Riprap Design

Maynord, Steve; Neill, Charles R.

doi:10.1061/9780784408148.apb

Cited by 10 publications

(24 citation statements)

References 21 publications

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“…when rocks start moving, it is suggested that ψ = 0.03-0.035 (CIRIA et al, 2007;Garge & Ranga Raju, 2000;Przedwojski et al, 1995;SANRAL, 2013;Simons & Sentürk, 1992). These values correspond to rather conservative values of ψ, as seen in However, Maynord et al (1989) suggest that other researchers have undoubtedly proven that ψ is not constant, but is in fact a function of the relative roughness (defined as the ratio particle size/flow depth).…”

Section: ( ) Equation 2-20mentioning

confidence: 99%

“…According to Maynord et al (1989), the conventional factors k α and k β give results that are too conservative. The results clearly indicate that Maynord's equation yields overly non-conservative results.…”

Section: 34mentioning

confidence: 99%

“…Table 2-5 presents a summary of the applicable formulae. This approach is widely criticised (Maynord et al, 1989) since significant problems arise when the logarithmic relationship is applied to rough surfaces like riprap.…”

Section: 7effect Of the Velocity Profilementioning

confidence: 99%

“…Maynord et al (1989) developed the US Army Corps of Engineers' preferred method for the design of riprap. Unlike the previously discussed method, Maynord's equation takes the thickness of a specific layer into account.…”

Section: )mentioning

confidence: 99%

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Incipient Motion of Riprap on Steep Slopes

Langmaak¹,

Basson

2015

J. Hydraul. Eng.

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Section: ( ) Equation 2-20mentioning

confidence: 99%

Section: 34mentioning

confidence: 99%

Section: 7effect Of the Velocity Profilementioning

confidence: 99%

Section: )mentioning

confidence: 99%

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Incipient Motion of Riprap on Steep Slopes

Langmaak¹,

Basson

2015

J. Hydraul. Eng.

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“…Most consider the general case of a continuous revetment ͑Stevens et al. 1976;Maynord et al 1987;Escarameia and May 1995;Pilarczyk 1998͒ or very specific protections such as those used for bridge piers, but there seems to be an increasing trend to use riprap in other river engineering works. Among these applications, two types of noncontinuous bed protections are widely used: ͑1͒ transverse protections ͑cross sectional͒, such as bed sills ͑Fig.…”

Section: Introductionmentioning

confidence: 99%

Riprap Stability: Transverse and Longitudinal versus Continuous Protections

Almeida

Vide

2009

J. Hydraul. Eng.

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An experimental study was conducted to determine the influence of length, width, and protrusion of noncontinuous riprap protections on shear failure conditions. The incipient motion of particles as a failure criterion and the reference transport method as the threshold of motion were used. In each test, riprap transport rates were measured at different time intervals using a sediment trap placed immediately downstream from the test reach so that time dependence could be well described. Results reveal that incipient motion conditions of transverse ͑cross-sectional͒ protections are strongly influenced by both the protrusion and length of bed protection, which indicates that stability significantly increases as protection length increases and decreases as protrusion increases. In the case of longitudinal protections, almost the same failure conditions were found as in the case of continuous protection. Furthermore, these conditions are unrelated to the width of the protection. A coefficient to correct design formulas obtained by other authors is proposed to take into account the effect of the geometry of transverse protections on their stability.

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Sizing Loose Rock Riprap to Protect Stream Banks

Froehlich

2011

River Research & Apps

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Stability of loose rock riprap used to protect stream banks from erosive forces because of flowing water is evaluated based on the ratio of static moments resisting overturning and those promoting overturning of a single rock particle. The ratio of moments defines a safety factor that describes the potential for riprap failure. The buoyant force acting on a particle is treated separately from the gravitational force and is further split into components that resist and promote overturning. This approach provides consistency in reasoning throughout the formulation, which results in a particle safety factor that tends to unity as rock-specific gravity approaches one. The safety factor formulation is tested using 38 onsite measurements of riprap-lined stream channels that have experienced floods approaching or exceeding the flow rates used to design the protective covers. Comparison to two other commonly used riprap-sizing methods by means of the Hanssen-Kuipers skill score and the equitable threat score shows that the particle stability procedure provides significantly better damage predictions and, for this reason, is shown to be more accurate. Based on the onsite measurements, safety factors that provide increasing levels of security against failure are suggested for use in calculating the size of loose rock riprap needed to protect stream banks against erosion by currents. Figure 6. Graphical relations between K r , the bank side-slope ratio m and the safety factor f s for standard values of coefficients and rock properties SIZING LOOSE ROCK RIPRAP TO PROTECT STREAM BANKS

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Riprap Design

Cited by 10 publications

References 21 publications

Incipient Motion of Riprap on Steep Slopes

Incipient Motion of Riprap on Steep Slopes

Riprap Stability: Transverse and Longitudinal versus Continuous Protections

Sizing Loose Rock Riprap to Protect Stream Banks

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