Keywordschromosomes, dam, genetic algorithm, global. Dam failure can take several forms, including a collapse of, or breach in, the structure. Shape optimization of gravity dam by bem sciencedirect. Hydropower irrigation water for domestic consumption drought and flood control for navigational facilities other additional utilization is to develop fisheries structure of dam heel. Design and construction of concrete gravity dams nptel. Diagrams of base pressures acting on a gravity dam. Concrete dam engineering 1 0401544 hydraulic structures university of sharjah dept. The romans built their gravity dams in the iberian peninsula region, north africa and in the middle east.
Sound rock capable of resisting dynamic forces including earthquake. Sliding safety of existing gravity dams final report. Safety evaluation of existing and new gravity and buttress concrete dams always includes. If the video does not play, watch it on the csdms website. Stability analysis of concrete gravity dam using fem dragan rakic1, milan bojovic1, snezana vulovic1, miroslav zivkovic1, dejan divac2, nikola milivojevic2 1faculty of engineering, university of kragujevac, sestre janjic 6, 34000 kragujevac, serbia. The geometry variables of dam are given in table 3. An arch gravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam. In optimum dam cross section, the ratio of is dam base to dam height is almost equal to 0.
Shear resistance on an existing joint in rock foundation of a gravity dam 4. Gravity dams are classified as solid or hollow and are generally made of either concrete or masonry. Ppt gravity dam powerpoint presentation free to view. When a risk analysis is conducted on a gravity dam, considering the. If the density of concrete is 2400 kgm 3 and that of water is kgm 3, determine the maximum compressive stress at section mn if the depth of the water behind the dam is h 15 m. Factor of safety and probability of failure in concrete dams l. For the former it is usual to design the dam so that the resultant of all forces intersects the base within its middle third. The strength reserve factor method is applied to safety coefficient. The use is primarily intended for dam consequence class a and b facilities and largermore important facilities in class c, but may be used for all facilities. Figure 1 shows the system of forces that acts on a typical dam. Only after the collapse of bouzey dam, in 1895, and. Comparison of design and analysis of concrete gravity dam 19. Stability evaluation of gravity concrete structures. All the predominant forces that act on the dam have been shown in the figure itself.
The upstream face may be kept throughout vertical or partly slanting for some of its length. Gravity dams are designed so that each section of the dam is stable and independent of any other dam section. Gravity dam loads on concrete dams loads can be classified in terms of applicabilityrelative importance as primary loads, secondary loads, and exceptional loads. Dams it is important for a gravity or buttress dam to maintain its structural integrity and remain stable against sliding. It combines the strengths of two common dam forms and is considered a compromise between the two. Stable valley and abutment slopes foundation with elastic constants preferred water tight reservoir in order to resist erosion and adverse effects of wetting, drying, freezer and thawing. Chapter 6 concrete dam engineering with examples 1. Gravity dam free download as powerpoint presentation. The design of rcc gravity dams is similar to conven.
This will provide a factor of safety in excess of 2. How do civil engineers explain what gravity dams are. Stability evaluation of gravity concrete structures dams. The optimum location of the drainage gallery underneath gravity dam is the goal of this study. Computer aided stability analysis of gravity damscadam. A progressive methodology is normally adopted starting with the gravity method based on rigid body equilibrium and beam theory before considering linear or nonlinear finite element models, if necessary. Failure analysis of highconcrete gravity dam based on. The second case is intended to represent an aged dam or a damaged dam, characterized by a youngs modulus of 15 gpa. Introduction design philosophy the bureau of reclamation s philosophy of con crete dam design is founded on rational and consist ent criteria which provide for safe, economical, functional, durable, and easily maintained struc. Gravity dams require maximum amounts of concrete for their construction as compared with other kinds of concrete dams, and resist. What is the laying and jointing procedure of concrete pipes. Gravity dams forces acting on gravity dam a gravity dam is subjected to the following main forces. Modes of dam failure and monitoring and measuring techniques.
This courses covers general design considerations for gravity dam design based on army corps of engineers manual em 111022200 chapters 12. Concrete face rockfill dam compared to roller compacted. Comparison of design and analysis of concrete gravity dam. Touileb and others published gravity dam probability of sliding failure with overtopping and conditional drainage. The solid form is the more widely used of the two, though the hollow dam is frequently more economical to construct. Dam dam is a solid barrier constructed at a suitable location across a river valley to store flowing water. Presents instructions, procedures, and standards for use in the design of concrete gravity dams. A drainage gallery is generally provided in order to relieve the uplift pressure exerted by the seeping water.
Initially a gravity dam was considered safe with respect to sliding. Gravity dams may be classified by plan as straight gravity dams and curved gravity. Masonry dams are dams made out of masonry mainly stone and brick, sometimes joined with mortar. The largest masonry dam in the world is nagarjunasagar dam, telangana, in india visual examples. Nevertheless, even the gravity method, which is relatively simple to. The purpose of this continuing education course is to provide technical criteria and guidance for the planning and design of concrete gravity dams for civil works projects. That is, the dam has a center of gravity low enough that the dam will not topple if unsupported at the abutments. A concrete gravity dam is a massive concrete structure, roughly triangular in shape, and designed so that its weight ensures structural stability against the hydrostatic pressure of the impounded water and other forces that may act on the dam. Calculation example the crosssection of the concrete gravity dam of yan tan is shown in fig. The purpose is to give a basis that may be used for probability based assessment of existing dams. Failure of gravity dam occurs due to overturning, sliding, tension and compression. The procedures in this manual cover only dams on rock foundations.
This engineer manual supersedes em 111022200 dated 25 september 1958. Another rudimentary form of gravity dam was supposedly fabricated around 3000 b. Ferc, cda, usace, ancold, and usbr present guidelines for dam safety assessment based on the gravity method. Both of the dams present a stable geometry but the wall volumes differ by about 45%. A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by primarily using the weight of the material alone to resist the horizontal pressure of water pushing against it. Gravity structures depend mainly upon its own weight to resist the effecting forces, specially upward force. Storage of water is utilized for following objectives. Dec 14, 2016 chapter 6 concrete dam engineering with examples 1. The main objective is to obtain the relationships between factors of safety and the probability of failure against sliding for a given damreservoir system. A concrete gravity dam has a cross section such that with a flat bottom, the dam is free standing. Optimal position of drainage gallery underneath gravity dam.
It is intended to implement an internal drainage facility, which would reduce uplift pressure by about 20%. Shape of dam with geometry variables is shown in figure 3. Stability analysis of gravity dams for the maximum. The computerized methodology may provide the help for computation of the optimal top width for a wide range of height of a gravity dam. As early as around 29502750 bc, the egyptians built a masonry gravity dam of 14 m high at the nile river, called in arabic sadd elkafara meaning dam of the pagans, which was discovered over 100 years ago in egypt. Concrete dams case histories of failures and nonfailures with. While most dams have storage volumes small enough that failures have few or no repercussions, dams storing large amounts can cause significant flooding downstream. The dam section shown in figure 1a satisfies the criteria above, while the section shown in. A detailed sketch of a gravity dam is shown in fig.
A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Masonry gravity dams a numerical application for stability. Failure of gravity dams causes and its failure modes. Problem 911 a concrete dam has the profile shown in figure p911. Failure analysis of high concrete gravity dam based on strength reserve factor method was taken into consideration 7 89. The dam is composed of three blocks of equal heights. The dam was loaded by fluid pressure on the upstream face and upward forces simulating the uplift pressure. Analysis and design of gravity dam in seismic zone v project by. A gravity dam may fail by the failure of its material. Causes of failures of earthfill dams the constructor. Gravity dams 2 gravity dams forces acting on gravity. Gravity dam definition is a dam so proportioned that it will resist overturning and sliding forces by its own weight.
A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by primarily utilizing the weight of the material alone to resist the horizontal pressure of water pushing against it. In fact, it can be noticed that, mainly for traditional reasons, straight gravity structures, conventional or rcc gravity dams, but also fill dams with a core or a. An experimental study of failure of a gravity dam on a. Gravity dam definition of gravity dam by merriamwebster. It serves as a guide to sound engineering practices in the design of concrete gravity dams and provides the technically trained, qualified design engineer with specialized and technical information that can be readily used in the design of such a dam. That study listed and discussed dam failures that have occurred over the past 900 years.
Measured and computed uplift pressures for shasta dam. Gravity dam may be the earliest water retaining structure in the human history. Upward force can be reduced by using a drainage gallery somewhere beneath the floor of the structure. This compilation shows clearly the impact of the u. Any stability analysis of the dam should seek to apply forces that are compatible with the failure mechanism being assumed. Earthfill dams are less rigid and more susceptible to failure. Introduction to gravity dams a concrete gravity dam has a cross section such that with a flat bottom, the dam is free standing. Gravity dams are constructed from masonry or concrete.
View gravity dams 2 from engineerin 101 at tarlac state university. Figure 1 illustrates the increase in water storage from 1900 to the present on a global basis. There have been several studies of dam failures published in the last 30 years. Ansys 14 is used for the analysis of the gravity dam section. Dams dams dam is a solid barrier constructed at a suitable location across a river valley to store flowing water. Figure 1 forces acting on a concrete gravity dam the correlation between these forces, to maintain equilibrium, is given by the expression. Different causes of failure of earthfill dams are explained below. Quantitative failure metric for gravity dams request pdf. A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using the weight of the material alone to resist the horizontal pressure of water pushing against it. A gravity dam must be designed to safeguard against overturning and sliding. Pdf gravity dam probability of sliding failure with overtopping and. This courses covers general design considerations for gravity dam design based on army corps of. It is intended to implement an internal drainage facility, which would reduce uplift pressure by. These gravity dams were part of a water supply system.
Gravity dams 2 gravity dams forces acting on gravity dam. Learning outcome after this lecture, students should be able to 1. Of these, the most comprehensive is the 1983 volume by jansen 1 published by the u. An archgravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam. Effect of soil structure interaction on gravity dam.
Gravity dams three major potential modes of failure of gravity dams include. Probability of failure for concrete gravity dams for. A gravity dam may collapse in one or more sections which have been. They are either the gravity or the archgravity type. It is a dam that curves upstream in a narrowing curve that directs most of the water pressure against the canyon rock walls, providing the force to compress the dam. Forces acting on a gravity dams with diagram geography. A gravity dam is designed in such a way that it resists all external forces acting on the dam like water pressure, wind pressure, wave pressure, ice pressure, uplift pressure by its own selfweight. Only after the collapse of bouzey dam, in 1895, and the uplift effect begin to be accounted for as an important load. A gravity dam may fail by the failure of its material, i. Exercise problem 1 a concrete gravity dam 15 m height will be constructed with the dimensions shown in the figure below. Factor of safety and probability of failure in concrete dams. Like most of engineering structures, earth dams may fail due to various reasons such as faulty design, improper construction and poor maintenance practices, etc.
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