Experimental investigation of local scour around circular bridge piers under steady state flow conditions

Abstract

Local scour around bridge piers is one of the main causes of bridge failures. In this study, scour depths and scour hole geometries around circular bridge piers were investigated under clear water scour conditions for various flow rates. The experiments were carried out in a rectangular flume 80 cm wide, 18.6 m long and 75 cm high by using uniform sediment with a median diameter of 1.63 mm and geometric standard deviation of 1.3. The flow rates and approach flow depths were measured with an electromagnetic flow meter and ultrasonic level sensors, respectively. A new empirical equation for the determination of scour depth is proposed based on the experimental findings of the present study and on experimental data available in the literature. The experimental results were also compared with those calculated using several empirical equations developed by previous studies. The proposed new equation to predict scour depth around a circular bridge pier was evaluated in terms of determination coefficient (R2) and scatter index (SI). The Fisher (f)test was also applied to test the statistical significance of the proposed equation.

The Variation of Scour Depth near Vertical and Inclined Cylindrical Bridge Piers: An Experimental Study

“…The evaluation was conducted according to the accuracy results of each formula using the statistical analysis by mean absolute percentage error (MAPE). As it is apparent in Table 3, the minimum value of MAPE is 3.839%, and it occurs in accordance with the estimated scour depth by Aksoy and Eski [21], so the present results of experiments support using this formula, which can be written as follows:…”

“…Generally, the decrease in scour depth proportional to strength of downward flow near the pier and the difference in the interaction between approach velocity vector and the angle of pier (ϴ), the increase (ϴ) would lead to reduce the strength of downward flow near the pier face due to separation of the approach velocity into two components as compared with one normal component for vertical pier. Table 3 illustrates the obtained results of scour depth for vertical pier as compared with that estimated by the most common formulas from previous studies [5,[18][19][20][21]. These formulas have been concluded for wide range of experiments and hydraulic condition.…”

“…To develop new empirical formula for scour depth estimation with inclined piers, this study adopted the modification of the empirical formula concluded by Aksoy and Eski [21] using the coefficient of inclination of pier (Kϴi). Figure 5 shows the trending curves of (Kϴi) for V/Vc = 0.495 to 0.989, and 10° ≤ ϴ ≤ 22°, this figure can give a good estimation for the value of (Kϴi) required to consider the effect of pier inclination.…”

Investigation of Local Scour Hole Dimensions around Circular Bridge Piers under Steady State Conditions

“…Local scour around bridge piers is the one of the main reasons of the bridge failures. There are many studies related to scour depth estimation [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]. But there is still a lack of studies related to scour hole dimension estimation.…”

Effects of the skew angle and road embankment length on the hydraulic performance of bridges on compound channels

“…Bridges are the most important and costly communication components in transportation systems. Since the most serious riverbridge destruction factor during floods is the scouring around its foundation and abutments (Aksoy & Eski 2016), knowing the scour-affecting factors such as the flow pattern and bed shear stress is vital.…”