نتایج جستجو برای: time development of scour depth

تعداد نتایج: 21355274  

2016
Jian-Hao Hong Wen-Dar Guo Cheng-Hsin Chen Ataur Rahman

The evolution of bridge pier scour is very important for bridge safety warning and assessment. During typhoon seasons in Taiwan, the torrential river flow often causes scour monitoring instruments to fail in their attempt to measure the temporal variations of pier scour depths. To better understand the scouring phenomenon during a large flood event, this study proposes a fast and reliable metho...

2003
Robert Ettema Tatsuaki Nakato

The paper describes the range of scour types that may occur at bridge abutments, and addresses the extensive attendant difficulties confronting accurate estimation of abutment-scour depth. The difficulties, which include similitude aspects of laboratory experiments on scour at bridge abutments, complicate the development of reliable scour-estimation relationships. In a practical sense, the diff...

Journal: :journal of water sciences research 2011
t esmaeili a.a dehghani m.r pirestani 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...

2012
Sabita Madhvi Singh P. R. Maiti

Local scour around a cylindrical pier in a channel with an erodible bed or natural bed is a common problems in bridge or pile supported structure. The highly unsteady complex flow field around a circular pier produces scour hole mainly for the presence of vortices. The main mechanism that drives the formation and evolution of the scour hole around bridge pier is horse shoe vortex motion. In the...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم انسانی و اجتماعی 1389

today the image of a permanent skeletal space of cities affected by some forces or mechanisms is put in time with social-economic development and while imposes a new face and perspective to physical anatomy of cities, and prepares field to changes in content and social- economic structures of cities too. simultaneously with quitting villages in order to settle in cities by villagers, the phen...

2010
Farhad Ansari

Local bridge scour is caused by the interference of bridge piers with the flow of water and is characterized by the formation of scour holes. Local scour occurs at a bridge pier when the local flow field is strong enough to remove bed materials. Several variables affect the scour depth including the flow intensity, the relative flow depth, the pier-width, and the properties of the river bed mat...

2013
Prabhat Dahal Dongming Peng Yaoqing Yang Hamid Sharif

Bridge Scour is one of the major causes of bridge failures all around the world and there have been significant efforts for its detection and measurement using different acoustic approaches. In this paper, we propose and investigate an effective method to utilize Received Signal Strength (RSS) for measuring scour depth where acoustic sensors are deployed. We also extend a statistical testing to...

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی - دانشکده علوم اجتماعی 1393

the present study is paid to the evaluation of the welfare program of the unemployment insurance in iran. the main purpose which was the main reason for performing this thesis, was the unemployment insurance plan’s challenges in iran such as financial problems of this plan, prolongation of the credit receipt for some insured people, unemployment slow exiting from the unemployment insurance fund...

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