A TEMPORAL, SPATIAL PIER SCOUR MODEL

Civil engineers are faced with problems involving all aspects of aging infrastructure. One area in critical need of attention is the design, monitoring, and maintenance of bridge piers where local pier scour is a concern. The scour depth at a particular time during the design life of a bridge is a function of the flow-duration characteristics of storms that occurred before the time of interest. Current scour models and equations provide a single-valued estimate of the ultimate scour depth for a design discharge; the engineer does not have a time-dependent estimate of the scour depth. The objective of this study was to develop a conceptual, time-dependent pier scour model and a methodology to assess the risk of bridge failure because of pier scour over the life of the bridge. The time-dependent pier scour model was formulated and calibrated with laboratory data and observations as well as field observations. The time dependency enables the engineer to estimate the scour depth at any time during the life of the bridge.