The use of riprap protection as a countermeasure against scour downstream of two compound piers

2004 ◽  
pp. 1827-1833
Author(s):  
A Kadota ◽  
R Aragão ◽  
K Suzuki ◽  
V Srinivasan
Keyword(s):  
Riprap Protection

Remote Real-time Riprap Protection Erosion AssessmenT on large rivers

2020 ◽  
Author(s):  
Gordon Gilja ◽  
Antonija Cikojević ◽  
Kristina Potočki ◽  
Matej Varga ◽  
Nikola Adžaga
Keyword(s):  
Real Time ◽  
Large Rivers ◽  
Bridge Piers ◽  
Hybrid Modelling ◽  
Field Surveys ◽  
Scour Monitoring ◽  
Scour Hole ◽  
Riprap Protection ◽  
Model Phase ◽  
Modelling Approach

<p>Large number of bridges in Europe is at the end of their life span, while the frequency of occurrence for extreme climatic events, driven by climate change, is increasing. Floods influence morphodynamic changes in the riverbed, such as scouring of the riverbed next to the bridge substructure, that can undermine the overall stability of the bridge. Placement of riprap protection around bridge piers is an approach that doesn’t solve scouring problem, it rather displaces the scour hole elsewhere in the river channel, where its location is unknown because it is formed in the interaction between the flow and the structure, in site-specific conditions. Traditional approach to scour monitoring is effective only if surveys are conducted during the flood conditions, while the data acquired post-flood can underestimate the full potential of flood hazard. Detailed field surveys of hydraulic parameters during floods are essential in the understanding of morphodynamic evolution of the river channel, but are often scarce because they are time-consuming and require extensive resources (e.g. the survey equipment). Therefore, the majority of research was conducted using hydraulic flumes where both flow and the riverbed conditions are idealized </p><p>The goal of the R3PEAT project (Remote Real-time Riprap Protection Erosion AssessmenT on large rivers) is to bridge the gap between the real-time scour hole development and flow environment through development of real-time scour monitoring system. The research focus of the project is investigation of scouring processes next to the riprap protection around bridge piers - existing structures whose stability and safety are unknown in the hydraulic environment under the influence of climate change. Research methodology combines experimental investigations on scaled physical model (Phase I) with 3D numerical model (Phase II) into hybrid modelling approach, calibrated and validated with field surveys. The research objectives of the project are: (1) develop ScourBuoy prototype (2); calibrate the physical model with field surveys; (3) improve existing empirical equations for equilibrium scour hole development using hybrid modelling approach; (4) investigate the dependence between turbulent flow characteristics and temporal scour hole development and (5) investigate dependence between turbulent conditions and incipient motion of sediment particles. The impact of the proposed project on the bridge management systems is expected through the development of a practical remote real-time system for erosion estimation around the riprap protection on large rivers that can be basis for the real-time decision support system.</p><p><strong>Acknowledgment:</strong><br>This work has been supported in part by Croatian Science Foundation under the project R3PEAT (UIP-2019-04-4046)</p>

scholarly journals ROCK MOVEMENT IN LARGE-SCALE TESTS OF RIPRAP STABILITY UNDER WAVE ACTION

1966 ◽  
Vol 1 (10) ◽  
pp. 55
Author(s):  
Thorndike Saville
Keyword(s):  
Large Scale ◽  
The United States ◽  
Wave Action ◽  
Wave Tank ◽  
Engineering Research ◽  
Reflected Wave ◽  
Wave Generator ◽  
Graded Material ◽  
Riprap Protection ◽  
Large Scale Tests

There have been several instances in the past four or five years of damage to the riprap protection of some earth dams and embankments in major reservoirs in the middle western portion of the United States. In particular, in small sections of the embankment of the Snake Creek sub-impoundment in the Garrison Reservoir in North Dakota, some riprap was removed by a severe storm in 1964. It was recognized at the time of construction that the riprap protection to be placed on this embankment was considerably lighter than desirable, and was knowingly placed as an experiment to see if lighter graded material might still provide sufficient protection in a reservoir where the water surface elevation changed periodically. High waves can develop over the 32-mile fetch in this area of frequent high wind velocity. Loss of some riprap in this area has led to an investigation of various schemes of upgrading the riprap. As a part of this investigation, tests have been made at the Coastal Engineering Research Center in Washington, D.C. of various types of riprap exposed to wave action. Tests have been made at both small and large scale. As with most wave tank tests of breakwater or embankment structures, the tests must be run as a short series of bursts of waves, followed by periods of calm. This is necessary because when the wave approaches the structure and breaks upon it, a small portion of the wave energy is not absorbed in the breaking process, but is reflected back along the wave tank. This reflected wave, upon reaching the wave generator, is re-reflected and travels again down the tank toward the structure. If mechanical generation of waves continues after the wave is re-reflected from the generator, this re-reflected wave adds to the mechanically generated wave, and gives a higher wave at the structure than is desired for tests. Accordingly, the wave generator must be stopped at the time the wave reflected from the structure has travelled to and reaches the generator. Thus the tests are run in a short burst of perhaps 10 or 1$ waves, followed by a period of time sufficient to allow the tank water level to calm, and then again a burst of 10 or 1'j waves.

ScourBuoy – concept for scour monitoring system

2021 ◽  
Author(s):  
Antonija Harasti ◽  
Gordon Gilja ◽  
Matej Varga ◽  
Robert Fliszar
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Functional System ◽  
Small Scale ◽  
Single Beam ◽  
Scour Monitoring ◽  
Inner Diameter ◽  
3D Positioning ◽  
Riprap Protection ◽  
Echo Sounder

<p>The objective of this paper is to present the ScourBuoy – concept for scour monitoring system. The ScourBuoy prototype is currently under development within the R3PEAT project (Remote Real-time Riprap Protection Erosion AssessmenT on large rivers), which aims to investigate scouring processes next to the riprap protection around bridge piers. ScourBuoy integrates commercially available technical devices into a functional system for scour monitoring during flood conditions. Sensors used are single beam echo sounder that collects depth and temperature data, multi-GNSS device for 3D positioning, compass for orientation respective to the True North and motion sensor for pitch and roll data. Combined output from the sensors allows user to calculate river depth and monitoring of scour development during floods. Advantage of ScourBuoy is adaptability to the field conditions, such as placement over the scour hole, as well as simpler deployment and reallocation in comparison to fix-mount solutions. ScourBuoy prototype was built using a common small-scale pipe float with an 80 mm inner diameter hole, which was used as a holder for an aluminium pipe. Aluminium pipe is used as a casing for echo sounder, positioned as downward-looking, so it stays submerged during deployment. The rest of the sensors are enclosed in the waterproof housing placed atop of the buoy, permanently above the waterline. The ScourBuoy will be a practical and affordable system which will allow researchers and engineers to collect measurements for scouring estimation. It will be used as a support system for rapid and timely decision making. Finally, developed Scour Buoy will present an alternative for real-time scour monitoring which allows responsive adapting to the specific conditions at the locations affected by scour.</p>

Sign in / Sign up

Export Citation Format

Share Document