Study On The Aerodynamic Parameters Of Truss Members Of Bridges

Aerostatic performances of truss girders and arch ribs under wind are investigated by using wind tunnel testing and numerical simulations in this thesis.A sectional model test with a double deck truss type section (MinPu Bridge) is carried out. Two-dimensional aerodynamic forces of the sectional model under the cross wind normal to the deck are identified. 2-D and 3-D numerical simulations for identification of the aerodynamic forces of the section are performed. The testing results are compared with those from 2-D and 3-D simulations. For the deck of this type, the aerodynamic performance under skew wind is not clear because of the complexity of truss structures. The aerostatic performances of the deck under skew wind are tested by a skew wind force measuring device. The comparison of the deck under skew wind and normal wind are compared in the end.The drag coefficients of members of truss structure are defined in Wind-resistant Design Specification for Highway Bridges. The relations between the drag coefficients and the solid area rations and the sheltering effects of truss structures are also established. In this chapter, different solid area ratios and sheltering effects of truss structures are studied. The changes of drag coefficients of truss members are obtained. At the same time, a series of wind tunnel testing of paratactic square columns are carried out. The testing results are compared with those from numerical simulations, as well as the clauses from Wind-resistant Design Specification for Highway Bridges. At the end of this chapter, the amendment suggestions for these clauses are given.Aerostatic performance of arch ribs with the sections of a single tubes, double tubes, triple tubes and four tubes are identified through numerical simulations at the end of the thesis.