This paper proposes a new probabilistic methodology for analyzing the stability of Earth Dams, based on the
technique of the First Order Reliability Method for Structural Reliability. Differently from others methodologies
present in literature, the proposed method interprets the involved variables as random ones. So, three results are
provided here: the Structural Reliability Index, the Probability of Rupture and the most probable values of the
random variables for the occurrence of a dam break. In order to illustrate it, real data from a cross section of the
Left Bank Earthfill Dam of Itaipu Hydroelectric Power Plant (IHPP), located on the city of Foz do Iguaçu,
Paraná, Brazil were used. The numerical results achieved by the proposed methodology evidence that IHPP dam
has currently good structural conditions, confirming that the safety procedures adopted in Itaipu Dam may be
considered as appropriate. The use of the proposed method enables to complement the previously existing
knowledge about the structural conditions, improving the process of risk management.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Analytical assessment on progressive collapse potential of new reinforced con...eSAT Journals
Abstract Progressive collapse is a catastrophic partial or total failure that mostly occurs when a structure looses a primary structural component or more like a column or any vertical load resisting component due to natural or manmade hazard. In this research paper a new undergoing construction of Reinforced concrete 12 storied building located in Whitefield, Bangalore is modelled in accordance with the actual drawings according to Indian standard codes and analysed for progressive collapse potential by using structural design and analysis software Etabs2013. For evaluating the effect of progressive collapse in accordance with the guidance of U.S General Service Administration (GSA) linear static method is followed. The analytical model is checked for Demand capacity ratio by removing primary vertical support, one column at a time and evaluating whether the member is resistance to progressive collapse. Many such columns are removed and analysed to know the behaviour of building on abnormal loading conditions. The result shows that progressive collapse can be resisted by providing proper detailing and adequate reinforcement to the beams and columns. Keywords: Progressive collapse, Demand Capacity Ratio (DCR), General Service Administration standards (GSA), Design software Etabs2013, linear static
Determination of stress intensity factor for a crack emanating from a hole inIAEME Publication
This document describes a study determining the stress intensity factor (SIF) for a crack emanating from a hole in a pressurized cylinder using the finite element method. A cylinder model with a hole and through crack is created in CATIA and imported into ANSYS for meshing and analysis. The SIF is evaluated using the displacement extrapolation method. The results show that the SIF value rises sharply when the crack tip is near the hole and stabilizes as the crack tip moves farther from the hole. The SIF values from finite element analysis agree well with theoretical equations, validating the proposed methodology.
Integrated Methodology for the Seismic Design of Reinforced Embankments with ...IRJET Journal
This document presents an integrated methodology for the seismic design of reinforced soil embankments with berms (slopes with stepped terraces). The methodology is based on limit analysis and the quasi-static approach. It accounts for seismic loading conditions and considers cohesionless soils that deform plastically according to the Coulomb failure criterion. A software application was designed to implement this methodology for seismic design. It allows the user to define seismic hazard and design reinforced slopes based on potential failure planes. The results are compared to conventional methods and finite element analysis. Continuous slopes are also compared to slopes with berms, highlighting the advantages of composite geometries for high embankments.
IRJET- Seismic Analysis of Plan Regular and Irregular BuildingsIRJET Journal
This document analyzes the seismic performance of regular and irregular 15-story reinforced concrete buildings using ETABS 2015 software. Two irregular buildings (Models 2 and 3) and one regular building (Model 1) are modeled and analyzed. Both equivalent static analysis and response spectrum analysis are conducted. The results show that story displacement is highest for the irregular Models 3 and 2 compared to the regular Model 1. Base shear is highest for the regular Model 1 building compared to the irregular models. In conclusion, plan irregularity increases story displacement, while decreasing base shear compared to a regular building.
Dynamic Analysis of an Offshore Wind Turbine: Wind-Waves Nonlinear InteractionFranco Bontempi
An offshore wind turbine can be considered as a relatively complex structural system
since several environmental factors (e.g. wind and waves) affect its dynamic
behavior by generating both an active load and a resistant force to the structure’s
deformation induced by simultaneous actions. Besides the stochastic nature, also
their mutual interaction should be considered as nonlinear phenomena could be
crucial for optimal and cost-effective design. Another element of complexity lies in
the presence of different parts, each one with its peculiar features, whose mutual
interaction determines the overall dynamic response to non-stationary environmental
and service loads. These are the reasons why a proper and safe approach to the
analysis and design of offshore wind turbines requires a suitable technique for
carrying out a structural and performances decomposition along with the adoption of
advanced computation tools. In this work a finite element model for coupled windwaves
analysis is presented and the results of the dynamic behavior of a monopiletype
support structure for offshore wind turbine are shown.
This document provides an overview of fracture mechanics. It discusses the goal of fracture mechanics, which is to predict critical loads that cause failure in structures. It then summarizes different subfields of fracture mechanics like linear elastic and plastic fracture mechanics. The document also discusses various failure mechanisms like brittle versus ductile failure, static fatigue, and failure under cyclic loading conditions. It describes features of different failure modes and factors that influence failure like material properties, stress state, temperature and environment.
Failure Mode Superposition Approach To Structural Appraisal of a Building dur...IOSR Journals
The reliability of the concrete components in any civil engineering structure is a function of the
reliability of the individual components that make up the structure. In this paper, a simple failure mode
superposition approach is invoked in the estimation of reliability indices of all the concrete components of an
ongoing construction. The probability of failure of concrete components in the structure is assumed to be the
superposition of the probability of failure of the individual components of the entire structure. The strength
parameters employed in this study was obtained from the non-destructive test that was carried out on the
concrete components of the laboratory Block at college of Continuing Education, University of Port Harcourt,
Nigeria. The safety index value for the structure obtained from the formulated model was 2.54 which was
compared with the code specified values for the various structural members involved. It was found to be less
than 4.9 for beams in bending or flexure, 3.6 for beams in shear,4.5 for slabs and 3.9 for columns under deadlive
load combination showing that the structure cannot perform satisfactorily in service and may cause loss of
lives and damage of properties on collapse.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Analytical assessment on progressive collapse potential of new reinforced con...eSAT Journals
Abstract Progressive collapse is a catastrophic partial or total failure that mostly occurs when a structure looses a primary structural component or more like a column or any vertical load resisting component due to natural or manmade hazard. In this research paper a new undergoing construction of Reinforced concrete 12 storied building located in Whitefield, Bangalore is modelled in accordance with the actual drawings according to Indian standard codes and analysed for progressive collapse potential by using structural design and analysis software Etabs2013. For evaluating the effect of progressive collapse in accordance with the guidance of U.S General Service Administration (GSA) linear static method is followed. The analytical model is checked for Demand capacity ratio by removing primary vertical support, one column at a time and evaluating whether the member is resistance to progressive collapse. Many such columns are removed and analysed to know the behaviour of building on abnormal loading conditions. The result shows that progressive collapse can be resisted by providing proper detailing and adequate reinforcement to the beams and columns. Keywords: Progressive collapse, Demand Capacity Ratio (DCR), General Service Administration standards (GSA), Design software Etabs2013, linear static
Determination of stress intensity factor for a crack emanating from a hole inIAEME Publication
This document describes a study determining the stress intensity factor (SIF) for a crack emanating from a hole in a pressurized cylinder using the finite element method. A cylinder model with a hole and through crack is created in CATIA and imported into ANSYS for meshing and analysis. The SIF is evaluated using the displacement extrapolation method. The results show that the SIF value rises sharply when the crack tip is near the hole and stabilizes as the crack tip moves farther from the hole. The SIF values from finite element analysis agree well with theoretical equations, validating the proposed methodology.
Integrated Methodology for the Seismic Design of Reinforced Embankments with ...IRJET Journal
This document presents an integrated methodology for the seismic design of reinforced soil embankments with berms (slopes with stepped terraces). The methodology is based on limit analysis and the quasi-static approach. It accounts for seismic loading conditions and considers cohesionless soils that deform plastically according to the Coulomb failure criterion. A software application was designed to implement this methodology for seismic design. It allows the user to define seismic hazard and design reinforced slopes based on potential failure planes. The results are compared to conventional methods and finite element analysis. Continuous slopes are also compared to slopes with berms, highlighting the advantages of composite geometries for high embankments.
IRJET- Seismic Analysis of Plan Regular and Irregular BuildingsIRJET Journal
This document analyzes the seismic performance of regular and irregular 15-story reinforced concrete buildings using ETABS 2015 software. Two irregular buildings (Models 2 and 3) and one regular building (Model 1) are modeled and analyzed. Both equivalent static analysis and response spectrum analysis are conducted. The results show that story displacement is highest for the irregular Models 3 and 2 compared to the regular Model 1. Base shear is highest for the regular Model 1 building compared to the irregular models. In conclusion, plan irregularity increases story displacement, while decreasing base shear compared to a regular building.
Dynamic Analysis of an Offshore Wind Turbine: Wind-Waves Nonlinear InteractionFranco Bontempi
An offshore wind turbine can be considered as a relatively complex structural system
since several environmental factors (e.g. wind and waves) affect its dynamic
behavior by generating both an active load and a resistant force to the structure’s
deformation induced by simultaneous actions. Besides the stochastic nature, also
their mutual interaction should be considered as nonlinear phenomena could be
crucial for optimal and cost-effective design. Another element of complexity lies in
the presence of different parts, each one with its peculiar features, whose mutual
interaction determines the overall dynamic response to non-stationary environmental
and service loads. These are the reasons why a proper and safe approach to the
analysis and design of offshore wind turbines requires a suitable technique for
carrying out a structural and performances decomposition along with the adoption of
advanced computation tools. In this work a finite element model for coupled windwaves
analysis is presented and the results of the dynamic behavior of a monopiletype
support structure for offshore wind turbine are shown.
This document provides an overview of fracture mechanics. It discusses the goal of fracture mechanics, which is to predict critical loads that cause failure in structures. It then summarizes different subfields of fracture mechanics like linear elastic and plastic fracture mechanics. The document also discusses various failure mechanisms like brittle versus ductile failure, static fatigue, and failure under cyclic loading conditions. It describes features of different failure modes and factors that influence failure like material properties, stress state, temperature and environment.
Failure Mode Superposition Approach To Structural Appraisal of a Building dur...IOSR Journals
The reliability of the concrete components in any civil engineering structure is a function of the
reliability of the individual components that make up the structure. In this paper, a simple failure mode
superposition approach is invoked in the estimation of reliability indices of all the concrete components of an
ongoing construction. The probability of failure of concrete components in the structure is assumed to be the
superposition of the probability of failure of the individual components of the entire structure. The strength
parameters employed in this study was obtained from the non-destructive test that was carried out on the
concrete components of the laboratory Block at college of Continuing Education, University of Port Harcourt,
Nigeria. The safety index value for the structure obtained from the formulated model was 2.54 which was
compared with the code specified values for the various structural members involved. It was found to be less
than 4.9 for beams in bending or flexure, 3.6 for beams in shear,4.5 for slabs and 3.9 for columns under deadlive
load combination showing that the structure cannot perform satisfactorily in service and may cause loss of
lives and damage of properties on collapse.
Design study of stressed mirror polishing (smp) fixtureeSAT Journals
Abstract
Stressed Mirror Polishing (SMP) is a technique developed for the fabrication of off-axis aspheric mirror segments in a rapid and
cost effective manner. In SMP, the polishing of the mirror is carried out along with specific loads which are capable of deforming
a spherical mirror into any desired aspherical shape and thus reducing the difficulty of aspheric mirror polishing. When the blank
is removed from SMP after spherical polish and metrology, the blank will relax to the required aspherical surface with-in desired
PV & RMS surface figure accuracies. This paper discusses the different FEM approaches that can be adopted for simulating the
deformations in the mirror blank. For preliminary study purpose, a 36-cm diameter off-axis, meniscus shaped parabolic roundel
and a Spherical roundel mirror blanks are taken and required deformations are achieved through various FEM approaches. The
net deformed surface is validated and compared with a best fit near spherical surface. Additionally the reversibility of the
technique is also proved with-in required Surface accuracies. It is felt necessary that these preliminary simulations should form
the basis in understanding the warping process and their locations, so that full SMP fixture can be designed which is capable of
warping the mirrors.
Keywords: Stressed Mirror Polishing, Segmented Primary Mirror, Aspheric Segment Fabrication, Bending Fixture
This document provides a review of state-of-the-art nonlinear inelastic analysis methods for steel structures. It discusses five different analysis methods ranging from simple to rigorous, including plastic-zone, quasi-plastic hinge, elastic-plastic hinge, notional-load hinge, and refined-plastic hinge analysis. It also summarizes several experimental studies on nonlinear behavior of steel frames. Finally, it addresses considerations for modeling, analysis, and design using nonlinear inelastic analysis methods. The goal is to review research enabling the use of these advanced analysis techniques directly for frame design.
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
ISEISMIC PERFORMANCE OF RC FRAMED BUILDINGS UNDER LINEAR DYNAMIC ANALYSISjcie...IAEME Publication
The construction of multi-storey buildings is increasing constantly all over the world. The
development of highly advanced structural system is mainly based on the quality of aesthetic
expression, structural efficiency, and geometric versatility. The selected structural system should be
such that it has to be effectively utilized for structural requirements. The unique geometrical
configuration of the diagrid structural systems have driven them to be used for high rise buildings
providing the structural efficiency and aesthetic potential. In this present work, four different
models of I section of a 30 storey RC Frame building with plan size 18 m × 18 m located in seismic
zone V have been considered for analysis. Steel diagrid structure of 2 storey and 6 storey models
and Infill wall model are analyzed and compared with conventional RC Frame model and is
studied using linear dynamic analysis. ETabs software is used for modeling and analysis of
structural members. Comparison of analysis results in terms of storey Displacement, Drift, Bending
Moment, Axial forces, Time period, Base shear is presented and the results obtained were
compared with those obtained from other models.
Determination of Stress Concentration factor in Linearly Elastic Structures w...IJERA Editor
Stress concentration is the localization of stress around stress raisers. Sudden changes in the geometry of
structures give rise to stress values that are higher than those obtained by elementary equations of solid
mechanics. Therefore the evaluation of stress state at such locations needs specialized techniques such as Finite
Element Method (FEM).The finite element method is a numerical procedure that can be used to obtain solution
to a large variety of engineering problems such as structural, thermal, heat transfer, electromagnetism and fluid
flow.
In the present investigation, focus has been kept on the finite element modeling and determination of stress
concentration factor (SCF) in linearly elastic structures with different stress-raisers such as circular and elliptical
holes and double semicircular notch at different locations in a finite plate. The results obtained from FEM are
compared with those obtained by analytical relations as given in literature. A commercially available finite
element solver ANSYS has been used for the modeling and analysis in the investigation. Throughout the
investigation, plane82, which is an eight node two-dimensional element is used for the discretization.
STABILITY ASSESSMENT OF STEEL MOMENT FRAMES AGAINST PROGRESSIVE COLLAPSEcivej
Analyzing progressive collapse plays a pivotal role in diagnosing structure stability caused by earthquake,
explosion, car crashes, and fire and so on. In the current research, condition of progressive collapse has
been analyzed in structures which have been designed based on current codes in Iran. For this purpose, a
couple of steel buildings with steel moment frame systems that have many stories and various bay, have
been evaluated. With sudden removal of each column, the possibility of bridging over other elements has
been studied; besides, alternative path method introduced by the UFC 4-023-03 code has been applied in
the assessment process. Results indicate that the beams located on the highest floor do not have a suitable
performance and in case of sudden removal of each of the columns, it will be impossible to bridge overother elements and it will face collapse and progressive collapse in spite of the fact that other members are
resistant against the collapse.
A study on plastic hinge formation in rc frame by nonlinear static analysiseSAT Journals
This document presents a study on plastic hinge formation in reinforced concrete (RC) frames under nonlinear static pushover analysis. A single-bay, single-story RC frame is modeled and analyzed using SAP2000 software. The order and location of plastic hinge formation is observed as the frame is subjected to incremental lateral loading. Four plastic hinges form in total. The sequence of hinge formation is found to control the deformation behavior of the frame. Understanding hinge formation and the gap between successive hinges forming provides better insight into the performance of the structure under earthquake ground motions.
A computational approach for evaluating helical compression springseSAT Journals
Abstract Helical compression springs are generally synthesized and evaluated by determining the maximum torsional stress, fatigue life, natural frequency, and/or load loss due to stress relaxation. To this end, researchers have developed finite element analysis (FEA) modeling methods to simulate the design performance of helical compression springs. The intent of this paper was to make a useful contribution to the published works for evaluating round wire helical compression springs. Specifically, commercially available FEA software was used to construct a structural model of a helical compression spring to simulate its full range of compression. The proposed FEA modeling methodology considers coil-to-coil contact and the end coils were modeled as rigid surfaces. With 9 mm of compression, the predicted spring rate correlated with the analytically calculated value to within 5%. Keywords: Helical compression spring, machine component design, spring FEA
This document summarizes a computational analysis of flow behavior over a multi-stage launch vehicle with strap-on boosters. A structured grid and commercial CFD software Fluent were used to model the 2D flow field. Finer meshes were generated near vehicle surfaces to capture shocks accurately. Both Euler and Navier-Stokes solvers were tested using various turbulence models. Results aimed to understand complex flow interactions over the multi-component vehicle configuration.
IRJET- Behavior of Reinforced Cement Concrete Multistorey Building under Blas...IRJET Journal
This document analyzes the behavior of reinforced cement concrete multi-story buildings under blast loading through analytical and finite element methods. Two models of a 3-story building - a 3D frame model and a lumped mass model - are subjected to surface and subsurface blast explosions in MATLAB and finite element software. Results such as displacement, acceleration, shear forces are compared between the two models and different blast scenarios. The study aims to help predict blast loads and their effects on building components, as well as suggest blast resistant techniques.
Application of extended n2 method to reinforced concrete frames with asymmetr...IAEME Publication
The extended N2 method was applied to analyze two reinforced concrete buildings with asymmetric setbacks. The extended N2 method accounts for higher mode effects by combining results from a pushover analysis and an elastic modal analysis. It was applied to a 5-story and 9-story building. For the 5-story building, the extended N2 method provided results close to the displacement coefficient method in FEMA 356. Correction factors from the modal analysis were less than 1, so the basic N2 method results were used. This shows the extended N2 method can accurately analyze buildings with vertical irregularities like asymmetric setbacks.
A review and buckling analysis of stiffened plateeSAT Journals
Abstract It happens many times that the structure is safe in normal stress and deflection but fails in buckling. Buckling analysis is one of the method to go for such type of analysis.It predicts various modes of buckling. Plates are used in many applications such as structures, aerospace, automobile etc. Such structures are subjected to heavy uniformly distributed load and concentrated load many times over it’s life span. Strength of these structures are increased by adding stiffeners to its plate. This paper deals with the analysis of rectangular stiffened plates which forms the basis of structures. A comparison of stiffened plate and unstiffened plate is done for the same dimensions. In order to continue this analysis various research papers were studied to understand the previous tasks done for stiffened plate. Hyper mesh and Nastran is used in this research work.Buckling analysis is performed for the component with aspect ratio of 2.Rectangular flat bar is used as stiffener Keywords: Stiffened Plate; Dynamic load; Buckling; Aspect ratio;Buckling Analysis.
This document discusses estimating the stress intensity factor (SIF) on cracked components using finite element analysis. It begins with an introduction to fracture mechanics and SIF. Then it describes using FEA to model edge cracks and center cracks in plates to calculate SIF and compare results to theoretical solutions. Finally, it explains how the same FEA process was used to model cracks in a connecting rod component to determine SIF at various crack lengths. The document concludes the SIF values increase with crack length and FEA results closely match theoretical solutions.
Seismic performance assessment of the torsional effect in asymmetric structur...eSAT Journals
Abstract In the recent time we come across many structures which are irregular in shape, this type of cannot be avoided due to the functional and architectural requirements. These type of structures have irregular distribution of centre of mass and centre of rigidity which causes the torsional effect on the structures which is one of the most important factor influencing the seismic damage of the structure. Structures with asymmetric distribution of mass and rigidity undergoes torsional motions during earthquake. To assess the torsional effect on the structures in the present study four types of structures are considered with varying eccentricity subjected to Pushover Analysis and Non-Linear Time History Analysis. The performance of the structures are assessed as per the procedure prescribe in ATC-40 and FEMA-356. The analysis of the structural models is done in ETABS. The results have shown that the structures with less eccentricity and in the direction of the columns orientation are performing well, also ductility, drift, and lateral displacement depends on the eccentricity of the structures. Key Words: Symmetric Structure, Asymmetric Structure, Pushover Analysis, Non-Linear Time History Analysis.
This paper presents a probabilistic approach to predict high cycle fatigue (HCF) behavior of metallic parts. The approach accounts for uncertainties in both material properties and applied loading. It uses the multi-axial HCF Crossland criterion and models the Crossland material parameters and loading amplitudes as random variables. The first order reliability method is used to compute fatigue reliability. Iso-probabilistic Crossland diagrams are generated for different coefficients of variation of the loading and material parameters. The method is applied to a hard steel subjected to torsion and bending loading, and allows evaluation of the influence of different dispersions on HCF reliability prediction.
Computational approach to contact fatigue damage initiation and deformation a...eSAT 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.
Performance of Flat Slab Structure Using Pushover AnalysisIOSR Journals
Performance Based Seismic Engineering is the modern approach to earthquake resistant design. It
is a limit-state based design approach extended to cover complex range of issues faced by structural engineers.
Flat slabs are becoming popular and gaining importance as they are economical as compared to beam-column
connections in conventional slab. Many existing flat slabs may not have been designed for seismic forces so it is
important to study their response under seismic conditions and to evaluate seismic retrofit schemes. In this
paper we have discussed the results obtained by performing push over analysis on flat slabs by using most
common software SAP2000. A (G+7) frame having 5 bays is considered for analysis. It is observed that the
performance point of flat slab is more as compared to conventional building.
Renewable Energy Based Floating Power Generator (Rivers and Canals)IJERA Editor
1) Researchers in India have developed a floating power generator system that can generate electricity from flowing water in rivers and canals without needing to be permanently installed.
2) The system consists of fiberglass floats connected to a water wheel that spins a waterproof generator as water flows between the floats.
3) Testing of a prototype in Mahi River in India showed it could generate up to 250 watts of power at a water flow rate of 6 cubic meters per second.
Investigation on Bridges Connection to Network Carrefour in Existing Roads in...IJERA Editor
The rapid and continuous growth of populations and vehicles has caused very big traffic volume in most of
African big cities. In order to ensure a better distribution of traffic and enables quick access to vehicles,
reasonable interchange can be designed to allow greater connection and realizes rapid dividing of vehicles at
existing road network carrefour. This paper uses Cotonou, which is the largest urban and economic city of Benin
Republic as a case study. Firstly, the paper reviews literatures on history and development of interchanges bridge
systems. Based on the case study, the paper then mainly introduces a typical interchange at Godomey carrefour,
explains difficulties encountered in engineering design and realizes rapid dividing of vehicles by designing
reasonable interchange at Godomey carrefour, so as to accumulate certain experience in the construction of
interchange at existing road network carrefour. By studying this case, the research seeks to identify and expand
on lessons learned under the first interchange bridge design in Benin. Using the lessons learned government
agencies, engineering and construction communities could adopt reasonable structure and construction method
according to local conditions based on current situations.
Seismic Analysis and Optimization of RC Elevated Water Tank Using Various Sta...IJERA Editor
This document presents a study on the seismic analysis and optimization of reinforced concrete elevated water tanks with different staging arrangements. 36 tank configurations were analyzed considering variations in the number of columns, number of staging levels, and column sizes. Radial staging with six levels was found to provide the best structural response. An optimization was performed to determine the column diameter and number that results in the lowest cost, considering material quantities and market rates. It was found that a configuration with eight 300mm diameter columns in a radial six-level staging arrangement provided the lowest cost.
Development of 30 Watt Solar Bag with Wireless Power Transmission UnitIJERA Editor
The development of 30 watt Solar bag with wireless power transmission unit using photo voltaic cells to charge
tablets, mobile phones, smart phones, digital cameras and all types of batteries (Including 12 volt acid and dry
cell for emergency situations) using in such kind of appliances. The phenomenon that we have implanted in our
project to transmit wireless power is resonant coupling. The Battery backup of the solar bag would be around 2
hours with load estimation of around 30 watts. Our product is very user friendly as it allows us the power
transmission in the range of 12 inches, whereas we have also implemented the overall logic by using PIC
Microcontroller based model 16F877A to enhance its versatility.
Modelling Framework of a Neural Object RecognitionIJERA Editor
In many industrial, medical and scientific image processing applications, various feature and pattern recognition
techniques are used to match specific features in an image with a known template. Despite the capabilities of
these techniques, some applications require simultaneous analysis of multiple, complex, and irregular features
within an image as in semiconductor wafer inspection. In wafer inspection discovered defects are often complex
and irregular and demand more human-like inspection techniques to recognize irregularities. By incorporating
neural network techniques such image processing systems with much number of images can be trained until the
system eventually learns to recognize irregularities. The aim of this project is to develop a framework of a
machine-learning system that can classify objects of different category. The framework utilizes the toolboxes in
the Matlab such as Computer Vision Toolbox, Neural Network Toolbox etc.
Design study of stressed mirror polishing (smp) fixtureeSAT Journals
Abstract
Stressed Mirror Polishing (SMP) is a technique developed for the fabrication of off-axis aspheric mirror segments in a rapid and
cost effective manner. In SMP, the polishing of the mirror is carried out along with specific loads which are capable of deforming
a spherical mirror into any desired aspherical shape and thus reducing the difficulty of aspheric mirror polishing. When the blank
is removed from SMP after spherical polish and metrology, the blank will relax to the required aspherical surface with-in desired
PV & RMS surface figure accuracies. This paper discusses the different FEM approaches that can be adopted for simulating the
deformations in the mirror blank. For preliminary study purpose, a 36-cm diameter off-axis, meniscus shaped parabolic roundel
and a Spherical roundel mirror blanks are taken and required deformations are achieved through various FEM approaches. The
net deformed surface is validated and compared with a best fit near spherical surface. Additionally the reversibility of the
technique is also proved with-in required Surface accuracies. It is felt necessary that these preliminary simulations should form
the basis in understanding the warping process and their locations, so that full SMP fixture can be designed which is capable of
warping the mirrors.
Keywords: Stressed Mirror Polishing, Segmented Primary Mirror, Aspheric Segment Fabrication, Bending Fixture
This document provides a review of state-of-the-art nonlinear inelastic analysis methods for steel structures. It discusses five different analysis methods ranging from simple to rigorous, including plastic-zone, quasi-plastic hinge, elastic-plastic hinge, notional-load hinge, and refined-plastic hinge analysis. It also summarizes several experimental studies on nonlinear behavior of steel frames. Finally, it addresses considerations for modeling, analysis, and design using nonlinear inelastic analysis methods. The goal is to review research enabling the use of these advanced analysis techniques directly for frame design.
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
ISEISMIC PERFORMANCE OF RC FRAMED BUILDINGS UNDER LINEAR DYNAMIC ANALYSISjcie...IAEME Publication
The construction of multi-storey buildings is increasing constantly all over the world. The
development of highly advanced structural system is mainly based on the quality of aesthetic
expression, structural efficiency, and geometric versatility. The selected structural system should be
such that it has to be effectively utilized for structural requirements. The unique geometrical
configuration of the diagrid structural systems have driven them to be used for high rise buildings
providing the structural efficiency and aesthetic potential. In this present work, four different
models of I section of a 30 storey RC Frame building with plan size 18 m × 18 m located in seismic
zone V have been considered for analysis. Steel diagrid structure of 2 storey and 6 storey models
and Infill wall model are analyzed and compared with conventional RC Frame model and is
studied using linear dynamic analysis. ETabs software is used for modeling and analysis of
structural members. Comparison of analysis results in terms of storey Displacement, Drift, Bending
Moment, Axial forces, Time period, Base shear is presented and the results obtained were
compared with those obtained from other models.
Determination of Stress Concentration factor in Linearly Elastic Structures w...IJERA Editor
Stress concentration is the localization of stress around stress raisers. Sudden changes in the geometry of
structures give rise to stress values that are higher than those obtained by elementary equations of solid
mechanics. Therefore the evaluation of stress state at such locations needs specialized techniques such as Finite
Element Method (FEM).The finite element method is a numerical procedure that can be used to obtain solution
to a large variety of engineering problems such as structural, thermal, heat transfer, electromagnetism and fluid
flow.
In the present investigation, focus has been kept on the finite element modeling and determination of stress
concentration factor (SCF) in linearly elastic structures with different stress-raisers such as circular and elliptical
holes and double semicircular notch at different locations in a finite plate. The results obtained from FEM are
compared with those obtained by analytical relations as given in literature. A commercially available finite
element solver ANSYS has been used for the modeling and analysis in the investigation. Throughout the
investigation, plane82, which is an eight node two-dimensional element is used for the discretization.
STABILITY ASSESSMENT OF STEEL MOMENT FRAMES AGAINST PROGRESSIVE COLLAPSEcivej
Analyzing progressive collapse plays a pivotal role in diagnosing structure stability caused by earthquake,
explosion, car crashes, and fire and so on. In the current research, condition of progressive collapse has
been analyzed in structures which have been designed based on current codes in Iran. For this purpose, a
couple of steel buildings with steel moment frame systems that have many stories and various bay, have
been evaluated. With sudden removal of each column, the possibility of bridging over other elements has
been studied; besides, alternative path method introduced by the UFC 4-023-03 code has been applied in
the assessment process. Results indicate that the beams located on the highest floor do not have a suitable
performance and in case of sudden removal of each of the columns, it will be impossible to bridge overother elements and it will face collapse and progressive collapse in spite of the fact that other members are
resistant against the collapse.
A study on plastic hinge formation in rc frame by nonlinear static analysiseSAT Journals
This document presents a study on plastic hinge formation in reinforced concrete (RC) frames under nonlinear static pushover analysis. A single-bay, single-story RC frame is modeled and analyzed using SAP2000 software. The order and location of plastic hinge formation is observed as the frame is subjected to incremental lateral loading. Four plastic hinges form in total. The sequence of hinge formation is found to control the deformation behavior of the frame. Understanding hinge formation and the gap between successive hinges forming provides better insight into the performance of the structure under earthquake ground motions.
A computational approach for evaluating helical compression springseSAT Journals
Abstract Helical compression springs are generally synthesized and evaluated by determining the maximum torsional stress, fatigue life, natural frequency, and/or load loss due to stress relaxation. To this end, researchers have developed finite element analysis (FEA) modeling methods to simulate the design performance of helical compression springs. The intent of this paper was to make a useful contribution to the published works for evaluating round wire helical compression springs. Specifically, commercially available FEA software was used to construct a structural model of a helical compression spring to simulate its full range of compression. The proposed FEA modeling methodology considers coil-to-coil contact and the end coils were modeled as rigid surfaces. With 9 mm of compression, the predicted spring rate correlated with the analytically calculated value to within 5%. Keywords: Helical compression spring, machine component design, spring FEA
This document summarizes a computational analysis of flow behavior over a multi-stage launch vehicle with strap-on boosters. A structured grid and commercial CFD software Fluent were used to model the 2D flow field. Finer meshes were generated near vehicle surfaces to capture shocks accurately. Both Euler and Navier-Stokes solvers were tested using various turbulence models. Results aimed to understand complex flow interactions over the multi-component vehicle configuration.
IRJET- Behavior of Reinforced Cement Concrete Multistorey Building under Blas...IRJET Journal
This document analyzes the behavior of reinforced cement concrete multi-story buildings under blast loading through analytical and finite element methods. Two models of a 3-story building - a 3D frame model and a lumped mass model - are subjected to surface and subsurface blast explosions in MATLAB and finite element software. Results such as displacement, acceleration, shear forces are compared between the two models and different blast scenarios. The study aims to help predict blast loads and their effects on building components, as well as suggest blast resistant techniques.
Application of extended n2 method to reinforced concrete frames with asymmetr...IAEME Publication
The extended N2 method was applied to analyze two reinforced concrete buildings with asymmetric setbacks. The extended N2 method accounts for higher mode effects by combining results from a pushover analysis and an elastic modal analysis. It was applied to a 5-story and 9-story building. For the 5-story building, the extended N2 method provided results close to the displacement coefficient method in FEMA 356. Correction factors from the modal analysis were less than 1, so the basic N2 method results were used. This shows the extended N2 method can accurately analyze buildings with vertical irregularities like asymmetric setbacks.
A review and buckling analysis of stiffened plateeSAT Journals
Abstract It happens many times that the structure is safe in normal stress and deflection but fails in buckling. Buckling analysis is one of the method to go for such type of analysis.It predicts various modes of buckling. Plates are used in many applications such as structures, aerospace, automobile etc. Such structures are subjected to heavy uniformly distributed load and concentrated load many times over it’s life span. Strength of these structures are increased by adding stiffeners to its plate. This paper deals with the analysis of rectangular stiffened plates which forms the basis of structures. A comparison of stiffened plate and unstiffened plate is done for the same dimensions. In order to continue this analysis various research papers were studied to understand the previous tasks done for stiffened plate. Hyper mesh and Nastran is used in this research work.Buckling analysis is performed for the component with aspect ratio of 2.Rectangular flat bar is used as stiffener Keywords: Stiffened Plate; Dynamic load; Buckling; Aspect ratio;Buckling Analysis.
This document discusses estimating the stress intensity factor (SIF) on cracked components using finite element analysis. It begins with an introduction to fracture mechanics and SIF. Then it describes using FEA to model edge cracks and center cracks in plates to calculate SIF and compare results to theoretical solutions. Finally, it explains how the same FEA process was used to model cracks in a connecting rod component to determine SIF at various crack lengths. The document concludes the SIF values increase with crack length and FEA results closely match theoretical solutions.
Seismic performance assessment of the torsional effect in asymmetric structur...eSAT Journals
Abstract In the recent time we come across many structures which are irregular in shape, this type of cannot be avoided due to the functional and architectural requirements. These type of structures have irregular distribution of centre of mass and centre of rigidity which causes the torsional effect on the structures which is one of the most important factor influencing the seismic damage of the structure. Structures with asymmetric distribution of mass and rigidity undergoes torsional motions during earthquake. To assess the torsional effect on the structures in the present study four types of structures are considered with varying eccentricity subjected to Pushover Analysis and Non-Linear Time History Analysis. The performance of the structures are assessed as per the procedure prescribe in ATC-40 and FEMA-356. The analysis of the structural models is done in ETABS. The results have shown that the structures with less eccentricity and in the direction of the columns orientation are performing well, also ductility, drift, and lateral displacement depends on the eccentricity of the structures. Key Words: Symmetric Structure, Asymmetric Structure, Pushover Analysis, Non-Linear Time History Analysis.
This paper presents a probabilistic approach to predict high cycle fatigue (HCF) behavior of metallic parts. The approach accounts for uncertainties in both material properties and applied loading. It uses the multi-axial HCF Crossland criterion and models the Crossland material parameters and loading amplitudes as random variables. The first order reliability method is used to compute fatigue reliability. Iso-probabilistic Crossland diagrams are generated for different coefficients of variation of the loading and material parameters. The method is applied to a hard steel subjected to torsion and bending loading, and allows evaluation of the influence of different dispersions on HCF reliability prediction.
Computational approach to contact fatigue damage initiation and deformation a...eSAT 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.
Performance of Flat Slab Structure Using Pushover AnalysisIOSR Journals
Performance Based Seismic Engineering is the modern approach to earthquake resistant design. It
is a limit-state based design approach extended to cover complex range of issues faced by structural engineers.
Flat slabs are becoming popular and gaining importance as they are economical as compared to beam-column
connections in conventional slab. Many existing flat slabs may not have been designed for seismic forces so it is
important to study their response under seismic conditions and to evaluate seismic retrofit schemes. In this
paper we have discussed the results obtained by performing push over analysis on flat slabs by using most
common software SAP2000. A (G+7) frame having 5 bays is considered for analysis. It is observed that the
performance point of flat slab is more as compared to conventional building.
Renewable Energy Based Floating Power Generator (Rivers and Canals)IJERA Editor
1) Researchers in India have developed a floating power generator system that can generate electricity from flowing water in rivers and canals without needing to be permanently installed.
2) The system consists of fiberglass floats connected to a water wheel that spins a waterproof generator as water flows between the floats.
3) Testing of a prototype in Mahi River in India showed it could generate up to 250 watts of power at a water flow rate of 6 cubic meters per second.
Investigation on Bridges Connection to Network Carrefour in Existing Roads in...IJERA Editor
The rapid and continuous growth of populations and vehicles has caused very big traffic volume in most of
African big cities. In order to ensure a better distribution of traffic and enables quick access to vehicles,
reasonable interchange can be designed to allow greater connection and realizes rapid dividing of vehicles at
existing road network carrefour. This paper uses Cotonou, which is the largest urban and economic city of Benin
Republic as a case study. Firstly, the paper reviews literatures on history and development of interchanges bridge
systems. Based on the case study, the paper then mainly introduces a typical interchange at Godomey carrefour,
explains difficulties encountered in engineering design and realizes rapid dividing of vehicles by designing
reasonable interchange at Godomey carrefour, so as to accumulate certain experience in the construction of
interchange at existing road network carrefour. By studying this case, the research seeks to identify and expand
on lessons learned under the first interchange bridge design in Benin. Using the lessons learned government
agencies, engineering and construction communities could adopt reasonable structure and construction method
according to local conditions based on current situations.
Seismic Analysis and Optimization of RC Elevated Water Tank Using Various Sta...IJERA Editor
This document presents a study on the seismic analysis and optimization of reinforced concrete elevated water tanks with different staging arrangements. 36 tank configurations were analyzed considering variations in the number of columns, number of staging levels, and column sizes. Radial staging with six levels was found to provide the best structural response. An optimization was performed to determine the column diameter and number that results in the lowest cost, considering material quantities and market rates. It was found that a configuration with eight 300mm diameter columns in a radial six-level staging arrangement provided the lowest cost.
Development of 30 Watt Solar Bag with Wireless Power Transmission UnitIJERA Editor
The development of 30 watt Solar bag with wireless power transmission unit using photo voltaic cells to charge
tablets, mobile phones, smart phones, digital cameras and all types of batteries (Including 12 volt acid and dry
cell for emergency situations) using in such kind of appliances. The phenomenon that we have implanted in our
project to transmit wireless power is resonant coupling. The Battery backup of the solar bag would be around 2
hours with load estimation of around 30 watts. Our product is very user friendly as it allows us the power
transmission in the range of 12 inches, whereas we have also implemented the overall logic by using PIC
Microcontroller based model 16F877A to enhance its versatility.
Modelling Framework of a Neural Object RecognitionIJERA Editor
In many industrial, medical and scientific image processing applications, various feature and pattern recognition
techniques are used to match specific features in an image with a known template. Despite the capabilities of
these techniques, some applications require simultaneous analysis of multiple, complex, and irregular features
within an image as in semiconductor wafer inspection. In wafer inspection discovered defects are often complex
and irregular and demand more human-like inspection techniques to recognize irregularities. By incorporating
neural network techniques such image processing systems with much number of images can be trained until the
system eventually learns to recognize irregularities. The aim of this project is to develop a framework of a
machine-learning system that can classify objects of different category. The framework utilizes the toolboxes in
the Matlab such as Computer Vision Toolbox, Neural Network Toolbox etc.
Seasonal Variation of Groundwater Quality in Parts of Y.S.R and Anantapur Dis...IJERA Editor
Groundwater is used for domestic, industrial water supply and for irrigation all over the world. The groundwater
quality is a function of natural processes as well as anthropogenic activities. The safe potable water is
enormously essential for living and groundwater is one of the sources for human consumption in both urban as
well as rural areas. The area is located in the survey of India toposheet Number 57 J/3 lying between east
780
00’
0
’’ to 780
15’
0
” longitudes and 140
15’ 0
’’ to 140
30’
0
’’ North latitudes covering an area of 720 sq. kms.
Geologically, it is underlain mainly by Peninsular gneisses of Archean age followed by Gulcheru and Vemapalli
formations comprising quartzites, conglomerates, dolomites and shales. Major geomorphic units are
denudational hills, residual hills, pediments, pediplains, structural hills and valleys. The study area experiences a
semiarid climate. Physicochemical parameters viz., pH, total hardness, calcium, chloride, total dissolved solids,
fluoride were analyzed. Most of parameter show higher value than permissible limit in pre and post monsoon.
Further, a moderation in water quality was observed after the monsoon season, which can be attributed to a
possible dilution due to groundwater recharge People dependent on this water may prone to health hazard.
Therefore some effective measures are urgently required to enhance the quality of water in these areas
A Computational Investigation of Flow Structure Within a Sinuous DuctIJERA Editor
In the present investigation the distribution of mean velocity are experimentally studied on three constant area
rectangular curved ducts with an aspect ratio of 2.4. First one is C-shape, second one is S-shape and third one
is a DS-shape duct. The experiment is carried out at mass averaged mean velocity of 40m/s for all the ducts.
The velocity distribution shows for C-duct, the bulk flow shifting from outer wall to the inner wall along the
flow passage and for S-duct, the bulk flow shifting from outer wall to the inner wall in the first half and from
inner wall to the outer wall in the second half along the flow passage of curved ducts are very instinct. Due to
the imbalance of centrifugal force and radial pressure gradient, secondary motions in the forms of counter
rotating vortices have been generated within both the curved duct. For DS-duct the velocity distributions shows
the Bulk of flow shifting from inner watt to outer wall in the first bend and third bend of the duct and outer wall
to inner wall in the second bend and forth bend of the duct along the flow passage is very instinct. Flow at end
of the DS-duct is purely uniform in nature due to non existence of secondary motion. The experimental results
then were numerically validated with the help of Fluent, which shows a good agreement between the
experimental and predicted results for all the ducts
Application of Rapid Bioassay Method for Assessing Its Water Purification by ...IJERA Editor
Appreciated integral toxicity of four water samples taken from various sources, urban and rural environment,
and explored some of the properties of the reagent chemical purification of water - potassium ferrate K2FeO4.
These data allow suggesting for practical use test system based on bacterial luminescence for express evaluation
of the toxicity of chemical reagents used for water purification, selection of their effective concentrations and
optimal processing time of water samples.
Seismic Vulnerability and Mitigation on Non-Engineered Traditional Buildings ...IJERA Editor
Earthquake is one of the most deadly phenomena which disturb the harmonious living among human
beings and claimed large number of lives without any notice and warning. However one should always be
ready to learn, how to live with seismic hazard and minimize its adverse effect on built environment, as its
happening can’t be prevented. The 6.1magnitute Earthquake of 21st September, 2009 caused huge damage in
the eastern part of Bhutan and adjoining areas like Indian states and Bangladesh. This incident has now
exposed to the seismic vulnerability and raised concerns over the safety of the built environment in Bhutan –
particularly, the traditional stone and timber houses, some of which were badly affected during the earthquake.
This paper presents an overview of damages observed in the region and its causes and performances of building
during earthquake. It also describes, the seismic performance of those structures can be improved from life
safety point of view, by adopting simple low-cost modifications to the existing construction practices and
material selection with alternative solutions to make building earthquake resistant.
Investigations in Effective Viscosity of Fluid in a Porous MediumIJERA Editor
In this work we address the quantification of Brinkman’s effective viscosity, which arises due to the presence of
the porous medium and its effect on increasing or decreasing the fluid viscosity in relation to the base fluid
viscosity. This work is motivated in the main part by the lack of consensus in the available literature on the
ranges of effective viscosity. To this end, this work provides a model of quantifying the effective viscosity by
incorporating the porous microstructure in the volume-averaged Navier-Stokes equations. Extensive analysis and
testing are provided in the current work which considers five different porous microstructures, and the effective
viscosity is quantified in each case under Poiseuille flow
Efficient Image Compression Technique using Clustering and Random PermutationIJERA Editor
Multimedia data compression is a challenging situation for compression technique, due to the possibility of loss
of data as well as it require large amount of storage place. The minimization of storage place and proper
transmission of these data need compression. In this dissertation we proposed a block based DWT image
compression technique using genetic algorithm and HCC code matrix. The HCC code matrix compressed into
two different set redundant and non-redundant which generate similar pattern of block coefficient. The similar
block coefficient generated by particle of swarm optimization. The process of particle of swarm optimization is
select for the optimal block of DWT transform function. For the experimental purpose we used some standard
image such as Lena, Barbara and cameraman image. The size of resolution of this image is 256*256. The source
of image is Google
Analytical and Experimental Studieson Fracture Behaviour of Foundry Sand Conc...IJERA Editor
The document analyzes the fracture behavior of concrete with partial replacement of foundry sand. Three point bending tests were conducted on beams with 0%, 30%, and 40% replacement of foundry sand. The following conclusions were reached:
1. The critical J-integral and stress intensity factors, which are fracture parameters, increased when comparing beams with 0% foundry sand to those with 30% and 40% replacement.
2. Beams both with and without pre-cracks were tested to determine the fracture parameters.
3. The study found that using foundry sand as a partial replacement in concrete can improve fracture properties compared to normal concrete without foundry sand.
Optimization of Test Pattern Using Genetic Algorithm for Testing SRAMIJERA Editor
This document proposes optimizing test patterns for testing SRAM using genetic algorithms. The genetic algorithm approach generates a compact set of test vectors requiring fewer configurations while detecting all stuck-at, open, and bridging faults. It reduces redundancy and optimizes the test patterns, resulting in reduced testing time and power consumption compared to previous methods. The optimized test patterns are generated using a linear feedback shift register and genetic operations including selection, crossover and mutation. Results show the proposed method achieves fault detection with a minimum time constraint of 1.5-2 ns and low power consumption of 220-230 mW.
E-Commerce: Study, Development and PrototypingIJERA Editor
This project was a study of the development of an electronic commerce in Paraguay, tracking laws and
regulatory decrees formulated by the technical agencies. As a result, a prototype is developed, which reproduces
the steps to follow in a web-based e-commerce transaction using fictitious credit cards as payment method. A
particular digital certificate created for testing purposes was used, performing secure connection via https
protocol and the digital certificate issued by the Enforcement Authority and the Ministry of Industry and Trade.
The results were obtained through the measurement of the database log, matching planned rules for transactions
with the results obtained
Introduction to Mail Management System IJERA Editor
Developing different techniques to overcome this problem and protect the consumer, which planted in the hearts
of trust people and encouraged them to purchase via the internet. At first you must know what is the main reason
for the work of the filtration email the mail service is fast and easy way to exchange messages are singing from
the use of traditional mail, there are a large number from of services in the internet requires that you have one
email sometimes one of us would like to cancel his participation in one of the sites because of the large number
of incoming messages to him from the site does not know and have for a way unsubscribe to get rid of these
messages, or would like one of us that some of the messages is prohibited from specific people or locations for
some of these problems has the following solution is the work of a filter to any e-mail and work ban for
unwanted messages application spam filtering as a last resort, you can set up your own spam blocker with your
email application's built-in filter capability Email filtering is the processing of email to organize it according to
specified criteria.
Evaluation of Energy Contribution for Additional Installed Turbine Flow in Hy...IJERA Editor
This document evaluates the energy contribution of installing an additional turbine unit at the Spilje hydroelectric power plant in Macedonia. It analyzes technical parameters like water inflow and reservoir storage capacity over a 45-year period. Simulations show the existing 3-unit plant generates 279 GWh annually but loses 8 GWh to spilling. Installing a 4th unit capturing spill energy could generate an extra 16 GWh and increase annual income by €2.35 million compared to the existing plant. A financial analysis estimates the investment cost at €20-30 million and calculates economic indicators like net present value, benefit-cost ratio, and payback period to determine the potential profitability of the additional unit investment.
A Study on Relationship between Employee Satisfaction and Its DeterminantsIJERA Editor
This document summarizes a study on the relationship between employee satisfaction and its determinants in an organization. Some key points:
- The study examines factors that affect employee satisfaction like working hours, respect from superiors, salaries, welfare facilities, decision making freedoms, training opportunities, and authority for duties.
- A literature review is presented on previous research related to employee satisfaction and its importance for organizational effectiveness and productivity.
- The methodology section outlines the research design, sampling, data collection through questionnaires, and statistical analysis tools used like percentages, chi-square, and correlation.
- The results section presents data in tables on employee satisfaction levels for different factors and finds a positive relationship between satisfaction and most determin
Role of the Biochemistry Labs in Promoting the Health Care Services for the I...IJERA Editor
The health care in the State of Kuwait depends to a greater extent on the biochemical and clinical labs attached
at each hospital. The data obtained from these laboratories will facilitate the process of diagnosing the disease
accurately. This will have a positive impact on the selection of appropriate treatment for the patients in general
and for diabetics specifically.
The main objective of this research was to build a profile for lab analysis and a database for building a
comprehensive system of integrated activities to raise health care for diabetic patients in Kuwait. The study
revealed the burden of admitted diabetic cases on the blood chemistry laboratory in Sabah Hospital (in relation
to length of stay and total numbers of lab requests). The aim was fulfilled by designing a model of the
biochemical tests for diabetics; filling in forms from the reality of patient data, completing and analyzing the
results electronically.
The study showed the importance of biochemical and clinical labs since they act as the link of patient's
information at the secondary health care level.
Analysis of Seed Proteins in Groundnut Cultivars (Arachis hypogaea L.)IJERA Editor
The seed protein contents and protein banding pattern were studied in commonly cultivated groundnut cultivars.
The groundnut cultivars such as ICGV00351, TMV-7, CO-4,CO-6 and TG-374 were used for quantitative and
qualitative analysis of seed proteins. The protein contents varied among the different varieties of groundnut. The
maximum protein content was observed in CO-6 followed by CO-4, TMV-7, ICGV00351 and TG-374. There
was a slight differences in protein content among the different cultivars. All the five cultivars of groundnut were
subjected to SDS-PAGE analysis. The results revealed that the variation in total number of bands and MW-Rf
values. The maximum number of MW-Rf value was noticed in TG-374 and ICGV00351, and the minimum
MW-Rf value was 11 recorded in CO-6 and TMV-7.
This document discusses pitting corrosion, including its morphology and characterization. It provides background on pitting corrosion, how pits form, and factors that influence pit growth rates. It also describes challenges in characterizing pits and different methods that have been used, including sectioning, replication, microscopy techniques, and eddy current probes. The document provides examples of standards for pit characterization and unexpected pitting found in aircraft components in service.
STRUCTURAL RELIABILITY ASSESSMENT WITH STOCHASTIC PARAMETERSP singh
The performance of a structure [23] is assessed by its safety [1], serviceability [1] and economy [1]. Since we do not know the exact details of loads [4] acting on a structure at any time, there is always some uncertainty about the total loads on structure. Thus random variables (means stochastic variable) of loads and other parameters are the main criteria of design variables [18]. They vary with space and time. The input variables is never certain and complete. The safety factor provided in the existing codes and standers primarily based on practice, judgment and experience, may not be adequate and economical. Using the techniques presented earlier, we can design or analyze individual members in the contest of structural reliability [2][3][22][24]. However we are not examined how the system performs [23] or how to calculate the reliability of the structure as a whole.
Reliability Assessment of Tower Crane Structural Members-G03178 Idzuari AzliIdzuari Azli Bin Kamilan
This document discusses reliability assessment methods for tower crane structural members. It introduces concepts of time-dependent and stress-strength interference reliability modeling. Stress-strength interference methods compare random variables for stress (demand) and strength (supply). Monte Carlo simulations and Sobol sensitivity analysis are presented as methods to assess failure probability and sensitivity of input parameters. The goal is to develop a probabilistic approach for quantifying reliability of crane members over operating time.
RELIABILITY ANALYSIS OF CONCRETE BEAMS: A Complete ReviewIRJET Journal
This document provides a literature review on reliability analysis methods for reinforced concrete beams. It discusses 5 reliability analysis methods: Fault Tree Analysis, First Order Reliability Method (FORM), Monte Carlo Simulation, Three-Term Conjugate Map (TCM), and Hasofer-Lind Method. For each method, it provides an overview and example application to analyzing reinforced concrete beams. It finds that safety index increases with beam depth and characteristic strength, but decreases with length. The Three-Term Conjugate Map provides accurate results for non-linear structural components. Overall, the review evaluates different probability-based design methods for accounting for uncertainties in structural analysis of reinforced concrete beams.
This document presents the final report of a research project on developing a tool for risk-based integrity assessment of process components. The report describes the development of a risk-based framework that includes methodologies for risk-based design, risk-based integrity modeling, and risk-based inspection and maintenance planning. Case studies were used to demonstrate the application of the developed methodologies and the results that can be obtained. The framework aims to help industry optimize asset integrity management and safety through risk-informed decision making.
The objective of this project is to calculate the factor of safety of a complex slope situation. The stress distribution zones are also shown in the project. The probability of slope failure can be shown using FLAC3D software.
Reliability Analysis of Slope Stability by Central Point MethodIJERA Editor
Given uncertainty and variability of the slope stability analysis parameter, the paper proceed from the perspective of probability theory and statistics based on the reliability theory. Through the central point method of reliability analysis, performance function about the reliability of slope stability analysis is established. What’s more, the central point method and conventional limit equilibrium methods do comparative analysis by calculation example. The approach’s numerical results are consistent with the traditional limit equilibrium method and meet the objective reality. The accuracy and practicality of reliability analysis is confirmed in order to provide reliability theory a scientific basis for the feasibility of slope stability analysis.
This document summarizes research characterizing damage in thin acrylonitrile butadiene styrene (ABS) plates under uniaxial loading. Experiments were conducted on smooth and notched ABS plate specimens. Results showed mechanical properties like ultimate stress and stiffness decreased with increasing notch diameter due to stress concentration. A damage model based on the unified damage theory was applied to quantify damage. Damage increased linearly with the fraction of life and reached a maximum of 0.9 at failure. Stress concentration factor was also examined, decreasing with increasing notch to width ratio. In conclusion, the experiments and modeling successfully characterized ABS plate damage and the effects of notches on stress concentration and mechanical properties.
An Experimental Approach to Fluctuation of Stress Intensity Factor Distributi...IJERA Editor
The fluctuation of stress intensity factor distribution and fatigue crack propagation in HSLA steel were
investigated, for this purpose fatigue crack growth test were carried out on five mutually similar configured
standard 1CT specimens with reduced thickness using constant amplitude loading cycles under mode-I, with 0.3
stress ratio and maximum load held 11.8 kN. The fluctuation of stress intensity factor distribution were studied
experimentally as a function of crack length, elapsed fatigue life cycle and compliance, along with the behavior
of fatigue crack propagation in HSLA steel. The fracture morphology was observed by field emission scanning
microscopy. ΔK in starting not increased significantly as increasing crack length, number of cycle and
compliance, but after reaching the region-II, it is increasing very significantly and slow fatigue crack propagation
behavior were observed by the material.
Interfacial delamination failure in bonded concrete overlay systems a review...IAEME Publication
This document reviews theories and modeling methods for describing delamination failure at the interface between two bonded cementitious materials. It discusses traditional stress-based and energy-based failure criteria approaches. It presents the interface cohesive zone model (ICZM) as a viable approach for describing and predicting delamination in bonded concrete overlay systems. The ICZM treats delamination as a progressive failure involving both crack initiation and propagation. It considers distinct analytical cases involving material and structural property variables. The concluding model shows that numerical values of delamination coefficients and energy release rates vary depending on overlay scale, problem type, and material property mismatches.
INTERFACIAL DELAMINATION FAILURE IN BONDED CONCRETE OVERLAY SYSTEMS - A REVIE...IAEME Publication
This study reviews the theories and modelling methods for describing interfacial delamination failure process between two bonded cementitious materials. Complex interfacial stress
conditions at discontinuities and areas of high stress concentrations were primary areas of concern. Distinct analytical cases involving intrinsic material and structural property variables were considered. An approach based on plane strain analysis within the context of Interface Cohesive
Zone Model (ICZM) was cited and presented as viable for describing and predicting delamination mode of failure in bonded concrete overlays systems (BCOs).
This paper addresses the fracture toughness ( ), or also known as critical stress intensity Factor, according to
conditions of Lineal Elastic Fracture Mechanics (LEFM). The characterization of the mechanical properties in
tensile and fracture toughness of structural steel pipes API-5L used in hydrocarbons transportation was
performed. For fracture toughness, the material was tested through fatigue crack propagation on standardized
compact specimen (CT) according to ASTM E-399 norm. A thickness (B) equal to and a crack size (a) equal
to 0.5w were used. With the porpoise of establishing the adequate conditions at the crack tip, the specimens were
subjected to fatigue pre-cracking by application of repeated cycles of load in tensile-tensile and constant load
amplitude with a load ratio of R = 0.1. The experimental Compliance method was used based on data obtained
from load vs. Crack Mouth Opening Displacement (CMOD). The results show a Stress Intensity factor of 35.88
MPa√m for a 25 mm crack size specimen. The device used for testing is a MTS-810 machine with capacity of
100KN and 6 kHz sampling rate, which meets the conditions of the ASTM E-399 standard. The cracking
susceptibility of steel is influenced by the size, morphology and distribution of non-metallic inclusions,
thermochemical interaction with the environment and microstructure.
IRJET- Accomplishment Interpretation and Reformative Study for RCC Struct...IRJET Journal
1) The document analyzes the effects of blast loading on reinforced concrete structures using finite element analysis software ANSYS.
2) A 3-story frame structure and a 7-story building are modeled and subjected to explosive blasts from TNT at varying distances.
3) Results show heavy sections and shear walls can reduce deformation and stresses in the structure compared to the original design, but increase costs slightly. Proper interior and exterior design can also help mitigate explosive energy.
Dynamic Response and Failure Analysis of INTZE Storage Tanks under External B...IRJET Journal
This document analyzes the dynamic response and failure of elevated INTZE storage tanks under external blast loading. It describes modeling INTZE tanks in SAP2000 software and applying blast loads to study displacements, reactions, stresses over time. Frame and shaft footed tanks of varying heights were analyzed both empty and full. Results show shaft footed tanks resist blast loads better due to more mass concrete. Displacements increase with frame tank height but decrease for shaft tanks. Stresses also increase with height for both, but are lower for shaft tanks. Failure analysis indicates pillars and connections initially fail from stress concentrations. The conclusion is shaft footed tanks with maximum height best resist blast loads.
“Comparison of Maximum Stress distribution of Long & Short Side Column due to...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
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
Probabilstic seismic risk evaluation of rc buildings eSAT Journals
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A Method for Probabilistic Stability Analysis of Earth Dams
1. T. R. Mafioleti et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 1) January 2016, pp.76-82
www.ijera.com 76|P a g e
A Method for Probabilistic Stability Analysis of Earth Dams
T. R. Mafioleti*, A. Chaves Neto**, J. Patias***, L. A. Teixeira Junior****
*(Academic Department of Physics Statistics and Mathematics, Federal Technological University of Paraná,
Francisco Beltrão, Paraná, Brazil
**(Statistics Department, Federal University of Paraná, Polytechnic Center, Curitiba, Paraná, Brazil)
***(Division of Engineering Civil and Architecture, Itaipu Binational, Foz do Iguaçu, Paraná, Brazil)
****(Federal University of Latin American Integration, Foz do Iguaçu, Paraná, Brazil)
ABSTRACT
This paper proposes a new probabilistic methodology for analyzing the stability of Earth Dams, based on the
technique of the First Order Reliability Method for Structural Reliability. Differently from others methodologies
present in literature, the proposed method interprets the involved variables as random ones. So, three results are
provided here: the Structural Reliability Index, the Probability of Rupture and the most probable values of the
random variables for the occurrence of a dam break. In order to illustrate it, real data from a cross section of the
Left Bank Earthfill Dam of Itaipu Hydroelectric Power Plant (IHPP), located on the city of Foz do Iguaçu,
Paraná, Brazil were used. The numerical results achieved by the proposed methodology evidence that IHPP dam
has currently good structural conditions, confirming that the safety procedures adopted in Itaipu Dam may be
considered as appropriate. The use of the proposed method enables to complement the previously existing
knowledge about the structural conditions, improving the process of risk management.
Keywords - Earth Dams, Probability of Rupture, Reliability Index, Stability Analysis, Structural Reliability.
I. Introduction
Regarding the safety analysis of Civil
Engineering structures, [1] highlight that the current
society is increasingly aware about the inherent risks.
The technical community of engineering has been
recognizing that no absolute structural safety can be
ensured, so that there are residual risks when it is
treated using only traditional safety standards. In
Brazil, Law number 12,334 from 2010 [2] establishes
that national dams must be evaluated regarding their
risk according to a methodology that, besides
considering technical and conservation techniques,
also considers economic, social, environmental and
personal impacts. According to the mentioned law,
the employer, who is the responsible by the dam,
must provide the necessary resources to ensure the
structural safety and, therefore, one of the exigencies
is the elaboration and presentation of a safety plan for
the dam.
Deterministic analysis about the stability of
embankment dams is based in calculating the Factor
of Safety (FS). However, geotechnical variables
involved in calculating FS are subject to variability
due to several reasons, among them: simulating the
field conditions of the geotechnical tests, different
interpretations during the performance of tests,
human failures during tests, spatial variability
inherent to the soil properties in distinct places, [3].
Once FS value is determined, without considering the
randomness of its variables, its value leaves aspects
when indicating the safety level of the structure. The
consideration about the stochastic fluctuation of the
variables involved in the structural safety analysis by
researches originated the so-called “Methods of
Structural Reliability” [4]. In these methods, the
probability of failure and the Reliability Index for the
structure are estimated. Due to the several causes for
the variability of geotechnical variables, the
geotechnical problems were present since the
beginning of the development of Structural
Reliability techniques. In order to describe the
structural safety more precisely, methods of
probabilistic Stability Analysis of dams are included
in current proposals.
In face of this, this paper proposes an alternative
probabilistic methodology based on the First Order
Reliability Method (FORM) for the Stability
Analysis of Earth Dams. The structural failure to be
analyzed is the simulated rupture of the downstream
slope. In order to illustrate the method, data from the
cross section of Station 122+00 from the Left Bank
Earthfill Dam (LBED) of Itaipu Hydroelectric Power
Plant (IHPP) are used.
This paper is divided into five Sections. In
Section 2 exhibits the Station 122+00 of the LBED,
which is used to explain the theory part involved in
the proposed methodology. Section 3 brings a review
of how the Structural Reliability method is performed
- which is the base for the proposed method; in
addition, alternatives used for bypassing some
difficulties from the FORM algorithm are discussed
there. In Section 4, about materials and methods, data
from the section of Station 122+00 are presented as
well as explanation the iterative actions from the
RESEARCH ARTICLE OPEN ACCESS
2. T. R. Mafioleti et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 1) January 2016, pp.76-82
www.ijera.com 77|P a g e
proposed method. Main results from applying the
method to the section of Station 122+00 are
displayed and commented upon in Section 5.
Importantly, the results are estimated are: the
Reliability Index, the Probability of Rupture and the
most likely values that the random variables must
assume for resulting in rupture. Conclusions about
the proposed methodology, its results as wells as
about its use to complement the risk management of
dams, among which LBED stands out, are discussed
in Section 6.
II. Cross section of Station 122+00
The Left Bank Earthfill Dam has an extension of
2,294 meters of length. The cross section of Station
122+00 is shown in Fig. 1.
The whole structure of Fig. 1 is over dense
basalt, a rock of volcanic origin. The dense basalt,
after suffering processes of disintegration and
decomposition, (in other words, weathering), gave
rise to the yellow layer, known as weathered basalt.
Weathered basalt, after suffering more processes of
weathering, gave rise to the saprolite layer that is the
orange layer. The purple layer, which is the plastic
clay of foundation, has originated from the saprolite
disintegration processes. The dam body, represented
in brown, is composed by clay from the lending area
near the place of LBED construction. In the body
structure, a gray filter, which is made with sand, can
be noted. Green parts are the berms, composed by
materials from excavations performed for building
other parts of the dam. In pink, upstream, represents a
layer of rip rap, rocks with several sizes, gradually
organized, in order to avoid erosion that might be
caused by the water of the reservoir [5].
Figure 1: cross section of Station 122+00
It is important to highlight that the cross section
of Station 122+00 of the LBED of Itaipu
Hydroelectric Power Plant, besides illustrating the
proposed analysis method, is also used to explain the
theory involved in the present Literature Review, in
Section 3.
III. Literature review
This section, addresses the main concepts used
as base for the proposed method for evaluating the
stability analysis of dams. So, subjects on Structural
Reliability are explained in Section 3.1, among them:
the Simplified Bishop Factor of Safety used in the
analysis (Subsection 3.1.1), and the First Order
Reliability Method (FORM) algorithm (Subsection
3.1.2). In face of the difficulties for using the Factor
of Safety in analysis, an alternative procedure is
indicated, also in that Section.
3.1 Structural Reliability
According [4], among the objectives of
Structural Reliability is the estimated calculation of
the probability of occurrence of fail in the
engineering structures, in any stage of their life. In
order to apply the methods of Structural Reliability,
first, it is necessary to define the structural failure to
be analyzed. This failure is mathematically
represented by a function G, which, regarding
Structural Reliability is called limit state function.
Values that G assumes are interpreted as performance
indicators of a structure being analyzed. In this paper
the limit state function considered is the Simplified
Bishop Factor of Safety (FS). The good performance
of the structure happens when FS > 1; if FS = 1, then
the structure is under imminence of rupture; and,
finally, if FS < 1, it means that the structure breaks
[6]. The structural failure, indicated by the simulated
rupture of the dam in this paper, is known, in terms of
Structural Reliability, as the violation of this limit
state. The function of the Factor of Safety is
presented in Subsection 3.1.1.
Assuming that X is the vector of random
variables of resistance and load acting over the
structure, G(X) is the function describing the
structural performance for which the violation of the
limit happens when G(X) < 0; and fX(x) is the joint
probability density function (p.d.f.) of X, then the
probability of failure, denoted by pf, is defined in (1):
xdxfXGPp X
XG
f )(...]0)([
0)(
(1)
In most of the times, the calculation of the
multiple integral (1) is unviable by analytical
methods. Besides, the joint p.d.f. of resistance and
load variables may be unknown, so this must be
estimated or previously known. In face of that, an
alternative for obtaining the probability of failure is
the use of numerical methods of Structural Reliability
[7]. The First Order Reliability Method (FORM)
technique of Structural Reliability is presented on
Subsection 3.1.2 for solving the problem of stability
of dams approached in the current paper.
3.1.1 Limit state function
The desired failure is the simulated rupture of the
downstream slope, which may be evaluated by the
Factor of Safety, whose values are interpreted: FS > 1
indicates safety, if FS = 1, the structure is on the
verge of rupture; and FS < 1 indicates rupture [6]. For
calculating the Factor of Safety, a cross section of the
dam is considered. The analysis is performed two-
dimensionally and the soil over the rupture surface
divided into slices. For instance, in Fig. 2 is observed
the cross section of Station 122+00, with circular
rupture surface and over this surface the soil slices, in
green.
3. T. R. Mafioleti et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 1) January 2016, pp.76-82
www.ijera.com 78|P a g e
Figure 2: Rupture surface associated with methods
subject to limit equilibrium hypotheses
Considering that: the soil breaks abruptly, FS is
the same along the whole rupture surface and
equations of static equilibrium are satisfied until the
imminence of rupture. The Simplified Bishop Factor
of Safety is defined by the ratio between moment of
resistance (MR) and load moment (ML):
L
R
k
M
M
FS 1 (2)
The Factor of Safety is called simplified when
only the equilibrium of strengths or moments is
considered [8]. The equilibrium of moments is
analyzed in each one of the slices, represented in
green in Fig. 2. An arbitrary slice of the rupture
surface of Fig. 2, to be used for evaluating the rupture
by FS of Simplified Bishop is generically presented
in Fig. 3.
Figure 3: Forces in a generic slice for the Simplified
Bishop Factor of Safety [9]
In Figure 3:
P: total weight of the slice;
R: radius of the rupture circle;
Xn,Xn+1: vertical shear forces on the sections n and
n+1;
En,En+1: resultants of the horizontal forces on the
sections n and n+1;
l: length of the base of the slice;
N: normal total force acting in the base of the slice;
S: shear force acting on the slice base;
: inclination angle of the slice base;
x: horizontal distance from the center of the slice
until the axis of rotation;
h: height of the slice.
Moment of resistance (MR) is defined by the sum of
moments of resistance from each one of the slices.
Shear strength mobilized τmob is calculated by the
Mohr-Coulomb criterions, such that c’ is the effective
cohesion, σ is the normal stress, u is the pore pressure
(water pressure in pores) and tgφ’ the tangent of
effective friction angle φ’:
]')('[
1
tguc
FSk
mob (3)
Thus, the moment of resistance (MR) is given by:
]')('[
tguc
FS
R
M
k
R
(4)
And load moment (ML) is defined as
xPML (5)
By replacing (4) and (5) in (2), after some
deductions and simplifying assumptions, the
Simplified Bishop Factor of Safety [6] is found.
Where γ is the specific weight of soil, b the slice
breadth, secα the secant of angle α and tg α the
tangent of angle α:
u
tgPbc
senP
FSk 1''
1
1
kFS
tgtg '
1
sec
(6)
Nowadays there exists some software capable to
calculate the Factor of Safety. Here the software
SLOPE/W®
(http://www.geo-
slope.com/support/geostudio2007/examples.aspx) has
been adopted to do so.
3.1.2 First Order Reliability Method
FORM algorithm is carried out in the linear
space on which the random variables have standard
normal distribution (i.e., normal p.d.f. whose average
equals zero and standard deviation equals one) and
are also stochastically independent. This linear space
is usually referred to as a “small space”. The limit
state function – that is written as a function of
variables from the reduced space – provides the rise
to the failure surface. Furthermore, this surface
describes both the safety region and the failure
region. During the development of FORM algorithm,
firstly the Reliability Index is obtained – that consists
of the smaller distance from the origin of the reduced
space to the failure surface. Then the probability of
failure is determined. The nearer geometric point on
the failure surface of the origin indicates the most
probable values that random variables must assume
so that violation of the limit state happens. This point
is called project point. The iterative actions of FORM
for the case when variables are normal and correlated
are described next [7]:
4. T. R. Mafioleti et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 1) January 2016, pp.76-82
www.ijera.com 79|P a g e
Action 1: Transform the random variables in
standardized normal and independent ones.
Here the random vector X is written as a function of
vector z of variables belonging to a reduced space
which helps to calculate the diagonal matrix of
standard deviations estimated for X (denoted by [σX]).
The vector of the estimated averages of X is
represented by [μX], and T denotes the matrix
composed by the normalized eigenvectors of the
estimated correlation matrix R. Accordingly, X can be
decomposed in (7):
XX zTX ][ (7)
Action 2: Obtain limit state equation, or equivalently,
the failure surface.
The limit state function G(X) is written as a function
of variables from the reduced space (z) and equated
to zero. That is:
0)( zg (8)
Action 3: Write a new project point.
The new project point z* consists of a function of the
Reliability Index (β), which must be determined in
Action 4, as well as of the vector of direction cosines
(α). That is:
][
*
zz (9)
The direction cosines consists of a vector function of
partial derivatives vector of g in relation to variables
of z
z
g
as well as of the diagonal matrix of
standard deviations estimated of variables X from the
reduced space ([σz]) which are defined by the root of
eigenvalues of matrix R. So, it follows that:
z
g
z
g
z
z
][
][
(10)
Action 4: Calculate a new Reliability Index.
The new Reliability Index is obtained from the roots
of the limit state equation (9), when it is written as a
function of the new project point (z*), as in (11):
0)()(
*
gzg (11)
Action 5: Verification of the stopping criterion of the
algorithm.
If the difference between Reliability Indexes from the
last two successive iterations is an acceptable value,
then the execution of the algorithm is stopped and the
flow goes to Action 6. Unlike, a new project point is
calculated with (9) and the procedure restarts from
Action 3.
Action 6: Check the final results of the algorithm
execution.
By means of the Reliability Index (β) from the
last interaction, the project point of the reduced space
is achieved by employing (9), that is then written in
the original space with (7). In turn, through the
standard normal cumulative distribution function (Φ)
the probability of failure (pf) is estimated. That is:
)(1 fp (12)
The use of recursive functions such as the Factor of
Safety of (5) as a function of the limit state may
difficult the execution of FORM in Actions which the
calculation of partial derivatives and of the roots of
the limit state equation is required. In effect, an
alternative procedure proposed in this paper is
detailed next.
Alternative Procedure
The partial derivatives described in Action 3 must be
determined by numerical approximation where t is a
value to be incremented:
t
zzzgztzzg
z
g
nini
i
),...,,...,(),...,,...,( 11
(13)
In order to obtain the roots of the limit state function
described in Action 4, [10] suggest the approximation
of the equation by a second order Taylor Series
centered in a supposed initial Reliability Index β0:
00
2
02
2
)(
2
1
)(
gg
g
0)()( 00 g (14)
Such as g(β0) corresponds to the value of g in the last
new project point of (9) with β = β0.
The partial derivative of g in relation to β with β = β0
is given by:
n
i
i
i
z
z
gg
1
00
(15)
where
iz
g
is obtained from (13) and
0
iz
from (9) making β = β0.
The partial second derivative of g in relation to β
with β = β0 is given by:
n
i
i
i
z
z
gg
1
2
2
2
2
2
00
(16)
5. T. R. Mafioleti et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 1) January 2016, pp.76-82
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where
0
iz
is obtained from (9) making β =
β0 and
2
2
iz
g
is given as follow:
2
1
2
2
),...,2,...,(
t
ztzzg
z
g ni
i
),...,,...,(),...,,...,(2 11 nini zzzgztzzg
(17)
The calculation of the Reliability Index (β) implicates
in calculating the roots of (14) approximated. Once a
Reliability Index is obtained from those roots, the
procedure of executing FORM continues from Action
5.
IV. Material and methods
The purpose of this Section is to treat on
questions concerning the practical application of the
proposed method. In Subsection 4.1 the data adopted
for applying the underlying method in the Stability
Analysis by the cross section of Station 122+00 are
thoroughly presented. In turn, the explanation of the
operational procedures is approached in Subsection
4.2.
4.1 Data for analysis of structural reliability for
the section of Station 122+00
Variables interpreted as random ones with their
averages and standard deviations for materials of the
dam are shown in Table 3 and Table 4. Notice that
the normal distribution is supposed here to them.
Table 3: Variables considered as random in the
reliability analysis
Effective cohesion (Kpa)
Material Average Standard Deviation
Dam body clay 55.5181 13.4967
Foundation clay 18.2649 6.0682
Table 4: Variables considered as random in the
reliability analysis
Effective friction angle (degrees)
Material Average Standard Deviation
Dam body clay 27.275 1.3892
Foundation clay 25 1.4142
The estimated correlation matrix (R) named
Pearson’s correlation [11], between variables X is
given by:
1000
0100
0015401.0
005401.01
R
Is pointed out that the random variables effective
cohesion and effective friction angle of the clay in the
dam body is -0.5401, and that the other random
variables are uncorrelated. On the other hand, the
variables exhibited in Table 5 were assumed to be
deterministic ones and used for performing the
Stability Analysis.
Table 5: Variables considered as deterministic in
Reliability Analysis
Material
Specific
Weight
(KN/m3
)
Effective
cohesion
(KPa)
Effective
friction
angle
(degrees)
Dam body clay 19.025 ------ ------
Berms 19.025 58.2517 24
Sand of filters 22.065 0 40
Foundation clay 17.8482 ------ ------
Saprolite 18.0443 0 25
Weathered
basalt 19.1427 19.123 28
Rip rap 21.5747 0 40
4.2 Proposed method for probabilistic analysis of
Earth Dams stability
During the development of the FORM algorithm
for calculating the partial derivatives by numerical
approximation as described in Action 3 (13), an
access are made to SLOPE/W®
. The value t = 0.001
is incremented in the variable of reduced space (z),
and the values of variables in the original space are
obtained from (7). Thus, accesses are made to
SLOPE/W®
in order to determinate the values of the
Factor of Safety (function of the limit state), with the
variables in the original space and not in the reduced
one. Due to this alternative procedure, it is not
necessary to write the equation of limit state as a
function of variables of the reduced space (z),
according to (8) of Action 2. For obtaining a new
Reliability Index (Action 4), the proposed method
suggests the approximation of the limit state (11) by a
second-order Taylor Series (14) as a function of the
Reliability Index (β). Thus, Action 4 is performed
without the need of writing (8) (limit state equation)
due to the new project point, according to (11). In
this procedure, the limit state (8) of Action 2 is
treated indirectly, according to approximations given
by (13) and (14) indicated in the alternative
procedure.
The rupture surface was considered as fixed,
passing through the saprolite layer. This is one
because the material layer, is highly permeable.
The method presented in this Section allows
performing stability analysis of Earthfill dams
account for the randomness of some variables,
unlikely traditional methods. Importantly, even if a
dam is considered to be safe according to traditional
stability analysis, there exists residual risk that should
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www.ijera.com 81|P a g e
be taken into account. Hence the proposed method
aims to mitigate the risk management and to give
more support to final decision of the responsible
technical sector.
V. Results
Results from the analysis of Structural
Reliability of the LBED through the section of
Station 122+00, using the proposed method (Section
3), with the Simplified Bishop Factor of Safety as a
function of the limit state, are in Table 6. The
Reliability Indexes had close values in both analysis,
as well as the respective Rupture Probabilities. Those
values, once determined, are not unique, but they
depend on the Reliability Index chosen to begin the
iterative process. Two results are presented, one for a
initial Reliability Index of 2.0 and another for 2.4. It
is important to observe that the dam is in good safety
conditions, because the values of the Reliability
Index and consequently the ones of Probability of
Rupture, are inside the interval considered as safe,
established by [12] for Earth Dams.
Table 6: Reliability and Probability of Rupture
Indexes
Initial Reliability
Index
Final Reliability
Index
Probability
of Rupture
2.0 4.682 0.000142%
2.4 4.512 0.000321%
The values of effective cohesion and of effective
friction angle (project point) resulting from the
analysis are presented in Table 7. Similar values are
observed for all variables in both analysis. For clay
from dam body, for instance, the values of effective
cohesion were 12.271o
and 11.769o
. It is observed
that a small change in the initial Reliability Index
may change the project point at the end of the
analysis. Close values of the initial Reliability
Indexes generate values close to the project point.
This procedure indicates intervals for the project
point variables.
Table 7: Project point resulting from analysis with
distinct initial Reliability Indexes
Dam body clay Foundation clay
Initial
Reliability
Index
c’
(KPa)
υ'
(degrees) c’ (KPa)
υ'
(degrees)
2.0 12.217 25.839 15.034 23.945
2.4 11.769 26.405 15.489 23.094
The rupture surface with its slices at the end of
both analysis is similar, since the rupture surface was
considered as fixed. The surface is shown in Fig. 5.
Figure 5: Rupture surface resulting from analysis
with initial Reliability Index 2.0 and 2.4
It was verified that the convergence of the
proposed model is associated with the selection of the
initial Reliability Index and of the increment value t.
Accordingly, the beginning of the analysis have taken
more time. For analysis executed with both initial
Reliability Index 2.0 and 2.4, the selected value of
increment t was the same – namely, t = 0.001.
VI. Conclusion
In this paper a method for probabilistic analysis
of Earth Dam stability is put forward. Given a cross
section of the dam, the proposal, based on the First
Order Reliability Method aims to obtain the
Probability of Rupture of the Earthfill, the Reliability
Index for the structure and the more probable values
that the random variables must assume for the rupture
to happen. Two analysis were executed according to
the initially chosen Reliability Indexes: 2.0 and 2.4.
In both analysis the function describing the
performance of the structure (limit state function)
was the Simplified Bishop Factor of Safety. The
probabilistic methods of Stability Analysis differ
from traditional deterministic methods by considering
the randomness of the variables involved in the
problem at hand. In the proposed methodology, the
variables considered as random ones were the
effective cohesion and the effective friction angle of
materials: clay from dam body and clay from
foundation.
By applying the underlying method, information
from the cross section of Station 122+00 on the Left
Bank Earthfill Dam of Itaipu Hydroelectric Power
Plant was used. The results obtained from the
application evidence the excellent performance of the
proposed method, as well as the good security
conditions in which the dam is, according to
comments about results in Section 4.
Furthermore, it was verified that both analysis
have values close to the Index of Reliability and
Probability of Rupture. The numerical analysis
performed by traditional methods of Structural
Reliability was also indicated. The application of the
Monte Carlo Simulation Method, with the same limit
state functions considered in this paper, will probably
point to values of Index of Reliability and Probability
of Rupture close to the obtained ones. The greater the
amount of information is, more precision there is to
infer about structural security and for indicating
procedures of risk management.
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ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 1) January 2016, pp.76-82
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The probabilistic view of the question, by
considering the randomness of variables involved in
the stability problem, favors the execution of analysis
taking into account the risks, and that, by providing a
vision closer to reality, may complement the
previously existing knowledge about the structural
conditions. The technical complexity, presented by
the mathematical resources structuring the proposed
methodology, is no bar for applying the method in
Earthfill dams, since they may be operated with
relative simplicity, using the software used for the
analysis development of this paper.
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