Case Study: New Zealand Bridge Scour Experiences

Abstract

Details of three case studies of scour damage for New Zealand bridges are presented. These cases cover ranges of bed materials, flood magnitudes, and river morphologies, and illustrate a range of scour processes occurring at bridge foundations. The case study details facilitate evaluation of proposed bridge scour calculation methodologies. Such a proposed methodology for the assessment of scour depths at a bridge site is illustrated for the presented case studies. The resulting scour predictions highlight the value of a judicious use of the proposed methodology, the effect of sediment supply and transport balance considerations for engineering projects, aspects of river morphology to be considered in bridge foundation design, and that the combination of various components of scour needs to be considered when assessing bridge scour.