The occlusion and dislocation of the shear keys within the longitudinal joints have an impact on seismic resistance of the gravity dams. Similarly, a gravity dam with longitudinal joints must have a monolithic section in an upstreamdownstream direction. No caulking or caps are required to seal out rain and snow. Maximum height of a single pour o concrete called lift is usually about 1. A shaking table model test is conducted to study the dynamic response and failure mode of a 185 m high concrete gravity dam with longitudinal joints. Gibe iii, located in the southern nations, nationalities and peoples region of ethiopia, is the third plant of the gibe. It is the highest gravity dam in the united states, and also the. Subsequent underwater investigations of the upstream face in these locations identified cracks offset from. Visual examination is an essential tool by which the engineer, technician, owner or other. Arch dams and gravity arch dams require contact across transverse contraction joints in order for the structure to function in the threedimensional manner in which it has been designed. Previous ferc gravity dam guidance dealt with nappe forces by ignoring the. Another rudimentary form of gravity dam was supposedly fabricated around 3000 b. Classification the higher the class the higher the standard of duty and standard of care required and watershed characteristics. Pdf effects of base and lift joints on the dynamic response of.
This normally requires grouting with effective grout stops at both the upstream and downstream faces of the dam, similar to conventional concrete arch dams. Moreover, the effects of various shear keys on the seismic resistance of the gravity dam are discussed. In order to thoroughly study the seismic resistance of gravity dams with longitudinal joints, a contact model based on constraint function method is used to simulate the shear keys within the joints and a concrete smeared crack model is selected to present the cracking characteristics of concrete materials. The design of rcc gravity dams is similar to conven. Provision for the construction of these structures must in clude measures by which the concrete is cooled and. Their width is usually more than 15 morso, in large dams. Gravity dam design united states army corps of engineers. Design and construction of concrete gravity dams nptel. Public safety standards of the republic of india law is the.
Incremental dynamic analysis of concrete gravity dams. The vertical joints developed are called as transverse joints. The purpose of this manual is to provide technical criteria and guidance for the planning and design of concrete gravity dams for civil works projects. Dworshak is a gravity dam with the maximum height of 219 m and maximum bottom width of 152 m, the concrete volume is 525. Gravity dams are classified as solid or hollow and are generally made of either concrete or masonry. Chapter 6 concrete dam engineering with examples 1. It includes a 250 m high rcc gravity dam which is the worlds highest of its kind. They are usually spaced about 15m apart, experience having shown that cracks are likely to develop in monoliths much wider than this. Diagram of the vacuum chutetype rcc transport system used for the construction of the dam. 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. The upstream face may be kept throughout vertical or partly slanting for some of its length.
Learning outcome after this lecture, students should be able to 1. Multiple step method of design of gravity dam and comparison with cadam software. Gravity dam loads on concrete dams loads can be classified in terms of applicabilityrelative importance as primary loads, secondary loads, and exceptional loads. Pdf design and construction of gravity dams dian eka. Your model should be scaled down from the real dam. Cracking in mass concrete structures is undesir able as it affects the watertightness, durability, appearance, and internal stresses of t,he structures. The gravity profile is essentially triangular to ensure stability and to avoid overstressing of the dam or its foundation. For structures consisting of a section of concrete gravity dam within an. Forces acting on a dam structure and calculations different types of forces acts on a dam structure such as water pressure, self weight, wave pressure etc. Strength of rock mass is highly influenced by the discontinuities like joints present in it because of the fact that foundation may fail due to shear displacement of the jointed blocks. And the arch stress and crest displacements were evaluated. You would model a crosssection of the gravity dam, like the crosssection shown above. It is the highest gravity dam in the united states, and also the highest gravity dam without longitudinal joint in the world.
To simulate grouting, temperature of all joints with opening 0. Giuseppe pittalis alessandro cagiano antonio pietrangeli binyam tesfamariam studio ing. The 3d dam model was subjected to external temperature cycles for a 20 year period, until all hydration heat had dissipated. It is good practice for normal methods of construction to provide contraction joints in gravity dams. Any dam constructed of excavated natural materials, such as both earthfill and rockfill dams, or of industrial waste materials, such as a.
Sufficient drains are installed in the dam to reduce such uplift pressures as may develop along. Since that time, saskpower has experienced problems with significant water inflows entering the headworks drainage gallery through various construction joints. An embankment dam in which more than 50% of the total volume is formed of compacted earth layers are generally smaller than 3inch size. Gravity dams are designed so that each section of the. The objective ofthis study is to investigate the seismic behaviour ofconcrete gravity dams, built with keyed contraction joints. A drainage gallery is generally provided in order to relieve the uplift pressure exerted by the seeping water. Dec 14, 2016 chapter 6 concrete dam engineering with examples 1. Emagineered solutions monolith joints cylutions remedial. Experimental study on the dynamic response of a gravity. The influence of the friction angle and lift joint slope on the response parameters are investigated and the various limitstates of the dam are recognized. Further details on temperature control methods are provided in chapter 6. A concrete gravity dam is entirely dependent upon its own mass for stability. Pdf multiple step method of design of gravity dam and.
They shall run through the entire length of the dam but shall be staggered between transverse joints. Steel a relatively new development in the construction of gravity dams is incorporation of posttensioned steel into the structure. Transverse joints are inevitable every 15 m for preventing. Gravity dams gravity dams criteria for selection of dam site, construction material, forces acting on gravity dam, modes of failure, stability analysis, safety criteria, methods of design, stress analysis and stress contours, galleries, instrumentation, joints, keys, water seals, temperature control in concrete dams, foundation treatment. This manual applies to all hqusace elements, major subordinate commands. Its heavy weight and large size create the force to push back against the force of the water. 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. The number of lift joints, where the tensile strength is lower and varies depending on the efficiency of the construction process, is in the order of six to seven times. Two longitudinal joints are provided in the dam model. Seismic analysis of concrete gravity dams with keyed. The effect of a weak foundations rock joint on the stability of a concrete gravity dam conference paper pdf available october 2014 with 1,324 reads how we measure reads.
Divisional index public safety standards of the republic of india. This helped reduce the cross section of allt na lairige dam in scotland to only 60 percent of that of a conventional gravity dam of the same height. This type of a structure is most durable and solid, and requires very little maintenance. The horizontal joints are developed at each lift height and will extend through entire width of dam section. Expansion joints contraction joints construction joints you can learn different types of joints in this video in. The nipawin hydroelectric station was constructed in the early 1980s on the saskatchewan river. Find your dam expansion joint easily amongst the 4 products from the leading brands emac. The most ancient gravity dam on record was built in egypt more than 400 years b. Profile for expansion joints made of our exclusive material maxi. Comparison of design and analysis of concrete gravity dam.
Dl51081999 design specification for concrete gravity dam. Some gravity dams are gently curved in plan for aesthetic or other reasons, and. This oversight was only discovered after the dam had experienced significant downstream movement. The results show that the seismic responses of shear keys are resulted in designed forms. The romans built their gravity dams in the iberian peninsula region, north africa and in the middle east. If failing waterstops in monolith joints are the problememagineered solutions is the solution. Sliding safety of existing gravity dams final report. In the gravity dam and arch dam, which have a thick dam body, dissipation of heat is mainly from the horizontal construction joints, the effectiveness of heat dissipation is the determinant factor of the thickness of concrete lift. The horizontal distance from the toe of the dam to the resultantbase intersection point is. Effects of base and lift joints on the dynamic response of concrete gravity dams to pulselike excitations. Comparison of design and analysis of concrete gravity dam 19. The rcc dam construction procedure is similar to gravity dam 3. Pdf the effect of a weak foundations rock joint on the.
Folsom dam, a gravity dam in sacramento county, ca. Aug 14, 2018 what are the different types of concrete joints. In the present research, the ida of a concrete gravity dam considering a nonlinear concrete behavior, and sliding planes within the dam body and at the damfoundation interface, is performed. 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. It needs neither forms nor finishing, nor does it contain dowels or steel reinforcing. Gravity dams are designed so that each section of the dam is stable and independent of any other dam section. Cracking in mass concrete will normally occur when tensile stresses are developed which exceed the tensile strength of the concrete. A curved gravity dam resists the external forces by its weight and not by arch action. Ppt gravity dam powerpoint presentation free to view. During the first filling of the enlarged cotter dam, an 87m high rcc gravity dam located west of canberra, excessive seepage developed in the gallery, primarily from two of the monolith joints. These gravity dams were part of a water supply system.
Shear strength evaluation for dam foundations on rock. The construction joints in a concrete gravity dams provide passage through the dam. To the right, a model of a gravity dam with an inspection passageway is shown. Rcc gravity dams, but also fill dams with a core or a concrete face, are. A gravity dam has been defined as a structure which is designed in such a way that its own weight resists the external forces. Strength of rock mass is highly influenced by the discontinuities like joints present in it because of the fact that foundation may fail. Examine product characteristics and technical specifications for major brands view pdf. The plant, with its 1870 mw of installed power and 6400 gwh of annual energy production, is one of the most. Gravity dams may be classified by plan as straight gravity dams and curved gravity. Types of concrete gravity dams joints to remove the weak laitance film on the surface during curing include green cutting, wet sandblasting, basically, gravity. A buttress dam is a specific type of gravity dam in which the large mass of concrete is reduced, and the forces are diverted to the dam foundation through vertical or sloping buttresses. The size of blocks will depend upon the size of dam and necessity of contraction joints. Gravity dams are constructed of vertical blocks of concrete with flexible seals in the joints between the blocks.
These characteristics make rcc simple, fast, and economical. This discussion addresses the onsite inspection of concrete and masonry dams and presents information with regard to the recognition of potential dam safety concerns. Determination of various forces which acts on the structure is the first step in the design of dams. A gravity dam is mostly straight in plan and is known as straight gravity dam. The gravity intake and relief ventilators are nonpowered and work on pressure differential between the inside and outside of the building. Should the decision then be taken to close the joints, to achieve an averaged overall. Multiple step method of design of gravity da m and comparison. There are likely over 1,900 dams in the united states that are reported as high hazard potential dams.
Stability analysis of gravity dams for the maximum design. Made available to the public under the provisions of the bureau of indian standards act of 1986 and the right to information act of 2005. Operation, maintenance, and safety inspection dam maintenance factors factors that affect proper maintenance of dams. Contraction joints are properly grouted under adequate pressures, or open slots are properly filled with concrete, so that the dam may be considered to act as a monolith. Pdf gravity dam design engineer manual ivan ramirez. The solid form is the more widely used of the two, though the hollow dam is frequently more economical to construct.
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