Bulbous Pier: An Alternative to Bridge Pier Extensions as a Countermeasure against Bridge Deck Splashing

Bridge deck splashing causes deterioration to a bridge’s structure and renders the bridge unsafe for motorists and pedestrians. The traditional countermeasure for bridge deck splashing has been pier extension. Pier extensions move the pier wave and the associated splash away from the bridge deck, but retrofitting existing bridges with pier extensions is costly. This research evaluates the use of a bulbous added to the pier as an alternative to pier extension. A bulb placed on the upstream side of a bridge pier affects the splashing. The energy in the passing water is redirected from the impact by streamlining the flow. This study proposes a mathematical model for bulbous pier design, based on a model used for a mono-hull ship. Under the mono-hull model, the bulb length extends, reaching the region where viscous resistance is dominant. Unlike wave-making resistance, which is achieved through modeling, the proposed model does not require modeling to calculate pier wave reduction.