Lake lanier, north carolina this constantradius concrete arch dam. Types of arch dam construction there are four types of arch dam construction i. Army corps of engineering emphasize that the analysis of abutment stability requires very careful application of both engineering geology and rock mechanics and analytical techniques 6. It has been shown that the volume of concrete is minimum when the central angle is 3 34. A dam like this is called a constant angle arch dam because the angle 2. The arch thickness is calculated by the thin cylinder formula.
Another australian arch dam is the junction reefs dam completed in 1897. Such a spillway is better suited for a thin arch dam whose downstream face is nearly vertical. The design of such a dam can, thus be made by adopting best central angle of 3 degrees and 34 minutes. The variable radius arch dam is an intermediate choice, using 58 % of the concrete used by constant radius arch dam. Pdf design and analysis of arch dams by the membrane method. The constant angle arch dam is a special type of variable radius arch dam in which the central angle of the horizontal. Length, thickness, and central angle of arch at crest of. The upstream face is usually vertical while the downstream face is battered. An arch dam is a thick shell structure that derives strength from its curved profile. Twodimensional elastic arches were assumed to carry the entire load imposed on the dam. It is essential that the engineering geologist be intimately familiar with all of these methods because they provide ways of determining, relatively unambiguously, whether a. While at the firm, he also completed work on other dams, such as lost creek dam and the diablo dam on the skagit river in washington 1929. The basic arch dam shapes are the constant radius arch, the constant angle arch and the double curvature arch with increasing complexity. The issue of safety of arch dams, particularly high dams, is a major consideration in design.
Army corps of engineers built wing dams to improve navigation on the ohio river. A constant angle arch dam is the one in which the central angle of the. Constant angle arch dam, is a dam in which central angle of every arch ring is constant throughout the height of an arch dam. Since the flow usually drops into the stream bed, objectionable scour may occur in some cases and a deep plunge pool may be formed. Jurgensen advanced the idea of the economic central angle, more subtle designs with. In this paper, we find all constant slope surfaces in the euclidean 3space, namely those surfaces for which the position vector of a point of the surface makes constant angle with the normal at. Constraints geometric and stress constraints are two types of constraint which should be satis ed in the shape optimization of concrete arch dams 14. Classification of an arch dam depends on its angle, radius and. Arch dams are good for sites that are narrow and have strong abutments. Constant angle arch dam the geometry of a constant angle arch dams is characterized by equal angles of the surfaces of the abutment. Typically the angle subtended by the arch at the crest is between 90.
Since it was built, over 100 such dams have been constructed all over the world. The salmon creek dam is a concrete arch dam on the salmon creek, 3 miles 5 km northwest of juneau, alaska. Shape optimization of concrete arch dams considering abutment. The history of federal involvement in dam construction goes back at least to the 1820s, when the u. Analysis of constant radius and constant angle arch dams using. Finite element models of arch dam, foundation rock, and. Design considerations and challenges of construction doug johnson, p. The basic arch dam shapes are the constantradius arch, the constantangle arch and the doublecurvature arch with increasing complexity. Constant angle arch dam it is type of arch dam in which all the arch rings have a constant angle. It is obtained by the modification of variable radius arch dam.
Safe and best central angle 3 0 34 is used as central angle in this case. An arch dam is a structure curving upstream, where the water thrust is transferred either directly to the valley sides or indirectly through concrete abutments. The location of the dam is in a remote area, only accessible by foot or helicopter, and has. Arch dam an arch dam is a curved dam which is dependent upon arch action for its strength. This led to the development of the constant angle or variable radius arch dam, first built at salmon creek in alaska in 1914. Built in 1914, it is the worlds first constantangle arch variable radius dam. Another advanced design was the coolidge dam globe ariz. Two types of single arch dams are in use, namely the constant angle and the constant radius dam. Hydroelectric power plants in washington state, 18901938 mps.
According to thin cylinder theory of design of arch dams, the volume of concrete required for an arch dam is minimum if the central angle of the arch rings is 334. The behavior is shown to range from elementary beam bending at one end to a state of pure compression at the. The first constant angle arch dam was completed in 1914. The constantradius arch design, also called the singleradius arch, is a cylindrical shape fig. Containing 90,000 cubic yards of concrete, the dam impounds 453,350 acrefeet of water. Stability analysis of arch dam abutments has been the topic of many studies. The constant angle arch concept used for over 30 dams in the us, is typical of this category. Theory of slope stability portland state university. The constant angle arch dam is a special type of variable radius arch dam in which the central angle of the horizontal arch rings is of the same magnitude at all elevations. The constant angle arch dam is a special type of variable radius arch dam, in which the centeral angles of the horizontal arch rings are of the same magnitude at all elevations. In general, 30 design variables are used in the process of optimization as shown in table 1.
Rubble at base of dam is remnant of shotcrete facing applied in 1960s. A universally accepted fundamental of concrete arch dam design philosophy is the use of rational and consistent cri teria to ensure safe, economical. Stability analysis of arch dam abutments due to seismic loading. In the lecture part of this course we will discuss a variety of methods of analysis of slope stability and instability. Built in 1914, it is the worlds first constant angle arch variable radius dam. Any structure in a reservoir, dam, or river through which water can be drawn into an outlet pipe, flume, etc.
In the case of an embankment dam the junction is referred to as the upstream toe of the dam. According to thin cylinder theory of design of arch dams, the volume of concrete required for an arch dam is minimum if the central angle of the arch. The constant angle arch concept used for over 30 dams in. A constant angle arch dam is the one in which the central angle of the arch rings at all elevations from top of the dam to its base has the same magnitude. Damsite topography and required dimensions for nomographs and layout of dam. In a constant angle dam, also known as a variable radius dam, this subtended angle is kept a constant and the variation in distance between the abutments at various levels are taken care of by varying the radii. The present paper describes numerical techniques to the computational simulation of the membrane method for the shape determination of arch dams and subsequent stress analysis in the dam shell. Arch dam are thinner and therefore require less material than any other type of dam. Oo m so 70 so so 40 so so,oo 400 so00 pooo notes dlmonsions roquirod for using shotis h sestimotod structural height of dam from crest to bore including assumed depth of excavation. Stress and displacement estimates for arches clive l. Lessons from serious incidents at seven arch dams asdso. The maximum design reservoir level is 1770 m asl, with a volume.
The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes into its foundation or abutments. The consta n t a ngl e arch dam is that in which the c entral angl es of t he ho rizontal arch rings are of the same magnitude at all elevations. The analysis of stresses and design of multiplearch dam. It is made watertight by pointing the joints with cement. The constant radius arch design, also called the singleradius arch, is a cylindrical. Gordon dam, australia definition a barrier constructed to hold back water and raise its level, forming a reservoir used to generate electricity or as a water supply. Two types of singlearch dams are in use, namely the constant angle and the constant radius dam. An arch gravity dam or arched dam is a dam with the characteristics of both an arch dam and a gravity dam. Salmon creek hydro topo map starting points are pp14 and an unlisted flattened heli in front of the road bridge about midway the salmon creek dam is a concrete arch dam on the salmon creek, 3 miles 5 km northwest of juneau, alaska. Modern concrete arch dam designs were introduced in northamerica at the beginning of the 20th century. The beauregard dam is a 2 m high concrete arch gravity dam built between 1951 and 1960 on the dora di valgrisenche river. In this theory, the stress in an arch dam is assumed to be the same as in a cylindrical ring of equal external radius. This paper presents analytical estimates of the behavior exhibited by curved, archlike structures under radially directed and gravitational line loads.
Guide for preliminary design of arch dams i i i, w l figure 1. The salmon creek dam is a concrete arch dam on the salmon creek, northwest of juneau, alaska. Explain arch dam and buttress dam and mention their types. By transferring forces, having the same angle, to the ground, the thickness of the arch dam and therefore the volume can be reduced. The junction of the upstream face of a gravity or arch dam with the foundation surface. If erosion cannot be tolerated, a plunge pool is created by constructing an auxiliary dam downstream of the main dam. Salman farsi ghir dam, currently under construction, is located at the entrance of the karzin gorge on the ghareaghaj river approximately 180 km south east of the city of shiraz in iran, 20 km north east of salman farsi ghir city.
Oct 19, 2012 arch dam for a verywide v shaped canyon upper san joaquin dam showing the progression from layout through design appendix j2. It is a special variable radius arch dam in which central angle of the horizontal arch rings is of the same value at all the elevations. Jan 28, 2014 advantages greater arch efficiency saving in concrete over 50 % useful to meet foundation requirements, and preferred than constant radius arch dam 18. It is 1,111 feet long, including gravity wing abutments, and has a thickness that telescopes from 52 feet at the base to eight feet at the top. Demanding conditions salmon creek dam, owned by alaska electric light and power company aelp, was built in 1914 and is the worlds. Demanding conditions that required an alternative to lidar. Arch dam cross section plain view material of construction. Check dam is a small dam designed to reduce flow velocity and control soil erosion diversion dam is a type of dam that diverts all or a portion of the flow of a river from its natural course masonry dam is a type of dam constructed with masonry. These were reinforcedconcrete singleradius thinarches, the worlds oldest reinforcedconcrete thin arch dams. Eigenvalue linear buckling analysis of a high arch dam has been conducted by zhou and chang 8, who considered the dam to be safe against buckling if the calculated buckling load was greater than the strengthlimit load. Since no major design breakthrough has taken place and modern arch dams are based upon the singleradius, constant angle or doublecurvature arch design. However, for the third type of arch dam stronger foundation is required as it involves overhangs at the abutment sections. Dec 09, 2019 concrete variable radius arch dam explained.
Arch dams are thinner and therefore require less material than any other type of dam. Ussd the challenges of dams in cold climates september 2017 dams in cold climates. An arch dam is a solid dam made of concrete that is curved upstream in plan. List of medium and minor dams irrigation agriculture. The constant radius type employs the same face radius at all elevations of the dam, which means that as the channel grows narrower towards the bottom of the dam the central angle subtended by the face of the dam becomes smaller. Although the volume is decreasing when using that arch dam type, effort is. The dam has a single curvature, constant radius and constant central angle.
From the time it was built, over 100 such dams have been constructed all over the world. Constant radius dams are much less common than constant angle dams. Downstream face of dam first constant angle arch dam in us. The constant radius arch design, also called the single radius arch, is a cylindrical shape figure 2. A constant angle arch dam on the other hand, uses about 43 % of the concrete used by a constant radius arch dam. Guide for preliminary design of arch dams mo ii00,000 000 so0 700 sw so0. In progress design of doublecurvature arch dams planning. The last design variable is the angle of rotation of the dam around the zaxis figure 5. The constant angle arch dam is that in which the central angles of the horizontal arch rings are of the same magnitude at all elevations. 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. Modern concrete arch dam designs were introduced in north america at the beginning of the 20th century. Guide for preliminary design of arch dams bureau of reclamation.
Analysis of the abutment movements of high arch dams due. Developed layouts and designs of singlecentered uniformthickness doublycurved arch dam for a medium wide v shaped canyon upper san joaquin dam with thrust. Evolution of arch dam design evolution of design of the modern arch dam maybe divided into three phases. This dam with a gated spillway has a height of 2 m and 1400 million m3 of reservoir volume. Theoretically, the ideal constant angle arch in a vshaped valley has a central angle of 3 of curvature.