Scour at Wide Bridge Piers

Evaluation of Pier-Scour Predictions for Wide Piers Using Field Data

“…Most of these class, such as the ratio of water depth to structure diameter (y/b), can be kept constant between the model from laboratory and the prototype structure. Nevertheless, as there is a lower limit on the sediment particle size before cohesive forces become crucial, those class involving sediment size cannot be kept constant between the prototype and model [1]. If the sediment-to-structure-length scales are not correctly calculated for in the predictive formulas, problems will occur when the formulas are used in conditions which differ from the laboratory situations on which they are built.…”

“…If the sediment-to-structure-length scales are not correctly calculated for in the predictive formulas, problems will occur when the formulas are used in conditions which differ from the laboratory situations on which they are built. The problems will be related to the model not being able to maintain the proper scale between model and prototype sediment as the size of the prototype structure increases [1]. This condition always occurs in huge gravity structures such as in the case of large coastal and inland bridge piers.…”

“…[5] established an upper threshold at y/b = 3 beyond which the depth of scour is relatively independent of the relative depth. However, [1] conducted experiments with large piers which indicate that the threshold should be closer to 2, although data below these thresholds are included in a number of empirical formulas that overestimated prototype scour depths. There are various researchers who have attempted to deal with this problem.…”

“…(3). Jones and Sheppard equations [1] include the b/d50 ratio and thus should be directly applicable to large structures (wide piers). They concluded that the pier width affects the equilibrium scour depth in two methods.…”

The Environmental Implications of Sediment Transport in the Waters of Prince Rupert, British Columbia, Canada: A Comparison Between Kinematic and Dynamic Approaches

“…In 1988 Jones and Sheppard, 2000 [34] developed the Superposition of Scour Components Method of Analysis for complex piers. Each of the scour components is computed from the basic pier scour equation using an equivalent sized pier to represent the irregular pier components, adjusted flow depths and velocities as described in a list of variables, and height adjustments for the pier stem and pile group.…”