Assessing energetic flow structures responsible for bridge pier scour

2020 ◽  
Author(s):  
Yi Xu ◽  
Manousos Valyrakis ◽  
Panagiotis Michalis
Keyword(s):  
Bridge Pier ◽  
Bridge Piers ◽  
Flow Structures ◽  
Scour Depth ◽  
Dynamical Process ◽  
Bridge Scour ◽  
Earth Surface ◽  
Mean Flow ◽  
Geophysical Research ◽  
Hydraulic Infrastructure

<p>Scour has been recognized as one of the primary reasons for bridge pier destabilization. As extreme weather intensifies and hydraulic infrastructure such as bridge piers and abutments (many constructed since the Victorian era, for the case of the UK) continues to age, the challenge of scour-induced hazards will keep growing impacting the resilience of our society. Thus, there is an increasing value in studying the highly dynamical process of scour around hydraulic infrastructure. Maximum scour depth estimation has been broadly studied by researchers over the past decades, using phenomenological or empirical approaches, linking mean flow properties, bridge pier and riverbed materials characteristics [1, 2].</p><p>This study aims to get a better understanding of how the turbulent flow field modified by the bridge pier, interacts with the bed surface towards the generation of the scour hole. This is pursued by following a dynamical approach via assessing the flow structures that are sufficiently energetic [3] to remove bed material from the vicinity of the bridge pier.</p><p>A series of scour experiments with different lengthscale of model bridge piers is conducted in a water recirculating research flume. For each of these cases flow velocity profiles are collected downstream the bridge pier using high resolution acoustic Doppler velocimetry (ADV). Using the raw data collected near the bed surface and information for the bed surface material, the criterion of impulse [4] is used as a metric for assessing the extend and maximum scour depth. The results are compared for the different measurement locations are compared to better understand the process of scour downstream different model piers.</p><p>[1]. M Valyrakis, P Michalis, H Zhang, (2015). A new system for bridge scour monitoring and prediction, Proceedings of the 36th IAHR World Congress, 1-4.</p><p>[2]. Yagci, O., Celik, M. F., Kitsikoudis, V., Ozgur Kirca, V.S., Hodoglu, C., Valyrakis, M. , Duran, Z. and Kaya, S. (2016) Scour patterns around isolated vegetation elements. Advances in Water Resources, 97, pp. 251-265.(doi:10.1016/j.advwatres.2016.10.002)</p><p>[3]. Valyrakis, M. , Diplas, P. and Dancey, C.L. (2013) Entrainment of coarse particles in turbulent flows: an energy approach. Journal of Geophysical Research: Earth Surface, 118(1), pp. 42-53. (doi:10.1029/2012JF002354)</p><p>[4]. Valyrakis, M. , Diplas, P., Dancey, C.L., Greer, K. and Celik, A.O. (2010) Role of instantaneous force magnitude and duration on particle entrainment. Journal of Geophysical Research: Earth Surface, 115(F02006), 18p. (doi:10.1029/2008JF001247)</p>

scholarly journals Local Scour of Bridge Pier Sited on a Multi-Layered Sedimentary Bed in Rivers

2020 ◽  
Vol 144 ◽  
pp. 01008
Author(s):  
Shaolin Yue ◽  
Huan Zhou ◽  
Wenlong Zhu ◽  
Minxi Zhang
Keyword(s):  
Local Scour ◽  
Bridge Pier ◽  
Maximum Depth ◽  
Bridge Piers ◽  
Scour Depth ◽  
Bridge Safety ◽  
Particle Sorting ◽  
River Bed ◽  
Weihe River ◽  
Sediment Particles

The riverbeds or sea beds are usually composed of multi-layers of sediments. The scour around bridge piers sited on such beds is vital to the bridge safety, but is still very difficult to be predicated as its complicated interaction between the flow and bed layers. A simple model is proposed in this study for calculating the local scour maximum depth around bridge piers sited on multi-layer of sedimentary bed, which is based on HEC-18 formula revised by Richardson and Davis (2001) and the formula of the repose angle of sediment particles proposed by Cheng (1993). This model considers the particle sorting when the scour proceeds. An application of the model into the local scour depth of Guopan bridge pier sited on the Weihe River bed in Baoji city of China preliminarily demonstrates its reliability to calculate the local scour maximum depth around bridge piers sited on multi-layer of sedimentary bed.

scholarly journals Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3015
Author(s):  
Takuma Kadono ◽  
Sho Kato ◽  
Shinichiro Okazaki ◽  
Toshinori Matsui ◽  
Yoshio Kajitani ◽  
...  
Keyword(s):  
Water Level ◽  
Local Scour ◽  
Bridge Pier ◽  
Angle Of Repose ◽  
Bridge Piers ◽  
Scour Depth ◽  
Water Level Change ◽  
Protection Zone ◽  
Level Change ◽  
In Situ Experiments

To evaluate the stability of bridge piers affected by the local scouring, the existing formulas for estimating the maximum local scour depth have been developed based on the results of experiments conducted under a constant water level. However, the applicability of these formulas to the cases where the water level rises and falls, such as a water level change in a real river, is not clear. In this study, water flow experiments were conducted on cylindrical and oval bridge pier models to investigate the effect of iterated water level change on the progression of local scour around piers. Results of experiments with cylindrical and oval pier showed that the local scour depth and length increased by an iterated action of the water level change; however, these values converged after the number of iterated actions reached a certain time. The local scour length at upstream of the bridge pier was approximately 1.8 times larger than the theoretical value, which was calculated through the local scour depth and angle of repose in water. The local scour length is an important parameter for defining the streambed protection zone, which is one of the measures against local scour, and we showed that the streambed protection zone needs to be defined more widely.

scholarly journals Evaluation of nonparametric tree models for predicting the scour depth of bridge piers

2019 ◽  
Vol 9 (3) ◽  
pp. 1-7
Author(s):  
R. Dalvand ◽  
M. Komasi
Keyword(s):  
Grain Size ◽  
Mean Square Error ◽  
Depth Estimation ◽  
Bridge Piers ◽  
Coefficient Of Determination ◽  
Scour Depth ◽  
Bridge Scour ◽  
Mean Square ◽  
Flow Depth ◽  
Tree Models

One of the main causes of damage to bridges, especially during flood event is the scour around the bridge. Determination of the depth of scour around the bridge piers plays a very important role in designing the bridges against this destructive factor. The complexity of the bridge scour and the effects of different parameters on its estimation more clearly reveal the necessity of using a nonlinear and comprehensive model in this field. In this present study, decision tree models, as nonparametric models, are used to estimate the scour depth. Furthermore, the statistics of different bridges and four tree methods are used. The data used to train and test decision trees including flow the velocity of upstream, the median grain size, flow depth, and the pier width, the skew of the pier to approach flow, the length of the pier, the grain size of bed material for which 84 percent is finer, a multiplying factor, input variables, and the depth of scour as output in the model. 75% of the available data is used for model training and the remaining 25% for testing. The results show that among the four models (CART, C5, QUEST, CHAID) examined, C5 model, considering the comparison of the root mean square error parameters and the coefficient of determination, is more accurate in computing the scour depth of the bridge, the amount coefficients of determination in this model is in training and testing steps are 0.92 and 0.76, as well as the mean square error values of the error is 0.56 and 0.72 respectively. Furthermore, the results reveal the QUEST model does not have a proper accuracy in scour depth estimation. Furthermore, the analysis of the models shows flow depth, the flow velocity in the upstream have the greatest effect on the scour depth.

scholarly journals Application of Improved GMDH Models to Predict Local Scour Depth at Complex Bridge Piers

2020 ◽  
Vol 6 (1) ◽  
pp. 69-84 ◽  
Author(s):  
Habibeh Ghodsi ◽  
Mohammad Javad Khanjani
Keyword(s):  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Group Method ◽  
Scour Depth ◽  
Empirical Equations ◽  
Depth Prediction ◽  
Pile Cap ◽  
Data Points ◽  
Statistical Criteria

Scour depth prediction is a vital issue in bridge pier design. Recently, good progress has been made in the development of artificial intelligence (AI) to predict scour depth around hydraulic structures base such as bridge piers. In this study, two hybrid intelligence models based on combination of group method of data handling (GMDH) with harmony search algorithm (HS) and shuffled complex evolution (SCE) have been developed to predict local scour depth around complex bridge piers using 82 laboratory data measured by authors and  615 data points from published literature. The results were compared to conventional GMDH models with two kinds of transfer functions called GMDH1 and GMDH2. Based upon the pile cap location, data points were divided into three categories. The performance of all utilized models was evaluated by the statistical criteria of R, RMSE, MAPE, BIAS, and SI. Performances of developed models were evaluated by experimental data points collected in laboratory experiments, together with commonly empirical equations. The results showed that GMDH2SCE was the superior model in terms of all statistical criteria in training when the pile cap was above the initial bed level and completely buried pile cap. For a partially-buried pile cap, GMDH1SCE offered the best performance. Among empirical equations, HEC-18 produced relatively good performances for different types of complex piers. This study recommends hybrid GMDH models, as powerful tools in complex bridge pier scour depth prediction.

scholarly journals Non-Intrusive Underwater Measurement of Local Scour Around a Bridge Pier

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2063 ◽  
Author(s):  
Poggi ◽  
Kudryavtseva
Keyword(s):  
Low Cost ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Laser Source ◽  
Scour Depth ◽  
Spatial Evolution ◽  
Clear Water ◽  
Water Conditions ◽  
Scour Hole ◽  
Temporal And Spatial

A non-intrusive low-cost technique for monitoring the temporal and spatial evolution of the scour hole around bridge piers is presented. The setup for the application of the technique is simple, low-cost and non-intrusive. It couples a line laser source and commercial camera to get a fast and accurate measurement of the whole scour hole in the front and behind the bridge pier. A short campaign of measurements of the scour hole around a bridge pier in clear-water conditions is presented to provide a control test and to show how to apply the new method. Finally, the results are compared with two of the most used equations, for the time evolution of the maximum scour depth in clear-water conditions, to show the effectiveness of the proposed technique.

Reduction of local scour around a bridge pier by using different shapes of pier slots and collars

2020 ◽  
Vol 20 (3) ◽  
pp. 1006-1015 ◽  
Author(s):  
A. Bestawy ◽  
T. Eltahawy ◽  
A. Alsaluli ◽  
A. Almaliki ◽  
M. Alqurashi
Keyword(s):  
Three Dimensional ◽  
Laser Scanner ◽  
Local Scour ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Contour Maps ◽  
Reduction Methods ◽  
Analysis System ◽  
Bridge Failure

Abstract Local scour around bridge piers is one of the main causes of bridge failure all over the world. Experimental and hydraulic models were carried out to investigate two types of scour reduction methods around a single cylindrical pier, namely the pier's slots and collars. The efficiency of various types of pier slots and circular collars around the pier's base in reducing scour were studied. A new shape of a conical collar was developed by the authors and examined along with other shapes. The results revealed that collars, in general, have more influence in reducing scour depth than slots made in the front and rear of bridge piers. The sigma-slot acts better than other tested slots, with a reduction in the scour depths of 59.3% and 52.8% at the upstream and downstream of the pier, respectively. On the other hand, the conical collar appeared to be the most effective collar shape in reducing the scour around the bridge pier, with a 61.1% reduction in the scour depth downstream of the pier. A three-dimensional laser scanner was used to capture the bed topography at the end of each experiment and contour maps of the deformed bed were produced. A one-dimensional Hydrologic Engineering Center-River Analysis System model was developed with a single bridge pier to predict the scour depth around the pier in an attempt to introduce new values for the pier nose shape factor, , which describes the tested piers.

scholarly journals Effects on Scour for Different Foundation Geometry of Compound Circular Bridge Piers

2019 ◽  
Vol 8 (2) ◽  
pp. 2439-2446
Keyword(s):  
Experimental Study ◽  
Rate Of Change ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Flowing Water ◽  
Sound Design ◽  
Flow Conditions ◽  
The Past ◽  
Bridge Failure

This experimental study examines the variation of scour depth with time of Clearwater scour condition around compound circular bridge piers for steady flow conditions. Most of the circular bridge piers are resting on the bigger diameter caissons known as the compound circular bridge piers and are widely used in India for construction of road and railways bridge across the rivers. In past studies, it has been observed that most bridge failure occurs because of scouring due to flowing water around a bridge pier across a river. Most of the past studies were done on the uniform bridge pier and a very few studies have been done so far on scouring around non-uniform bridge piers. Estimation of scour depth is required for the economical and a sound design of bridge pier foundation. In present study, an experimental investigation has been done in a tilting flume for computation of rate of change of depth of scour with time at two different models of compound circular bridge piers by varying the foundation top position with respect to level of bed, i.e., 1. The foundation top at the level of bed, and 2. The foundation top below the level of bed (viz. 10mm, 20mm, 30mm and 40mm) for uniform sediments.

scholarly journals Experimental Study of Inclined Bridge Pier Scouring

2020 ◽  
Vol 39 (4) ◽  
pp. 859-870
Author(s):  
Fakhar Muhammad Abbas ◽  
Usman Ali Naeem ◽  
Usman Ghani ◽  
Amina Khan ◽  
Talat Farid Ahmad
Keyword(s):  
Experimental Study ◽  
Inverse Relationship ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Clear Water ◽  
Lower Strength ◽  
Flow Rates ◽  
Laboratory Flume ◽  
Horseshoe Vortices

The bridges are one of important structures in any country. The failure of bridges occurs due to many factors including design flaws and manufacturing construction errors. Among all imperfections scouring around the pier is the most detrimental. So, the estimation of local scouring around a bridge pier is of fundamental importance for the safe design of bridges. Although numerous researches have been done on local scouring around a single bridge pier. The present study investigates the effect of angle of inclination of dual bridge pier configuration on local scouring around bridge piers. Principally rectangular shaped dual bridge piers were installed in sand bed of laboratory flume at angle of inclination of 0°,7°,12°,15° and 19° with vertical respectively. Three different flow rates 9, 14 and 18L/sec were considered during each trial. The duration of each trial was kept around 2 hours. The scour depth was measured separately around both piers with the help of point gauge under clear water condition. The value of scour depth around upstream pier was larger as compared to downstream pier because of the lower strength of horseshoe vortices around downstream pier. From the experimental results, it can be concluded that there is an inverse relationship between the angle of inclination and scour depth, an increase in the angle of inclination leads to decrease in scour depth around both piers. The value of scour depth was maximum when piers were at 0° and minimum at 19°. It was also found that scour depth increases with the increase in flow rate.

scholarly journals Optimum Design for Controlling the Scouring on Bridge Piers

2019 ◽  
Vol 5 (9) ◽  
pp. 1904-1916 ◽  
Author(s):  
Abdul-Hassan K. Al-Shukur ◽  
Manar Hussein Ali
Keyword(s):  
Experimental Investigation ◽  
Optimum Design ◽  
Bridge Pier ◽  
Physical Models ◽  
Bridge Piers ◽  
Optimum Shape ◽  
Scour Depth ◽  
Bridge Failure

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%. 

scholarly journals Prediction of Bridge Pier Scour Depth and Field Scour Depth Monitoring

2018 ◽  
Vol 40 ◽  
pp. 03007
Author(s):  
Fong-Zuo Lee ◽  
Jihn-Sung Lai ◽  
Yuan-Bin Lin ◽  
Kuo-Chun Chang ◽  
Xiaoqin Liu ◽  
...  
Keyword(s):  
Numerical Model ◽  
Real Time ◽  
Earthquake Engineering ◽  
Model Simulation ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Scour Depth ◽  
Pier Scour ◽  
River Bed ◽  
Bridge Pier Scour

In practice, it is a major challenge in real-time simulation and prediction of bridge pier scour depth, especially using 3-D numerical model. The simulation time spend too much to use 3-D numerical model simulation and inefficiently to predict bridge pier scour depth in real-time. With heavy rainfall during flood season in Taiwan, abundant sediment with flash flood from upstream watershed is transported to downstream river reaches and transportation time is limited within one day. The flood flow tends to damage bridge structures and affect channel stabilization in fluvial rivers. In addition, the main factors affecting the erosional depth around bridge piers and river bed stabilization are hydrological and hydrographic characteristics in river basin, the scouring and silting of river bed section near the bridge piers, the bridge geometry and protection works of bridge piers. Therefore, based on the observed rainfall data provided by the Central Weather Bureau and the hydrological conditions provided by the Water Resources Agency during flood event as the boundary condition, we develop an effective simulation system for scour depth of bridge piers. The scour depth at the bridge pier is observed by the National Center for Research on Earthquake Engineering for model calibration. In this study, an innovative scour monitoring system using vibration-based Micro-Electro Mechanical Systems (MEMS) sensors was applied. This vibration-based MEMS sensor was packaged inside a stainless sphere with the proper protection of the full-filled resin, which can measure free vibration signals to detect scouring/deposition processes at the bridge pier. It has demonstrated that the measurement system for monitoring bridge scour depth evolution is quite successful in the field.

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