Loose Riprap Grade Control Structure Design
The Soil Conservation Service has been using loose riprap grade control structures based on the equal energy concept for several years with mixed success. Previous model studies resulted...

Cofferdam Rip-Rap Protection for the New Esna Barrage
A 1:60 undistorted mobile bed model of the Nile River in the vicinity of Esna Barrage was constructed at the Hydraulics and Sediment Research Institute to test rip-rap protection of the...

Update: Bridge Scour
Nearly 500 bridges have failed because of hydraulic conditions—primarily scour—since 1950, but the collapse of the Route 90 bridge over Schoharie Creek in April 1987 focused national attention...

Diffusion Barrier Transport Properties of Unsaturated Paintbrush Tuff Rubble Backfill
Diffusion coefficients (D) were experimentally determined in unsaturated tuff gravel to evaluated the effectiveness of tuff gravel and rubble as a diffusion barrier to ionic transport...

The Influence of Uniformity on Riprap Stability
Studies have shown that size uniformity influences the stability of riprap. The ratio of fractional sizes of the riprap mixture, D60/D10,...

Riprap Stability Results from Large Test Channel
Velocity data from a large test channel were used to determine the distribution of depth-averaged velocity and shear stress on the side slope of both straight and curved channels. From...

Minimum Lifetime Cost Design of Coastal Structures—A Proposal of Design Method for Rubble Sloping Breakwaters
The authors propose herein a rational design method for coastal structures with consideration for their repairs. The special characteristics of the proposal are that a certain extent of...

Vegetation on Riprap Revetment—Problem Definition and Study Approach

Rubble Mound Breakwater Considering Low-Quality Materials and Seismic Displacement

Dynamic Stability of Dumped Riprap

Model Study of Side Slope Riprap
Laboratory experiments were conducted in 10-m long channels having 1.5 H : 1 V side slopes protected with a 20.7-mm diameter rock layer 1.5 diameters thick. Four models were tested. In...

Breakwater Choices
Most of the maritime breakwaters built throughout the world are of the rubble mount type, with a protective armor constructed of artificial blocks. Despite the multitude of different shapes...

Scour Protection at the Straight Drop Spillway
Tests were conducted to determine the scour and the effect of tailwater on scour downstream of the straight drop spillway stilling basin. Preliminary results are presented on performance...

Riprap Stability in Channel Bends
A systematic test series is underway in a large test channel to define the stability of riprap on the outer bank of channel bends. A 'practical equilibrium' concept...

Riprap and Armor Stone

Rock Armouring to Unconventional Breakwaters: The Design Implications for Rock Durability
This paper identifies the need for quantitative durability testing of rock for use on dynamically stable rock armored slopes. The derivation and use of a suite of engineering tests for...

Riprap Design by Modified Safety Factor Method
The Safety Factor method for designing riprap is based upon straight forward physics combining rock properties and flow characteristics. M.A. Stevens developed the method by summing the...

Design of Riprapped Scour Holes for Flip Bucket and Overfall Spillways
Presented in this paper is a simple method of predicting pre-excavated scour depths and geometry for riprapped basins below flip bucket spillways. The input data needed for establishing...

Armor Protection for Rubble Mound Breakwaters
A brief summary of past practices in breakwater armor system design is presented. The limitations of current design procedures for rubble mound breakwaters are discussed and improved methods...

Riprap Stability on Channel Slide Slopes
The stability of riprap placed on a sloping bank is decreased because one component of gravity tends to displace the rock down the slope. Results of riprap stability tests on sloping banks...

 

 

 

 

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