Study On The Style Of Apron Protection Against Scour At Piers And Abutments Of Shallow Foundation Bridge

Inadequate pier foundation depth caused by flooding scour is a major cause of the destruction of bridges around the world. Whether the bridge pier protection project can withstand the test of floods, achieve the desired protection effect, not only depend on the category of protection, but also on its construction type, location and size. Plenty of domestic and international experimental study on protection of bridge pier scour showed that apron can effectively reduce pier scour, but there isn’t universal law can be used to guide the type design of apron. Currently, there are a lot of shallow foundation bridges need to set a local scour protection in our country, so the relevant research has important and practical significance.This paper combed the concepts and theories of bridge pier scour and protection, systematically summarizes the flow structure around pier, scour mechanism, research achievement of local scour protection issues。Using river model test methods studied the optimal apron types. The study analyzes the impact of apron design parameters on local scour protection effect, when the apron near the general erosion line and for the specific project proposed reasonable apron types.Analyzing experimental data of the river model test, some results were as following:The type design of apron should comprehensively consider the apron planar form, the depth of top surface, extension length of apron head, protection width, inclination apron skirt and other design parameters’ influence on the apron protection effect; and then determine the final apron protection type size.Set apron around the pier as local scour protection project is feasible, when comparing with unprotected piers and, scour depth in front of the bridge pier and bridge pier side reduced by more than 50%, which proves that scour protection effect is obvious.