Temporal Evolution of Local Scour Depth around Side-by-side Piers

Due to geotechnical and economic considerations, bridge designs often lead to use complex piers or pier groups. The estimation of temporal evolution of scour around bridge pier is important for design of bridge foundation. This study focuses on temporal variation of scour depth around two side-by-side piers with various distances between piers. Based on experimental data, an equation was developed based on new definition of equivalent pier diameter in Kothyari et al. (2007) equation for estimating the time evolution of scour depth by taking into account the effect of space between the piers. The results show that good agreement exists between proposed equation and measured scour data. It is also revealed that by increasing the distance between piers, the equilibrium scour depth around side by side piers decreases and close to values of single pier and scour depth reached to the isolated pier when G/D=6.