Experimental study of local scour around diamond bridge piers subject to transverse standing waves

Abstract

Numerous bridges around the world have been destroyed due to local scour around their piers and abutments. Transverse standing waves (perpendicular to the flow direction) generated by obstacles, such as bridge piers, can affect the extent of local scour around piers and abutments. Since this topic has not been investigated so far, this study aimed to investigate the effect of the first mode of the transverse standing waves on the local scour around diamond bridge piers under different hydraulic conditions. For this purpose, three different pier groups of 3 × 4, 2 × 4, and 1 × 4 were used in the experiments, where each of the two figures represents the number of columns and rows, respectively. The results showed that transverse standing waves increased the maximum depth of local scour around the piers. The maximum scour depths obtained from the transverse standing wave experiments in the 3 × 4, 2 × 4, and 1 × 4 pier groups were, respectively, 17, 24, and 16% higher than the experiments without transverse waves. This study has found that the wave amplitude increased by increasing the number of piers in each row. Moreover, in each pier group, increasing the wave amplitude led to an increase in the scour depth.

Keywords

• Local scour
• Transverse standing waves
• Diamond piers
• First wave mode