Author(s): Christine S. Lauchlan; Stephen E. Coleman; Bruce W. Melville

Linked Author(s): Stephen E. Coleman, Bruce W. Melville, Christine Lauchlan

Keywords: Local scour; Abutment; Temporal scour; Bridge

Abstract: Laboratory studies were undertaken to assess the temporal development of clear-water local scour depths at bridge abutments in uniform sand beds. A series of experiments was performed using a range of vertical wall abutments to quantify the influence of flow duration on the depth of local scour. Comparison of results is also made with a number of previous local abutment scour studies. Similar to previous studies of temporal local scour at bridge piers, a dimensionless equilibrium time scale is defined, namely t* = t_eV/L, where V = flow velocity and L = abutment length. The data show that both t* and the equilibrium local scour depth dse are subject to the influences of flow, sediment and abutment parameters. An expression is presented for determination of the time t_e for development of d_se for a given abutment, sediment and approach flow velocity, the results indicating that t_e increases with V/V_c and y/L, where V_c = flow velocity for sediment entrainment, and y = flow depth. A second expression enables estimation of the local scour depth ds at any stage during the development of the equilibrium scour hole. The expressions for te and d_s = f (t) are consistent with the findings for temporal development of pier scour.

DOI:

Year: 2001