Proposed new Canadian wind provisions for the design of gable roofs

2000 ◽  
Vol 27 (5) ◽  
pp. 1059-1072 ◽  
Author(s):  
Ted Stathopoulos ◽  
Kai Wang ◽  
Hanqing Wu
Keyword(s):  
Research Study ◽  
Original Study ◽  
Wind Pressure ◽  
Building Code ◽  
Code Design ◽  
Pressure Coefficients ◽  
Building Models ◽  
Open Country ◽  
Roof Angle ◽  
Design Pressure

Wind pressure coefficients for gable roofs of low buildings are strongly dependent on roof angle, particularly for intermediate roof slopes (roof angle 10°-30°). This paper addresses the suitability of wind pressure coefficients specified in the National Building Code of Canada (NBCC) for gable roofs in the intermediate slope range. In a recent research study, a series of low building models with different roof slopes were tested in a boundary layer wind tunnel under simulated open country conditions. This was different from the original study in the 1970s, which produced the current wind provisions on the basis of a model tested only for a single roof slope (4:12) in this intermediate roof slope range. The results of the study suggest that a modification of the wind provisions of NBCC would be warranted to make them more representative of the true local and area-averaged wind loads imposed on gable roofs of intermediate slope.Key words: building, code, design, pressure, roof, standard, wind.

Design recommendations for wind loading on buildings of intermediate height

1989 ◽  
Vol 16 (6) ◽  
pp. 910-916 ◽  
Author(s):  
T. Stathopoulos ◽  
M. Dumitrescu-Brulotte
Keyword(s):  
Tall Buildings ◽  
Building Code ◽  
Wind Loads ◽  
Wind Loading ◽  
Code Design ◽  
Building Models ◽  
Concordia University ◽  
Open Country ◽  
Design Loads ◽  
Wind Pressures

The National Building Code of Canada (NBCC) specifies wind loads for the design of tall (height, H > width, W) and low (H < 10 m, or H < W and H < 20 m) buildings. Since there are no specifications for the design of buildings of intermediate height, the present project has been undertaken to help define wind loads appropriate for the design of such buildings. The experimental study was carried out at the boundary layer wind tunnel of the Centre for Building Studies at Concordia University. The methodology used for this project consisted of testing five square building models (12, 25, 55, 100, and 145 m high) under conditions simulating strong turbulent wind blowing over an open country terrain exposure. Both the lowest and the tallest buildings were tested for validation purposes. Statistics of wind induced pressures were measured at several points and areas on the walls and the roof of all buildings for both normal and oblique wind directions. Experimental data show good agreement with previous studies of buildings of similar height tested under different environmental and proximity conditions. Results for the intermediate height buildings are presented in the paper. Wind pressures are compared with the NBCC specifications for low and tall buildings. Key words: building, code, design, loads, pressure, roof, wall, wind.

scholarly journals Prognosis of Wind-tempted Mean Pressure Coefficients of Cross-shaped Tall Buildings Using Artificial Neural Network

2020 ◽  
Author(s):  
Rajdip Paul ◽  
Sujit Kumar Dalui
Keyword(s):  
Mean Squared Error ◽  
Pressure Coefficient ◽  
Tall Buildings ◽  
Parametric Models ◽  
Wind Pressure ◽  
Pressure Coefficients ◽  
Building Models ◽  
Wide Range ◽  
Close Relationship ◽  
Artificial Neural

The present paper focuses on the study of wind-induced responses of cross-plan shaped tall buildings. Initially, three parametric building models are studied for the purpose with a constant plan area 22500 mm2. The length and velocity scales are taken as 1:300 and 1:5, respectively. Wind angle of attack (WAA) is considered from 0° to 330° with an increment of 30°. At first, the external surface pressure coefficients (Cp) at different faces of the models are carried out for different wind occurrence angles employing Computational Fluid Dynamics method of simulated wind flow. Again, Fast Fourier Transform (FFT) fitted expressions as the sine and cosine function of WAA are proposed for attaining mean wind pressure coefficient on the building faces. The accuracy of the Fourier series expansions is justified by presenting histograms of sum square error (SSE), R2 value and root mean square error (RMSE). The results are also compared by training Artificial Neural Networks (ANN). Training is continued till Regression (R) values are more than 0.99 and Mean Squared Error (MSE) tends to 0, ensuring a close relationship among the outputs and targets. The face-wise value of (Cp) obtained using all three methods, are plotted. The error histograms of the ANN models show that the fitting data errors are spread within a reasonably good range. It is observed that the deviation in the result is not more than 5% in any case. Finally, the ANN predictions are presented for nine parametric models to cover a wide range of possible cross-shaped buildings.

Turbulent wind loading of roofs with parapet configurations

1988 ◽  
Vol 15 (4) ◽  
pp. 570-578 ◽  
Author(s):  
T. Stathopoulos ◽  
A. Baskaran
Keyword(s):  
Experimental Data ◽  
National Standards ◽  
Building Code ◽  
Wind Loading ◽  
Geometrical Parameters ◽  
Code Design ◽  
Turbulent Wind ◽  
Open Country ◽  
Design Loads ◽  
Flat Roofs

This paper reviews the available experimental data regarding the effect of parapet configurations on the wind loading of roofs of buildings of various geometries and under different exposures. Particular reference is given to the recent study carried out by the authors in a boundary layer wind tunnel. This study deals with the effects of wind on a variety of flat roofs with and without parapets when exposed to simulated open country and urban terrains. Geometrical parameters examined include the effect of building height (ranging from 12 to 145 m) and parapet height (0–3 m) on both local and area-averaged roof pressures for a variety of wind directions. Results show that parapets generally reduce the high suctions on roof edges and may slightly increase the suctions on the interior areas of the roof. Roof corner suctions, however, increase significantly for low parapet heights.Additional parapet configurations have been examined to reduce these high local corner suctions. Parapet cuts or slots around corners have proven to be effective in this respect. The effect of one-sided, as opposed to perimetrical, parapet has also been examined. Extensive comparisons of the data and recommendations for the wind load provisions of the National Building Code of Canada (NBCC) and the American National Standards Institute (ANSI) are also made. Key words: building, code, design, loads, pressure, project, roof, wind.

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.

Model Code Design Force Provisions for Elements of Structures and Nonstructural Components

2000 ◽  
Vol 16 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Richard M. Drake ◽  
Leo J. Bragagnolo
Keyword(s):  
Building Code ◽  
Code Design ◽  
Structural System ◽  
Nonstructural Components ◽  
Model Code ◽  
Earthquake Design ◽  
Significant Change ◽  
New Buildings

With the publication of the 1997 Uniform Building Code ( UBC) and the 1997 NEHRP Recommended Provisions for the Seismic Regulations for New Buildings and Other Structures, there has been a significant change in the earthquake design force provisions for buildings, structures, elements of structures and nonstructural components. Engineers and architects need to become informed regarding a variety of earthquake design force provisions, primarily those published in the UBC and those developed as part of the NEHRP Provisions. Both sources provide design force provisions for the building structural system and separate design force provisions for elements of structures and nonstructural components. This paper describes the development, evolution, and application of the earthquake design force provisions for elements of structures and nonstructural components.

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.

Sign in / Sign up

Export Citation Format

Share Document