Temporal Evolution of Clear-Water Local Scour at Aligned and Skewed Complex Bridge Piers

被引:39
作者
Yang, Yifan [1 ]
Melville, Bruce W. [1 ]
Macky, Graham H. [1 ]
Shamseldin, Asaad Y. [1 ]
机构
[1] Univ Auckland, Dept Civil & Environm Engn, Private Bag 92019, Auckland 1142, New Zealand
关键词
TIME; SCALE; GEOMETRY; DEPTH;
D O I
10.1061/(ASCE)HY.1943-7900.0001732
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
Scour at bridge piers is time-dependent. In this paper, temporal evolution of clear-water scour at complex bridge piers is studied experimentally. The pier model has a typical form comprising three components, namely a rectangular column, a rectangular pile-cap, and a group of vertical piles underneath. Various relative pile-cap positions and skew angles (alpha) from 0 degrees to 45 degrees were used to investigate their influence on scour evolution. New functions are proposed to fit temporal data and determine the equilibrium scour depth with better accuracy. The results show that the locations for scour initiation and the maximum scour depth may be different, and their relationship varies with pile-cap position and pier skew angle. Highly skewed piers tend to overcome the influence of width ratio of column to pile-cap (Dc/Dpc) on scour evolution, as the column itself becomes dominant. The sensitivity of scour evolution to pier skew angle decreases with higher pile-cap position, especially when it is entirely above the original bed. Four scour development stages were identified for complex piers, including initiation, stagnation, a developing stage, and equilibrium, with each stage being highly dependent on the degree of exposure of each of the pier components. The description of each development stage for different situations is given. The equilibrium time scale t* and the equilibrium scour depth dse for complex piers have similar dependence on flow shallowness ratio (y0/De) and sediment coarseness ratio (De/d50), as per the equation proposed by an authors' previous study (Yang et al. 2018). A new equation is proposed to correct the percentage rate of scour development. The correction is especially useful for aligned complex piers, for which the rate of scour time development may be much lower than that for single-column piers. In general, we recommend using the modified Sheppard-Melville method and the corrected time-scale equation in this paper to predict clear-water equilibrium scour depth and scour evolution at complex bridge piers.
引用
收藏
页数:15
相关论文
共 44 条
[1]  
[Anonymous], 1980, THESIS
[2]  
[Anonymous], P IEEE RSJ INT C INT
[3]   Scour Hole Influence on Turbulent Flow Field around Complex Bridge Piers [J].
Beheshti, A. A. ;
Ataie-Ashtiani, B. .
FLOW TURBULENCE AND COMBUSTION, 2016, 97 (02) :451-474
[4]   Experimental Study of Three-Dimensional Flow Field around a Complex Bridge Pier [J].
Beheshti, A. A. ;
Ataie-Ashtiani, B. .
JOURNAL OF ENGINEERING MECHANICS, 2010, 136 (02) :143-154
[5]  
Bertoldi D. A., 1998, P STREAM STAB SCOUR, P181
[6]   Effects of time and channel geometry on scour at bridge abutments [J].
Cardoso, AH ;
Bettess, R .
JOURNAL OF HYDRAULIC ENGINEERING-ASCE, 1999, 125 (04) :388-399
[7]  
Chabert J., 1956, Etude des affonillements author des piles des ponts
[8]   Evolution of scour depth at circular bridge piers [J].
Chang, WY ;
Lai, JS ;
Yen, CL .
JOURNAL OF HYDRAULIC ENGINEERING, 2004, 130 (09) :905-913
[9]  
Chiew Y. M., 1984, Local scour at bridge piers
[10]   Clear-water scour development at bridge abutments [J].
Coleman, SE ;
Lauchlan, CS ;
Melville, BW .
JOURNAL OF HYDRAULIC RESEARCH, 2003, 41 (05) :521-531