Computer Aided Analysis of Flow through River Bridges: Fid-Bau Portal

Computer Aided Analysis of Flow through River Bridges

Yanmaz, A. Melih / Bulut, Ferdi

The major failure mode of a bridge results mainly from hydraulic deficiencies in the design. Flow conditions through bridge openings should be investigated to observe the degree of hydraulic conformity for the given structural system. A computer program is developed to carry out hydraulic and structural computations jointly for bridges crossing rivers having irregular cross-sections with flood plains. The program has analysis and design options. In the analysis part of the program, steady state water surface profile through a specified bridge opening is obtained. Four different types of bridge opening, which are characterized by geometric features of abutments and embankments, are considered in the program. The energy and momentum approaches are used in the flow analysis. The program is capable of performing computations for low and high flows through the bridge opening. The analysis option can be executed under various discharges to observe the possibility of upstream choking, formation of hydraulic jump in close vicinity of the bridge opening, and to estimate the maximum depths of scour around bridge piers and abutments. The design part of the program is based on the determination of slab deflection, number of piers, sizes of piers and abutments and depths of footings of piers and abutments. The specifications of the American Association of State Highways and Transportation Officials (AASHTO) and Turkish codes are used in the structural analysis. With the use of the program, various combinations of span lengths and pier sizes can be tested from hydraulic and structural safety viewpoints. An application is presented to illustrate the use of the program.