Aerodynamic Admittance Research on Wide-body Flat Steel Box Girder
Abstract: Aerodynamic admittance is a key parameter affecting the analysis accuracy of the bridge buffeting response. However, few articles have covered the issue of the wide-body flat box girder with much smaller depth-width ratio (such as 1/12 studied in this paper). Therefore, to explore the real buffeting force of the wide-body flat box girder, experiments of the static force coefficients and aerodynamic admittance are carried out in wind tunnel. Wooden segmental model has a scale ratio of 1/60 to an actual 42 m wide suspension bridge girder. Using the high-frequency-force-balance (HFFB) equipment fixed with the segmental model under the conditions of different wind speeds and different wind attack angles, wind power spectrums of the buffeting force are measured and the variation of aerodynamic admittance parameters is analyzed. The results show that the aerodynamic admittance of the box girder measured in the experiment with this so much smaller depth-width ratio differs from the corresponding classical Sears expression. Some inspiration can be presented for the future study of the buffeting response for this kind of much wider bridge with the similar ratio in this paper.
Aerodynamic admittance functions and buffeting forces for bridges via indicial functions
Abstract Buffeting forces on bridge decks are commonly modelled by Sears’ function. However, it is well known that Sears’ function is reliable only for very streamlined bridge deck sections and that a complete model would require a suitable formulation of buffeting forces in time domain. In this paper, self-excited and buffeting loads are modelled by means of indicial functions. Corresponding aerodynamic admittance functions are numerically evaluated for rectangular sections and compared with experimental and analytical results. A complete time-domain model for cross-sections including vertical turbulence is presented. Numerical simulations are performed on a sample rectangular section. Comparison with experimental results and relevant flutter analyses are also discussed.
Using Infrared Thermography to Detect Moisture in Historic Masonry: A Case Study in Indiana
Nondestructive testing mapped water infiltration in the decoratively painted interior of a Masonic Temple in Muncie, Indiana.