نتایج جستجو برای: local scour

تعداد نتایج: 533069  

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...

Journal: :journal of rehabilitation in civil engineering 2014
mohammad mehdi razmi mojtaba sanei cyrus ershadi

scour around hydraulic structures is an inevitable phenomenon . recognition of this phenomenon and dealing with it is an issue considering which will ensure the project success . local scour at piers has been reported as the most important factor in the destruction of the bridges . the use of submerged and non-submerged piles is one of the scour control methods . submerged piles have been rarel...

F Omidi M Saneie R Fazlola

One of the important issues in hydraulic engineering is inspection of local scour depth around bridge pier. Using piles is one of the ways for confronting local scour and erosion. In this study, the experiments were conducted in an 8m long, 0.5m deep and 0.25m wide flume. And the effectof using piles and number of them observed on the amount of scour in three different Frude numbers. The shape ...

Journal: :تحقیقات مهندسی کشاورزی 0
رضا عزیزی استادیار گروه مهندسی آب، دانشکده کشاورزی، دانشگاه زنجان محمود شفاعی بجستان استاد گروه سازه های آبی، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز مهدی قمشی استاد گروه سازه های آبی، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز

the shape of a submerged vane is a major factor in the design of a vane system and affects the performance and secondary currents generated by the vanes. this study investigated the effect of five vane shapes on bed sediment processes (local scour at the leading edge and transverse distribution of sediment downstream of the vanes) at four flow intensities for a total of 20 experiments. the resu...

2014
S. A. Begum A. K. Barbhuiya

Local scour around bridge abutment is a common problem encountered worldwide. Extensive laboratory and field studies have been carried out in this field and the equations derived so far are applicable to particular circumstances only. This paper presents an alternative to the empirical equations for Prediction of Local Scour at Vertical Bridge Abutment in the form of genetic programming (GP). T...

N. A. Obied, S. I. Khassaf

The most important causes of bridge failure are local scour. In this study, laboratory experiments were conducted to investigate the effectiveness of slot as a protection device in reduction of depth of scour at cylindrical piers under clear water flow conditions. The development time of scour depth at the circular pier with and without a slot as a protection device was conducted. The experimen...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1391

in this study, scour of mashkid bridge pier located in mashkid river of saravan county has been studied and to measure the scour rate, the numerical model hec-ras 4.0 has been used. upon selection of mashkid river as the case study and whereas the studied zone is important with respect to the climatic conditions and showery monsoon raining and flowing the great and destructive floodwaters, ther...

حسین افضلی مهر, , محسن نادری بنی, , منوچهر حیدرپور, ,

The use of slot through a pier is a new method proposed to control local scour at bridge piers. In this study, control of local scour at bridge pier is studied using 20 pier models under clear water conditions. The models consist of one circular pier without slot, three round-nosed piers without slot, and 16 piers with slot. Two slot lengths were chosen (yl=b and yl=2b, where y1 is the length o...

2014
Md Abdullah Al Faruque Frank Hanna

Laboratory tests were carried out to assess the local scour by three-dimensional wall jets from a square crosssection nozzle. To this end, three different tailwater depths were used and the jet expansion ratio was held greater than ten. Velocity measurements were conducted using a one component laser Doppler anemometer. The jet exit Reynolds number was maintained to 1x10 and this value can be c...

Journal: :journal of agricultural science and technology 2010
s. kouchakzadeh

most previous laboratory studies of local scour at bridge abutments were performed in rectangular channels in which the distributions of flow velocity and bed shear stress were considered uniform in the transverse direction. in reality however, bridge abutments are usually located in the floodplain zone of rivers where velocity and shear stress distributions are directly affected by the lat...

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