Wind Tunnel Test Study of Aerostatic Drag Shielding Factor of a Truss Bridge Section

Author(s):  
Qinghai Guan ◽  
Xin Che ◽  
Jiawu Li ◽  
Jianxin Liu ◽  
Youqin Huang
2012 ◽  
Vol 446-449 ◽  
pp. 3092-3095
Author(s):  
Ji Zhou ◽  
Yuan Ming Dou ◽  
Xi Yuan Liu ◽  
Ji Shu Sun

The majority of low-rise buildings are generally susceptible to wind damage in previous wind disaster, thus it is necessary to gain understanding of the characteristics of wind pressure for these types of building. Based on Wind Tunnel Test, the shape coefficients were studied with pressure measurement on gable roofs laying aside purlin of low-rise building roof in this paper. Three aspects were arerespectively discussed: the lows of shape coefficients and the shape coefficient value with specific wind angle on roofs of the houses completely closed, the house opened doors and windows and the house opened the hole on roof with different wind angle. The laws of shape coefficients were propounded for low-rise buildings with different positions of openings in contrast to load code. A detailed analysis of the experimental results shows that the shape coefficients will increase notably when there are the openings on metope and on roof, and the one is outward of roof, another is inward of roof. It is expected that the results should be valuable for the wind-resistance design of low-rise buildings.


2021 ◽  
pp. 136943322199249
Author(s):  
Huan Li ◽  
Xuhui He ◽  
Liang Hu ◽  
Guoji Xu

This study presents an investigation to quantify the aerodynamics of truss bridge-girders via wind tunnel test and kriging surrogate model. Currently, the conventional methods documented in design specifications only take into consideration the mean drag force at null attack angle. To gain an in-depth understanding on the aerodynamics of truss bridge-girders, experiments on simplified bridge-girder models with various geometric parameters were carried out in uniform flow. A total of 15 truss bridge-girder models with aspect ratio (the ratio of width to height) B/D = 1.0, 1.3, 1.6, 1.9, and 2.2, solidity ratio (the ratio of projected to envelope areas) Φ = 0.20, 0.25, 0.30, 0.35, and 0.40, and two typical truss topologies (Warren and Pratt trusses) were examined in the most concerned range of wind angle of attack α = [–6°, 6°]. These truss bridge-girder models cover most of the high-speed railway bridges widely used in China. Experimental results show that the truss topology has limited effects on the aerodynamics of truss bridge-girders, whereas the effects of α, B/D, and Φ are significant. Based on these wind tunnel results, the ordinary kriging surrogate model was utilized to approximate the aerodynamics of truss bridge-girders. In using this model, aerodynamic force values for test cases can be interpolated with zero variance and uncertainties in unsampled design zones where geometric parameters can be quantified with Gaussian variance.


2014 ◽  
Vol 488-489 ◽  
pp. 813-816
Author(s):  
Min Duan ◽  
Jia Qi Wang ◽  
Xiu Zhen Wang ◽  
Ping Shi Li

In response to the estimation of the peak values of wind pressure on the maintenance structure, the results with TTU low-rise building standard model of different methods are analyzed and compared. The results show: the results of peak-to-average method and Cook & Mayne method are very close for the long sample estimation of the peak values of wind pressure, the former is the most ideal method for estimation of extreme wind pressure; For short sample estimation, the peak-to-average method fails because the sampling is not long enough, but the Cook & Mayne method can estimate accurate peak value of wind pressure by the short sample (the corresponding prototype time not less than 600s); The peak factor method based on the assumption of normal distribution is not applicable to low-rise building and the results are relatively dangerous.


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