PSI - Issue 3

Alberto Lorenzon et al. / Procedia Structural Integrity 3 (2017) 370–379 A. Lorenzon et al. / Structural Integrity Procedia 00 (2017) 000–000

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Figure 1 - Time histories of C D (Huang et al. (2007))

4.2. Long span bridges -

In Mannini et al. (2016), (2010) the authors have performed 2D Unsteady RANS of the flow field around a trapezoidal box-girder bridge section. Even if these models show some limit, it has been shown that they are able to predict correctly most complex flow features, while requiring low computing resource. - In Sarwar et al. (2008) and in Watanabe and Fumoto (2008) the authors conducted LES analyses of box girder bridge sections. Both analyses have shown a very good agreement with experimental data. - In Scotta et al. (2016) the authors proposed an engineering procedure that uses numerical analyses based on CFD models to bypass wind-tunnel tests in order to calculate aerodynamic and aeroelastic parameters of bridges subject to wind. The authors were able to obtain a good estimate of many parameters of primary importance ( c p , c D , c’ L , c’ M St ) and evaluated the numerical procedure to be suitable as an alternative to wind tunnel tests for bridge design, at least in its initial phase. 4.3. Large roofs - In Lu et al. (2012) the flow field around a large roof was studied and the authors reported that LES models correctly predict mean and RMS pressure coefficients. The ability to conduct LES analyses for full-scale size model, to use large Reynolds numbers and to capture high pressure gradients in small areas makes this method particularly attractive also in comparison to wind tunnel tests. 5. Discussion and conclusions The analysis of published results have shown that CFD methods are able to provide an adequate estimate of the aerodynamic and aeroelastic parameters in many cases of civil engineering interest and therefore they could be used in place of wind tunnels within the frequency domain-based methods for the calculation of the accumulation of wind-induced fatigue damage. Regarding the use of CFD methods with models for the calculation of wind-induced fatigue damage in the time domain, it is outlined that the CFD models could be used as a basis for the definition of synthetic time series generated by stochastic Monte Carlo methods. Moreover, the cycle counting carried out directly from the time series of pressures obtained as a result from CFD analyses may be developed in analogy to what has been done in Flamand et al. (1996) (ensuring that the spectral resonant components of wind action are correctly identified). Because of the