Design criteria for rounded rock riprap steven abt and humberto gallegos purpose develop design criteria for roundedangular rock riprap in overtopping flow expand the database of rounded rock riprap to include higher embankment slopes increase the understanding of the behavior of rounded rock riprap in overtopping flow 19. This force, which is simply the pull of water on the wetted area, is known as the tractive force chow, 1959. A number of overtopping protection systems were developed for embankment dams. Care must be exercised in the design so that stones are of good quality, sized correctly, and placed to proper thickness. Freezing and thawing, wetting and drying, abrasive wave action, and other natural processes will eventually break down the riprap. General design and construction considerations for earth.
Consideration should be given that other methods maybe more appropriate in freezethaw regions of the country. This manual presents fundamental principles underlying the design and construction of. For an additional 9 years he was a principal advisor to. Background riprap, or zone 3 rockfihl, is the most common cover material for embankment dams, including those owned by reclamation. Its useful life varies with the characteristics of the stone used. Paul guyer is a registered mechanical engineer, civil engineer, fire protection engineer and architect with over 35 years experience in the design of buildings and related infrastructure. Riprap may be placed on slope either by hand or it may be simply dumped. The plan designer will be required to assess field conditions and apply engineering principles to determine dimensions and specifications. The upstream slopes of embankment dams and dikes typically require protection against the damaging effects of wave action, surface runoff, weathering, ice, and floating debris.
Section vi contains an example procedure for design of a riprap outlet commonly used for waterway or diversion outlets or for designing riprap channels. Four methods of protecting a highway embankment from stream erosion are. Excel program to design rock chutes for grade stabilization based on the research presented by robinson, rice, and kadavy for the design of rock chutes, transactions of the asae 41, 3. A conventional rule used by many engineers required the depth of riprap or concrete blockwork on dams in the uk to be not less than one sixth of. Design of riprap slope protection against wind waves. Rock riprap consists of a heterogeneous mixture of irregular shaped rocks placed. The runup from a significant wave on an embankment slope with riprap protection can be predicted using. In the traditional deterministic approach to slope stability analysis and design, the shear strength, slope geometry, external. Arizona department of transportation 206 south 17th avenue. All books are in clear copy here, and all files are secure so dont worry about it. Increasing freeboard or designing the spillway for the passage of larger flood flows.
A conventional rule used by many engineers required the depth of riprap or concrete blockwork on dams in the uk to be not less than one sixth of the significant wave height in the design event. Guidelines for the design of other types of riprap are presented in chapter 6. The reader is directed to fema 333, federal guidelines for dam safety. Disadvantagesproblems wellgraded riprap forms a dense. Riprap remains one of the most common and costeffective means of providing erosion protection, structure stability, and slope stabilization from overtopping flow conditions. Service spillway is the principal or firstused spillway during flood flows.
Reclamations earth manual usbr, 1974, 1990 identifies the following. Modifications to embankment dams to accommodate new or revised inflow. Anyone who is involved in designing protection against waves and water erosion. The design thickness of the riprap should extend a minimum of 3 feet horizontally from the slope. Rock suitable for riprap can be sourced from quarries, from screening oversized rock from earth borrowpits or from collecting rock from fields. Dam safety resources kansas department of agriculture. Ussd committee on materials for embankment dams craig w. Practitioners guide and field evaluation of riprap methods. Geological survey waterresources investigations report 864127 prepared in cooperation with federal highway administration o i o 00 sacramento, california 1986. Section v contains a design example of an outlet protection used below of a pond barrel pipe. For each of these topics, design and construction considerations are presented. Recent experience on design, construction, and performance of cfrd dams, in. Design of riverbank riprap using large, individually. This chapter presents guidelines for sitespecific design of riprap slope protection figure 7.
Dam facing slopes, spillways and stormwater conveyance channels can be built economically with the geoweb system, and designed to meet specific site requirements with either a vegetated, aggregate armored, or a concrete solution. A part of the cross section of an embankment dam comprising material of high permeability. Many studies have been published that provide guidance for determining the wave runup height on slopes. The design and construction of earth and rockfill dams are complex because of the nature of the varying foundation conditi ons and range of properties of the materials available for use in the embankment. United states society on dams materials for embankment dams. Overtopping protection for dams fema p1014 may 2014 best practices for design, construction, problem identification and evaluation, inspection, maintenance, renovation, and repair embankment dams has become more fully developed and accepted. Performance can be further improved by the use of geotextile fabrics, meshes, or reinforcement mats.
California bank and shore rock slope protection design. For river bank protection a typical critical mass for dumped riprap is 250 kg. Geotextiles in embankment dams iv management agency fema has a hazard classification system that is clear and succinct, and this system was adopted for the purposes of this document. Riprap should be provided in areas where strong winds that could generate waves in the reservoir are possible. Guidelines for design of dams january 1985 revised january 1989. Slope protection is usually needed to protect the upstream slope against erosion. Save this page as a printable dam owners fact sheet pdf.
Riprap does not provide the habitat enhancement that vegetative practices do. Some types of embankment dams may be more susceptible than others to certain kinds of deficiencies. Rcc roller compacted concrete has also been used as slope protection and is designed and. As with any type of slope protection, problems will develop if the concrete facing has not been properly designed or installed. Riprap design for overtopped embankments us bureau. Optimum riprap side slope for a given size riprap figure 24.
The toe of the riprap should be keyed into a stable foundation at its base as shown in figure 5b. Design manual for rcc spillways and overtopping protection prepared by urs greiner woodward clyde por tland cement association. These design techniques encompass timber cribs, sheetpiles, riprap and gabions, reinforced earth and concrete overtop. For many years slope protection of dams has been designed empirically, with satisfactory results in most cases johnston, 1999. Small dams made of cohesive embankment soils have often performed well without such protection. California bank and shore rock slope protection design practitioners guide and field evaluations of riprap methods june 1996, nov 1997, oct 2000 6. Design of riverbank riprap using large, individually placed. Design guidelines for rock riprap are presented in chapter 4. The dam owner should expect some deterioration weathering of riprap. This section provides background information on the characteristics and types of embankment dams. Materials for embankment dams united states society on dams. For each of these topics, design and construction considerations are. Stone weight and equivalent stone dimension figure 23. Upstream slope protection association of state dam safety.
Soil cement slope protection and the portland cement. The best slope protection type for a given situation depends on the conditions where the installation is to be made, availability of protection material, cost of the various types, and protection desired. Riprap design hydraulics continued tractive force when water flows in a channel, a force is developed that acts in the direction of flow on the channel bed. A layer of large uncoursed stones, broken rock, or precast blocks placed in random fashion on the upstream slope of an embankment dam, on a reservoir shore, or on the sides of a channel as a protection against wave and ice action. This 66 page book is now out of print, but is available from ciria as a photocopy. Army corps of engineers cecwew washington, dc 20314 manual no. An introduction to slope stability and protection j. Erodible materials are protected by properly bedded riprap, soil cement, or. In the rollout presentation of the riprap design standard, chapter 7. Rock riprap design for protection of stream channels near highway structures volume 1 hydraulic characteristics of open channels by j. United states society on dams materials for embankment dams january 2011. Riprap design procedures presented in this manual requires input channel. Soil cement slope protection and the portland cement association soil cement construction handbook are good references for design engineers. Upstream slope protection association of state dam safety asdso.
Freezing and thawing, wetting and drying, abrasive wave action, and other natural processes will eventually break. The longitudinal transition embankment foundation condition is encountered where the alignment places the embankment alongside a hillside or where an existing embankment is to be widened. Extent of riprap protection on a channel bend figure 17. Freezing and thawing, wetting and drying, abrasive wave action, and other natural processes will eventually break down riprap. The newly placed fill tends to slide down the slope of the hillside or the existing embankment. Pdf protection of embankment dam toe and abutments under. Riprap design and construction guide ministry of environment. Often engineers need to know the riprap will provide adequate protection should the dam overtop. Gradations gradation is the size distribution of a particular riprap or aggregate. Discussion on previous laboratory and field work relevant to the design practice is also included. Design storm stage, velocity, depth of flow, channel geometry riprap properties density, shape, slope, gradation, thickness other considerations channel geometry, depth of scour, availability, vandalism vandalism andor theft of the stones is a serious problem in.