Abstract
Bridge pier scour threatens the stability of bridges. Several approaches practiced counterbalancing the base of piers from scour, but the use of a collar with protection is considered as effective countermeasure. Present study examines the scour around rectangular cross-sectional pier by applying a rectangular hooked collar, under clear water condition. Various dimensions of hooked collar wall height to hooked collar width (H-w/H-wh = 0.05 to 0.30) at the bed level are experimentally tested. To quantify the effectiveness of the scour protection, the result of unprotected rectangular pier is referenced. Similar trend is observed in all the side wall height that by changing the wall height from 0.3Wp scour starts increasing. Likewise, by reducing the width of the hooked collar up to 1.5Wp equilibrium scour depth is observed to be significantly decreased. Further, the laboratory experimental runs showed that width of 1.5Wp along with side wall height of 0.3Wp is the most effective dimension for a hooked collar which may be utilized for rectangular unprotected piers. Lastly, the most suitable configuration reduced almost 52.2% of scouring depth compared to referenced experimental run.