Six legged concrete (SLC) elements as scour countermeasures at wing wall bridge abutments

Abstract

ABSTRACT Previous research studies have shown that abutment scour makes a major contribution to bridge failures. Protecting bridges against scour is, therefore, a priority need. For existing bridges, armouring methods, such as riprap, have a wide application. In the areas where providing stones is expensive, concrete blocks or similar techniques are often used. In the present study, the application of the Six Legged Concrete (SLC) elements was experimentally investigated. The SLC elements were placed in three different densities (open, medium and dense) at three different placement depths (h/l = 0, 0.5 and 1; where h is the element installation height above the bed and l is element height). Each alternative was tested under different flow conditions for a wing-wall abutment. In general, the results showed that the SLC elements can considerably reduce the scour under different flow conditions. In an optimal arrangement, the elements reduced the scour depth at abutment nose up to 100%. The maximum reduction of scour depth was obtained when the SLC elements were placed densely on the bed (h/l = 1).