3749

3543

كارشناسي ارشد

آب

اصفهان: دانشگاه صنعتي اصفهان، دانشكده عمران

1386

[نه]، 106، [II]ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

محمدرضا چمني

محمدكريم بيرامي

04/09/86

عبدالرضا كبيري، منوچهر حيدر پور

1396/03/07

كتابنامه

عمران

مهندسي عمران

ID3543

به فارسي و انگليسي: قابل رؤيت در نسخه ديجيتال

AbstractMost bridges are damaged for the reason of scouring usually A lot of methods have beenused to reduce scour depth These methods are classified in two main groups The firstmethod is increasing the bed material resistance against the flow power The second oneis to reduce the effect of erosion operatives that the main examples for this method areusing slot or collar The main problem of the second group is that we can not raisingscouring completely by using it without any other application In this thesis we want toimprove the scouring hole and time with using the new shapes of collar For this purposewe have to experiment the last shapes of collars that are tried with other researchers 2times of pier width and 3 times of pier width and compare the results with results of fourthe new shapes of collar that are proposed with us The experimental model was carried out in Fluid Mechanics Laboratory in the Civilengineering department in Isfahan University of Technology Rectangle flume withlength of 11 meters and 405 millimeters wide and 700 millimeters height has been usedfor experiments Teflon tube with diameter of 40 millimeters was used as the pier Thebed material was consists of uniform sand with diameter of 600 to 800 micron andspecific gravity of 2 65 Collars that used for experiments was collar with diameter of towtimes of the pier diameter collar with diameter of three times of the pier diameter collarnumber 1 circle with inside outgrowth collar number 2 eccentric circle with pier collar number 3 combination of semicircle and square and collar number 4 oval shape The criterion that used for equilibrium depth was criterion of Kummar et all 1999 Experiments showed that scouring begin in relative shear velocity of 0 5 for case ofwithout collar 0 53 for the case of collar with diameter of tow times of the pier diameter 0 61 for the case of collar number 1 and for other shapes of collar this amount is 0 58 The time development curve can be divided to three main parts that are lag time thatscour hole haven t reached to pier steal the middle time that scouring expand rapidly and the final part that scouring expand slowly From a reducing scour depth viewpointthe best collar was collar number 3 with 45 percent decreasing and the worst one wascollar with diameter of tow times of the pier diameter with 16 percent decreasing of scourdepth From a increasing equilibrium time viewpoint collar number 2 with 261 percentand collar with diameter of tow times of the pier diameter with 9 8 percent increasingtime related to the case of without collar were the best and worst shapes of collar Thecollar shapes that are proposed in this research don t prevent scouring completely but fordelaying of scour process are very effective and can be used in operational application asa suitable instrument for reducing damage of bridge pier scouring

محمدرضا چمني

محمدكريم بيرامي

عبدالرضا كبيري، منوچهر حيدر پور