intersecting the curves, it determines the design load carried by each support system when the ground and lining reach equilibrium after tunnel excavation.
Effectiveness Evaluation of Seismic Protection Devices for Bridges in the PB...Franco Bontempi
Seismic protection measures for bridges can be used both for obtaining acceptable performances from new structures that for retrofitting existing ones. With the modern design philosophy based on probabilistic Performance-Based Earthquake Engineering (PBEE) approaches, the engineers are allowed to investigate different design solutions in terms of vulnerability assessment. However, if probabilistic PBEE approaches are nowadays well established and widely studied also for bridges, the topic of using the PBEE frameworks for the evaluation of the effectiveness of seismic protection devices for bridges is not extensively treated in literature.
The first objective of this work is to deal with the problem of assessing the earthquake performance of an highway bridge equipped with different bearing device: the
elastomeric bearings (ERB) and the friction pendulum systems (FPS). The second purpose is to evaluate the efficiency of a structure-dependent IM in case of isolated system. The examined structure is an highway bridge with concrete piers and steel truss deck. A FE model of the bridge is developed by using nonlinear beam-column elements with fiber section and the devices are modeled by specific elements implementing their
nonlinear behavior. The effectiveness of the different retrofitting strategies has been carried out in terms of damage probability. Choosing the example of slight damage, and referring to the curvature ductility as EDP, the probability of damage during a period of 50 years is: 23% for the structure without isolation, 7% for the structure equipped with ERB, and 3% for the structure equipped with FPS isolation.
DYNAMIC ANALYSIS OF CONCRETE GIRDER BRIDGES UNDER STRONG EARTHQUAKES: THE EFF...IAEME Publication
This paper presents the dynamic analysis of concrete girder bridges taking into account the effect of collision on parapet wall. In addition, adopting of seismic isolation rubber on pier structure and wing wall on parapet were analyzed. Two spans concrete girder bridges with variation of gap were examined in theoretically by 3D FEM model of ABAQUS. The abutment was simplified by parapet wall which was modeled by 3D reinforced concrete structure. In order to examine the seismic behavior of bridge, six different inputs of seismic ground accelerations were applied at footing of pier structure.
Mechanical Response Analysis of Asphalt Pavement StructureIJERA Editor
Generally, the Chinese designed life of the high- grade asphalt concrete pavement is required 15 years, however,
the designed life of the road in surface is often lower than the designed life, and even premature failure.
Especially in heavy traffic conditions, the early damage of some high grade-asphalt pavement in China is
serious. According to some investigations, we founded the main reason of the long-life asphalt pavement is
to determine the function of each structure layer. According to the stress of pavement structure layer, so as to
select the structure layer materials. Based on the viewpoint of mechanics, asphalt pavement damage mode is
divided into three categories, such as top-down crack, fatigue cracking and rutting. Therefore, this paper uses
ANSYS finite element software as calculation tool, the combination of road vehicle load and the primary
influence on asphalt pavement structure mechanics response characteristics were analyzed.
In this paper, the method of analysis is control variable: that means under different vehicle axle load, only
change surface layer modulus and observe the pavement structure mechanical response trends to compare the
effect. By using the same method, the response of the pavement base course parameters to the pavement
mechanical structure is analyzed.
Application of Elastic Layered System in the Design of RoadIJERA Editor
Elastic layered system is widely used in road design because of its reasonable assumptions, simple calculation model and typical represent activeness. Although the hypothesis is partly different from the actual structure, it is irreplaceable and worthy of further study in the current level of science and technology. This paper lists and briefly describes the application of elastic layered system theory in the calculation of asphalt pavement thickness and subgrade the stress analysis of cement concrete pavement and porous concrete base load to illustrate the generalizability of application of elastic layered system and look to the future road.
Fixity depth of offshore piles in elastoplastic soft clay under dynamic loadeSAT Journals
Abstract
This work represents study of dynamic behavior of offshore piles embedded in elastoplastic soft clay, and estimating the fixity depth of pile. ABAQUS finite element program which used to simulate the problem. The soil was modeled in two case elastic state model and elastoplastic state model represented by cam-clay model, three dimension element used to represent the interaction between pile and soil, and laboratory tests used to getting the real properties of clayey soil and to descried interface. The results obtained developed two empirical equations used to calculate depth of pile fixity for pile embedded in elastic and elastoplastic soil respectively. Also, show the depth of pile fixity is increase about (40 %) due to change soil model from elastic to plastic, when pile embedded in elastoplastic soil its dependent on soil strength, interface properties and pile rigidity. The pile head displacement is increase about 90 % while the bending moment is decease 10 % at pile head.
Effectiveness Evaluation of Seismic Protection Devices for Bridges in the PB...Franco Bontempi
Seismic protection measures for bridges can be used both for obtaining acceptable performances from new structures that for retrofitting existing ones. With the modern design philosophy based on probabilistic Performance-Based Earthquake Engineering (PBEE) approaches, the engineers are allowed to investigate different design solutions in terms of vulnerability assessment. However, if probabilistic PBEE approaches are nowadays well established and widely studied also for bridges, the topic of using the PBEE frameworks for the evaluation of the effectiveness of seismic protection devices for bridges is not extensively treated in literature.
The first objective of this work is to deal with the problem of assessing the earthquake performance of an highway bridge equipped with different bearing device: the
elastomeric bearings (ERB) and the friction pendulum systems (FPS). The second purpose is to evaluate the efficiency of a structure-dependent IM in case of isolated system. The examined structure is an highway bridge with concrete piers and steel truss deck. A FE model of the bridge is developed by using nonlinear beam-column elements with fiber section and the devices are modeled by specific elements implementing their
nonlinear behavior. The effectiveness of the different retrofitting strategies has been carried out in terms of damage probability. Choosing the example of slight damage, and referring to the curvature ductility as EDP, the probability of damage during a period of 50 years is: 23% for the structure without isolation, 7% for the structure equipped with ERB, and 3% for the structure equipped with FPS isolation.
DYNAMIC ANALYSIS OF CONCRETE GIRDER BRIDGES UNDER STRONG EARTHQUAKES: THE EFF...IAEME Publication
This paper presents the dynamic analysis of concrete girder bridges taking into account the effect of collision on parapet wall. In addition, adopting of seismic isolation rubber on pier structure and wing wall on parapet were analyzed. Two spans concrete girder bridges with variation of gap were examined in theoretically by 3D FEM model of ABAQUS. The abutment was simplified by parapet wall which was modeled by 3D reinforced concrete structure. In order to examine the seismic behavior of bridge, six different inputs of seismic ground accelerations were applied at footing of pier structure.
Mechanical Response Analysis of Asphalt Pavement StructureIJERA Editor
Generally, the Chinese designed life of the high- grade asphalt concrete pavement is required 15 years, however,
the designed life of the road in surface is often lower than the designed life, and even premature failure.
Especially in heavy traffic conditions, the early damage of some high grade-asphalt pavement in China is
serious. According to some investigations, we founded the main reason of the long-life asphalt pavement is
to determine the function of each structure layer. According to the stress of pavement structure layer, so as to
select the structure layer materials. Based on the viewpoint of mechanics, asphalt pavement damage mode is
divided into three categories, such as top-down crack, fatigue cracking and rutting. Therefore, this paper uses
ANSYS finite element software as calculation tool, the combination of road vehicle load and the primary
influence on asphalt pavement structure mechanics response characteristics were analyzed.
In this paper, the method of analysis is control variable: that means under different vehicle axle load, only
change surface layer modulus and observe the pavement structure mechanical response trends to compare the
effect. By using the same method, the response of the pavement base course parameters to the pavement
mechanical structure is analyzed.
Application of Elastic Layered System in the Design of RoadIJERA Editor
Elastic layered system is widely used in road design because of its reasonable assumptions, simple calculation model and typical represent activeness. Although the hypothesis is partly different from the actual structure, it is irreplaceable and worthy of further study in the current level of science and technology. This paper lists and briefly describes the application of elastic layered system theory in the calculation of asphalt pavement thickness and subgrade the stress analysis of cement concrete pavement and porous concrete base load to illustrate the generalizability of application of elastic layered system and look to the future road.
Fixity depth of offshore piles in elastoplastic soft clay under dynamic loadeSAT Journals
Abstract
This work represents study of dynamic behavior of offshore piles embedded in elastoplastic soft clay, and estimating the fixity depth of pile. ABAQUS finite element program which used to simulate the problem. The soil was modeled in two case elastic state model and elastoplastic state model represented by cam-clay model, three dimension element used to represent the interaction between pile and soil, and laboratory tests used to getting the real properties of clayey soil and to descried interface. The results obtained developed two empirical equations used to calculate depth of pile fixity for pile embedded in elastic and elastoplastic soil respectively. Also, show the depth of pile fixity is increase about (40 %) due to change soil model from elastic to plastic, when pile embedded in elastoplastic soil its dependent on soil strength, interface properties and pile rigidity. The pile head displacement is increase about 90 % while the bending moment is decease 10 % at pile head.
Abutment pile-soil interaction of a psc bridge under seismic loadingeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Analytical study of abutment and pile behaviour of iab with soil interactioneSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Main objective of the executed researches was justification of the location of entry
providing its maintenance in a bearing pressure zone. Researches were carried out for
conditions of the Prokopyevsk and Kiselevsky field of the Kuznetsk coal basin
(Russia). Researches were conducted by a finite element method. When performing
researches the provision entry relative of a regional part of the massif and property of
coal changed. As a result of researches influence of strength of coal and the location
of entry on the stress and strain state of the massif is established and the conclusion is
drawn on need of increase in height of a slice up to 10 m. Recommendations of
increase in height of each subsequent slice at mining of soft coals are also made. The
novelty of work consists in establishment of dependences of the stress and strain state
of the massif on height of the mining slice.
Three dimensional finite element modeling of pervious concrete pavementeSAT Journals
Abstract Pervious concrete has the unique characteristic of allowing water to pass through its porous matrix. . Pervious concrete pavement systems usually have three main layers, pervious concrete on the top, a subbase layer of aggregate for water storage in the middle and the subgrade (soil) layer below. Finite element modeling of this novel material is challenging due to its complex porous characteristics. In this paper, a method has been proposed to model pervious concrete pavement using finite element methods, which includes a modified approach to capture the unique vertical porosity distribution in the pervious concrete layer by averaging the distribution in three distinct vertical sections. The mechanical properties of the pervious concrete layer are assumed to vary along its depth since the porosity of the pervious concrete also varies with depth. ABAQUS, a general-purpose finite element software package was used to develop the model and perform the analysis. The model was validated through a convergence study, and in comparison with the analytical theory of tensile stress and deflection for traditional concrete pavement. In addition, the significance of the porosity distribution model was validated by comparing the results from EverFE – a specific software for pavement structure analysis. It was found that there is significant difference in tensile stress if modeled using the modified vertical porosity distribution in the previous concrete layer to more fully capture its vertical porosity distribution, as compared to an averaged porosity model in the previous concrete layer. It was also noted that compressive stress demand may have increased importance for pervious concrete, but only for highly porous applications which are not commonly used. Keywords: pervious concrete, vertical porosity, finite element, critical loading, stress, deflection
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Determination of load transfer in reinforced concrete solid slabs by finite e...IOSR Journals
According to the ACI building code, the concrete slab can be divided into two types depending on
the ratio of the long side to the short side. Regarding the results of the ratio, the concrete slab can be divided as
one-way and two-way slabs. The main objective of this paper is to study the stress or moments distribution in
solid slab panel in its two directions and compare with ACI code assumption that the load is transferred mainly
in short direction and most of the load is transferred in one direction only if the ratio of the longer span to the
shorter span is greater than one. This will be discussed by analyzing one panel of solid slab using the computer
software SAP2000. Two types of panels will be used; the first one a panel that is supported simply on its four
sides and the second panel is supported only by four pin supports and beams. This paper shows that the gravity
load on the slab is transferred to long and short direction. This means that one-way concrete solid slab doesn't
exist and all concrete solid slabs work as a two-way concrete slab.
Study on Soil-Foundation Interaction under a Bridge Pierijtsrd
This study focuses on the behaviour of soil-foundation interaction under a bridge pier. In 2016, August 25, a magnitude of 6.8 happened near Bagan region. Pakokku Bridge, the longest of the bridges over the Irrawaddy, is situated on 37.8 miles from the epicentre of 2016 Chauk earthquake. That is why the safety performance of long-span Bridge especially for the safety of the foundation system subjected to soil-foundation interaction is necessary to investigate for static and seismic excitation. So, study on the behaviour of soil-foundation interaction under Bridge pier in static condition is presented in this study. Firstly super structural loadings on the pile cap are estimated by using STAAD PRO V8i. And then, theoretical ultimate soil resistance pcr and pcd due to wedge and flow failure are determined to produce critical depth xcr. Based on the value of critical depth, p-y curves are generated by Reese 1974 method for the static condition. After that, finite element software ABAQUS is used for the analysis of soil-foundation interaction under a bridge pier. In this study, the behaviour of soil-foundation interaction such as deflections, settlements, shear stresses and shear strains are produced. According to the analysis results, it is found that the vertical and horizontal displacements at the pile tip are 1.27mm and 4.68mm respectively. Maximum shear stress and strain are found out the base of the pile cap. Finally it is found that the soil-foundation interaction under a bridge pier presented in this study is reliable and reasonable with the limitation of AASHTO Standard Specifications for Highway Bridges. Zin May Hnin | Nyan Myint Kyaw | Kyaw Kyaw "Study on Soil-Foundation Interaction under a Bridge Pier" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-1 , December 2018, URL: http://www.ijtsrd.com/papers/ijtsrd19008.pdf
http://www.ijtsrd.com/engineering/civil-engineering/19008/study-on-soil-foundation-interaction-under-a-bridge-pier/zin-may-hnin
Abutment pile-soil interaction of a psc bridge under seismic loadingeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Analytical study of abutment and pile behaviour of iab with soil interactioneSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Main objective of the executed researches was justification of the location of entry
providing its maintenance in a bearing pressure zone. Researches were carried out for
conditions of the Prokopyevsk and Kiselevsky field of the Kuznetsk coal basin
(Russia). Researches were conducted by a finite element method. When performing
researches the provision entry relative of a regional part of the massif and property of
coal changed. As a result of researches influence of strength of coal and the location
of entry on the stress and strain state of the massif is established and the conclusion is
drawn on need of increase in height of a slice up to 10 m. Recommendations of
increase in height of each subsequent slice at mining of soft coals are also made. The
novelty of work consists in establishment of dependences of the stress and strain state
of the massif on height of the mining slice.
Three dimensional finite element modeling of pervious concrete pavementeSAT Journals
Abstract Pervious concrete has the unique characteristic of allowing water to pass through its porous matrix. . Pervious concrete pavement systems usually have three main layers, pervious concrete on the top, a subbase layer of aggregate for water storage in the middle and the subgrade (soil) layer below. Finite element modeling of this novel material is challenging due to its complex porous characteristics. In this paper, a method has been proposed to model pervious concrete pavement using finite element methods, which includes a modified approach to capture the unique vertical porosity distribution in the pervious concrete layer by averaging the distribution in three distinct vertical sections. The mechanical properties of the pervious concrete layer are assumed to vary along its depth since the porosity of the pervious concrete also varies with depth. ABAQUS, a general-purpose finite element software package was used to develop the model and perform the analysis. The model was validated through a convergence study, and in comparison with the analytical theory of tensile stress and deflection for traditional concrete pavement. In addition, the significance of the porosity distribution model was validated by comparing the results from EverFE – a specific software for pavement structure analysis. It was found that there is significant difference in tensile stress if modeled using the modified vertical porosity distribution in the previous concrete layer to more fully capture its vertical porosity distribution, as compared to an averaged porosity model in the previous concrete layer. It was also noted that compressive stress demand may have increased importance for pervious concrete, but only for highly porous applications which are not commonly used. Keywords: pervious concrete, vertical porosity, finite element, critical loading, stress, deflection
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Determination of load transfer in reinforced concrete solid slabs by finite e...IOSR Journals
According to the ACI building code, the concrete slab can be divided into two types depending on
the ratio of the long side to the short side. Regarding the results of the ratio, the concrete slab can be divided as
one-way and two-way slabs. The main objective of this paper is to study the stress or moments distribution in
solid slab panel in its two directions and compare with ACI code assumption that the load is transferred mainly
in short direction and most of the load is transferred in one direction only if the ratio of the longer span to the
shorter span is greater than one. This will be discussed by analyzing one panel of solid slab using the computer
software SAP2000. Two types of panels will be used; the first one a panel that is supported simply on its four
sides and the second panel is supported only by four pin supports and beams. This paper shows that the gravity
load on the slab is transferred to long and short direction. This means that one-way concrete solid slab doesn't
exist and all concrete solid slabs work as a two-way concrete slab.
Study on Soil-Foundation Interaction under a Bridge Pierijtsrd
This study focuses on the behaviour of soil-foundation interaction under a bridge pier. In 2016, August 25, a magnitude of 6.8 happened near Bagan region. Pakokku Bridge, the longest of the bridges over the Irrawaddy, is situated on 37.8 miles from the epicentre of 2016 Chauk earthquake. That is why the safety performance of long-span Bridge especially for the safety of the foundation system subjected to soil-foundation interaction is necessary to investigate for static and seismic excitation. So, study on the behaviour of soil-foundation interaction under Bridge pier in static condition is presented in this study. Firstly super structural loadings on the pile cap are estimated by using STAAD PRO V8i. And then, theoretical ultimate soil resistance pcr and pcd due to wedge and flow failure are determined to produce critical depth xcr. Based on the value of critical depth, p-y curves are generated by Reese 1974 method for the static condition. After that, finite element software ABAQUS is used for the analysis of soil-foundation interaction under a bridge pier. In this study, the behaviour of soil-foundation interaction such as deflections, settlements, shear stresses and shear strains are produced. According to the analysis results, it is found that the vertical and horizontal displacements at the pile tip are 1.27mm and 4.68mm respectively. Maximum shear stress and strain are found out the base of the pile cap. Finally it is found that the soil-foundation interaction under a bridge pier presented in this study is reliable and reasonable with the limitation of AASHTO Standard Specifications for Highway Bridges. Zin May Hnin | Nyan Myint Kyaw | Kyaw Kyaw "Study on Soil-Foundation Interaction under a Bridge Pier" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-1 , December 2018, URL: http://www.ijtsrd.com/papers/ijtsrd19008.pdf
http://www.ijtsrd.com/engineering/civil-engineering/19008/study-on-soil-foundation-interaction-under-a-bridge-pier/zin-may-hnin
The effect of disturbance factor on the stability of tunnels (Case study: Tun...IJRES Journal
Disturbance factor (D) is related to excavation method and cause damage and stress relief in the rock masses. The convergence and plastic zone around tunnels depends on the disturbance factor of rocks.This study has been in the tunnel No.2 of Kurdistan in NW of Iran which is composed of shale rocks. In tunnel modeling, different disturbance factors(0 to 1) areanalyzed using phase2 software and the amount of displacement and extent of plastic zone in around the tunnelis determined. The obtain results show that by increasing of disturbance factor, the displacement and plastic zone around the tunnel has increased and the most increase has occurred in disturbance factors 0.8 to 1. Therefore, for excavation of this tunnel, the blasting method should not be used and instead of it, the mechanical methods must be used.
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study
SUGGESTING DEFLECTION EXPRESSIONS FOR RC 2-WAY SLABSIAEME Publication
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study.
Ultimate Behavior of Lightweight High Strength Concrete Filled Steel Tube (LW...IOSR Journals
Strength and ductility of concrete members can be significantly improved with lateral confinement, usually achieved by using a steel tube casing. The concrete confinement can be utilized to make bridge lighter and have longer spans. In addition, a significant portion of the load carried concrete bridge girders is the self-weight of the girders and deck. If all or part of the girder and deck can be made using high strength lightweight concretes, there is a potential for appreciable economic savings since the self-weight could be reduced by as much as 15-20%. The study described herein investigates the static nonlinear behavior of lightweight high strength concrete filled steel tube (LWHCFST) bridges up to failure. The current study had two specific goals. The first was to experimentally determine the static modulus of elasticity of confined high strength lightweight concrete mixture. The second was to develop a nonlinear finite element computer program to study the ultimate behavior of a filled tube (LWHCFST) example bridge. The nonlinear stress-strain behavior of confined high strength lightweight concrete is evaluated experimentally by the authors and is used to help establish a comparison between the ultimate behavior of the bridge using confined normal weight concrete and confined high strength lightweight concrete. The ultimate strength of the bridge is related to the occurrence of an equivalent failure mechanism. The study indicated that the use of (LWHCFST) is beneficial for extending bridge girder lengths
HIGHWAY AND TRANSPORT ENGINERING EXAM AND ANSWER-2HIGHWAY AND TRANSPORT ENGINERING EXAM AND ANSWER-2HIGHWAY AND TRANSPORT ENGINERING EXAM AND ANSWER-2HIGHWAY AND TRANSPORT ENGINERING EXAM AND ANSWER-2HIGHWAY AND TRANSPORT ENGINERING EXAM AND ANSWER-2HIGHWAY AND TRANSPORT ENGINERING EXAM AND ANSWER-2
Study of Dynamic Analysis for Immersed Tube Tunnelijceronline
The main aim of the project is to connect the two coats of the Dharamtar creek i.e. Rewas in Alibaug and Karanja in Uran by an immersed tunnel. The construction of proposed immersed tunnel will reduce the travel time from Mumbai to Alibaug from 3 hours to 1 hour. But this reduction in time includes the consideration of the sea-link from Sewri to Nhava Seva (Uran).Which was proposed by government and is already under construction. Thus construction of this immersed tunnel will ease the transportation of the city. In this study, a preliminary analysis of IZMIR immersed tube is carried out for validating purpose. The static analysis of the tunnel was made in finite element program. The vertical displacement of the tube unit under static loads was calculated. Afterwards, the seismic analysis was made to investigate stresses developed due to both racking and axial deformation of the tunnel during an earthquake. It was found that, maximum stress due to axial deformation is longer than compressive strength of the concrete. The high stresses in the tube occur, because of the tube stiffness.
Numerical and Analytical Solutions for Ovaling Deformation in Circular Tunnel...IDES Editor
Ovaling deformations develop when waves propagate
perpendicular to the tunnel axis. Two analytical solutions are
used for estimating the ovaling deformations and forces in
circular tunnels due to soil–structure interaction under
seismic loading. In this paper, these two closed form solutions
will be described briefly, and then a comparison between these
methods will be made by changing the ground parameters.
Differences between the results of these two methods in
calculating the magnitudes of thrust on tunnel lining are
significant. For verifying the results of these two closed form
solutions, numerical analyses were performed using finite
element code (ABAQUS program). These analyses show that
the two closed form solutions provide the same results only
for full-slip condition.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
1. Paper: ASAT-13-CV-15
th
13 International Conference on
AEROSPACE SCIENCES & AVIATION TECHNOLOGY,
ASAT- 13, May 26 – 28, 2009, E-Mail: asat@mtc.edu.eg
Military Technical College, Kobry Elkobbah, Cairo, Egypt
Tel : +(202) 24025292 – 24036138, Fax: +(202) 22621908
Application of the Convergence-Confinement Approach to
Analyze the Rock-Lining Interaction in Tunnels
(Case Study: Shimizu Tunnel)
Ayman A Mariee*, Adel M Belal**, Ahmed El-Desouky**
Abstract: The Convergence-Confinement approach is a procedure in which the ground-liner
interaction is analyzed by considering the behavior of the ground and the lining
independently. This method enables calculation of average radial pressure applied to the
support by the intersection of two curves representing the radial stresses as a function of
radial strain, one for the ground and the other for the liner. This paper discusses the
application of the Convergence-Confinement method of tunnel analysis to rock masses that
satisfies the Hoek-Brown failure criterion. The Shimizu Tunnel has been studied using this
method to analyze the structural interaction between rock and different types of individual
support systems such as; steel ribs, shotcrete, rock bolts and compound systems of these
supports. The equations that govern the behavior of the rock-support interaction are given
through two basic components of the Convergence-Confinement method which are, Ground
Reaction Curve (GRC) and Support Characteristics Curve (SCC). According to the analytical
results, a comparison has been conducted between the different support systems according to
the maximum capacity pressure of the support and the estimated lining load based on the
Convergence-Confinement method. The value of this load depends on the timing of lining
installation and consequently the value of the ground radial displacement due to the releasing
of stresses.
Keywords: Convergence-Confinement approach, Ground Reaction Curve, Rock bolts,
Shotcrete, Structural interaction, Support Characteristics Curve.
1. Introduction
Controlling ground-lining interaction is one of the most critical processes during the
implementation of tunneling projects. Some of the design and construction decisions during
these projects are very critical to reduce the ground movements around the excavated tunnel.
These movements have a direct effect on the tunnel stability and the design load of the lining
system. Many lining systems have been used to support tunnels opening. Concrete segments,
shotcrete, rock bolts, composite sections of steel and shotcrete, steel ribs and shotcrete and
rock bolts are examples of the commonly used tunnel linings.
Choice of the appropriate lining system depends mainly on the geological conditions, ground
stiffness, configuration of the tunnel and the in-situ stress field around the opening.
*
Syrian Department of Armed Forces
Egyptian Armed Forces
**
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2. Paper: ASAT-13-CV-15
In rock tunnels, the quality of the rock mass is an important factor to determine the suitable
lining system. For moderately to hard homogeneous rock, a thin shotcrete thickness is
sufficient to protect the rock surface, while in case of poor highly jointed rock, a stiffer lining
system is needed according to the presence of joints, folds, faults and separated blocks. The
main aim of this research is to investigate the behavior of the ground-lining interaction using
the Convergence-Confinement approach.
2. Case Study: Shimizu Tunnel
The Shimizu Tunnel No. 3 located along Japan’s Tomei-Meishin Expressway (Tomei II), The
1.1 km long Shimizu tunnel No. 3, was completed in Japan in 1988. The excavated diameter
of the Shimizu Tunnel was 7.5m, advanced using Tunnel Boring Machines (TBMs).as shown
in Figure. 1
2.1 Subsurface Profile and Geotechnical Properties
The ground at the site of Shimizu Tunnel No. 3 is composed of soft sedimentary rock
formations, and a geological longitudinal section along is shown in Figure 2. There are five
rock formations, and the main rock formation is the weathered soft sandstone of the late
Miocene and Pliocene.
2.2 Lining System
Choosing lining system for a specific tunnel depends on the excavation technology, which is
used for tunnel construction Support systems used in Shimizu Tunnel No. 3 (Japan Highways,
1998 Shotcrete20cm, and H200 steel arches at a spacing of 1.0 m.and 6.0 m long rock bolts
installed at a circumferential spacing of 1.2 m.
2.3 Ground Reaction Curve (GRC)
The Ground Reaction Curve (GRC) for sandstone can be constructed using the elasto-plastic
solution for circular opening subject to uniform far-field stresses and uniform internal
pressure by using equations (1:14) as proposed by Carranza-Torres and Fairhurst (2000).
Table 1 contains the data required for these calculations.
GSI 100
)
28
pi
s
Pi
2
m b ci m b
s
S
2
m b ci m b
1
Picr (1 1 16S ) 2
16
s
pcr (Picr 2 )m b ci
i
mb
GSI 100
s exp(
)
9
m b mi exp(
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(1)
(2)
(3)
(4)
(5)
(6)
3. Paper: ASAT-13-CV-15
GSI
)
200
p
u el ( i )R
r
2G rm
E rm
G rm
2(1 )
Erm 1000C( ci )10 (GSI 10)/ 40
a 0.65 (
(7)
(8)
(9)
(10)
R pl Re xp[2( Picr Pi )]
K
(11)
1 sin
1 sin
(12)
K 1
R pl K 1
R pl 2 1 2
Picr
u pl 2G rm
2
1 2
r
(
)
[ln(
)] [
R pcr K 1 K 1 R
4(S Picr )
R
K 1 S Picr
i
(13)
R pl
R pl K 1
1 K 1
1
][(K 1) ln(
)(
)
1]
2
cr
2 (K 1) S Pi
R
R
R pl 2
R pl 2
Picr
u pl 2G rm
1 2
1 2
r
[
1](
)
[ln(
)]
cr
cr
cr
R pi
2 S Pi
R
4(S Pi )
R
(14)
R pl
Picr
1 2
[2 ln(
) 1]
cr
2 S Pi
R
Table 1 Required Data for Constructing the GRC.
Radius of the tunnel (R)
7.5 m
Unit weight for bedrock (γ)
25 KN/m3
Poisson's ratio (õ)
0.3
Geotechnical Strength Index (GSI)
40
Unconfined compressive strength (σci)
75 MPa
mi (dimensionless parameter for intact rock)
19
Shear modulus (Grm)
1873.084 Mpa
Coefficient of lateral pressure(k0)
0.83
where:
mb: dimensionless parameter for rock mass depends on both the intact rock parameter mi
and the GSI value.
mi: dimensionless parameter of intact rock, the value of which depends on the type of
rock being tested.
GSI: Geotechnical Strength Index.
Pi: scaled internal pressure (kPa).
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4. Paper: ASAT-13-CV-15
pi: uniform internal pressure (kPa)
σci: unconfined compressive strength (kPa).
σº: far-field stress (kPa).
Sº: scaled far-field stress (kPa)
picr: critical internal pressure (kPa).
Picr: scaled critical pressure (kPa).
urel: radial displacement in the elastic part of the GRC (mm).
urpl: radial displacement in the plastic part of the GRC (mm).
Grm: rock mass shear modulus (kPa).
Erm: rock mass modulus (MPa).
υ: Poisson's ratio.
R: tunnel radius (m).
Rpl: radius of the plastic zone (m).
KΨ: dilation angle, (KΨ=1 for Ψ= 0 and KΨ=3 for Ψ= 30).
s: dimensionless parameter depends on GSI which satisfies equation (6) for GSI
≥ 25, for GSI < 25 s =0.
a: dimensionless parameter depends on GSI which satisfies equation (7) for GSI
< 25, for GSI ≥ 25 a =0.
For equation (10):
if σci ≥ 100 MPa
if σci ≤ 100 MPa
C (σCi) = 1
C (σCi) = (σCi / 100)1/ 2
The GRC for the sandstone is constructed in the following analysis, considering the maximum
overburden height of hard layer is equal to 80 m, the maximum overburden pressure is
calculated as the product of unit weight γ by depth h and it is found to be 1.83 Mpa.
The GRC shown in Figure 3. Illustrates the critical pressure value picr= 0.033 MPa, which
marks the transition from elastic to plastic behavior of the rock-mass and a maximum plastic
zone having Rpl =7.58 m. The calculated maximum closure (i.e., the
radial displacement)
urmax = 4.05 mm at zero internal pressure (i.e., the tunnel is unsupported). The previous results
were evaluated for the value of the coefficient of lateral earth pressure equal to (k◦ =0.83).
2.4 Support Characteristics Curve (SCC)
The Support Characteristics Curve (SCC) has been constructed using three support systems
steel ribs, shotcrete, and rock bolts.
2.4.1 Support Characteristic Curve for steel ribs
The maximum pressure (psmax) sustainable from the steel ribs and the elastic stiffness (Ks) of
a closed circular steel ribs is given by the following simplified expression after eliminating
the effect of timber lagging:
p s m ax
3 ys A S
2 SR
1
SR 2
Ks Es As
where:
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(16)
5. Paper: ASAT-13-CV-15
Psmax : maximum pressure (MPa)
бys: yield strength of the steel (MPa)
A: cross-sectional area of the section (m 2)
S: steel set spacing along the tunnel axis (m)
R: tunnel radius (m)
Ks: elastic stiffness
Es: young's modulus of steel (MPa)
The SCC shown in Figure 4. Illustrates the maximum calculated pressure (psmax) is 0.254
MPa and the calculated elastic stiffness of steel ribs (Ks) is 19.017 MPa/m. The maximum
calculated radial displacement at that moment of collapse after the full yielding of support
system (urmax) is 0.25 mm.
2.5 Application of Convergence-Confinement Approach
The interaction between the sandstone and the support system takes place after the installation
of the support system. During the advance of the tunnel, the sandstone and the support system
deform together and the support system receives part of the load that the tunnel face had been
carrying previously before installing the support system. Once the TBM has moved ahead, the
sandstone and the support system reach equilibrium and the support system carries the final
load or design load (psD), which is indicated by point (Ds) as shown in Figure 5. The values of
psD for steel ribs in case of (k◦ =0.83), is 0.034 MP. At this time the effect of the face has
disappeared and the ground had converged by the final amount (urD). The values of urD for
steel ribs in case of (k◦ =0.83) is 0.09 mm. This deformation is the value of the radial
convergence of the tunnel wall which resulted from the releasing of stresses before the start of
the ground interaction with the support system.
2.6. Support Characteristic Curve for shotcrete
The structural behavior of shotcrete lining system is evaluated by using Equations (17, 18) to
provide the maximum pressure that the shotcrete can sustain before collapse (psmax ) and the
elastic stiffness (Ks),
ps
max
cc
(R t c )2
[1
]
2
R2
Ec
R2 (R tc )2
KS
(1c )R (1 2c )R2 (R tc )2
(17)
(18)
where:
σcc: unconfined compressive strength of the shotcrete (MPa).
Ec: Young's modulus of shotcrete (MPa).
νc: Poisson's ratio the shotcrete.
tc: thickness of shotcrete (m).
R: tunnel radius (m).
Table 2. Presentes the required data for these calculations. The shotcrete of 20 cm thickness
can withstand a Pressure (psmax) is 0.928 MPa before collapse,. The calculated elastic stiffness
of shotcrete (Ks) is 116.342 MPa/m. The maximum calculated radial (Urmax) is 6.7 mm
displacement at the moment of collapse after the full yielding of the shotcrete Figure.3 shown
the Support characteristic curve shotcrete.
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6. Paper: ASAT-13-CV-15
Table 2 Required data for constructing SCC for shotcrete lining
Property
σcc
Ec
νc
tc
R
Value
35.3 MPa
18000 MPa
0.25
0.20 m
7.5 m
The interaction between the sandstone and the shotcrete lining (thickness 20 cm) will take
place directly after lining of shotcrete is sprayed. During the advance of the tunnel the
sandstone and the shotcrete deform together and the shotcrete receives part of the load that the
tunnel face had been carrying previously before shotcreting.
Once the tunnel face has moved ahead far enough, the sandstone and the shotcrete is in
equilibrium and the shotcrete carries the final load or design load psD is0.034 MPa, which is
indicated by point (Dc) in Figure 6. At that time the effect of the face has disappeared and the
shotcrete and the ground have converged together by the final amount of about urD is 0.59
mm.
2.7 Support Characteristic Curve for rock bolts
Assuming that the bolts are equally spaced in circumferential direction, the maximum support
pressure (psmax) provided by the support system and the elastic stiffness (Ks), can be evaluated
using following equations.
ps max
Tbf
s cs l
1
4L
s cs l[
Q]
Ks
d b2E s
(19)
(20)
where:
db: bolt diameter (m).
L: free length of the bolt (m).
Tbf: ultimate load obtained from a pull-out test (MN).
Q: deformation load constant for the bolt and the head (m/MN).
Es: Young's modulus for bolt (MPa).
Sc: circumferential bolt spacing, (sc =2 Π R/ nb, where nb is the total
number of equally spaced bolts installed in cross section. (m)
Sl: longitudinal bolt spacing in (m).
Table 3. Presentes the required data for these calculations. The SCC of rock bolts as shown in
Figure 7. illustrates the maximum calculated pressure (psmax) is 0.133 Mpa, and the calculated
elastic stiffness of the rock bolts (Ks) is 5.796 MPa/m. The maximum calculated radial
displacement at the moment of collapse after the full yielding of the rock bolts is (urmax) is
22.23 mm.
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7. Paper: ASAT-13-CV-15
Table 3 Required Data for Constructing SCC for Rock Bolts Lining.
Property
Value
db
0.022 m
L
3m
Tbf
0.196 MN
Q
0.042 m/MN
Es
210×103 MPa
Sc
3.14 m
Sl
1m
The values [db, L, Tbf, Q] determined for expansion shell bolts in field tests, which depend on
the rock type. The radial displacement of the rock bolts is considered from the value ur˚ is
3.0mm, which is the value of the radial convergence of the tunnel wall which associated with
the release of stresses before the rock bolts activation.
2.8 Compound Effect of Support Systems
If more than one of the support systems are installed as composite lining, their combined
effect can be determined by adding the elastic stiffnesses for each of the individual supports.
This has the effect of increasing the total elastic stiffness of the whole system. Consider for
example, the case in which two supports characterized by maximum pressure ps1max and ps2max
and elastic stiffnesses Ks1and Ks2, respectively are installed in a section of tunnel. The
stiffnesses Ks for the two systems acting together can be computed as following:
KS K1 K 2
(21)
This value is assumed to remain valid until one of the two supports achieves its maximum
possible elastic deformation urmax computed as:
u r1max
ps1max
K s1
(22)
u r 2 max
ps2max
K S2
(23)
u r max u r1max u r 2 max
(24)
The combined support system is assumed to fail at that point. The support with the lowest
value of urmax determines the maximum support pressure available for the two supports acting
together because if one assumes that the collapse of the support system coincides with
collapse of the weakest element, so the maximum support pressure that the system can sustain
before collapse is computed as follows:
ps max u r,min max K s
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8. Paper: ASAT-13-CV-15
Support Characteristics Curve for Different Compound Support Systems
This type is divided to rock bolts and steel ribs as primary lining, which is installed after
ground convergence by 0.5 mm. The results of this type of support system are listed in Table
4. In addition, the table presents the field measurements. The SCC is shown in Figure 8.
Table 4 Results of Shotcrete and Steel Ribs and Rock Bolts Support System.
Method
Psmax (MPa)
Convergence
1.125
Method
Field
1.4
Measurement
Difference
19 %
(%)
psD (MPa )
urmax (mm)
urD (mm)
0.033
3.43
1.1
0.045
4.0
1.35
27 %
14 %
18 %
3. Conclusions
Based on the work presented in this paper, the following could be concluded:
The paper presented a comparison between the different support systems according to
the maximum capacity pressure of the support and the lining load, which result from
the point of intersection between the GRC and SCC (i.e., the equilibrium position).
Results of the analysis suggest that the shotcrete lining is the better support system as
it yielded the highest value of maximum capacity pressure (0.928 MPa) of the support
in case of using the Roadheader machine.
This value of maximum capacity pressure is 73% and 86% higher than those values
obtained when using steel ribs and rock bolts, respectively.
In case of using compound systems, the maximum capacity pressure will be increased
and the final radial displacement of the support systems will be decreased.
The convergence method resulted in lower values compared to the field
measurements. For most obtained results, the percentage of difference is less than
20%.
4. References
[1]
Carranza-Torres, C. and Fairhurst, C. (2000), “Application of The ConvergenceConfinement Method of Tunnel Design to Rock Masses that Satisfy The Hoek-Brown
Failure Criterion.”
[2] Sotirios S. Vardakos , Marte S. Gutierrez , Nick R. Barton " Back-analysis of Shimizu
Tunnel "
[3] Lama and Vutukuri (1978) and Goodman (1980)." Engineering Properties of Soil and
Rock "
[4] Bieniawski, Z. T., “ Engineering Classification of Jointed Rock Masses”, The Civil
Engineer in South Africa, South Africa Institution of Civil Engineers, Transvaal, South
Africa, December (1973), p.335-343 , (Quoted from Golder Associates, “Tunnelling
Technology”, 1979).
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9. Paper: ASAT-13-CV-15
[5]
Carranza-Torres, C. and Fairhurst, C., “Application of The Convergence-Confinement
Method of Tunnel Design to Rock Masses That Satisfy The Hoek-Brown Failure
Criterion.”, Magazine, Tunnelling and Underground Space Technology, Vol. 15, No. 2,
Published by Elsevier Science Ltd., (2000),
[6] Deere, D. U., Peck, R. B., Monseesn, J. E. and Schmidt, B., “ Design of
Tunnel
Liners and Support Systems” , Report for U.S. Department of Transportation, OHSGT
Contract 3-0152, No. PB 183799, NTIS, Spring Field, Virginia, U.S.A., (1969), p.278,
(Quoted from Golder Associates, “Tunneling Technology”, 1979).
[7] Barton, N.R., Lien, R., Lunde, J., 1974. Engineering classification of rock mass for the
design of tunnel support.
Fig 1. Longitudinal geological section along the western sector tunnel.
Fig. 2 Standard cross-section used in Shimizu tunnel No.3.
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