نتایج جستجو برای: scour reduction

تعداد نتایج: 493198  

Journal: :مهندسی عمران فردوسی 0
حسین خزیمه نژاد مهدی قمشی یوسف رمضانی

scour around bridge piers is one of the most important fields of hydraulic research. local scour around bridge piers and abutment is one of the main reasons of bridge failures. in the field of scour at the bridges, researches are more focus on scour of piers in compare with abutment. while the available information on the bridge failures required cost, the major problems are related to abutment...

ژورنال: علوم آب و خاک 2011
داود فرسادی زاده , , علی حسین زاده دلیر, , پریا شجاعی, ,

Submerged vanes are low aspect ratio flow-training structures mounted vertically on the river bed at an angle to the prevailing flow. The aim of application of vane is to generate a secondary circulation in the main flow, designed to modify the near-bed flow pattern and thus redistribute flow and sediment transport within the channel cross section. Collar is a flat sheet with low thickness fixe...

An experimental study has been conducted on the effectiveness of two types of flow-altering countermeasures placed around a cylindrical pier under clear water condition, which include sacrificial piles and submerged vanes. Their arrangements follow the optimal configurations recommended in the published articles with some modification. The temporal evolution of maximum scour depth and its equil...

2009
Abdel-Azim M. Negm

Scour downstream (DS) of hydraulic structures (HS) may endanger the safety of the structures if the necessary precuations are not considered during the design stage. Normally, different measures produce different effects on reducing the maximum scour depth DS of HS. One of the important HSs is the abruptly enlarged (or sudden expanding) stilling basins. In this paper, the effects of different a...

A.A Dehghani M.R Pirestani T Esmaeili Tetsuya Sumi

Local scouring around bridge piers is a natural phenomenon caused by the erosive process of flowing stream on alluvial beds. The 3D flow field around bridge piers interacting with the bed materials increases complexity of local scour process. The local scour depth develops in accelerated flows and if it is not predicted correctly, the bottom level of local scour hole will exceed the original le...

Journal: :Marine pollution bulletin 2011
Richard J S Whitehouse John M Harris James Sutherland Jon Rees

Analysis and interpretation of monitoring data for the seabed bathymetry local to offshore windfarm foundations has shown how the scour develops in time and highlighted variations between sites with different seabed sediment characteristics, i.e. sands and clays. Results from European offshore windfarms have generated a unique dataset for comparison with previously published data. Where surfici...

2014
Shatirah Akib Noor Liana Mamat Hossein Basser Afshin Jahangirzadeh

The present study examines the use of collars and geobags for reducing local scour around bridge piles. The efficiency of collars and geobags was studied experimentally. The data from the experiments were compared with data from earlier studies on the use of single piles with a collar and with a geobag. The results showed that using a combination of a steel collar and a geobag yields the most s...

2009
Y. A. Hamed M. H. El-Kiki A. M. Mirdan

Scour in bed material downstream weirs is considered the most unfavorable process which threats the overall stability of the weir. Weirs with oblique angle in the horizontal plan will affect the scour profile downstream the structure and may reduce it. The objective of this paper is to investigate the effect of oblique weir angle on the scour profile. Furthermore, the effect of V-notch angle on...

2017
Wen-Dar Guo Jian-Hao Hong Cheng-Hsin Chen Chih-Chiang Su Jihn-Sung Lai

The modeling of flood-induced bend scour near embankment toes can provide important information for river engineering, embankment safety warnings, and emergency action management. During the rainy seasons, short-term general scour and bend scour are the most common causes for the failure of reinforced concrete embankments in Taiwan. To gain a deeper understanding of the scouring process near le...

2007
A. M. Negm Y. A. Mohamed

Failures barrages or parts of them may be expected when excessive scour patterns are observed downstream of such structures. Severe and excessive scour may be largely due to unsymmetric operation of gates especially when a multi-vents barrage or regulator is being considered. Previous investigations proved that the scour patterns downstream hydraulic structures are functions of the bottom veloc...

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