scholarly journals EVALUATION OF EXTERNAL WIND PRESSURE COEFFICIENTS FOR THE MAIN WIND FORCE RESISTING SYSTEMS OF LOW-RISE STEEL STRUCTURES BASED ON LOAD EFFECTS

2021 ◽  
Vol 27 (67) ◽  
pp. 1171-1176
Author(s):  
Seiya GUNJI ◽  
Yasushi UEMATSU ◽  
Kosuke SATO
Keyword(s):  
Steel Structures ◽  
Wind Pressure ◽  
Wind Force ◽  
Pressure Coefficients ◽  
Load Effects

DESIGN WIND PRESSURE COEFFICIENTS FOR LOW-RISE GABLE-ROOFED STEEL BUILDINGS

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Seiya Gunji ◽  
Kosuke Sato ◽  
Yasushi Uematsu
Keyword(s):  
Time History ◽  
Bending Moment ◽  
Maximum Load ◽  
Wind Pressure ◽  
Steel Buildings ◽  
Wind Force ◽  
Pressure Coefficients ◽  
History Of ◽  
Load Effects ◽  
Building Standards

The present paper discusses the wind pressure coefficients for the main wind force resisting systems of low-rise gable-roofed steel buildings, based on a wind tunnel experiment and a two-dimensional frame analysis. The wind pressure coefficients should be determined so that they reproduce the maximum load effects. Here, focus is on the bending moments involved in the members as the load effects. The Load Response Correlation (LRC) method is employed for evaluating the equivalent static wind pressure coefficients. Using the time history of wind pressure coefficients, the maximum load effects were computed for all combinations of frame location and wind direction. The results indicate that the most critical condition occurs on the windward frame in a diagonal wind. The largest bending moment was compared with that predicted from the wind pressure coefficients specified in the Japanese building standards, which are based on the area-averaged mean wind pressure coefficients. Finally, more reasonable wind pressure coefficients for designing the main wind force resisting systems are proposed.

scholarly journals Probability Characteristics, Area Reduction, and Wind Directionality Effects of Extreme Pressure Coefficients of High-Rise Buildings

2021 ◽  
Vol 11 (15) ◽  
pp. 7121
Author(s):  
Shouke Li ◽  
Feipeng Xiao ◽  
Yunfeng Zou ◽  
Shouying Li ◽  
Shucheng Yang ◽  
...  
Keyword(s):  
Probability Distribution ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Extreme Pressure ◽  
Distribution Law ◽  
Distribution Fitting ◽  
Pressure Coefficients ◽  
High Rise ◽  
Area Reduction ◽  
The Mean

Wind tunnel tests are carried out for the Commonwealth Advisory Aeronautical Research Council (CAARC) high-rise building with a scale of 1:400 in exposure categories D. The distribution law of extreme pressure coefficients under different conditions is studied. Probability distribution fitting is performed on the measured area-averaged extreme pressure coefficients. The general extreme value (GEV) distribution is preferred for probability distribution fitting of extreme pressure coefficients. From the comparison between the area-averaged coefficients and the value from GB50009-2012, it is indicated that the wind load coefficients from GB50009-2012 may be non-conservative for the CAARC building. The area reduction effect on the extreme wind pressure is smaller than that on the mean wind pressure from the code. The recommended formula of the area reduction factor for the extreme pressure coefficient is proposed in this study. It is found that the mean and the coefficient of variation (COV) for the directionality factors are 0.85 and 0.04, respectively, when the orientation of the building is given. If the uniform distribution is given for the building’s orientation, the mean value of the directionality factors is 0.88, which is close to the directionality factor of 0.90 given in the Chinese specifications.

CFD Modeling of Pressure Coefficients for a Natural Ventilation Study in an Experimental Low Rise Building

2013 ◽  
Author(s):  
Robel Kiflemariam ◽  
Cheng-Xian Lin
Keyword(s):  
Natural Ventilation ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Analytical Models ◽  
Cfd Modeling ◽  
Engineering Practice ◽  
Pressure Coefficients ◽  
Wind Pressure Coefficient ◽  
Detailed Assessment ◽  
Ventilation Rates

Mean wind pressure coefficient (Cp) is one of the major input data for natural ventilation study using building energy simulation approach. Due to their importance, they need to be accurately determined. In current engineering practice, tables and analytical Cp models only give mostly averaged results for simpler models and configurations. Considering the limitation of tables and analytical models, Computational Fluid Dynamics (CFD) could provide a means for an accurate and detailed assessment of Cp. In this paper, we make use of a relatively high resolution, detailed experiments done at Florida Intentional University to validate a CFD modeling of the pressure coefficients Cp. The results show that existing CFD model has a good agreement with experimental results and gives important information of distribution of Cp values over the surface. The local values of the Cp are investigated. In addition, the CFD derived Cp and discharge coefficient (Cd) values are utilized in semi-analytical ventilation models in order to get a more accurate value of ventilation rates.

Wind tunnel test on mean wind forces and peak pressure acting on ellipsoidal nacelles of wind turbine

2021 ◽  
pp. 0309524X2110445
Author(s):  
Hiroshi Noda ◽  
Takeshi Ishihara
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Peak Pressure ◽  
Wind Tunnel Test ◽  
Load Case ◽  
Wind Force ◽  
Pressure Coefficients ◽  
Force Coefficients ◽  
Design Load ◽  
Mean Pressure

Mean wind forces and peak pressures acting on ellipsoidal nacelles are investigated by wind tunnel tests. The wind force coefficients of the ellipsoidal nacelles for the wind turbine design and the peak pressure coefficients for the nacelle cover design are proposed based on the experimental data. The wind force coefficients are expressed as functions of yaw angles. The proposed formulas are compared with Eurocode, Germanischer Lloyd and ASCE7-16. It is found that the mean wind force coefficients for the wind turbine nacelles are slightly underestimated in Eurocode. The equivalent maximum and minimum mean pressure coefficients are proposed for use in Design Load Case 6.1 and Design Load Case 6.2 of IEC 61400-1. The peak pressure coefficients are derived using a quasi-steady theory. The proposed equivalent maximum and minimum mean pressure coefficients are much larger than those specified in Germanischer Lloyd.

scholarly journals Calibrating Partial Factors – Methodology, Input Data and Case Study of Steel Structures

2019 ◽  
Author(s):  
Vitali Nadolski ◽  
Árpád Rózsás ◽  
Miroslav Sýkora
Keyword(s):  
Input Data ◽  
Structural Reliability ◽  
Construction Materials ◽  
Steel Structures ◽  
Structural Performance ◽  
Limit States ◽  
Different Types ◽  
Load Effects ◽  
Previous Design

Partial factors are commonly based on expert judgements and on calibration to previous design formats. This inevitably results in unbalanced structural reliability for different types of construction materials, loads and limit states. Probabilistic calibration makes it possible to account for plentiful requirements on structural performance, environmental conditions, production and execution quality etc. In the light of ongoing revisions of Eurocodes and the development of National Annexes, the study overviews the methodology of probabilistic calibration, provides input data for models of basic variables and illustrates the application by a case study. It appears that the partial factors recommended in the current standards provide for a lower reliability level than that indicated in EN 1990. Different values should be considered for the partial factors for imposed, wind and snow loads, appreciating the distinct nature of uncertainties in their load effects.

scholarly journals Study of Wind Loads and Wind Speed Amplifications on High-Rise Building with Opening by Numerical Simulation and Wind Tunnel Test

2020 ◽  
Vol 2020 ◽  
pp. 1-24
Author(s):  
Fu-Bin Chen ◽  
Xiao-Lu Wang ◽  
Yun Zhao ◽  
Yuan-Bo Li ◽  
Qiu-Sheng Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Pressure ◽  
Wind Loads ◽  
Structural Safety ◽  
Pressure Coefficients ◽  
High Rise ◽  
High Rise Building ◽  
The Mean

High-rise buildings are very sensitive to wind excitations, and wind-induced responses have always been the key factors for structural design. Facade openings have often been used as aerodynamic measures for wind-resistant design of high-rise buildings to meet the requirement of structural safety and comfort. Obvious wind speed amplifications can also be observed inside the openings. Therefore, implementing wind turbines in the openings is of great importance for the utilization of abundant wind energy resources in high-rise buildings and the development of green buildings. Based on numerical simulation and wind tunnel testing, the wind loads and wind speed amplifications on high-rise buildings with openings are investigated in detail. The three-dimensional numerical simulation for wind effects on high-rise building with openings was firstly carried out on FLUENT 15.0 platform by SST k − ε model. The mean wind pressure coefficients and the wind flow characteristics were obtained. The wind speed amplifications at the opening were analyzed, and the distribution law of wind speed in the openings is presented. Meanwhile, a series of wind tunnel tests were conducted to assess the mean and fluctuating wind pressure coefficients in high-rise building models with various opening rates. The variation of wind pressure distribution at typical measuring layers with wind direction was analyzed. Finally, the wind speed amplifications in the openings were studied and verified by the numerical simulation results.

scholarly journals Distribution of the external pressure coefficients on the elliptic tower: experimental measurement compared with numerical modelling

2020 ◽  
Vol 313 ◽  
pp. 00047
Author(s):  
Michal Franek ◽  
Marek Macák ◽  
Oľga Hubová
Keyword(s):  
Cfd Simulation ◽  
Flow Simulation ◽  
External Pressure ◽  
Wind Pressure ◽  
Wind Flow ◽  
Suitable Model ◽  
Pressure Coefficients ◽  
Building Model ◽  
High Rise ◽  
Experimental Values

The wind flow around the elliptical object was investigated experimentally in the BLWT wind tunnel in Bratislava and subsequently solved by computer wind flow simulation. On a high-rise building model, the external wind pressure coefficients were evaluated for different wind directions and then compared with the numerical CFD simulation in ANSYS, where different models of turbulence and mesh types were used. The aim of the article was to evaluate and compare the obtained values and after analysing the results to choose the most suitable model of turbulence and mesh types, which showed the smallest deviations from the experimental values.

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