On the deviation of mean pressure coefficients in wind loading standards for a low-rise, gable-roofed building with boundary walls

Structures ◽  
2022 ◽  
Vol 36 ◽  
pp. 50-64
Author(s):  
D.P.P. Meddage ◽  
C.S. Lewangamage ◽  
A.U. Weerasuriya
Keyword(s):  
Wind Loading ◽  
Pressure Coefficients ◽  
Mean Pressure

Wind Loading on Catenary Domes

2019 ◽  
Author(s):  
Richard M. van Gool ◽  
Ryan A. Bradley ◽  
Mitchell Gohnert
Keyword(s):  
Pressure Coefficient ◽  
Wind Loading ◽  
Pressure Coefficients ◽  
Hemispherical Dome ◽  
Circular Profile ◽  
Mean Pressure ◽  
Efficient Alternative ◽  
Base Radius ◽  
The Mean ◽  
Layer Flow

<p>Catenary domes are a less conventional, but structurally efficient, alternative to traditional circular-profile domes. Unlike the more common circular forms, there is a dearth of wind loading information for catenary structures. This paper aims to provide some insight in this regard. A series of wind tunnel tests were undertaken to investigate the effects of geometry and Reynolds number on the mean pressure coefficient distributions over catenary domes in a turbulent boundary layer flow. A hemispherical dome was also assessed, and the results compared with that for the catenary shapes. These parameters were evaluated to elucidate their influence on the loading on these structures. Only the results relating to mean pressure coefficients are reported in this paper. An important finding was that the height to base radius (H/R) of the catenary dome had a substantial influence on the mean pressure coefficient distributions over the structure. Finally, the results of the investigation and their implications on the design of catenary domes are discussed. This may be of value to designers because at present no wind loading information exists for catenary domes</p><p>– at least to the author’s knowledge.</p>

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.

Wind Effects on Structures

1970 ◽  
Vol 185 (1) ◽  
pp. 301-317 ◽  
Author(s):  
C. Scruton
Keyword(s):  
Maximum Amplitude ◽  
Accurate Prediction ◽  
Wind Tunnels ◽  
Wind Loading ◽  
Functional Requirements ◽  
Time Dependency ◽  
Wind Force ◽  
Pressure Coefficients ◽  
Aerodynamic Instability ◽  
Natural Wind

After several spectacular collapses caused by wind, there has been increased interest in the accurate prediction of the wind loading to which buildings and structures are subjected. The reliability of these design wind loads depends to a very large extent on the accurate prediction of the most severe wind conditions to be experienced for many years into the future, and on the accuracy of the wind force and pressure coefficients applicable to the structure. Many factors influence these coefficients and hitherto many of these factors have not been reproduced in measurements on models in wind tunnels, so much of the existing data is of uncertain reliability. For many structures it is sufficient to regard the wind as causing static loadings and for this purpose to use time-averaged wind forces. However, the advent of modern design and fabrication of structures has rendered them more prone to respond to the dynamic action of wind. Increasing attention is therefore being given to the time-dependency of the wind forces resulting either from the fluctuations of speed caused by the turbulence of natural wind, or from some form of aerodynamic instability arising from the interaction of the structure with the airstream. The calculation of the dynamic response to turbulent winds involves the application of statistical theories to calculate the maximum amplitude of the response (stress or displacement) and the frequency of its occurrence, coupled with the concept of an acceptable degree of risk that the structure will not fulfil its functional requirements during its lifetime.

WIND PRESSURE DISTRIBUTION ON LOW-RISE BUILDINGS WITH CYLINDRICAL ROOFS

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Astha Verma ◽  
Ashok Kumar Ahuja
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Wind Tunnel ◽  
Pressure Distribution ◽  
Open Circuit ◽  
Wind Pressure ◽  
Wind Loads ◽  
Wind Loading ◽  
Pressure Coefficients ◽  
Available Information

Wind is one of the important loads to be considered while designing the roofs of low-rise buildings. The structural designers refer to relevant code of practices of various countries dealing with wind loads while designing building roofs. However, available information regarding wind pressure coefficients on cylindrical roofs is limited to single span only. Information about wind pressure coefficients on multi-span cylindrical roofs is not available in standards on wind loads. Present paper describes the details of the experimental study carried out on the models of low-rise buildings with multi-span cylindrical roofs in an open circuit boundary layer wind tunnel. Wind pressure values are measured at many pressure points made on roof surface of the rigid models under varying wind incidence angles. Two cases namely, single-span and two-span are considered. The experimental results are presented in the form of contours of mean wind pressure coefficients. Results presented in the paper are of great use for the structural designers while designing buildings with cylindrical roofs. These values can also be used by the experts responsible for revising wind loading codes from time to time.

Experimental Investigation of Wind Loads on Fish-Shaped Roof Structures

2013 ◽  
Vol 639-640 ◽  
pp. 434-443
Author(s):  
Ming Liang Zhang ◽  
Qiu Sheng Li
Keyword(s):  
Experimental Investigation ◽  
Lower Surface ◽  
Shape Coefficient ◽  
Pressure Coefficients ◽  
Minimum Pressure ◽  
Mean Pressure ◽  
Wind Actions ◽  
Rigid Model ◽  
The Mean ◽  
Two Sides

Wind tunnel tests of 1:100 rigid model of fish-shaped roof structures were carried out. The mean, fluctuating (RMS) and peak pressure coefficients, the local shape coefficient distributions on fish-shaped roofs were presented and discussed. It was found that negative pressures (suctions) occurred on the most areas on the roofs, and high negative pressure coefficients occurred on the eaves and cantilevered roof parts. When wind flows blew along the corridors under the roofs, the flows enhanced suctions on the surfaces of the roofs, and the suctions on the lower surface were greater than those on the upper surfaces, positive pressures occurred on that area after superposition of wind actions on the two sides. The roof eaves and regions above the corridors experienced the worst RMS pressure coefficients and the worst minimum pressure coefficients. The distribution characteristics of the worst RMS and minimum pressure coefficients were found to be quite similar to those of the mean pressure coefficients. The results obtained from the experimental investigation are expected to be useful in the wind-resistant design of complex roof structures in typhoon-prone regions.

Pressure modes for hyperbolic paraboloid roofs

2020 ◽  
Vol 7 (1) ◽  
pp. 226-246
Author(s):  
Fabio Rizzo ◽  
Cristoforo Demartino
Keyword(s):  
Pressure Coefficient ◽  
Measured Signal ◽  
Hyperbolic Paraboloid ◽  
Pressure Coefficients ◽  
Truncated Svd ◽  
Mean Pressure ◽  
Vertical Displacements ◽  
Value Decomposition ◽  
Experimental Pressure ◽  
Polynomial Surface

AbstractThis paper presents a study on Singular Value Decomposition (SVD) of pressure coefficients hyperbolic parabolic roofs. The main goal of this study is to obtain pressure coefficient maps taking into account spatial non-uniform distribution and time-depending fluctuations of the pressure field. To this aim, pressure fields are described through pressure modes estimated by using the SVD technique. Wind tunnel experimental results on eight different geometries of buildings with hyperbolic paraboloid roofs are used to derive these pressure modes. The truncated SVD approach was applied to select a sufficient number of pressure modes necessary to reconstruct the measured signal given an acceptable difference. The truncated pressure modes are fitted through a polynomial surface to obtain a parametric form expressed as a function of the hyperbolic paraboloid roof geometry. The superpositions of pressure (envelopes) for all eight geometry were provided and used to modify mean pressure coefficients, to define design load combinations. Both symmetrical and asymmetrical pressure coefficient modes are used to estimate the wind action and to calculate the vertical displacements of a cable net by FEM analyses. Results clearly indicate that these load combinations allow for capturing large downward and upward displacements not properly predicted using mean experimental pressure coefficients.

Prediction of Wind-Induced Mean Pressure Coefficients Using GMDH Neural Network

2020 ◽  
Vol 33 (1) ◽  
pp. 04019104
Author(s):  
Monalisa Mallick ◽  
Abinash Mohanta ◽  
Awadhesh Kumar ◽  
Kanhu Charan Patra
Keyword(s):  
Neural Network ◽  
Pressure Coefficients ◽  
Mean Pressure

scholarly journals Experimental investigation of the aerodynamics of a large industrial building with parapet

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Aly Mousaad Aly ◽  
Matthew Thomas ◽  
Hamzeh Gol-Zaroudi
Keyword(s):  
Flow Pattern ◽  
Separation Bubble ◽  
Industrial Building ◽  
Pressure Coefficients ◽  
Industrial Buildings ◽  
Straight Line ◽  
Mean Pressure ◽  
The Mean ◽  
Wind Pressures ◽  
Peak Pressures

AbstractThe aerodynamic performance of a roof depends significantly on its shape and size, among other factors. For instance, large roofs of industrial low-rise buildings may behave differently compared to those of residential homes. The main objective of this study is to experimentally investigate how perimeter solid parapets can alter the flow pattern around a low-rise building with a large aspect ratio of width/height of about 7.6, the case of industrial buildings/shopping centers. Solid parapets of varied sizes are added to the roof and tested in an open-jet simulator in a comparative study to understand their impact on roof pressure coefficients. Roof pressures were measured in the laboratory for cases with and without parapets under different wind direction angles (representative of straight-line winds under open terrain conditions). The results show that using a parapet can alter wind pressures on large roofs. Parapets can modify the flow pattern around buildings and change the mean and peak pressures. The mean pressure pattern shows a reduction in the length of the separation bubble due to the parapet. The parapet of 14% of the building’s roof height is the most efficient at reducing mean and peak pressures compared to other parapet heights.

Steady and unsteady wind loading of buildings and structures

1971 ◽  
Vol 269 (1199) ◽  
pp. 353-383 ◽  
Keyword(s):  
Vortex Shedding ◽  
Structural Response ◽  
Wind Tunnels ◽  
Wind Loading ◽  
Structural Damping ◽  
Pressure Coefficients ◽  
Design Wind Speed ◽  
Aerodynamic Instability ◽  
Wind Characteristics ◽  
Time Average

Wind loads are conveniently divided into steady (time-average) loads and unsteady (time-dependent) loads. The latter arise from fluctuating forces due to turbulence as well as from self-excited aerodynamic instability. The relevant characteristics of atmospheric winds—speed profile and turbulence—and their dependence on the local terrain are briefly discussed. For design based on steady wind loadings the design wind speed is dependent on the acceptable degree of risk. Force and pressure coefficients may be influenced by Reynolds number, surface roughness, wind characteristics and proximity to other structures. Unsteady loadings due directly to turbulence are assessed through the concept of aerodynamic admittance. Only the vortex-shedding and galloping mechanisms leading to aerodynamic instability are reviewed here, together with some design features for avoiding such excitations. To predict the response of even conventional structures while in the design stages further information is needed on the speeds and turbulence characteristics of natural winds, especially of those over cities. Further investigations concerning the aerodynamic admittance and the aerodynamic excitation of practical structures are also needed. Research on these properties involves wind-tunnel studies in which the separate effects of intensity and scale of turbulence must be determined, and improved techniques for simulating the characteristics of natural winds in wind tunnels are required. A major difficulty in the application of these aerodynamic data to the prediction of structural response is the uncertainty in the assessment of values of the structural damping.

Effects of Geometrical Factors on Wind Pressure Characteristics of Cylindrical Roofs with Wind Tunnel Tests

2013 ◽  
Vol 351-352 ◽  
pp. 284-289 ◽  
Author(s):  
Bo Chen ◽  
Qing Shan Yang
Keyword(s):  
Wind Tunnel ◽  
Probability Distributions ◽  
Wind Pressure ◽  
Wind Tunnel Tests ◽  
Pressure Coefficients ◽  
High Rise ◽  
Mean Pressure ◽  
The Mean ◽  
Geometrical Factors ◽  
Pressure Characteristics

With wind tunnel tests, simultaneous pressure measurements are made on 4 cylindrical roof models with different rise-span ratios and roof inclinations. Effects of these geometrical factors on wind pressure characteristics of the roofs are investigated, including mean pressure coefficients, RMS pressure coefficients, skewness, kurtosis, and probability distributions of wind pressure. Results show that the mean vertical wind force coefficient of high rise-span ratio roof is larger than that of the low rise-span ration roof; the mean pressure coefficient distribution of the low rise-span ratio roof is similar to that of RMS pressure coefficients and the skewness (or the kurtosis); the vortex center line occurs at the windward edge for the low rise-span ratio roof with inclination 0°, which occurs at the roof apex for the high rise-span ratio roof. The roof inclination has more effects on the low rise-span ratio roof, the vortex moves from the windward edge to the apex for the roof with inclination 7.2°when the wind flows from the low eave to the high eave. The distribution of the skewness is strongly correlative to that of the kurtosis. The probability distributions of the roof edges and corners deviate obviously from the Guass distribution. If this point is ignored, the peak suction pressure will be underestimated.

Sign in / Sign up

Export Citation Format

Share Document