17. Wind Buffeting in Time Domain


The Verification Example 12. Wind Buffeting in Time Domain has the objective to provide theoretical background, testing, and validation of the wind buffeting solution in time domain implementation in RM Bridge. This additional development in the area of wind dynamics analysis was needed to allow the combination of wind and water results for floating bridges. As currents, waves, and floatation loadings are key to any floating bridge this becomes more computationally demanding for higher spans, and high spans are very susceptible to winds. With the introduction of cable and suspension bridges supported on TLP - Tension Leg Platforms, this has become particularly important. The implementation is based at a QSS - Quasi-Steady State where the buffeting and aerodynamic forces are expressed with coefficients and additional structural damping. 

       

As shown above, the validation example is based on a structural model of a simply supported beam; and for this Wind load type, a Wind Grid is created in the bridge longitudinal and vertical plane to allow its assignment to respective elements and nodes, and the load's application and variation in time. The Schedule and loadings, including the Wind properties, and WINDD are explained, as exemplified below. 

    

Comparison with theoretical and frequency domains results are suitable and a very good agreement is found concluding that both linear and non-linear loads are now available for a fully coupled analysis involving wind buffeting, hydrodynamic forces, wave and current loads, and other time, acceleration, velocity, and displacement dependent loads.

    

Much more extensive technical information can be found in the Verification Example document Wind Bufeting in Time Domain.pdf and by running the dataset "WindBuffeting.tcl"