Improving the Hydraulic Performance of Bridges Using Elliptical Guide Wall (Case Study: Kamar Bridge on Ghezel Ozan River)

Usually¡ in order to reduce the length of river bridges¡ some part of river floodplain is blocked by road body embankment and then width of the river becomes thin when flood happens. Width reduction increases water surface level¡ its velocity and shear stress in the upstream then pier and abutment scour happens and this may destroy the bridge. So¡ guide walls are used to achieve flood safe passage. In this research¡ we try to present guide wall design processes via a case study. Hydrologic studies have been explained briefly as hydraulic studies prerequisite. Initial design has been presented by empirical studies of predecessors and engineering judgment. Several tests were done to achieve final design. Optimal design has been presented by two dimensional numerical simulations on plan that determines hydraulic parameters including water depth¡ longitudinal velocity¡ latitudinal velocity and shear stress. The results showed that flow two dimensional investigation around bridge and guide wall can help us effectively to decide about and achieve safe and economical design.