Of these, the most comprehensive is the 1983 volume by jansen 1 published by the u. Measured and computed uplift pressures for shasta dam. Shear resistance on an existing joint in rock foundation of a gravity dam 4. If the video does not play, watch it on the csdms website. The geometry variables of dam are given in table 3. An experimental study of failure of a gravity dam on a. The romans built their gravity dams in the iberian peninsula region, north africa and in the middle east. The second case is intended to represent an aged dam or a damaged dam, characterized by a youngs modulus of 15 gpa. 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. When a risk analysis is conducted on a gravity dam, considering the. Gravity structures depend mainly upon its own weight to resist the effecting forces, specially upward force. 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. A detailed sketch of a gravity dam is shown in fig.
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. 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. What is the laying and jointing procedure of concrete pipes. Hydropower irrigation water for domestic consumption drought and flood control for navigational facilities other additional utilization is to develop fisheries structure of dam heel. Dam dam is a solid barrier constructed at a suitable location across a river valley to store flowing water. View gravity dams 2 from engineerin 101 at tarlac state university. 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. Upward force can be reduced by using a drainage gallery somewhere beneath the floor of the structure. Effect of soil structure interaction on gravity dam. The optimum location of the drainage gallery underneath gravity dam is the goal of this study.
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. It is intended to implement an internal drainage facility, which would reduce uplift pressure by about 20%. Sound rock capable of resisting dynamic forces including earthquake. Touileb and others published gravity dam probability of sliding failure with overtopping and conditional drainage. Diagrams of base pressures acting on a gravity dam. Stability evaluation of gravity concrete structures. Stability analysis of gravity dams for the maximum.
Comparison of design and analysis of concrete gravity dam 19. Masonry dams are dams made out of masonry mainly stone and brick, sometimes joined with mortar. Keywordschromosomes, dam, genetic algorithm, global. Dams it is important for a gravity or buttress dam to maintain its structural integrity and remain stable against sliding. Exercise problem 1 a concrete gravity dam 15 m height will be constructed with the dimensions shown in the figure below. A drainage gallery is generally provided in order to relieve the uplift pressure exerted by the seeping water. Failure of gravity dams causes and its failure modes. Gravity dams three major potential modes of failure of gravity dams include. A gravity dam may fail by the failure of its material, i. Problem 911 a concrete dam has the profile shown in figure p911.
Computer aided stability analysis of gravity damscadam. Gravity dams 2 gravity dams forces acting on gravity. Storage of water is utilized for following objectives. The largest masonry dam in the world is nagarjunasagar dam, telangana, in india visual examples.
A gravity dam may collapse in one or more sections which have been. Ferc, cda, usace, ancold, and usbr present guidelines for dam safety assessment based on the gravity method. While most dams have storage volumes small enough that failures have few or no repercussions, dams storing large amounts can cause significant flooding downstream. Both of the dams present a stable geometry but the wall volumes differ by about 45%. Probability of failure for concrete gravity dams for. 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. Pdf gravity dam probability of sliding failure with overtopping and. Dec 14, 2016 chapter 6 concrete dam engineering with examples 1. 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. Ansys 14 is used for the analysis of the gravity dam section. 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. It is intended to implement an internal drainage facility, which would reduce uplift pressure by.
The solid form is the more widely used of the two, though the hollow dam is frequently more economical to construct. This engineer manual supersedes em 111022200 dated 25 september 1958. Only after the collapse of bouzey dam, in 1895, and. The computerized methodology may provide the help for computation of the optimal top width for a wide range of height of a gravity dam. Learning outcome after this lecture, students should be able to 1. Modes of dam failure and monitoring and measuring techniques. In optimum dam cross section, the ratio of is dam base to dam height is almost equal to 0. The dam section shown in figure 1a satisfies the criteria above, while the section shown in.
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. Introduction to gravity dams a concrete gravity dam has a cross section such that with a flat bottom, the dam is free standing. That is, the dam has a center of gravity low enough that the dam will not topple if unsupported at the abutments. They are either the gravity or the archgravity type. Figure 1 illustrates the increase in water storage from 1900 to the present on a global basis. These gravity dams were part of a water supply system.
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. Comparison of design and analysis of concrete gravity dam. The upstream face may be kept throughout vertical or partly slanting for some of its length. Gravity dam definition of gravity dam by merriamwebster. Factor of safety and probability of failure in concrete dams l. Gravity dams 2 gravity dams forces acting on gravity dam. The strength reserve factor method is applied to safety coefficient. Design and construction of concrete gravity dams nptel. A gravity dam may fail by the failure of its material. Causes of failures of earthfill dams the constructor. 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 high concrete gravity dam based on strength reserve factor method was taken into consideration 7 89.
Factor of safety and probability of failure in concrete dams. Optimal position of drainage gallery underneath gravity dam. Presents instructions, procedures, and standards for use in the design of concrete gravity dams. Dam failure can take several forms, including a collapse of, or breach in, the structure. Gravity dam may be the earliest water retaining structure in the human history. Analysis and design of gravity dam in seismic zone v project by. Different causes of failure of earthfill dams are explained below. Quantitative failure metric for gravity dams request pdf. The main objective is to obtain the relationships between factors of safety and the probability of failure against sliding for a given damreservoir system. The purpose is to give a basis that may be used for probability based assessment of existing dams. The dam is composed of three blocks of equal heights. Gravity dam definition is a dam so proportioned that it will resist overturning and sliding forces by its own weight. 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. An arch gravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam.
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. Gravity dam loads on concrete dams loads can be classified in terms of applicabilityrelative importance as primary loads, secondary loads, and exceptional loads. Failure of gravity dam occurs due to overturning, sliding, tension and compression. Sliding safety of existing gravity dams final report. 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. There have been several studies of dam failures published in the last 30 years. Stability evaluation of gravity concrete structures dams.
Dams dams dam is a solid barrier constructed at a suitable location across a river valley to store flowing water. Initially a gravity dam was considered safe with respect to sliding. Failure analysis of highconcrete gravity dam based on. Figure 1 shows the system of forces that acts on a typical dam.
This courses covers general design considerations for gravity dam design based on army corps of. Gravity dam free download as powerpoint presentation. Shape optimization of gravity dam by bem sciencedirect. Gravity dams are classified as solid or hollow and are generally made of either concrete or masonry. Masonry gravity dams a numerical application for stability. Gravity dams forces acting on gravity dam a gravity dam is subjected to the following main forces. Gravity dams are constructed from masonry or concrete. The procedures in this manual cover only dams on rock foundations.
Like most of engineering structures, earth dams may fail due to various reasons such as faulty design, improper construction and poor maintenance practices, etc. This courses covers general design considerations for gravity dam design based on army corps of engineers manual em 111022200 chapters 12. Chapter 6 concrete dam engineering with examples 1. Gravity dams require maximum amounts of concrete for their construction as compared with other kinds of concrete dams, and resist. Shape of dam with geometry variables is shown in figure 3. Any stability analysis of the dam should seek to apply forces that are compatible with the failure mechanism being assumed. It combines the strengths of two common dam forms and is considered a compromise between the two. Only after the collapse of bouzey dam, in 1895, and the uplift effect begin to be accounted for as an important load.
Figure 1 forces acting on a concrete gravity dam the correlation between these forces, to maintain equilibrium, is given by the expression. Ppt gravity dam powerpoint presentation free to view. This will provide a factor of safety in excess of 2. Gravity dams are designed so that each section of the dam is stable and independent of any other dam section. Another rudimentary form of gravity dam was supposedly fabricated around 3000 b.
Earthfill dams are less rigid and more susceptible to failure. Nevertheless, even the gravity method, which is relatively simple to. For the former it is usual to design the dam so that the resultant of all forces intersects the base within its middle third. A concrete gravity dam has a cross section such that with a flat bottom, the dam is free standing. An archgravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam. Gravity dam criteria for selection of site for a gravity dam. Rcc became very popular rapidly all over the world due to its low cost and fast deployment and is used for various purposes, including the construction of new dams, pavements, highways and the rehabilitation of existing dams. Further details on temperature control methods are provided in chapter 6. Concrete dams case histories of failures and nonfailures with.
Concrete dam engineering 1 0401544 hydraulic structures university of sharjah dept. That study listed and discussed dam failures that have occurred over the past 900 years. How do civil engineers explain what gravity dams are. 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. The design of rcc gravity dams is similar to conven. Forces acting on a gravity dams with diagram geography. All the predominant forces that act on the dam have been shown in the figure itself. Calculation example the crosssection of the concrete gravity dam of yan tan is shown in fig. Gravity dams may be classified by plan as straight gravity dams and curved gravity. Safety evaluation of existing and new gravity and buttress concrete dams always includes.
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