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Artículos de revistas sobre el tema "Scour countermeasure"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 5 de febrero de 2022

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1

Craswell, Tom y Shatirah Akib. "Reducing Bridge Pier Scour Using Gabion Mattresses Filled with Recycled and Alternative Materials". Eng 1, n.º 2 (31 de octubre de 2020): 188–210. http://dx.doi.org/10.3390/eng1020013.

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Scour is caused by the erosive action of flowing water, which causes materials from the bed and the banks of a river to be moved or unsettled. Hydraulic structures can be drastically impacted as a result of scour, which is why it is one of the most common causes of bridge failure around the world. With a predicted increase in climate conditions, the subsequent failure of hydraulic structures due to scour is likely to proliferate as the flooding of waterways is projected to rise. This study aims to determine the viability of introducing alternative materials to a scour countermeasure used in construction—gabion models—in a bid to improve the sustainability of a project whilst providing suitable scour mitigation measures. Existing literature was examined to comprehend the different scour countermeasures used, as well as the use of alternative materials that can be used as a scour countermeasure. A laboratory experiment was then carried out using a bridge pier embedded in a flume channel protected by gabion mattresses filled with alternative materials—stone, clothing and plastic—to analyse their effectiveness. The results demonstrate that stone filled gabions are most effective at reducing bridge pier scour. However, recycled clothing as a gabion fill could prove to be a viable alternative in construction projects, potentially leading to reduced construction costs and greater sustainability. However, more research on a greater scale is required to test this thesis.

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2

Wang, Shunyi, Kai Wei, Zhonghui Shen y Qiqi Xiang. "Experimental Investigation of Local Scour Protection for Cylindrical Bridge Piers Using Anti-Scour Collars". Water 11, n.º 7 (21 de julio de 2019): 1515. http://dx.doi.org/10.3390/w11071515.

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Local scour of bridge piers is one of the main threats responsible for bridge damage. Adopting scour countermeasures to protect bridge foundations from scour has become an important issue for the design and maintenance of bridges located in erodible sediment beds. This paper focuses on the protective effect of one active countermeasure named an “anti-scour collar” on local scour around the commonly used cylindrical bridge pier. A cylindrical pier model was set up in a current flume. River sand with a median particle size of 0.324 mm was selected and used as the sediment in the basin. A live-bed scour experimental program was carried out to study the protective effect of an anti-scour collar by comparing the local scour at a cylindrical bridge pier model with and without collar. The effects of three design parameters including collar installation height, collar external diameter and collar protection range, on the scour depth and scour development were investigated parametrically. According to the experimental results, it can be concluded that: the application of an anti-scour collar alleviates the local scour at the pier effectively; and the protection effect decreases with an increase in the collar installation height, but increases with an increase in the collar external diameter and the protection range. Design suggestions for improving the scour protective effect of the anti-scour collar are summarized and of great practical guiding significance to the development of anti-scour collars for bridge piers.

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3

Chen, Hsin Hung, Ray-Yeng Yang, Ping-Chiao Kuo y Hwung-Hweng Hwung. "PHYSICAL MODELING STUDY ON SCOUR AND SCOUR COUNTERMEASURE FOR SEA-CROSSING BRIDGE PIERS". Coastal Engineering Proceedings 1, n.º 33 (25 de octubre de 2012): 83. http://dx.doi.org/10.9753/icce.v33.sediment.83.

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There are significant engineering challenges in placing the sea-crossing bridge piers in more or les shallow coastal waters because, as well as having to withstand storm-force waves and tidal currents, the bridge piers have to remain stable on a sea bed that may be continuously changing. One of the major challenges faced by designers is how to predict, and prevent, scour of the seabed sediments around the sea-crossing bridge piers. This paper describes a physical model study on scour and scour countermeasure for sea-crossing bridge piers. A 1:49 scale movable bed model tests were carried out in the Near-shore Wave Basin (NSWB, 27m x 19m) at the Tainan Hydraulics Laboratory, National Chang Kung University (NCKU), Tainan, Taiwan, with the sea-crossing bridge piers in the test area. Three series of physical model tests were performed in this study. The aim of the first test series is to investigate the maximum scour depth for the initial construction of bridge piers with only one pier model. Then the second test series were conducted to investigate the greatest magnitude of local scour and potential scour area in the sand bed around the sea-crossing bridge group piers with no scour protection. Based on the analysis from the former NSWB experimental results, the suitable scour countermeasure for sea-crossing bridge piers would be proposed and validated its function of preventing scour in the third test series.

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4

Yanmaz, A. Melih y Meric Apaydin. "Bridge Scour Risk Assessment and Countermeasure Design". Journal of Performance of Constructed Facilities 26, n.º 4 (agosto de 2012): 499–506. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0000254.

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5

Li, Hua, Brian D. Barkdoll, Roger Kuhnle y Carlos Alonso. "Parallel Walls as an Abutment Scour Countermeasure". Journal of Hydraulic Engineering 132, n.º 5 (mayo de 2006): 510–20. http://dx.doi.org/10.1061/(asce)0733-9429(2006)132:5(510).

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6

Eisenhauer, Norbert O. y Bernd Rossbach. "Testing the Effectiveness of Scour Countermeasures by Physical Modeling". Transportation Research Record: Journal of the Transportation Research Board 1696, n.º 1 (enero de 2000): 251–57. http://dx.doi.org/10.3141/1696-71.

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The physical modeling of the scouring process at bridge piers is a proven method to obtain information about the size of the scour and the flow velocities that generate the scour. On the basis of this information, appropriate countermeasures can be designed. The advantage of the physical model is its application to all, even the most complex, pier geometries. Because approach flow is uniform in most cases, physical model tests can be carried out in a hydraulic flume, a method that gives fast and reliable results. The Federal Waterways and Engineering Institute (Bundesanstalt für Wasserbau) in Karlsruhe, Germany, conducted such model tests using piers of a new bridge over the Rhine River between the cities of Mannheim and Ludwigshafen. Shortly after sheet piles were driven into the riverbed as a formwork for the lower part of the pier, severe scouring of the riverbed occurred. Consequently, the stability of the sheet pile formwork was endangered. The ad hoc countermeasure of placing riprap into the scour did not stop local scouring. An additional cover layer of coarser stones was placed on top of the previous layer, stopping the erosion process at mean flow. Model tests were conducted to estimate the durability and stability of the ad hoc countermeasure for flood events. The tests proved that the riprap was stable, even at flood events, and that the scour had shifted away from the pier to the joint between the riprap and the original riverbed. A flood event with a peak of 3 days above the tested flood water level occurred in March 1999. No negative effects on the riprap have been observed until now.

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7

Korkut, Recep, Emilio J. Martinez, Reinaldo Morales, Robert Ettema y Brian Barkdoll. "Geobag Performance as Scour Countermeasure for Bridge Abutments". Journal of Hydraulic Engineering 133, n.º 4 (abril de 2007): 431–39. http://dx.doi.org/10.1061/(asce)0733-9429(2007)133:4(431).

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8

Farooq, Rashid y Abdul Razzaq Ghumman. "Impact Assessment of Pier Shape and Modifications on Scouring around Bridge Pier". Water 11, n.º 9 (23 de agosto de 2019): 1761. http://dx.doi.org/10.3390/w11091761.

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Previous experimental research on utilizing pier modifications as countermeasures against local scour has focused primarily on circular pier. It is of utmost importance to further investigate the most suitable pier shape for pier modification countermeasure separately and in combination. This experimental study aims to reduce the stagnation of the flow and vortex formation in front of the bridge pier by providing a collar, a hooked collar, a cable, and openings separately and in combination around a suitable pier shape. Therefore, six different pier shapes were utilized to find out the influence of pier shape on local scouring for a length–width ratio smaller than or equal to 3. A plain octagonal shape was shown as having more satisfactory results in reducing scour compared to other pier shapes. Furthermore, the efficiency of pier modification was then evaluated by testing different combinations of collar, hooked collar, cable, and openings within the octagonal bridge pier, which was compared to an unprotected octagonal pier without any modification. The results show that by applying such modifications, the scour depth reduced significantly. The best combination was found to be a hooked collar with cable and openings around an octagonal pier. It was revealed that the best combination reduced almost 53% of scour depth, as compared to an unprotected octagonal pier.

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9

Ferraro, Domenico, Andrea Fenocchi y Roberto Gaudio. "Hydrodynamics of a bordered collar as a countermeasure against pier scouring". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, n.º 2242 (octubre de 2020): 20200393. http://dx.doi.org/10.1098/rspa.2020.0393.

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An experimental campaign on long-term clear-water scour at bridge piers with different configurations was performed in a laboratory to investigate the effects of different countermeasures. Tests were performed in a flume with a movable sediment bed for an unprotected cylindrical pier, a cylindrical pier with a standard collar and a cylindrical pier with a bordered collar. The scoured beds at the equilibrium stage were acquired through the photogrammetry technique and the efficiencies of the tested countermeasures were measured. Results showed a reduction in the maximum scour depth as well as in the scour hole volume with respect to the unprotected pier. The maximum scour depth was reduced by 59.63% with the standard collar and by 63.51% with the bordered collar. The scoured volume was reduced by 43.80% with the standard collar and by 60.00% with the bordered collar. The three-dimensional Reynolds-averaged Navier–Stokes equations were solved numerically to reproduce the hydrodynamics of the experiments. The volume of fluid technique was used to reproduce the free surface. For each test, the results of the simulations were analysed to investigate the flow field around the pier both at the initial (flat-bed) and at the equilibrium stages, highlighting the changes in the velocity field owing to the presence of the standard collar and of the bordered collar.

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10

Khaple, Shivakumar, Prashanth Reddy Hanmaiahgari, Roberto Gaudio y Subhasish Dey. "Splitter plate as a flow-altering pier scour countermeasure". Acta Geophysica 65, n.º 5 (18 de septiembre de 2017): 957–75. http://dx.doi.org/10.1007/s11600-017-0084-z.

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11

Shafai Bejestan, Mahmood, Kheirollah Khademi y Hossein Kozeymehnezhad. "Submerged vane-attached to the abutment as scour countermeasure". Ain Shams Engineering Journal 6, n.º 3 (septiembre de 2015): 775–83. http://dx.doi.org/10.1016/j.asej.2015.02.006.

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12

Arabani, Alireza y Human Hajikandi. "Reduction of Local Scour Around A Bridge Pier Using Triple Rectangular Plates". Current World Environment 10, Special-Issue1 (28 de junio de 2015): 47–55. http://dx.doi.org/10.12944/cwe.10.special-issue1.08.

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The performance of vertical triple plates as a new countermeasure in control of local scour around a cylindrical model pier is studied. Two ones of the plates are attached to the side wall one of the pier at one pier diameter distance, extending toward upstream distance and the third one is located in the middle, attached to the pier nose. All the three plates are parallel to flow direction. Experiments are conducted for five different depths of flow and two different lengths of the lateral plates, namely 8 and 14 cm. all the runs are performed under the clear water flow over uniform sediment. The results showed a maximum efficiency of 76% in scour reduction for 8 cm long side plates and 85% for 14 cm long ones.it is also found that the proposed setup act simultaneously as both the bed armoring and flow altering countermeasure.

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13

Jahangirzadeh, Afshin y Shatirah Akib. "Experimental study for determination of collar dimensions around bridge pier". BALTIC JOURNAL OF ROAD AND BRIDGE ENGINEERING 10, n.º 1 (10 de marzo de 2015): 89–96. http://dx.doi.org/10.3846/bjrbe.2015.11.

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The shape and size of a collar is important to maximize its effect as a scour countermeasure. Current research shows that the depth of the scour hole is decreased by using rectangular collars around circular piers. This study determined the approximate optimum dimensions for rectangular collars to minimize the temporal trend of scouring around a pier model. Effects of different sizes of rectangular collars on a model pier were investigated both at the upstream and downstream of the flume. It was observed that irrespective of the rectangular collar dimensions the upstream and the downstream were estimated to be 0.86 and 1.42, respectively. The optimum collar width was estimated to be 2.8 times the diameter of the pier. By using this optimized collar dimension, the non-dimensional depth of scour reached a min value of 0.034 at 72 h. The reduction percentage of the scour depth reached 98% at 72 h.

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14

Tao, Junliang y Junhong Li. "Streamlining of Bridge Piers as Scour Countermeasures". Transportation Research Record: Journal of the Transportation Research Board 2521, n.º 1 (enero de 2015): 172–82. http://dx.doi.org/10.3141/2521-18.

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Pier streamlining is proposed as a flow-altering countermeasure to local scour for newly proposed piers. To obtain the optimal geometry, it is necessary to investigate the effect of the horizontal profile and vertical profile on the flow pattern around the piers. In a separate paper, the effect of the cross section was studied, and the optimal cross section was obtained. Continuing the effort, this paper investigates the effect of vertical profile curvatures. To achieve this goal, Bézier curves were used to parameterize the vertical curvatures. Fifty-one three-dimensional computational fluid dynamics models with different curvatures for the pier's vertical profile were constructed by varying the Bézier parameters and computed by COMSOL. All pier models in the flume had the same block ratio to ensure that results from test cases were comparable. Analysis and comparison of the simulation results showed that both a concave (or sloped) nose and a concave sidewall reduced the maximum shear stress around piers and that increasing the concave curvature of the sidewall enhanced the reduction effect. Increasing the concave curvature of the nose, however, tended to diminish the reduction effect. The practical implications from the findings are discussed in this paper.

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15

Heibaum, Michael H. "Scour Countermeasures Using Geosynthetics and Partially Grouted Riprap". Transportation Research Record: Journal of the Transportation Research Board 1696, n.º 1 (enero de 2000): 244–50. http://dx.doi.org/10.3141/1696-70.

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The main requirement of any scour countermeasure or scour protection measure is to prevent erosion, so a top layer has to be built that is sufficiently resistant against the hydrodynamic loads and that protects the subsoil. Single elements have to be large enough to withstand the scouring forces and require an appropriate layer thickness. Smaller, mutually connected elements allow for a moderate layer thickness but provide the same resistance. To avoid excess water pressures below the top layer, permeable systems are recommended. A very reliable system is partially grouted riprap, which meets all the requirements of strength, flexibility, and permeability. Permeable systems need a well-designed filter. Placement of a grain filter or a geotextile filter is complicated by the current, so special equipment is needed. In mild currents a “sandmat” (a sand-filled nonwoven geotextile) can be used. In stronger currents use of geosynthetic geocontainers is proposed to achieve both a high resistance against the current and a well-performing filter.

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16

Abdelhaleem, Fahmy Salah Fahmy. "Roughened bridge piers as a scour countermeasure under clear water conditions". ISH Journal of Hydraulic Engineering 25, n.º 1 (28 de diciembre de 2017): 94–103. http://dx.doi.org/10.1080/09715010.2017.1420498.

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17

Burns, R. S., L. M. Fotherby, J. F. Ruff y J. M. Carey. "Design Example for Bridge Pier Scour Measures Using Toskanes". Transportation Research Record: Journal of the Transportation Research Board 1523, n.º 1 (enero de 1996): 173–77. http://dx.doi.org/10.1177/0361198196152300121.

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Toskanes were developed as an alternative scour countermeasure where riprap is not feasible or available in large sizes. The Toskane design procedure is based on results of a hydraulic model study of several different piers and abutments. Toskanes can be fabricated in sizes to meet the design requirements. One example of installing Toskanes at a bridge with a pier and vertical abutments is presented. Criteria are provided to size the Toskane. Techniques for installation are suggested and costs for the project are estimated.

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18

Saneie, Mojtaba, Navid Alizadeh Vahid y Mehdi Azhdary Moghaddam. "Buried Wing Versus Wing Wall as Abutments and Spur Dykes Scour Countermeasure". Asian Journal of Applied Sciences 5, n.º 4 (1 de mayo de 2012): 192–204. http://dx.doi.org/10.3923/ajaps.2012.192.204.

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19

Khosravinia, Payam, Amir Malekpour, Ali Hosseinzadehdalir y Davod Farsadizadeh. "Effect of trapezoidal collars as a scour countermeasure around wing-wall abutments". Water Science and Engineering 11, n.º 1 (enero de 2018): 53–60. http://dx.doi.org/10.1016/j.wse.2018.03.001.

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20

Ashraf, Fahmidah U. y Peggy A. Johnson. "Assessing Relative Risk for the Failure Modes of a Bridge Scour Countermeasure". Journal of Bridge Engineering 21, n.º 5 (mayo de 2016): 04016010. http://dx.doi.org/10.1061/(asce)be.1943-5592.0000899.

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21

Hamidifar, H., M. Nasrabadi y M. H. Omid. "Using a bed sill as a scour countermeasure downstream of an apron". Ain Shams Engineering Journal 9, n.º 4 (diciembre de 2018): 1663–69. http://dx.doi.org/10.1016/j.asej.2016.08.016.

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22

Yang, Bo, Kexiang Wei, Wenxian Yang, Tieying Li, Bo Qin y Liwei Ning. "A Feasibility Study for Using Fishnet to Protect Offshore Wind Turbine Monopile Foundations from Damage by Scouring". Applied Sciences 9, n.º 23 (21 de noviembre de 2019): 5023. http://dx.doi.org/10.3390/app9235023.

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Offshore wind turbine monopile foundations are subjected to complex wind, wave, and flow coupling effects, which result in seabed scouring around the monopile. The consequent scour pits threaten the reliability, safety, and load-carrying capacity of the monopile. In order to develop a cost-effective measure to mitigate such an issue, a new countermeasure device, named “fishnet”, is studied in this paper using a combined approach of numerical simulations and experimental tests. In the research, the size of the fishnet, diameter of the fishnet thread, and the installation height of the fishnet were optimized in order to achieve the best protection to the monopile foundation. In the paper, both numerical simulations and laboratory tests proved the effectiveness of the proposed “fishnet” in reducing the scour around the wind turbine monopile foundations. Moreover, its contribution to erosion reduction can be further enhanced via optimization. It was found that, after optimization, the maximum shear force on the seabed could be reduced by 14% in the numerical study, and the maximum depth of the scour pit could be reduced by 38.2% in laboratory tests.

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23

Al-Shukur, Abdul-Hassan K. y Manar Hussein Ali. "Optimum Design for Controlling the Scouring on Bridge Piers". Civil Engineering Journal 5, n.º 9 (1 de septiembre de 2019): 1904–16. http://dx.doi.org/10.28991/cej-2019-03091381.

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The scouring around bridge pier can be considered the most important reasons of bridge failure. Therefore, we investigated by using physical models of piers and we used single pier with square collar , circular collar and interaction of two piers in laboratory channel, its width 1 m and applied three velocities (0.1, 0.08, and 0.07) m/sec. This experimental investigation was made to choose the optimum shape and location of collar of single pier and comparing it with the interaction of two piers, the results showed that both square and circular collar decrease the scour depth, but the square collar is more effective of reducing scouring and the best location at bed level for single pier, comparing the results of single pier with the interaction of two piers, the interaction of two piers without any countermeasure reduced scour depth about 58%.

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24

UEJIMA, Hirofumi y Shinji SATO. "A STUDY ON COUNTERMEASURE AGAINST SCOUR BEHIND COASTAL DIKE DUE TO TSUNAMI OVERFLOW". Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 74, n.º 2 (2018): I_355—I_360. http://dx.doi.org/10.2208/kaigan.74.i_355.

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25

Barlock, Rachael R., Brian D. Barkdoll y Juan A. González-Castro. "Experimental Demonstration of a New Extension Plate Scour Countermeasure Downstream of Stilling Basins". Journal of Hydraulic Engineering 142, n.º 10 (octubre de 2016): 06016013. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001183.

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26

Biswas, Piya y Abdul Karim Barbhuiya. "Countermeasure of river bend scour using a combination of submerged vanes and riprap". International Journal of Sediment Research 33, n.º 4 (diciembre de 2018): 478–92. http://dx.doi.org/10.1016/j.ijsrc.2018.04.002.

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27

YAMANO, Takashi, Ryuichi FUJIWARA, Kouji NOMURA y Kouichi SHIRAKI. "The Horizontal Characteristics to Local Scour around the Pile-supported Wave Absorbing Breakwater and the Effect of Countermeasure against Local Scour". Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 69, n.º 2 (2013): I_591—I_595. http://dx.doi.org/10.2208/kaigan.69.i_591.

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28

Shimizu, Takao, Akira Sasaki y Hisayosi Ujiie. "The New Countermeasure SPAC against Seabed Scour due to Submerged Discharge and Large Waves". PROCEEDINGS OF CIVIL ENGINEERING IN THE OCEAN 7 (1991): 301–6. http://dx.doi.org/10.2208/prooe.7.301.

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29

OYAMA, Naoki, Yutaka HASHIZUME, Kenji KANEKO, Toshio HAMANAKA y Daigo ISHII. "EXPERIMENTAL STUDY ON SCOUR COUNTERMEASURE BY GEOCEL REINFORCEMENT METHOD FOR FOUNDATION GROUND OF TIDE WALL". Geosynthetics Engineering Journal 30 (2015): 75–80. http://dx.doi.org/10.5030/jcigsjournal.30.75.

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30

Zhu, Yehui, Liquan Xie y Tsung-Chow Su. "Scour Protection Effects of a Geotextile Mattress with Floating Plate on a Pipeline". Sustainability 12, n.º 8 (24 de abril de 2020): 3482. http://dx.doi.org/10.3390/su12083482.

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Underwater pipelines are vital to the oil industry. Extending the service life of these pipelines is a key issue in improving the sustainability of oil transportation. A geotextile mattress with floating plate (GMFP) is a novel and sustainable countermeasure for scour and erosion control and is herein introduced to protect a partially buried pipeline from local scour in steady currents. A series of experiments was designed to verify the protection capabilities of the GMFP and investigate its parametric effects on protection. The average seepage hydraulic gradient under the pipeline was adopted to depict the protection effects of the GMFP, and was calculated with the pore pressure readings under the pipeline. The test results show that the GMFP is capable of protecting a pipeline from the onset of local scour in a unidirectional current. The average seepage hydraulic gradient below the pipeline decreases remarkably after a GMFP is installed. The average hydraulic gradient shows a descending trend with increased sloping angle α when 0.64 < sinα < 0.77. The hydraulic gradient hits a nadir at sinα = 0.77 and climbs with the increasing sloping angle when sinα > 0.82. The hydraulic gradient ascends when the bottom opening ratio δ increases from 0.167 to 0.231, due to the decreased intensity of the bottom vortex. The hydraulic gradient drops with a rising plate height, except for a fluctuation at Hp = 0.12 m. An approximate negative correlation is found between the obstruction height of the floating plate and the average hydraulic gradient under the pipeline. This could be partially attributed to the extension and amplification of the bottom vortex on the leeside of the pipeline due to the increased plate obstruction height.

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31

Yang, Wenxian y Wenye Tian. "Concept Research of a Countermeasure Device for Preventing Scour around the Monopile Foundations of Offshore Wind Turbines". Energies 11, n.º 10 (28 de septiembre de 2018): 2593. http://dx.doi.org/10.3390/en11102593.

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Scouring has long been considered to be a major issue affecting the reliability of the monopile foundations of offshore wind turbines (OWTs) on sandy seabeds. To reduce the impact of scouring, several tons of rock/stone are usually placed around the foundations shortly after the installation of them. Such a measure is costly. Moreover, rock and stone may spread widely on the seabed during the long-term service period of OWTs. It has no doubt that recycling these rock and stone on the seabed is quite difficult in future decommission. For this reason, a new scour-countermeasure device (SEMCD) is proposed and studied in this paper. Considering that the major driver of scouring is horseshoe vortices around the monopile foundation, a hollow horn-like SEMCD with an arc surface profile is designed for weakening the horseshoe vortices. The SEMCD is made of either cement or other kinds of corrosion resistant materials. It is light in weight, and easy to install and decommission. In the paper, the working mechanism of the SEMCD is first explained. Then, its scouring mitigation effect (SME), i.e., its contribution to the reduction of horseshoe vortices and the mitigation of seabed erosion around the foundation, is studied through investigating its influences on down/up-flow and seabed shear stress. Finally, the optimal size of the SEMCD is discussed through investigating the impact of its size on the speeds of up and down flows and the shear stress on seabed surface. The calculation results have shown that the proposed SEMCD has great potential to prevent scouring and seabed erosion, so that it is of significance to improve the reliability of the monopile foundations of OWTs.

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32

Tuama Al-Awadi, Aysar. "Aspects of Downstream Bed Sill Location for Investigating the Countermeasure with Local Scour around Cylindrical Bridge Piers". Smart Science 9, n.º 2 (16 de marzo de 2021): 113–20. http://dx.doi.org/10.1080/23080477.2021.1901186.

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33

Bao, Ruotian, Junhong Li, Lin Li, Teresa J. Cutright, Long Chen, Jiahua Zhu y Junliang Tao. "Effect of Microbial-Induced Calcite Precipitation on Surface Erosion and Scour of Granular Soils". Transportation Research Record: Journal of the Transportation Research Board 2657, n.º 1 (enero de 2017): 10–18. http://dx.doi.org/10.3141/2657-02.

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Erosion is relevant to a variety of infrastructure problems such as bridge scour, roadway shoulder erosion, coastal erosion, and riverbank and slope stability. This research investigated the feasibility of using microbial-induced calcite precipitation (MICP) as an erosion countermeasure. MICP is a natural phenomenon in which calcite precipitation occurs as a consequence of microbial metabolic activity. The precipitated calcite modifies the soil fabric and provides an additional bonding force between soil particles. In this paper, a preliminary experimental study on the erosional behavior of MICP-treated sand is presented. A standard soil, Ottawa graded sand, was treated with a bacterium (Sporosarcina pasteurii) in a full-contact reactor-one in which the soil in a fabric mold was fully immersed in the bacteria and cementation solution. The morphologies and crystalline structures of the precipitated calcite in porous sediments were characterized using microscopic imaging techniques. The treated soil samples were tested in a flume to investigate the erosional behavior; both surface erosion and bridge scour tests were conducted. Although the untreated soil is highly erodible, the erosion of the treated sand was found to be negligible under the circumstances of the test; however, some concerns were raised regarding practical applications. Efforts will be made in the future to identify alternative treatment procedures that are more applicable to the field.

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34

NAKAHARA, Yusuke, Takaaki SIGEMATSU y Takashi YAMANO. "A FUNDAMENTAL STUDY ON THE CHARACTERISTICS OF A LOCAL SCOUR UNDER A VERTICAL PLATE AND ITS COUNTERMEASURE IN WAVE FIELD". Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 74, n.º 2 (2018): I_814—I_819. http://dx.doi.org/10.2208/jscejoe.74.i_814.

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35

Franzetti, Silvio, Alessio Radice, Marcello Rabitti y Giuliano Rossi. "Hydraulic Design and Preliminary Performance Evaluation of Countermeasure against Debris Accumulation and Resulting Local Pier Scour on River Po in Italy". Journal of Hydraulic Engineering 137, n.º 5 (mayo de 2011): 615–20. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0000340.

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36

Chiew, Yee-Meng. "Scour and scour countermeasures at bridge sites". Transactions of Tianjin University 14, n.º 4 (agosto de 2008): 289–95. http://dx.doi.org/10.1007/s12209-008-0049-z.

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37

Li, Junhong y Junliang Tao. "Streamlining of Bridge Piers as Scour Countermeasures". Transportation Research Record: Journal of the Transportation Research Board 2521, n.º 1 (enero de 2015): 162–71. http://dx.doi.org/10.3141/2521-17.

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Bridge scour is one of the most critical causes of bridge failure. Existing scour countermeasures either passively prevent the development of scour holes by stabilizing the critical shear zone or actively reduce the turbulence intensity in the vicinity of the pier surface. This paper proposes streamlining of the bridge pier as an option to reduce turbulence intensity actively in the local zone and thus decrease overall local scour potential. The effect of the curvature of the pier cross section was evaluated with computational fluid dynamics (CFD) simulations. To reduce computational cost, two-dimensional CFD simulations were conducted to model the flow fields around test cases having different pier cross sections. Simulation results were systematically analyzed and compared to evaluate the effect of streamlining on the flow field. The cross section that resulted in the smallest value of the maximum bed shear stress was selected as the optimal cross section for the subsequent three-dimensional (3-D) study, which investigated the vortex structures around the pier. Results from this 3-D simulation were compared with those from two other test cases, in which piers had cross-section shapes that are commonly seen in practice. The pier model with the optimal cross section was found to significantly reduce the downward velocity in front of the piers, the maximum bed shear stress, and the overall scour potential. These findings are expected to inform the design of optimal streamlined piers for newly proposed bridges, which could diminish the overall scour potential around piers.

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38

Xie, Liquan y Yehui Zhu. "Scour Protection of Underwater Pipelines". Journal of Civil Engineering and Construction 7, n.º 4 (25 de noviembre de 2018): 171. http://dx.doi.org/10.32732/jcec.2018.7.4.171.

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A detailed literature review on the protection of local scour beneath a submarine pipeline is presented. The review covers two basic parts of countermeasures against the pipeline scour, namely preventing the onset of scour and stimulating the self-burial of a pipeline. The research progress on the methods of the two sections is discussed in detail separately. The methods preventing the onset of scour have been extensively studied, but the understanding on their mechanisms is yet to be improved. The progress in stimulating the self-burial of a pipeline mainly focuses on a spoiler attached to a pipeline, which is investigated comprehensively with both experiments and numerical simulations. Both parts of countermeasures have been applied in some practical engineering projects and the protection effects are generally satisfying.

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39

Habib, Ibtesam Abudallah, Wan Hanna Melini Wan Mohtar, Atef Elsaiad y Ahmed El-Shafie. "Nose-Angle Bridge Piers as Alternative Countermeasures for Local Scour Reduction". Baltic Journal of Road and Bridge Engineering 13, n.º 2 (25 de junio de 2018): 110–20. http://dx.doi.org/10.7250/bjrbe.2018-13.405.

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This study investigates the performance nose-angle piers as countermeasures for local scour reduction around piers. Four nose angles were studied, i.e., 90°, 70°, 60° and 45° and tested in a laboratory. The sediment size was fixed at 0.39 mm whereas the flow angle of attack (or skew angle) was varied at four angles, i.e., skew angles, i.e., 0°, 10°, 20° and 30°. Scour reduction was clear when decreasing nose angles and reached maximum when the nose angle is 45°. Increasing the flow velocity and skew angle was subsequently increasing the scour profile, both in vertical and transversal directions. However, the efficiency of nose angle piers was only high at low Froude number less than 0.40 where higher Froude number gives minimal changes in the maximum scour depth reduction. At a higher skew angle, although showed promising maximum scour depth reduction, the increasing pier projected width resulted in the increase of transversal lengths.

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40

Lagasse, P. F., E. V. Richardson y L. W. Zevenbergen. "Comprehensive Bridge Scour Evaluation Methodology". Transportation Research Record: Journal of the Transportation Research Board 1696, n.º 1 (enero de 2000): 204–8. http://dx.doi.org/10.3141/1696-64.

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In the United States, bridge scour technology is discussed primarily in three FHWA publications: Hydraulic Engineering Circular (HEC) 18: Evaluating Scour at Bridges; HEC-2: Stream Stability at Highway Structures; and HEC-23: Bridge Scour and Stream Instability Countermeasures. Together, these documents provide guidance to state highway agencies that is necessary for completing comprehensive scour and stream instability evaluations for the design of new bridges and for repairing existing bridges. Experience has shown that the relationships among the three documents are not always readily apparent, and some scour evaluations have relied primarily on HEC-18. A comprehensive flowchart that illustrates the interrelationship among the three FHWA scour-related documents has been developed. In addition, in 1998, FHWA, TRB, and AASHTO sponsored a scanning review of European practice for bridge scour and stream instability countermeasures. In 1999, ASCE published a compendium of papers on stream stability and scour at highway bridges, and FHWA prepared an annotated bibliography to support revisions to the three HECs. It is anticipated that the flow-chart and the substantial information from the scanning review, the compendium, and the annotated bibliography will be included in the next revisions to HEC-18, HEC-20, and HEC-23. On the basis of information from these sources, a comprehensive approach to bridge scour and stream instability evaluations is outlined, and an overview of planned revisions to the three FHWA HECs is provided.

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41

Richardson, Jerry R. y Kevin York. "Hydrodynamic Countermeasures for Local Pier Scour". Transportation Research Record: Journal of the Transportation Research Board 1690, n.º 1 (enero de 1999): 186–92. http://dx.doi.org/10.3141/1690-21.

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42

WANG, Chuan-Yi, Jen-Hao CHENG, Han-Peng SHIH y Jen-Wei CHANG. "Ring columns as pier scour countermeasures". International Journal of Sediment Research 26, n.º 3 (septiembre de 2011): 353–63. http://dx.doi.org/10.1016/s1001-6279(11)60099-1.

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43

Radice, Alessio y Vahid Davari. "Roughening Elements as Abutment Scour Countermeasures". Journal of Hydraulic Engineering 140, n.º 8 (agosto de 2014): 06014014. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0000892.

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44

Melville, Bruce, Sjoerd van Ballegooy, Stephen Coleman y Brian Barkdoll. "Scour Countermeasures for Wing-Wall Abutments". Journal of Hydraulic Engineering 132, n.º 6 (junio de 2006): 563–74. http://dx.doi.org/10.1061/(asce)0733-9429(2006)132:6(563).

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45

Bryson, David W., Daniel G. Ghere y William H. Hulbert. "European Practice for Bridge Scour and Stream Instability Countermeasures". Transportation Research Record: Journal of the Transportation Research Board 1696, n.º 1 (enero de 2000): 236–43. http://dx.doi.org/10.3141/1696-69.

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FHWA, AASHTO, and TRB sponsored a scanning review of European practice for bridge scour and stream instability countermeasures in October 1998. The review involved a panel of representatives from six state highway agencies (California, Illinois, Maryland, Minnesota, Oregon, and South Carolina), FHWA, two universities, and the private sector. The review included visits to hydraulic research laboratories, highway research institutes, and field sites in four countries—Switzerland, Germany, the Netherlands, and the United Kingdom. Findings during the scanning review can be classified as general observations and observations of specific countermeasures. General observations of European practice include design philosophy, risk analysis, environmental policy, river geomorphology, scour prediction, modeling, and inspection and monitoring. Observations of specific countermeasures include riprap design and construction, filter design and construction, river-training structures, riverbed degradation countermeasures, bioengineering, and flow-altering devices. These observations are contrasted with U.S. practice. The panel’s recommendations for modifying U.S. practice on the basis of the European experience and findings that deserve further evaluation are also presented.

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46

Pearson, David R., J. Sterling Jones y Stuart M. Stein. "Risk-Based Design of Bridge Scour Countermeasures". Transportation Research Record: Journal of the Transportation Research Board 1696, n.º 1 (enero de 2000): 229–35. http://dx.doi.org/10.3141/1696-68.

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HYRISK was originally developed to prioritize bridges with unknown foundations to determine where to spend limited resources to investigate those bridges. It was later modified to prioritize bridges of any type for scour evaluations where there are limited resources for the evaluations each year. The model is based on information that can be read from the National Bridge Inventory and accounts for average daily traffic, detour lengths, value of lost time, risks associated with scour at various types of foundations, bridge condition, bridge geometry, and bridge age. The model can readily be modified for use as a decision tool to select various levels of countermeasures for a bridge that has already been evaluate and determined to be scour critical for some probability flood event. For that application, the model can use the determined probability of failure and does not need to rely on the assumed risks for various foundation types. The model will need to account for the risk of loss of life on the basis of recent experience. The bridge owner will provide information on the expected life of the bridge and the costs of various levels of protection. The model will determine the optimum level of protection for the bridge and the maximum expenditures that should be accepted to increase the level of protection.

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47

I. Khassaf, Saleh y Hiba A. Abbas. "Study of the Local Scour Around L-Shape Groynes in Clear Water Conditions". International Journal of Engineering & Technology 7, n.º 4.20 (28 de noviembre de 2018): 271. http://dx.doi.org/10.14419/ijet.v7i4.20.25938.

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River training structures; such as groynes; are efficient engineered methods utilized to protect eroding river banks. But during groynes design stage; the designers faces one of the most significant issues which is the evaluation of the maximum depth of local scour around groynes. This is due to the flow area constriction in the groyne location itself; which in turn cause increasing in local velocity that consequently causes the scour. In the present study, the maximum scour depth around L-shape groyne was computed based on laboratory experiments where different number of groynes and distances between them were used as sort of countermeasures to reduce the scour around the groynes foundations. The results showed clear decreasing in scour depth at increasing number of groynes and also distance between them in the limitation of this study. A new formula based on experimental data was derived to calculate the local scour depth. This formula gave R2 =0.903 which reflecting good agreement to the results.

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48

Johnson, Peggy A. y Sue L. Niezgoda. "Risk-Based Method for Selecting Bridge Scour Countermeasures". Journal of Hydraulic Engineering 130, n.º 2 (febrero de 2004): 121–28. http://dx.doi.org/10.1061/(asce)0733-9429(2004)130:2(121).

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49

Deng, Lu y C. S. Cai. "Bridge Scour: Prediction, Modeling, Monitoring, and Countermeasures—Review". Practice Periodical on Structural Design and Construction 15, n.º 2 (mayo de 2010): 125–34. http://dx.doi.org/10.1061/(asce)sc.1943-5576.0000041.

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50

Melville, Bruce W. y Anna C. Hadfield. "Use of Sacrificial Piles as Pier Scour Countermeasures". Journal of Hydraulic Engineering 125, n.º 11 (noviembre de 1999): 1221–24. http://dx.doi.org/10.1061/(asce)0733-9429(1999)125:11(1221).

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