جستجو در تالارهای گفتگو

Evaluating Various Factors in Calculation of Scour Depth around Bridge Piers Using HEC-RAS Software, CSU2001 and Froehlich Equations Original Article, C59 Mousavi S.F and Daneshfaraz R. Journal. Civil Eng. Urban. 3(6):398-402. 2013 ABSTRACT:Today, scour is one of the important issues in river and coastal engineering science. Most of the existing structures exposed to the flowing water are destroyed by this phenomenon. Determining relationship between parameters influencing scour depth and maximum depth of scour, and also finding dominant function of them is one of the important issues in hydraulic engineering. Many equations and software have been presented by researchers to calculate local scour, such as Hec-Ras software. Ignorable errors of this software in vitro test make it one of the nominated options in evaluating local scour depth. Hec-Ras software uses CSU and Froehlich (1991) equations to calculate local scour. In this study, software output and manual calculation output of CSU and Froehlich equations were compared. Results of empirical equations and Hec-Ras in the scattering length of Haraz River were compared with each other to create equal hydrological and hydraulic conditions. Reviewing the Froude number, its measurement, and the effective coefficients of common empirical equations and software has significant effect on changes of these parameters in the results. The study also indicate that equations used in Hec-Ras will have acceptable results if their coefficients are examined with sufficient engineering , accurate perspective and controlling use or non-use of coefficients in ranges closer to the defined boundary. Keywords:Local Scour, Empirical Equations of Local Scour, Froude Number, Bridge Pier, Hec-Ras منبع: [Hidden Content] دانلود: [Hidden Content].,59-398-402.pdf J. Civil Eng. Urban.,59-398-402.pdf

The Effect of Geometric Parameters and Foundation Depth on Scour Pattern around Bridge Pier Original Article, C25 Eghbali P, Dehghani A.A, Arvanaghi H, Menazadeh M. Journal. Civil Eng. Urban. 3(4):156-163. 2013 ABSTRACT:Scour around bridge foundations is one of the major causes of serious damage to the bridge. In this study, the effect of shape, level and position angle of foundation on scour pattern was investigated experimentally. The experiments were conducted for 4 foundation shapes including; square, cylinder, aerodynamic along and across the channel, 5 foundation depths and 7 foundation alignments. The results show that the scour depth depends on the foundation depth, shape and foundation alignment to the approach flow. The best foundation shape which leads to minimum scour, was aerodynamic shape along the channel, square, aerodynamic across the channel and cylindrical shape, respectively. The results also show that positioning of foundation below the initial channel bed, leads to less values of scour depth around bridge pier. Also the best angle for positioning of foundation is zero, i.e. parallel to flow direction. Analyses of results also show that the appropriate level for positioning the foundation is 25 to 50 % pier diameter below the channel bed. Keywords:Local Scour, Non-Uniform Bridge Pier, Foundation Shape, Foundation Depth, Position Angle of Foundation منبع: [Hidden Content] دانلود: [Hidden Content].,25-156-163.pdf J. Civil Eng. Urban.,25-156-163.pdf