Experimental study about scour protection at circular piers

• Alix Moncada Universidad de los Andes-Venezuela
• Julián Aguirre Pe Universidad de los Andes-Venezuela
• Juan Bolívar Universidad de los Andes-Venezuela
• Edgar Flores Universidad de los Andes-Venezuela

Resumo

In this paper an experimen tal study of scour around a pier is carried out. The effect produced by a collar around a circular pier and by the perforation of a slot as devices for controlling the depth of scour was analyzed. Uniform sand with mean diameter of 1.4 mm and a circular pier of 7.3 cm diameter were used. Firstly, two collars of 14.6 and 21.9 cm diameter were employed. The collar was placed around the pier at different positions with regard to the bed level. Subsequently, a slot of 1.8 cm thickness and variable length was perforated at the pier. Finally, experiments were carried out to study the effect produced by the combination of a collar and a slot. It is found that when the collar is placed at the bed level the minimum depth of scour is produced. It is obtained that the scour depth is reduced when the diameter of the collar is increased. For the case of the slot, it is found that the most favorable location to decrease the local scour is obtained by placing the slot near the bed. On the other hand, it is obtained that when the length of the slot increases, the scour depth decreases. For the combination of collar and slot, the scour depth was reduced al together.