Статті в журналах: "Foundation scour"

1

Stahlmann, Arne, and Torsten Schlurmann. "PHYSICAL MODELING OF SCOUR AROUND TRIPOD FOUNDATION STRUCTURES FOR OFFSHORE WIND ENERGY CONVERTERS." Coastal Engineering Proceedings 1, no. 32 (January 27, 2011): 67. http://dx.doi.org/10.9753/icce.v32.sediment.67.

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As a step to further develop the share of renewable energies, the first German offshore test site alpha ventus has been installed in the North Sea in 2009 in water depths of 30 m, where experience shall be gained and made available for future offshore wind farms. Regarding converter foundations in deep water, it is well known that in most cases scour phenomena occur around the structures. Due to the complexity of the tripod foundations, significant knowledge gaps in scour progression in general and especially in detail as well as its probable effects on the stability and durability are given. Therefore, investigations on scouring phenomena around complex foundation structures like the tripod are carried out within the research project. The investigation method consists of a unique combination of local scour monitoring as well as physical and numerical modeling, whereas the physical modeling part was carried by means of 1:40 laboratory tests and 1:12 large-scale physical model tests in wave flumes. The results show that scours around the tripod foundation do not only occur directly around the foundation piles, but also in the near-field of the structure. Compared to first in-situ measured scours in the test site, at least a good qualitative agreement of the modeled scour depths and evolutions could be shown.

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2

Mara Jauane Nicholas, Ravindra Jayaratne, Takayuki Suzuki, and Tomoya Shibayama. "BUILDING FOUNDATION INSTABILITY INDUCED BY TSUNAMI SCOUR." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 29. http://dx.doi.org/10.9753/icce.v36v.currents.29.

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Understanding the role of tsunami-induced scour in building foundation instability can allow for the proper design of buildings located in areas prone to tsunami events. The process of tsunami scour around building foundations reduces the bearing capacity of the soil to support loading, lateral resistance and loss of soil- foundation friction (i.e. piles). Scour can cause loss of material around a foundation, due to increased pore pressure within the soil and removal of the soil during the tsunami, resulting in reduced bearing capacity of the soil (Macabuag et al., 2018). During the 2004 Indian Ocean Tsunami and the 2011 Great East Japan Earthquake and Tsunami, three similar failure modes of building foundations were experienced, namely overturning, sliding and bearing (scour) failure (Macabuag et al., 2018). According to Wright (2015), shallow foundations such as strip, slab or pad are vulnerable to erosion of surrounding soil causing scour during a tsunami. The present paper discusses the application of the scour depth predictive model of Nicholas et al. (2016) and the development of a Relative Risk Index for future design of building foundations accounting for tsunamis.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/u6QSmUe8YqA

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3

Yang, Ray-Yeng, Hsin-Hung Chen, Hwung-Hweng Hwung, Wen-Pin Jiang, and Nian-Tzu Wu. "EXPERIMENTAL STUDY ON THE LOADING AND SCOUR OF THE JACKET TYPE OFFSHORE WIND TURBINE FOUNDATION." Coastal Engineering Proceedings 1, no. 32 (January 21, 2011): 25. http://dx.doi.org/10.9753/icce.v32.structures.25.

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A 1:36 scale model tests were carried out in the Medium Wave Flume (MWF) and Near-shore Wave Basin (NSWB) at the Tainan Hydraulics Laboratory (THL) with the jacket type offshore wind turbine foundation located in the test area. The loading of typhoon wave with current on the jacket type offshore wind turbine foundation was investigated in the MWF with fixed bed experiment. Meanwhile, the scour around the jacket type offshore wind turbine foundation exposed to wave and current was conducted in the NSWB with the moveable bed experiment. Two locations (water depth 12m and 16m) of the foundations are separately simulated in this study. Based on the analysis from the former NSWB experimental results, the suitable scour protection of a four-layer work around the foundation is also proposed to the impact of scour. Finally, a four-layer scour protection is tested and found to be effective in preventing scour around jacket type foundation of offshore wind turbines at water depth 12m and 16m.

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4

Kariyawasam, Kasun D., Campbell R. Middleton, Gopal Madabhushi, Stuart K. Haigh, and James P. Talbot. "Assessment of bridge natural frequency as an indicator of scour using centrifuge modelling." Journal of Civil Structural Health Monitoring 10, no. 5 (July 18, 2020): 861–81. http://dx.doi.org/10.1007/s13349-020-00420-5.

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Abstract One of the most prevalent causes of bridge failure around the world is “scour”—the gradual erosion of soil around a bridge foundation due to fast-flowing water. A reliable technique for monitoring scour would help bridge engineers take timely countermeasures to safeguard against failure. Although vibration-based techniques for monitoring structural damage have had limited success, primarily due to insufficient sensitivity, these have tended to focus on the detection of local damage. High natural frequency sensitivity has recently been reported for scour damage. Previous experiments to investigate this have been limited as a result of the cost of full-scale testing and the fact that scaled-down soil-structure models tested outside a centrifuge do not adequately simulate full-scale behaviour. This paper describes the development of what is believed to be the first-ever centrifuge-testing programme to establish the sensitivity of bridge natural frequency to scour. A 1/60 scale model of a two-span integral bridge with 15 m spans was tested at varying levels of scour. For the fundamental mode of vibration, these tests found up to a 40% variation in natural frequency for 30% loss of embedment. Models of three other types of foundation, which represent a shallow pad foundation, a deep pile bent and a deep monopile, were also tested in the centrifuge at different scour levels. The shallow foundation model showed lower frequency sensitivity to scour than the deep foundation models. Another important finding is that the frequency sensitivity to “global scour” is slightly higher than the sensitivity to “local scour”, for all foundation types. The level of frequency sensitivity (3.1–44% per scour depth equivalent to 30% of embedment of scour) detected in this experiment demonstrates the potential for using natural frequency as an indicator of both local and global scour of bridges, particularly those with deep foundations.

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5

Stahlmann, Arne, and Torsten Schlurmann. "INVESTIGATIONS ON SCOUR DEVELOPMENT AT TRIPOD FOUNDATIONS FOR OFFSHORE WIND TURBINES: MODELING AND APPLICATION." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 90. http://dx.doi.org/10.9753/icce.v33.sediment.90.

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Regarding offshore constructions, there is still a lack in knowledge of scour progression for complex structures like foundations for offshore wind energy converters at present, which is however necessary for its dimensioning. As an example of such complex structure types, tripod foundations are constructed in German offshore wind farms at present. In order to describe physical processes and influencing factors on scour progression from a scientific point of view, comprehensive investigations on the scouring phenomena for tripod foundations have been carried out and will be partly presented here. The overall investigation method consists of a combination of 1:40 small and 1:12 large scale physical model tests in wave flumes, numerical simulations using CFD methods and in-situ measured scour data. For the numerical modeling part, a sediment transport model formulation has been implemented into OpenFOAM software code. The results show a general variability of scour depending on the load boundary conditions and structural parameters. Scours occur both at the foundation piles and directly under the structure, which in this form could not be predicted using standard approaches, but which has to be taken into account when regarding the soil mechanical stability and the final dimensioning of the foundations.

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6

Ni, Xuan, and Leiping Xue. "Experimental Investigation of Scour Prediction Methods for Offshore Tripod and Hexapod Foundations." Journal of Marine Science and Engineering 8, no. 11 (October 30, 2020): 856. http://dx.doi.org/10.3390/jmse8110856.

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Scour prediction is essential for the design of offshore foundations. Several methods have been proposed to predict the equilibrium scour depth for monopiles. By introducing an effective diameter, such methods could also be applied to predicting scour depth for pile groups. Yet, there are still difficulties in estimating the equilibrium scour depth of foundations in complex shapes, such as the tripod foundation. This study investigates the clear-water scour around the tripod and hexapod foundations through laboratory experiments, with uniform bed sediment and steady current. Here, the authors propose an approach to calculate the effective diameter for the tripod and hexapod models, which is similarly as for the pile groups. Three widely-used methods in predicting equilibrium scour depth have been evaluated, and the best method is recommended.

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7

Tu, Wenbo, Xiaoqiang Gu, Xianfeng Ma, and Dawei Huang. "Analysis of Lateral Dynamic Response of Caisson Foundation in Layered Clayey Soils considering Scour-Hole Dimensions." Shock and Vibration 2020 (October 16, 2020): 1–11. http://dx.doi.org/10.1155/2020/8827498.

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As a cross-sea or river deep-water foundation, it is clear that the caisson foundation will be subjected to significant lateral dynamic loads due to winds or waves and suffer from scouring under its long-term effect. In order to obtain the scour effect on the dynamic response of the foundation, an analytical model describing the scour-hole effect in terms of scour depth, scour width, and slope angle was constructed. Combined with the nonlinear Winkler theory, a method for the dynamic response of the caisson foundation considering the scour-hole dimensions was proposed. Comparisons against the results from the dynamic FEM demonstrate the reliability of this method. The effects of the scour width, slope angle, and scour depth on the dynamic response of the caisson were discussed. The results show that the scour depth affects the dynamic displacement and resonant frequency of the foundation most, whereas the scour width does less and the slope angle does the least; the dynamic response of caisson can be approximated as the case of the slope angle 5° and the scour width 5B when the slope angle is less than 5° and the scour width is greater than 5B, respectively; the effects of scour width and slope angle on the dynamic response of caisson have the similar change pattern in the displacement and resonant frequency when the scour depth is different. However, the effect of amplitude on dynamic response shows a nonlinear increase trend when the scour depth is relatively large.

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8

Wilms, Mayumi, Arne Stahlmann, and Torsten Schlurmann. "INVESTIGATIONS ON SCOUR DEVELOPMENT AROUND A GRAVITY FOUNDATION FOR OFFSHORE WIND TURBINES." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 35. http://dx.doi.org/10.9753/icce.v33.structures.35.

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Due to insufficient insights about the scour development around the STRABAG gravity foundation, the Franzius-Institute conducted small- and large-scale physical model tests in wave flumes on a scale of 1:50 and 1:17 in order to investigate the wave-induced scouring phenomena around the foundation and to design a scour protection system. The tests on scour development without a scour protection system show that the main areas which are vulnerable to scour are the contact areas of the foundation. Furthermore, the experiments show that a scour protection system is necessary for the given and investigated wave boundary conditions; the performance of the selected protection system using geotextile sand containers is verified. Additional numerical simulations indicate an amplification of the resulting flow around the foundation under combined loads (waves and current), but without significant change of the flow pattern

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9

Harris, John M., Richard J. S. Whitehouse, Nicholas S. Tavouktsoglou, and Pedro M. Godinho. "Foundation Scour as a Geohazard." Journal of Waterway, Port, Coastal, and Ocean Engineering 145, no. 6 (November 2019): 04019022. http://dx.doi.org/10.1061/(asce)ww.1943-5460.0000523.

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10

Pizarro, Alonso, Salvatore Manfreda, and Enrico Tubaldi. "The Science behind Scour at Bridge Foundations: A Review." Water 12, no. 2 (January 30, 2020): 374. http://dx.doi.org/10.3390/w12020374.

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Foundation scour is among the main causes of bridge collapse worldwide, resulting in significant direct and indirect losses. A vast amount of research has been carried out during the last decades on the physics and modelling of this phenomenon. The purpose of this paper is, therefore, to provide an up-to-date, comprehensive, and holistic literature review of the problem of scour at bridge foundations, with a focus on the following topics: (i) sediment particle motion; (ii) physical modelling and controlling dimensionless scour parameters; (iii) scour estimates encompassing empirical models, numerical frameworks, data-driven methods, and non-deterministic approaches; (iv) bridge scour monitoring including successful examples of case studies; (v) current approach for assessment and design of bridges against scour; and, (vi) research needs and future avenues.

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11

Liu, Feng, Qianen Xu, and Yang Liu. "Condition Diagnosis of Long-Span Bridge Pile Foundations Based on the Spatial Correlation of High-Density Strain Measurement Points." Sustainability 13, no. 22 (November 12, 2021): 12498. http://dx.doi.org/10.3390/su132212498.

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Pile foundations of long-span bridges are often deeply buried in soil, and their structural condition is difficult to accurately diagnose by conventional methods. To address this issue, a method for diagnosing the structural condition of bridge pile foundations based on the spatial correlation of high-density strain measurement points is proposed. The strain data of the high-density measurement points of a bridge pile foundation are obtained by using distributed optical fiber sensing technology based on Brillouin scattering, and then an algorithm for diagnosing the structural condition of the pile foundation based on geographically weighted regression analysis is presented. On this basis, aiming at the scour of the pile foundation of long-span bridges, an algorithm for estimating the scour depth of the pile foundation based on sliding plane clustering is proposed. Finally, the effectiveness of the proposed method is verified by numerical simulation and actual bridge data.

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12

Liu, Qin, Zhe Wang, Ning Zhang, Hongyu Zhao, Lei Liu, Kunpeng Huang, and Xuguang Chen. "Local Scour Mechanism of Offshore Wind Power Pile Foundation Based on CFD-DEM." Journal of Marine Science and Engineering 10, no. 11 (November 11, 2022): 1724. http://dx.doi.org/10.3390/jmse10111724.

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The local scour around offshore pile foundations often seriously affects the normal operation of offshore wind power. The most widely used numerical simulation method in the study of local scour is the Euler two-fluid model (TFM). However, the contact effect between sediment particles is neglected in this model. Thus, the momentum and energy transfer between sediment particles and the fluid is not realistically reflected, which limits its significance in revealing the mesoscopic mechanism of local scour. Therefore, the computational fluid dynamics-discrete element method (CFD-DEM) numerical model was applied in this study, which fully considers the contact between solid particles and momentum transfer between two phases. The model was first verified by experimental data of a local scour test under clear water scour. Then, the mechanism of local scour was further discussed from macro and micro perspectives. The results showed that CFD-DEM could be effectively used to study the local scour around a pile foundation. The local scour was comprehensively affected by flow velocity, gravity, fluid force, drag force, and interaction between particles, etc. Although the maximum average drag force happened in the area about 90° from the direction of incoming flow, the maximum scour depth always occurred at about 45°. Corresponding findings and conclusions can be used for future reference when designing and protecting the offshore wind power pile.

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13

Sun, Lam, Lam, Dai, and Hamill. "Temporal Evolution of Seabed Scour Induced by Darrieus-Type Tidal Current Turbine." Water 11, no. 5 (April 28, 2019): 896. http://dx.doi.org/10.3390/w11050896.

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The temporal evolution of seabed scour was investigated to prevent damage around a monopile foundation for Darrieus-type tidal current turbine. Temporal scour depths and profiles at various turbine radius and tip clearances were studied by using the experimental measurements. Experiments were carried out in a purpose-built recirculating water flume associated with 3D printed turbines. The scour hole was developed rapidly in the initial process and grew gradually. The ultimate equilibrium of scour hole was reached after 180 min. The scour speed increased with the existence of a rotating turbine on top of the monopile. The findings suggested that monopile foundation and the rotating turbine are two significant considerations for the temporal evolution of scour. The scour depth is inversely correlated to the tip-bed clearance between the turbine and seabed. Empirical equations were proposed to predict the temporal scour depth around turbine. These equations were in good agreement with the experimental data.

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14

Lan, Tianyang, Weimin Xu, Shichao Zhao, Feng Liu, and Yang Liu. "Advances in Vibration-Based Scour Monitoring for Bridge Foundations." IOP Conference Series: Materials Science and Engineering 1203, no. 2 (November 1, 2021): 022127. http://dx.doi.org/10.1088/1757-899x/1203/2/022127.

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Abstract Scouring around bridge foundations is one of the main factors causing structural damage of bridges. Traditional scour monitoring techniques generally require a large number of sensing devices set up underwater, which is difficult to be implemented for actual bridges. To address this issue, scour monitoring technology based on structural vibrations is paid attention gradually, because this technique can work well with less equipment and can be free from the influence of the submerged environment. This study presents a systematic summary and analysis of the selection of scour indicators, sensor deployment principles and other related research involved in scour monitoring technology based on structural vibration. On this basis, the research status of the bridge scour monitoring method based on vehicle excitation is further summarized. Finally, the prospects for the application of vibration-based bridge foundation scour monitoring technology are presented, discussing the technologies that are currently missing and urgently needed for this monitoring method and the challenges faced today.

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15

Hu, Ruigeng, Xiuhai Wang, Hongjun Liu, and Yao Lu. "Experimental Study of Local Scour around Tripod Foundation in Combined Collinear Waves-Current Conditions." Journal of Marine Science and Engineering 9, no. 12 (December 3, 2021): 1373. http://dx.doi.org/10.3390/jmse9121373.

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A series of laboratory experiments were conducted in a wave-current flume to investigate the scour evolution and scour morphology around tripod in combined waves and current. The tripod model was made using the 3D printing technology, and it was installed in seabed with three installation angles α = 0°, 90°and 180° respectively. In the present study, the scour evolution and scour characteristic were first analyzed. Then, the equilibrium scour depth Seq was investigated. Furthermore, a parametric study was carried out to study the effects of Froude number Fr and Euler number Eu on equilibrium scour depth Seq respectively. Finally, the effects of tripod’s structural elements on Seq were discussed. The results indicate that the maximum scour hole appeared underneath the main column for installation angle α = 0°, 90° and 180°. The Seq for α = 90° was greater than the case of α = 0° and α = 180°, implying the tripod suffered from more severe scour for α = 90°. When KC was fixed, the dimensionless time scale T* for α = 90° was slightly larger than the case of α = 0° and α = 180° and the T* was linearly correlated with Ucw in the range of 0.347 < Ucw < 0.739. The higher Fr and Eu both resulted in the greater scour depth for tripod in combined waves and current. The logarithmic formula can depict the general trend of Seq and Fr (Eu) for tripod in combined waves and current.

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16

Jing, Yuanxu, Yuan Wang, Jingqi Huang, Wei Wang, and Lunbo Luo. "Failure Envelopes of Composite Bucket Foundation for Offshore Wind Turbines under Combined Loading with considering Different Scour Depths." Shock and Vibration 2021 (August 12, 2021): 1–15. http://dx.doi.org/10.1155/2021/7922572.

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The composite bucket foundation of offshore wind turbines is subjected to a variety of loads in the marine environment, such as horizontal load H, vertical load V , bending moment M, and torque T. In addition, due to the characteristics of its connection section, the water flow around the foundation will produce scour pits of various degrees, reducing the depth of the bucket foundation, which has a nonnegligible impact on the overall stability of the bucket foundation. In this paper, the failure envelope characteristics of different combinations of loads on bucket foundations, including V -H-T, V -M-T, conventional V -H-M, and noncoplanar V -H-M, are numerically investigated with considering different scour depths. The numerical results indicate that the V -H-T, V -M-T, conventional V -H-M, and noncongruent V -H-M failure envelopes gradually shrink inwards with increasing scour depth, and the stability of the composite bucket foundation decreases; the conventional V -H-M failure envelope shows an asymmetry of convexity to the right, and the noncongruent V -H-M failure envelope shows an asymmetry of outward convexity to the left and right. The corresponding mathematical expressions for the failure envelope are obtained through the normalized fitting process, which can be used to evaluate the stability of the bucket foundation based on the relative relationship between the failure envelope and the actual load conditions, which can provide practical guidance for engineering design.

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17

Liu, Yong Jun, Xing Tao Ma, and Yong Mei Sun. "Flood Damage to Rural Buildings Result from Foundation Scour and Scour Protection Strategy." Applied Mechanics and Materials 166-169 (May 2012): 2627–30. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.2627.

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In China, flooding is one of the most common and frequent natural disasters, which can cause life and property losses partly due to heavily damage and collapse of rural buildings. Hence, it is very important to conduct comprehensive study on flood damage to rural buildings. In this paper, the flood damage to rural builds is described and analyzed with emphasis on the foundation scour, which may result in whole building collapse, and scour protection strategy. Damages or collapse caused by foundation scour of rural building can be categorized into two main groups according to the location of rural a building. After summarizing existing scour protection strategies, a new technology is suggested. The contents presented in this paper may be useful references for further study on flood damage to rural building and scour protection engineering practices.

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18

Fazeres-Ferradosa, Tiago, João Chambel, Francisco Taveira-Pinto, Paulo Rosa-Santos, Francisco V. C. Taveira-Pinto, Gianmaria Giannini, and Piet Haerens. "Scour Protections for Offshore Foundations of Marine Energy Harvesting Technologies: A Review." Journal of Marine Science and Engineering 9, no. 3 (March 8, 2021): 297. http://dx.doi.org/10.3390/jmse9030297.

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The offshore wind is the sector of marine renewable energy with the highest commercial development at present. The margin to optimise offshore wind foundations is considerable, thus attracting both the scientific and the industrial community. Due to the complexity of the marine environment, the foundation of an offshore wind turbine represents a considerable portion of the overall investment. An important part of the foundation’s costs relates to the scour protections, which prevent scour effects that can lead the structure to reach the ultimate and service limit states. Presently, the advances in scour protections design and its optimisation for marine environments face many challenges, and the latest findings are often bounded by stakeholder’s strict confidential policies. Therefore, this paper provides a broad overview of the latest improvements acquired on this topic, which would otherwise be difficult to obtain by the scientific and general professional community. In addition, this paper summarises the key challenges and recent advances related to offshore wind turbine scour protections. Knowledge gaps, recent findings and prospective research goals are critically analysed, including the study of potential synergies with other marine renewable energy technologies, as wave and tidal energy. This research shows that scour protections are a field of study quite challenging and still with numerous questions to be answered. Thus, optimisation of scour protections in the marine environment represents a meaningful opportunity to further increase the competitiveness of marine renewable energies.

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19

Lin, Yung-Bin, Tzu-Kang Lin, Cheng-Chun Chang, Chang-Wei Huang, Ben-Ting Chen, Jihn-Sung Lai, and Kuo-Chun Chang. "Visible Light Communication System for Offshore Wind Turbine Foundation Scour Early Warning Monitoring." Water 11, no. 7 (July 17, 2019): 1486. http://dx.doi.org/10.3390/w11071486.

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Offshore wind farms have a superior wind source to terrestrial wind farms, but they also face more severe environmental conditions such as severe storms, typhoons, and sea waves. Scour leads to the excavation of sediments around the foundations of structures, reducing the safe capacity of the structures. The phenomenon of pier scour is extremely complex because of the combined effects of the vortex system involving time-dependent flow patterns and sediment transport mechanisms. A real-time scour monitoring system can improve the safety of structures and afford cost-effective operations by preventing premature or unnecessary maintenance. This paper proposes an on-site scour monitoring system using visible light communication (VLC) modules for offshore wind turbine installations. A flume experiment revealed that the system was highly sensitive and accurate in monitoring seabed scour processes. This arrayed-VLC sensory system, proposed in this paper, has considerable potential for safety monitoring and also can contribute to improving the accuracy of empirical scour formulas for sustainable maintenance in the life cycle of offshore structures.

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20

Li, Junhan, Bin Zhang, Chao Shen, Xiaoli Fu, and Weichao Li. "Experimental Study on Local Scour Depth around Monopile Foundation in Combined Waves and Current." Sustainability 13, no. 24 (December 9, 2021): 13614. http://dx.doi.org/10.3390/su132413614.

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Local scour is one of the key factors that cause the collapse of structures. To avoid structure failures and economic losses in water, it is usually essential to predict the equilibrium scour depth of the foundation. In this study, several design models which were presented to predict the equilibrium scour depth either under steady clear water conditions and combined waves and current conditions were recommended. These models from China, the United States and Norway were analyzed and compared through experiments. Moreover, flume tests for monopile foundation embedded in sand under different flow conditions were carried out to observe the process and gauge the maximum depth around the pile. Based on this study, for predicting the equilibrium scour depth around bridge piers, the computational results of three design methods are all conservative, as expected. For the foundation of offshore structures in marine environment, most of the predicted scour depths by design methods are different from field data; in particular, the mean relative error with these design methods proposed may reach up to 966.5%, which may lead to underestimation of the problem, overdesign and consequently high construction cost. To further improve the ability of the scour prediction in a marine environment, data from flume tests and some field data from a previous study were used to derive the major factors of scour. Based on the dimensional analysis method, a new model to estimate the equilibrium scour depth induced by either current or waves is proposed. The mean relative error of the new formula is 49.1%, and it gives more accurate scour depth predictions than the existing methods.

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21

Hu, Ruigeng, Xiuhai Wang, Hongjun Liu, and Da Chen. "Numerical Study of Local Scour around Tripod Foundation in Random Waves." Journal of Marine Science and Engineering 10, no. 4 (March 29, 2022): 475. http://dx.doi.org/10.3390/jmse10040475.

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In this study, the local scour around tripods in random waves is numerically investigated. The seabed-tripod-fluid numerical model with an RNG k−ε turbulence model is built and validated. Following that, the scour characteristics and flow velocity distribution are analyzed using the present numerical model. Finally, a revised stochastic model is proposed to predict the equilibrium scour depth, Seq, around tripods in random waves. The results indicate that the present seabed-tripod-fluid numerical model is capable of depicting the scour process and of capturing the flow field around tripods with high accuracy. Due to the blockage effects of the main column and structural elements, there is enhanced flow acceleration underneath the main column and the lower diagonal braces, which increases the turbulence intensity and seabed shear stress, causing more particles to be mobilized and transported, resulting in more severe scour at the site. The revised stochastic model shows the best agreement with the numerical and experimental results when n = 20, but more experimental data and numerical results are still needed to verify the adaptation of the revised stochastic model for larger Keulegan–Carpenter (KC) number conditions (KCrms,a > 4).

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22

Lancaster, Orrin, Remo Cossu, Craig Heatherington, Scott Hunter, and Tom E. Baldock. "Field Observations of Scour Behavior around an Oscillating Water Column Wave Energy Converter." Journal of Marine Science and Engineering 10, no. 3 (February 23, 2022): 320. http://dx.doi.org/10.3390/jmse10030320.

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This study provides the first ever published measurements of scour and morphological change around an Oscillating Water Column (OWC) Wave Energy Converter (WEC) device at a real-world site, with the intention of informing future designs to reduce costs of the technology. A 200-kW prototype OWC WEC was deployed at King Island, Tasmania, Australia in January 2021, providing a unique opportunity to monitor the device using a combination of dive footage, multi-beam surveys and bedrock surveys. Settlement of the device was observed and monitored before ceasing once the foundation made contact with the underlying bedrock at the site. It is hypothesized that the settlement is caused by scour undermining the gravity structure’s foundations. The processes causing this scour are explored and possible future design modifications are suggested to reduce the risk of scour and settlement.

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23

Liao, Chung-Ta, Keh-Chia Yeh, Yin-Chi Lan, Ren-Kai Jhong, and Yafei Jia. "Improving the 2D Numerical Simulations on Local Scour Hole around Spur Dikes." Water 13, no. 11 (May 23, 2021): 1462. http://dx.doi.org/10.3390/w13111462.

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Local scour is a common threat to structures such as bridge piers, abutments, and dikes that are constructed on natural rivers. To reduce the risk of foundation failure, the understanding of local scour phenomenon around hydraulic structures is important. The well-predicted scour depth can be used as a reference for structural foundation design and river management. Numerical simulation is relatively efficient at studying these issues. Currently, two-dimensional (2D) mobile-bed models are widely used for river engineering. However, a common 2D model is inadequate for solving the three-dimensional (3D) flow field and local scour phenomenon because of the depth-averaged hypothesis. This causes the predicted scour depth to often be underestimated. In this study, a repose angle formula and bed geometry adjustment mechanism are integrated into a 2D mobile-bed model to improve the numerical simulation of local scour holes around structures. Comparison of the calculated and measured bed variation data reveals that a numerical model involving the improvement technique can predict the geometry of a local scour hole around spur dikes with reasonable accuracy and reliability.

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24

Kim, Young Jin, Ngo Duc Vu, and Dong Hyawn Kim. "Ultimate Limit State Risk Assessment of Penta Pod Suction Bucket Support Structures for Offshore Wind Turbine due to Scour." Journal of Korean Society of Coastal and Ocean Engineers 33, no. 6 (December 31, 2021): 374–82. http://dx.doi.org/10.9765/kscoe.2021.33.6.374.

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The scour risk assessment was conducted for ultimate limit state of newly developed penta pod suction bucket support structures for a 5.5 MW offshore wind turbine. The hazard was found by using an empirical formula for scour depth suitable for considering marine environmental conditions such as significant wave height, significant wave period, and current velocity. The scour fragility curve was calculated by using allowable bearing capacity criteria of suction foundation. The scour risk was assessed by combining the scour hazard and the scour fragility.

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25

Odeyemi, Samson Olalekan, Mutiu Adelodun Akinpelu, Rasheed Abdulwahab, Kazeem Adeshina Dauda, and Stella Chris-Ukaegbu. "Scour Depth Prediction for Asa Dam Bridge, Ilorin, Using Artificial Neural Network." International Journal of Engineering Research in Africa 47 (March 2020): 53–62. http://dx.doi.org/10.4028/www.scientific.net/jera.47.53.

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Bridge Scour is the localized loss of the geomaterials around the foundation of a bridge as a result of the movement of water around it. Scour is a great risk to the stability of a bridge’s foundation, thus leading to collapse, loss of lives and setback in a nation’s socio-economic life. Artificial Neural Networks (ANN) are collections of simple, highly connected processing elements that learn according to sets of input parameters and use that to simulate the networks of nerve cells of humans or animal central nervous system. The Asa Dam Bridge, one of the longest bridges in Ilorin, Kwara State, Nigeria, has five (5) spans of 20m each. The bridge connects Ilorin to the Ogbomosho Express way (leading to the western part of the country) and the Eyenkorin-Jebba road (leading to the north). Thus, the bridge has a high economic value. In this research, factors such as flow depth, average flow velocity of the river and median sediment size were investigated to show how they affect the depth of scour around the bridge pile foundation. Data were taken for a period of 48 weeks and ANN was applied to predict and generate a model that shows how these factors relate to the scour depth of the riverbed. The model revealed that the hydraulic parameters and soil grading around the pile cap of Asa River Bridge bears significant influence on the scour depth of its foundation. The model was compared with five (5) other established scour equations.

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26

Kim, Seon Min, Jong Kyu Kim, Yong Kwan Kim, and Seong Ho Seo. "Scour Protection Effect around the Monopile Foundation." Journal of the Korean Society for Marine Environment & Energy 20, no. 2 (May 31, 2017): 84. http://dx.doi.org/10.7846/jkosmee.2017.05.20.2.84.

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27

Kim, Seon Min, Jong Kyu Kim, Yong Kwan Kim, and Seong Ho Seo. "Scour Protection Effect around the Monopile Foundation." Journal of the Korean Society for Marine Environment and Energy 20, no. 2 (May 25, 2017): 84–90. http://dx.doi.org/10.7846/jkosmee.2017.20.2.84.

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28

Link, Oscar, Emmanuel Mignot, Sebastien Roux, Benoit Camenen, Cristián Escauriaza, Julien Chauchat, Wernher Brevis, and Salvatore Manfreda. "Scour at Bridge Foundations in Supercritical Flows: An Analysis of Knowledge Gaps." Water 11, no. 8 (August 10, 2019): 1656. http://dx.doi.org/10.3390/w11081656.

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The scour at bridge foundations caused by supercritical flows is reviewed and knowledge gaps are analyzed focusing on the flow and scour patterns, available measuring techniques for the laboratory and field, and physical and advanced numerical modeling techniques. Evidence suggests that the scour depth caused by supercritical flows is much smaller than expected, by an order of magnitude compared to that found in subcritical flows, although the reasons for this behavior remain still unclear. Important questions on the interaction of the horseshoe vortex with the detached hydraulic-jump and the wall-jet flow observed in supercritical flows arise, e.g., does the interaction between the flow structures enhance or debilitate the bed shear stresses caused by the horseshoe vortex? What is the effect of the Froude number of the incoming flow on the flow structures around the foundation and on the scour process? Recommendations are provided to develop and adapt research methods used in the subcritical flow regime for the study of more challenging supercritical flow cases.

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29

Hu, Ruigeng, Hongjun Liu, Hao Leng, Peng Yu, and Xiuhai Wang. "Scour Characteristics and Equilibrium Scour Depth Prediction around Umbrella Suction Anchor Foundation under Random Waves." Journal of Marine Science and Engineering 9, no. 8 (August 17, 2021): 886. http://dx.doi.org/10.3390/jmse9080886.

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A series of numerical simulation were conducted to study the local scour around umbrella suction anchor foundation (USAF) under random waves. In this study, the validation was carried out firstly to verify the accuracy of the present model. Furthermore, the scour evolution and scour mechanism were analyzed respectively. In addition, two revised models were proposed to predict the equilibrium scour depth Seq around USAF. At last, a parametric study was carried out to study the effects of the Froude number Fr and Euler number Eu for the Seq. The results indicate that the present numerical model is accurate and reasonable for depicting the scour morphology under random waves. The revised Raaijmakers’s model shows good agreement with the simulating results of the present study when KCs,p < 8. The predicting results of the revised stochastic model are the most favorable for n = 10 when KCrms,a < 4. The higher Fr and Eu both lead to the more intensive horseshoe vortex and larger Seq.

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30

Liu, Wen Tsung, Chia Chyi Chang, Kuei Hsiang Cheng, and Chen Wei Chi. "Numerical Analysis of Bridge Caisson Foundation due to Riverbed Erosion." Applied Mechanics and Materials 405-408 (September 2013): 342–48. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.342.

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Keywords： Scour Depth, Water flow Force, Finite Element Method ABSTRACT. In recent years, the researches on the impact stability of piers based on river erosion are concerned in Taiwan. Therefore, it is an important issue to estimate accurately the scour depth, to calculate the water flow force on bridge pier, and to establish the close mechanism of bridge for saving lives. This research is a case study on Paulon Bridge by finite element method (FEM) Plaxis 3D Foundation for simulating analysis the caisson foundation in bridge pier scour. Firstly, we infer the flood level, the speed of flow in the different frequency year, the whole bridge safety coefficient, and the inclination angle of pile based on the simulating analysis to build the warning system. We compare the data by FEM and observing data in order to confirm the validity of FEM.

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31

Ngo, Duc-Vu, Young-Jin Kim, and Dong-Hyawn Kim. "Risk Assessment of Offshore Wind Turbines Suction Bucket Foundation Subject to Multi-Hazard Events." Energies 16, no. 5 (February 24, 2023): 2184. http://dx.doi.org/10.3390/en16052184.

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For the offshore wind turbines (OWTs) located in a seismically active region, the occurrence of earthquakes combined with scour is a highly possible multi-hazard event. This study developed an alternative fragility analysis framework to assess the seismic performance of suction bucket-supported OWTs under the action of scour. First, the probabilistic approach was applied to calculate the occurrence probability of scour depth (SD) and earthquake events. Then, the possible combinations of these two events were considered in the analysis model to establish the fragility surface of the suction bucket foundation. Finally, by integrating the product of scour and earthquake hazard, as well as fragility curves, the suction bucket foundation failure probability was obtained. The developed framework provides a reliable approach to risk assessment for OWT-supporting structures in extreme event situations and can be applied to other complex natural hazards.

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32

Fazeres-Ferradosa, Taveira-Pinto, Rosa-Santos, and Chambel. "Probabilistic Comparison of Static and Dynamic Failure Criteria of Scour Protections." Journal of Marine Science and Engineering 7, no. 11 (November 7, 2019): 400. http://dx.doi.org/10.3390/jmse7110400.

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The present paper provides a reliability assessment of scour protections applicable to both the static and dynamic stability design. As a case study, Horns Rev 3 hindcast data is used to simulate different failure criteria for an exemplary scour protection suitable for an offshore monopile foundation. The results show that the probability of failure is influenced by several factors, namely the wave friction factor, the definition of the acceptable damage number or the formulations used to calculate the bed shear-stress. The reliability assessment also indicates that annual probabilities of failure, associated to each criterion, might be comparable with the values presented in reliability standards for marine structures. Based on the results, this paper highlights future recommendations to improve the reliability-based design and analysis of scour protections for offshore foundations.

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33

Khansari, A., H. Hoyme, and H. Oumeraci. "Scour protection effects on the dynamic response of jacket structures under extreme load events." IOP Conference Series: Materials Science and Engineering 1260, no. 1 (October 1, 2022): 012028. http://dx.doi.org/10.1088/1757-899x/1260/1/012028.

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Abstract A well-validated Finite Element (FE) model of a jacket structure (OC4 jacket) with pile foundation together with a Computational Fluid Dynamic (CFD) model (OpenFOAM-based) set-up for extreme waves on the structure are applied to perform systematic comparative analyses of the dynamic response of the structure to extreme wave loads with and without scour effects. The pile foundation model is considered by implementing a non-linear soil model to the foundation using load-deflection (p-y) approach to capture the non-linear behaviour of the soil for large pile foundation displacements. The results show that, the scour protection improves the foundation bearing capacity and consequently, decreases the failure probability in terms of both serviceability and ultimate limit states. Moreover, it enhances the dynamic response of the structure under extreme load events caused by breaking waves. Accordingly, an innovative solution for scour protection of offshore-fixed bottom structures has been introduced by “Biodegradable Soft Rock” (sand filled containers produced from bio-degradable geotextile product) which is the newest development in this section.

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34

Cui, Yonggang, Wei Haur Lam, Tianming Zhang, Chong Sun, Desmond Robinson, and Gerard Hamill. "Temporal Model for Ship Twin-Propeller Jet Induced Sandbed Scour." Journal of Marine Science and Engineering 7, no. 10 (September 27, 2019): 339. http://dx.doi.org/10.3390/jmse7100339.

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This research paper proposes the use of empirical equations to estimate the temporal maximum scour that is induced by twin-propeller ( ε t w i n = Ω t [ l n ( t ) ] Γ t ) when acting over non-cohesive bed materials. A purpose built experimental apparatus is used to obtain the measurement data required for the calculation of the empirical constants. The output from rigorous experimental investigations demonstrates that the maximum scour depth produced from the operation of twin-propeller ( ε t w i n ), within the confines of a harbour basin, varies as a logarithmic function of time. A dimensional analysis of the standard single propeller configuration is used as the foundation upon which the scour equation is postulated. This is extended to include the influence of the operating distance between the twin-propeller configurations for the first time. The division of scours by twin-propeller and single-propeller ( ε twin / ε m ) enables the establishment of mathematical relation to calculate C1, C2, A, and B. The constants are C 1 = 366.11, C 2 = 0.3376, A = 0.859, and B = 0.1571. The proposed scour equation is more reliable within the time zone up to two hours based on the experimental data.

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35

Kim, Young-Jin, Duc-Vu Ngo, Jang-Ho Lee, and Dong-Hyawn Kim. "Ultimate Limit State Scour Risk Assessment of a Pentapod Suction Bucket Support Structure for Offshore Wind Turbine." Energies 15, no. 6 (March 11, 2022): 2056. http://dx.doi.org/10.3390/en15062056.

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Scour risk assessment considering reaction force at foundation was proposed and applied to newly developed pentapod suction bucket support structures for a 5.5 MW offshore wind turbine under ultimate limit state environmental load. Scour hazard was obtained according to scour depth by using an empirical formula, which is the function of marine environmental conditions such as significant wave height, significant period, and current velocity. Fragility of the pentapod support structure was evaluated using the bearing capacity limit state criterion under ultimate limit state load case. Scour risk was assessed by combining the scour hazard and the fragility. Finally, scour risk of the developed pentapod suction bucket support structure under ultimate limit state has been assessed.

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36

Jawalageri, Satish, Soroosh Jalilvand, and Abdollah Malekjafarian. "Influence of soil properties on the shift in natural frequencies of a monopile-supported 5MW offshore wind turbine under scour." Journal of Physics: Conference Series 2265, no. 3 (May 1, 2022): 032020. http://dx.doi.org/10.1088/1742-6596/2265/3/032020.

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Abstract This paper studies the change in the natural frequencies of the NREL 5MW monopile-supported offshore wind turbine (OWT) due to scour. The natural frequencies are derived from accelerations arising under wind and wave loads, for a range of different soil properties. A model of the wind turbine is developed using OpenFAST and SESAM software which considers aerodynamic and hydrodynamic loading with soil-structure interaction. The superstructure behaviour is modelled using OpenFAST and the foundation behaviour is modelled with SESAM, where soil-structure interaction is incorporated using p-y springs. The influence of soil density and scour hole depth on the obtained natural frequencies are studied. Accelerations are extracted at nine locations along the tower resulting from applied wind and wave loads. The first two system natural frequencies are estimated using frequency domain decomposition (FDD) applied to the acceleration time-histories for each scour depth and soil type. It is shown that the increase in scour depth around the foundation of the OWT leads to a decrease in natural frequencies when compared to the case where there is no scour.

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37

Corvaro, Sara, Francesco Marini, Alessandro Mancinelli, and Carlo Lorenzoni. "SCOUR PROTECTION AROUND A SINGLE SLENDER PILE EXPOSED TO WAVES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 6. http://dx.doi.org/10.9753/icce.v36.papers.6.

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The study of the scour around a monopile foundation and, in particular, the evaluation of the performance of alternative scour protection systems made of geotextile sand containers (GSCs) are here presented. Different configurations of the scour protection system were experimentally analyzed. The scour protection efficiency has been tested with both regular and random waves. A design dynamic formula for the scour protections is developed based on the stability of the GSC and, hence, on the evaluation of the weight of the geotextile sand container by means of the stability number. A damage level has been defined and related with the modified stability number. The paper provides useful information for the design of the scour protections made of geotextile sand containers, for the evaluation of the performance of such systems in terms of scour reduction, sinking and damage level of the scour protections.

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38

Hafez, Youssef I. "Mathematical Modeling of Local Scour at Slender and Wide Bridge Piers." Journal of Fluids 2016 (June 14, 2016): 1–19. http://dx.doi.org/10.1155/2016/4835253.

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Most existing equations for predicting local scour at bridge piers suffer from overprediction of the scour depths which results in higher foundation costs. To tackle this problem, a mathematical model for predicting bridge pier scour is developed herein based on an energy balance theory. The present study equation was compared to commonly used bridge scour equations using scour field data in USA. The developed equation has several advantages among which we have the following: it adds to the understanding of the physics of bridge pier scour, is valid for slender and wide piers, does not suffer from overprediction of scour depths, addresses clear water and live bed scour, and includes the effects of various characteristics of the bed material such as specific gravity (or density), porosity, size, and angle of repose. In addition, the developed equation accounts for the debris effect and aids in the design of scour mitigation methods such as collars, side bars, slots, and pier protective piles.

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39

Wu, Minghao, Leen De Vos, Carlos Emilio Arboleda Chavez, Vasiliki Stratigaki, Tiago Fazeres-Ferradosa, Paulo Rosa-Santos, Francisco Taveira-Pinto, and Peter Troch. "Large Scale Experimental Study of the Scour Protection Damage Around a Monopile Foundation Under Combined Wave and Current Conditions." Journal of Marine Science and Engineering 8, no. 6 (June 8, 2020): 417. http://dx.doi.org/10.3390/jmse8060417.

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This paper presents a series of large-scale wave flume experiments on the scour protection damage around a monopile under combined waves and current conditions with model scales of 1:16.67 and 1:8.33. The main objective is to compare the damage data obtained from these large-scale models with existing monopile scour protection design approaches, which were proposed based on small scale wave flume experiments, and to study the applicability of the existing approaches. The static stability (onset of motion and bed shear stress) and the dynamic stability (three-dimensional damage numbers) of the scour protection are investigated. Both results show that the existing design approaches can be conservative when applied to large scale models, which highlights the need of further investigations on scale and model effects. In addition, this paper also analyses the scour protection damage depth. It is observed that damage depths of the scour protection layer under low Keulegan–Carpenter number (KC) conditions are smaller than predictions. The study provides valuable large scale experimental data for future research on the monopile scour protection design.

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40

Xiong, Wen, C. S. Cai, Bo Kong, Xuefeng Zhang, and Pingbo Tang. "Bridge Scour Identification and Field Application Based on Ambient Vibration Measurements of Superstructures." Journal of Marine Science and Engineering 7, no. 5 (April 26, 2019): 121. http://dx.doi.org/10.3390/jmse7050121.

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A scour identification method was developed based on the ambient vibration measurements of superstructures. The Hangzhou Bay Bridge, a cable-stayed bridge with high scour potential, was selected to illustrate the application of this method. Firstly, two ambient vibration measurements were conducted in 2013 and 2016 by installing the acceleration sensors on the girders and pylon. By modal analysis, the natural frequencies of the superstructures were calculated with respect to different mode shapes. Then, by tracing the change of dynamic features between two measurements in 2013 and 2016, the discrepancies of the support boundary conditions, i.e., at the foundation of the Hangzhou Bay Bridge, were detected, which, in turn, qualitatively identified the existence of bridge foundation scour. Secondly, an FE model of the bridge considering soil-pile interaction was established to further quantify the scour depth in two steps. (1) The stiffness of the soil springs representing the support boundary of the bridge was initially identified by the model updating method. In this step, the principle for a successful identification is to make the simulation results best fit the measured natural frequencies of those modes insensitive to the scour. (2) Then, using the updated FE model, the scour depth was identified by updating the depth of supporting soils. In this step, the principle of model updating is to make the simulation results best fit the measured natural frequency changes of those modes sensitive to the scour. Finally, a comparison to the underwater terrain map of the Hangzhou Bay Bridge was carried out to verify the accuracy of the predicted scour depth. Based on the study in this paper, it shows that the proposed method for identifying bridge scour based on the ambient vibration measurements of superstructures is effective and convenient. It is feasible to quickly assess scour conditions for a large number of bridges without underwater devices and operations.

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41

Campbell, Kris E. J., Alastair Ruffell, Jamie Pringle, David Hughes, Su Taylor, and Brian Devlin. "Bridge Foundation River Scour and Infill Characterisation Using Water-Penetrating Radar." Remote Sensing 13, no. 13 (June 29, 2021): 2542. http://dx.doi.org/10.3390/rs13132542.

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Inspections of engineered structures below water level are essential to ensure the long-term serviceability of bridge infrastructure and to avoid major damage or failure. This research aimed to investigate integrated geophysical technologies for the underwater inspection of bridge foundation-related scour and erodible scour-based infill. Survey methods focused on Water-Penetrating Radar (WPR), supplemented by sonar. Whilst the survey benefits of the sonar imaging water–sediment interface and structures are well known, those of WPR are not. However, it is ideally suited to the survey of the water base and sub-sediment in shallow (>10 m) freshwater, especially where suspended sediment, weed infestation or methane impede sonar results. Our work produced good WPR imagery acquired from small, manoeuvrable boats that allowed bathymetric profiles to be plotted, as well as the likely locations of soft-sediment scour in future high-water flow events. This study provides clear benefits for integrated sonar and WPR surveys in the quantitative assessment of engineered structures within freshwater.

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42

Wang, Jing, Jinbo Xie, Yingjie Wu, Chen Wang, and Fayun Liang. "An Investigation of the Effect of Utilizing Solidified Soil as Scour Protection for Offshore Wind Turbine Foundations via a Simplified Scour Resistance Test." Journal of Marine Science and Engineering 10, no. 9 (September 17, 2022): 1317. http://dx.doi.org/10.3390/jmse10091317.

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Offshore wind power is rapidly developing as a source of clean energy. However, as local scour of the foundation of an offshore wind turbine can create serious safety risks to the normal operation of the turbine, it is necessary to protect the foundation from scour. In this paper, a new scour protection countermeasure using solidified soil has been investigated via an updated apparatus for a simplified scour resistance test (SSRT). Two types of tests were carried out: an unconfined compressive test to determine geotechnical parameters and an SSRT test to reflect the scour resistance of the soil samples. The results show that unconfined strength is approximately related to the critical flow velocity of the scour resistance as a power function. Soil samples having an unconfined compressive strength of 300 kPa can resist erosion under flow conditions above 3.14 m/s after solidification. In addition, the solidification state of the solidified soil has a great impact on the scour resistance of the soil sample, and the critical scour velocity of the final solidified soil is increased by 80–150% as compared to an initial solidified soil having the same final unconfined strength. These results suggest that attention should be paid to the state of the solidified soil during the construction process. The engineers should control the ratio of cement, water, and soil of the solidified soil according to the hydraulic parameters at the time of construction so that no great loss of solidified soil will occur during the construction process.

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43

Yang, Bo, Kexiang Wei, Wenxian Yang, Tieying Li, Bo Qin, and Liwei Ning. "A Feasibility Study for Using Fishnet to Protect Offshore Wind Turbine Monopile Foundations from Damage by Scouring." Applied Sciences 9, no. 23 (November 21, 2019): 5023. http://dx.doi.org/10.3390/app9235023.

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Анотація:

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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44

Prendergast, L. J., D. Hester, and K. Gavin. "Development of a Vehicle-Bridge-Soil Dynamic Interaction Model for Scour Damage Modelling." Shock and Vibration 2016 (2016): 1–15. http://dx.doi.org/10.1155/2016/7871089.

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Анотація:

Damage detection in bridges using vibration-based methods is an area of growing research interest. Improved assessment methodologies combined with state-of-the-art sensor technology are rapidly making these approaches applicable for real-world structures. Applying these techniques to the detection and monitoring of scour around bridge foundations has remained challenging; however this area has gained attraction in recent years. Several authors have investigated a range of methods but there is still significant work required to achieve a rounded and widely applicable methodology to detect and monitor scour. This paper presents a novel Vehicle-Bridge-Soil Dynamic Interaction (VBSDI) model which can be used to simulate the effect of scour on an integral bridge. The model outputs dynamic signals which can be analysed to determine modal parameters and the variation of these parameters with respect to scour can be examined. The key novelty of this model is that it is the first numerical model for simulating scour that combines a realistic vehicle loading model with a robust foundation soil response model. This paper provides a description of the model development and explains the mathematical theory underlying the model. Finally a case study application of the model using typical bridge, soil, and vehicle properties is provided.

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45

Melville, Bruce W., and Arved J. Raudkivi. "Effects of Foundation Geometry on Bridge Pier Scour." Journal of Hydraulic Engineering 122, no. 4 (April 1996): 203–9. http://dx.doi.org/10.1061/(asce)0733-9429(1996)122:4(203).

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46

Mayall, Russell O., Ross A. McAdam, Richard J. S. Whitehouse, Harvey J. Burd, Byron W. Byrne, Steven G. Heald, Brian B. Sheil, and Phillipa L. Slater. "Flume Tank Testing of Offshore Wind Turbine Dynamics with Foundation Scour and Scour Protection." Journal of Waterway, Port, Coastal, and Ocean Engineering 146, no. 5 (September 2020): 04020033. http://dx.doi.org/10.1061/(asce)ww.1943-5460.0000587.

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47

Ngo, Duc-Vu, Young-Jin Kim, and Dong-Hyawn Kim. "Seismic Fragility Assessment of a Novel Suction Bucket Foundation for Offshore Wind Turbine under Scour Condition." Energies 15, no. 2 (January 11, 2022): 499. http://dx.doi.org/10.3390/en15020499.

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This study proposed a new suction bucket (SB) foundation model for offshore wind turbines (OWT) suitable for a shallow muddy seabed, using more than three single buckets through kinetic derivation. The performance of new optimal foundation was evaluated by its horizontal displacement capacity and compared with a conventional SB composed of three buckets. Under external loads such as earthquakes, wind, and the combination of the both, the stability of this novel SB foundation was verified. The seismic fragility curve was also evaluated at some scour depths. These results were compared with the response of a tripod suction bucket (TSB) foundation, which was also designed for a shallow muddy seabed. The results indicated that scour significantly changed the dynamic response of this novel SB foundation but it had a better bearing capacity than the TSB foundation, despite its smaller size and weight. The fragility of TSB is always higher than the developed foundation in the same environmental condition. With reasonable volume and size, this novel SB foundation has great potential for future industrialization and commercialization.

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48

Liu, Wen Bin, Run Liu, Shu Wang Yan, and Zhi Liang Huo. "Stability Analysis of the Scour Protection Structure for a Debarking Pipeline." Applied Mechanics and Materials 325-326 (June 2013): 1333–36. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.1333.

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The debarking location of a gas pipeline is at the area where typhoons take place frequently and the geotechnical condition of the slope is very complex. A sloping breakwater type structure is selected in this paper for the purpose of pipeline scour protection. Since part of the sloping foundation soil consists of silty clay whose strength is very low, the bearing capacity is checked with the base pressure induced by the breakwater. The stability of the foundation of the breakwater is analyzed with the method developed by Meyerhof. The scour protection structure is proved effective and stable.

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49

Hassan, Zahraa F., Ibtisam R. Karim, and Abdul-Hassan K. Al-Shukur. "Effect of Interaction between Bridge Piers on Local Scouring in Cohesive Soils." Civil Engineering Journal 6, no. 4 (April 1, 2020): 659–69. http://dx.doi.org/10.28991/cej-2020-03091498.

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Local scour at the piers is one of the main reasons of bridge foundation undermining. Earlier research studies focused mainly on the scour at a single bridge pier; nevertheless, modern designs of the bridges comprise wide-span and thus group of piers rather than a single pier are usually used to support the superstructure. The flow and scour pattern around group of piers is different from the case of a single pier due to the interaction effect. Reviewing the literature of local scour around bridge piers group revealed that the local scour around bridge piers group founded in cohesive soil bed was not investigated, and most of the scour studies were related to scour in cohesionless soils. The objective of the present study is to investigate the effect of the interaction between two in-line (tandem) circular bridge piers of variable spacings founded in cohesive soil on the local scour. A set of laboratory flume experiments were conducted under the clear-water scour condition to investigate this effect. This study is the first that investigates experimentally the scour around group of bridge piers in cohesive bed. It was found that the maximum scour depth at the upstream pier of the two in-line piers occurred at a spacing of two times the diameter of the pier, scour at the downstream pier was reduced due to a sheltering effect, the interference effect will be reduced for pier spacings larger than three times of the pier diameter. A recent pier scour equation was used to estimate the scour depths at the two in-line piers in cohesive soil and compare the estimated value with the measured scour depths in the laboratory. The comparison indicated that the proposed scour equation overestimates the scour depths at both the upstream and the downstream pier.

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50

Pearson, David R., J. Sterling Jones, and Stuart M. Stein. "Risk-Based Design of Bridge Scour Countermeasures." Transportation Research Record: Journal of the Transportation Research Board 1696, no. 1 (January 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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