Abstract
A new method called SRICOS is proposed to predict the scour depth z versus time t around a cylindrical bridge pier of diameter D founded in clay. The steps involved are ; 1. taking samples at the bridge pier site, 2. testing them in an Erosion Function Apparatus called the EFA to obtain the scour rate z versus the hydraulic shear stress applied $\tau$, 3. predicting the maximum shear stress r max which will be induced around the pier by the water flowing at ν Ο before the scour hole starts to develop, 4. using the measured z versus r curve to obtain the initial scour rate zi corresponding to r max , 5. predicting the maximum depth of scour zmax for the pier, 6. using zi and zmarx to develop the hyperbolic function describing the scour depth z versus time t curve, and 7. reading the z vs. t curve at a time corresponding to the duration of the flood to find the scour depth which will develop around the pier. A new apparatus is developed to measure the z vs t curve of step 2, a series of advanced numerical simulations are performed to develop an equation for the $\tau$ max value of step 3, and a series of flume tests are performed to develop an equation for the zmax value of step 5. The method is evaluated by comparing predictions and measurements in 42 flume experiments.