CFD-Based Model for Estimating the River Bed Morphological Characteristics near Cylindrical Bridge Piers Due to Debris Accumulation

2021 ◽  
Vol 48 (5) ◽  
pp. 763-773
Author(s):  
Aysar Tuama Al-Awadi ◽  
Mahmoud Saleh Al-Khafaji
Keyword(s):  
Morphological Characteristics ◽  
Bridge Piers ◽  
Debris Accumulation ◽  
River Bed

scholarly journals MORPHOLOGICAL CHARACTERISTICS OF THE GIANH RIVER (FROM CO CANG TO CUA GIANH) IN RELATION TO THE EROSION AND ACCUMULATION

2019 ◽  
Vol 18 (4) ◽  
pp. 384-392
Author(s):  
Hai Nguyen Tien ◽  
Dang Vu Hai ◽  
Phuc La The ◽  
Ha Nguyen Thai
Keyword(s):  
River Flow ◽  
Dominant Role ◽  
Morphological Characteristics ◽  
Straight Channel ◽  
Meandering Channel ◽  
Braided Channel ◽  
River Bed ◽  
Erosion And Accretion ◽  
Channel Bar

On the basis of morphological characteristics and erosion - accumulation of sediment, it is possible to divide the stretch of the Gianh River from Co Cang to Cua Gianh (about 54km in length) into 3 sections as follows: Meandering channel (from Co Cang to Tien Xuan Isles): the length of the channel is 27.69km and the width of the channel is 80-250m. The channel is in the form of a meandering, narrow riverbed, flow plays a dominant role, deposition activities develop strongly at the convex side, while erosion occurs strongly in the concave side (cut side); Braided channel (from Tien Xuan Isles to Quang Phu): the length of the channel is 17.06km and the width of the channel is 800-2,200m. The channel is straight, the river bed is large and the depth of the river bed is 2-11m. Sedimentation occurs mainly at the bottom of the channel and creates bar in the middle of the channel; Straight channel (from Quang Phu to Cua Gianh): the length of the channel is 9.23km and the width of the channel is 800-1,000m. The channel is straight and the depth of the river bed is 8-12.5m. In addition to the role of river flow, it is strongly influenced by marine dynamics. The erosion and accretion activities occur mainly in estuaries. The results above show trend of river development: i) Meandering channel is the most vulnerable to changes for morphology of channel by erosion and accretion of sediment and can create 1-2 horseshoe pools by the river change line; ii) Braided channel mainly changes in the bottom of channel by the formation of channel bar; iii) Straight channel mainly changes in the estuary (the mouth of the river can be moved, enlarged or narrowed).

UAV Based Multi-Hazard Vulnerability Assessment System for Bridges Exposed to Scour

2020 ◽  
Author(s):  
Okan Özcan ◽  
Orkan Özcan
Keyword(s):  
Load Capacity ◽  
Time History ◽  
Element Model ◽  
Lateral Load ◽  
Assessment System ◽  
Bridge Piers ◽  
Scour Depth ◽  
River Bed ◽  
Principal Axes

<p>Evaluating the multi-hazard performance of river crossing bridges under probable earthquake, flood, and scouring scenarios is a cumbersome task in performance-based engineering. The loss of lateral load capacity at bridge foundations may induce bridges to become highly vulnerable to failure when the effects of scour and floods are combined. Besides, the assessment of local scouring mechanism around bridge piers provides information for decision‐making regarding the pile footing design and for predicting the safety of bridges under critical scoured conditions. Thereby, accurate high-resolution Digital Elevation Models (DEMs) are critical for many hydraulic applications such as erosion, hydraulic modelling, sediment transport, and morphodynamics. In the present study, an automated unmanned aerial vehicle (UAV) based multi-hazard performance assessment system was developed to respond to rapid performance evaluation and performance prediction needs for river crossing reinforced concrete (RC) bridges. The Bogacay Bridge constructed over Bogacay in Antalya, Turkey was selected as the case study. In the developed system, firstly the seasonally acquired UAV measurements were used to obtain the DEMs of the river bed from 2016 to 2019. The transverse cross sections of the river bed that were taken close to the inspected bridge were used to measure the depth of the scoured regions along the bridge piles under the present conditions. Separately, in conjunction with the flood simulation and validation with 2003 flood event (corresponds to Q<sub>50</sub>=1940 m<sup>3</sup>/s), the scour depth after maximum probable flood load according to the return period of 500 years (Q<sub>500</sub>=2560 m<sup>3</sup>/s) were predicted by HEC-RAS software. Afterwards, the 3D finite element model (FEM) of the bridge was constituted automatically with the developed code considering the scoured piles. The flood loads were exerted on the modeled bridge with regard to the HEC-RAS flood inundation map and relevant water depth estimations around the bridge piers. For the seismic evaluation, nonlinear time history analyses (THA) were conducted by using scaled eleven scaled earthquake acceleration records that were acting in both principal axes of the bridge simultaneously by considering maximum direction spectra (SaRotD100) as compatible with the region seismicity. In the analyses; as the scour depth increased, the fundamental periods, shear forces and the bending moments were observed to increase while the pile lateral load capacities diminished. Therefore, the applicability of the proposed system was verified using the case study bridge.</p>

Study of Bridge Foundation Performance Under Dynamic Loading

1974 ◽  
Vol 11 (3) ◽  
pp. 409-419
Author(s):  
Robert B. Dodds ◽  
G. V. Ganapathy
Keyword(s):  
Bridge Piers ◽  
Bridge Structure ◽  
Railway Bridge ◽  
River Bed ◽  
Bridge Responses ◽  
Remedial Work ◽  
Bridge Foundation ◽  
Drill Holes ◽  
Work Done ◽  
Train Loading

Seismographic equipment was used to study the response of a railway bridge under dynamic train loading and thereby to determine the performance of the foundations of the bridge. The same methods were used to determine the effectiveness of remedial work done on the bridge piers and on the subsoil beneath the piers.The bridge was constructed in 1898 and is a three-span, masonry and stone arch bridge, 273 ft (83.2 m) in length. The east abutment is founded on bedrock, however, the west abutment and two piers in the river bed are founded on deep alluvial deposits.Seismographic studies indicated relatively large movements of one pier which were attributed to foundation scouring. A program of grouting the pier subgrade confirmed this assessment. Subsequent seismographic studies confirmed the effectiveness of the remedial works undertaken. The studies of the bridge responses under dynamic train loading provided sufficient data that scour areas beneath a pier could be pinpointed.The technique applied on this project determined bridge pier foundation conditions much more quickly and economically than a normal program of exploratory drill holes. The same technique could be used to assess the behavior of individual components of a bridge structure.

scholarly journals METHODS OF IMPROVING THE EFFICIENCY OF MONITORING OF CHANNEL DEFORMATIONS OF MOUNTAIN RIVERS NEAR BUILT-IN SETTLEMENTS: ON THE EXAMPLE OF THE BUKTYRMA RIVER

2018 ◽  
Vol 44 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Talgat TAUKENOV ◽  
Kulchikhan DZHANALEEVA ◽  
Zhuldyz YERZHANOVA
Keyword(s):  
Public Space ◽  
Morphological Characteristics ◽  
Control Measures ◽  
Mountain Rivers ◽  
Channel Processes ◽  
Channel Deformations ◽  
Geoinformation Systems ◽  
The Earth ◽  
River Bed ◽  
Scientific Justification

The results of research on the development of methods for increasing the efficiency of monitoring the channel deformations of mountain rivers using the methods of aerospace studies of the Earth and geoinformation systems are presented. Examples are given of estimating channel deformations, compiling morphological characteristics of the valley, floodplain and river bed, determining the scheme for the development of channel processes using public space imagery, scientific justification for erosion control measures.

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 Prediction of maximum scour depth around piers with debris accumulation using EPR, MT, and GEP models

2016 ◽  
Vol 18 (5) ◽  
pp. 867-884 ◽  
Author(s):  
Mohammad Najafzadeh ◽  
Mohammad Rezaie Balf ◽  
Esmat Rashedi
Keyword(s):  
Polynomial Regression ◽  
Gene Expression Programming ◽  
Laboratory Data ◽  
Experimental Studies ◽  
Local Scour ◽  
Bridge Piers ◽  
Scour Depth ◽  
Effective Parameters ◽  
Pier Scour ◽  
Debris Accumulation

Pier scour phenomena in the presence of debris accumulation have attracted the attention of engineers to present a precise prediction of the local scour depth. Most experimental studies of pier scour depth with debris accumulation have been performed to find an accurate formula to predict the local scour depth. However, an empirical equation with appropriate capacity of validation is not available to evaluate the local scour depth. In this way, gene-expression programming (GEP), evolutionary polynomial regression (EPR), and model tree (MT) based formulations are used to develop to predict the scour depth around bridge piers with debris effects. Laboratory data sets utilized to perform models are collected from different literature. Effective parameters on the local scour depth include geometric characterizations of bridge piers and debris, physical properties of bed sediment, and approaching flow characteristics. The efficiency of the training stages for the GEP, MT, and EPR models are investigated. Performances of the testing results for these models are compared with the traditional approaches based on regression methods. The uncertainty prediction of the MT was quantified and compared with those of existing models. Also, sensitivity analysis was performed to assign effective parameters on the scour depth prediction.

scholarly journals A method for evaluating local scour depth at bridge piers due to debris accumulation

2020 ◽  
Vol 173 (2) ◽  
pp. 86-99 ◽  
Author(s):  
Mohsen Ebrahimi ◽  
Slobodan Djordjević ◽  
Diego Panici ◽  
Gavin Tabor ◽  
Prakash Kripakaran
Keyword(s):  
Local Scour ◽  
Bridge Piers ◽  
Scour Depth ◽  
Debris Accumulation

scholarly journals Effect of debris accumulation on scour evolution at bridge pier in bank proximity

2021 ◽  
Vol 69 (1) ◽  
pp. 108-118
Author(s):  
Michele Palermo ◽  
Simone Pagliara ◽  
Deep Roy
Keyword(s):  
Bridge Piers ◽  
Scour Depth ◽  
Structural Failure ◽  
Clear Water ◽  
River Bank ◽  
Debris Accumulation ◽  
Equilibrium Morphology ◽  
Satisfactory Prediction ◽  
Prediction Capability ◽  
Water Depths

AbstractLarge debris transported by flood affects scour features at bridge piers and increases the risks of structural failure. Geometric characteristics of the debris and the relative position of the pier with respect to the river bank are important parameters for the scour process. The interaction between the water flow and debris accumulation increases the shear stress, turbulence and consequently enhances the scour depth at the pier. This paper aims at analyzing such effects on scour evolution at bridge piers. To this end, two series of tests were carried out under clear water condition with different debris geometries and percentage blockage ratios. Experimental evidences showed that the pier position only influences scour evolution and equilibrium morphology for low water depths. Conversely, its effect becomes negligible for scour at bridge piers with debris accumulation and higher water depths. Useful practical relationships have been derived, with satisfactory prediction capability of the scour evolution for all the tested configurations.

Vulnerability of bridge piers to general and local erosion of river bed

ce/papers ◽  
2018 ◽  
Vol 2 (2-3) ◽  
pp. 499-504
Author(s):  
Verka PROLOVIĆ ◽  
Zoran BONIĆ ◽  
Nebojša DAVIDOVIĆ ◽  
Elefterija ZLATANOVIĆ ◽  
Nikola ROMIĆ
Keyword(s):  
Bridge Piers ◽  
River Bed ◽  
Local Erosion
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