• Title, Summary, Keyword: wind pressure coefficients

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Wind pressure coefficients on low-rise structures and codification

  • Letchford, Chris;Holmes, J.D.;Hoxey, Roger;Robertson, Adam
    • Wind and Structures
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    • v.8 no.4
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    • pp.283-294
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    • 2005
  • This paper describes the work of the Working Group on wind pressure coefficients on low-rise structures, one of the groups set up by the International Association of Wind Engineering in 1999. General aspects of wind loading on low-rise structures are summarized. The definition, derivation and codification of loading coefficients is described. Comparisons of pressure coefficients on low rise structures are made between a selection of wind loading standards. Recommendations for consistency and for the harmonization of these coefficients are given.

Calculation of Wind Loads on the Cladding of Apartment Building according to Panel Size (패널 크기에 따른 아파트 건축물 외장재의 풍하중 산정)

  • Cho, Kang-Pyo;Jeong, Seung-Hwan;Kim, Won-Sool
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.739-744
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    • 2007
  • Wind loads for cladding can be estimated using the maximum wind pressure including gust effects from wind-tunnel tests. However, when estimating the maximum wind pressure with gust effects, wind pressure coefficients for cladding would be different according to the averaging time of wind pressures, In the paper, for wind pressures obtained from wind-tunnel tests for apartment buildings, whose window panes were damaged by actual strong wind, it was investigated how pressure coefficients varied according to the size of cladding and averaging time using TVL method of Lawson. In result, it was found that the lesser the size of cladding and averaging time were, the larger pressure coefficients became. Accordingly, to estimate wind loads for cladding of apartment buildings and design it, the averaging time of wind pressures should be considered properly.

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Estimation of Wind Pressure Coefficients on Even-Span Greenhouse Built in Reclaimed Land according to Roof Slop using Wind Tunnel (풍동을 이용한 간척지 내 양지붕형 온실의 지붕 경사에 따른 풍압계수 평가)

  • Kim, Rack-Woo;Kim, Dong-Woo;Ryu, Ki-Cheol;Kwon, Kyeong-Seok;Lee, In-Bok
    • Protected Horticulture and Plant Factory
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    • v.23 no.4
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    • pp.269-280
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    • 2014
  • To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

Determination of Wind Pressure Coefficients around Prismatic Structures with Different Aspect Ratios (종횡비 변화에 따른 사각주형 구조물주위의 풍압계수 결정)

  • Suh, S.H.;Lee, K.Y.;Yoo, S.S.;Roh, H.W.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.1
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    • pp.52-62
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    • 1995
  • The purpose of this study is to determine the wind pressure coefficients around prismatic structures with different aspect ratios. Air flows around a model of prismatic shape are investigated experimentally in the wind tunnel and simulated using finite volume method. Pressure distributions and the corresponding pressure coefficients are calculated from the experimental and numerical results. The effects of aspect ratios on the pressure coefficients are discussed extensively. The numerical results are compared with those of experiments. The simulated and experimental results for average wind pressure coefficients are considerably lower than those defined in the Korean Architectural Standard Code.

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Effects of vertical ribs protruding from facades on the wind loads of super high-rise buildings

  • Quan, Yong;Hou, Fangchao;Gu, Ming
    • Wind and Structures
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    • v.24 no.2
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    • pp.145-169
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    • 2017
  • The auxiliary structures of a high-rise building, such as balconies, ribs, and grids, are usually much smaller than the whole building; therefore, it is difficult to simulate them on a scaled model during wind tunnel tests, and they are often ignored. However, they may have notable effects on the local or overall wind loads of the building. In the present study, a series of wind pressure wind tunnel tests and high-frequency force balance (HFFB) wind tunnel tests were conducted on rigid models of an actual super high-rise building with vertical ribs protruding from its facades. The effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and the most unfavorable values of the local wind pressure coefficients were investigated by analyzing the distribution of wind pressure coefficients on the facades and the variations of the wind pressure coefficients at the cross section at 2/3 of the building height versus wind direction angle. In addition, the effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and power spectra of the overall aerodynamic force coefficients were studied by analyzing the aerodynamic base moment coefficients. The results show that vertical ribs significantly decrease the most unfavorable suction coefficients in the corner recession regions and edge regions of facades and increase the mean and fluctuating along-wind overall aerodynamic forces.

Wind loads on T-shaped and inclined free-standing walls

  • Geurts, Chris;van Bentum, Carine
    • Wind and Structures
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    • v.13 no.1
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    • pp.83-94
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    • 2010
  • Wind tunnel measurements on T-shaped free-standing walls and inclined free-standing walls have been carried out. Mean net pressure coefficients have been derived and compared with previous research. It was observed that the high loads at the free ends are differently distributed than those derived from the pressure coefficients for free-standing walls in EN 1991-1-4. In addition net pressure coefficients based on extreme value analysis have been obtained. The lack of correlation of the wind induced pressures at windward and leeward side result in lower values for the net pressure coefficients when based on extreme value analysis. The results of this wind tunnel study have been included in Dutch guidelines for noise barriers.

Comparison between wind load by wind tunnel test and in-site measurement of long-span spatial structure

  • Liu, Hui;Qu, Wei-Lian;Li, Qiu-Sheng
    • Wind and Structures
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    • v.14 no.4
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    • pp.301-319
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    • 2011
  • The full-scale measurements are compared with the wind tunnel test results for the long-span roof latticed spatial structure of Shenzhen Citizen Center. A direct comparison of model testing results to full-scale measurements is always desirable, not only in validating the experimental data and methods but also in providing better understanding of the physics such as Reynolds numbers and scale effects. Since the quantity and location of full-scale measurements points are different from those of the wind tunnel tests taps, the weighted proper orthogonal decomposition technique is applied to the wind pressure data obtained from the wind tunnel tests to generate a time history of wind load vector, then loads acted on all the internal nodes are obtained by interpolation technique. The nodal mean wind pressure coefficients, root-mean-square of wind pressure coefficients and wind pressure power spectrum are also calculated. The time and frequency domain characteristics of full-scale measurements wind load are analyzed based on filtered data-acquisitions. In the analysis, special attention is paid to the distributions of the mean wind pressure coefficients of center part of Shenzhen Citizen Center long-span roof spatial latticed structure. Furthermore, a brief discussion about difference between the wind pressure power spectrum from the wind tunnel experiments and that from the full-scale in-site measurements is compared. The result is important fundament of wind-induced dynamic response of long-span spatial latticed structures.

Prediction of downburst-induced wind pressure coefficients on high-rise building surfaces using BP neural network

  • Fang, Zhiyuan;Wang, Zhisong;Li, Zhengliang
    • Wind and Structures
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    • v.30 no.3
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    • pp.289-298
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    • 2020
  • Gusts generated by downburst have caused a great variety of structural damages in many regions around the world. It is of great significance to accurately evaluate the downburst-induced wind load on high-rise building for the wind resistance design. The main objective of this paper is to propose a computational modeling approach which can satisfactorily predict the mean and fluctuating wind pressure coefficients induced by downburst on high-rise building surfaces. In this study, using an impinging jet to simulate downburst-like wind, and simultaneous pressure measurements are obtained on a high-rise building model at different radial locations. The model test data are used as the database for developing back propagation neural network (BPNN) models. Comparisons between the BPNN prediction results and those from impinging jet test demonstrate that the BPNN-based method can satisfactorily and efficiently predict the downburst-induced wind pressure coefficients on single and overall surfaces of high-rise building at various radial locations.

Effects of different wind deflectors on wind loads for extra-large cooling towers

  • Ke, S.T.;Zhu, P.;Ge, Y.J.
    • Wind and Structures
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    • v.28 no.5
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    • pp.299-313
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    • 2019
  • In order to examine the effects of different wind deflectors on the wind load distribution characteristics of extra-large cooling towers, a comparative study of the distribution characteristics of wind pressures on the surface of three large cooling towers with typical wind deflectors and one tower without wind deflector was conducted using wind tunnel tests. These characteristics include aerodynamic parameters such as mean wind pressures, fluctuating wind pressures, peak factors, correlation coefficients, extreme wind pressures, drag coefficients and vorticity distribution. Then distribution regularities of different wind deflectors on global and local wind pressure of extra-large cooling towers was extracted, and finally the fitting formula of extreme wind pressure of the cooling towers with different wind deflectors was provided. The results showed that the large eddy simulation (LES) method used in this article could be used to accurately simulate wind loads of such extra-large cooling towers. The three typical wind deflectors could effectively reduce the average wind pressure of the negative pressure extreme regions in the central part of the tower, and were also effective in reducing the root of the variance of the fluctuating wind pressure in the upper-middle part of the windward side of the tower, with the curved air deflector showing particularly. All the different wind deflectors effectively reduced the wind pressure extremes of the middle and lower regions of the windward side of the tower and of the negative pressure extremes region, with the best effect occurring in the curved wind deflector. After the wind deflectors were installed the drag coefficient values of each layer of the middle and lower parts of the tower were significantly higher than that without wind deflector, but the effect on the drag coefficients of layers above the throat was weak. The peak factors for the windward side, the side and leeward side of the extra-large cooling towers with different wind deflectors were set as 3.29, 3.41 and 3.50, respectively.

Analysis of External Peak Pressure Coefficients for Cladding in Elliptical Retractable Dome Roof by Wind Tunnel Test (풍동 실험을 통한 타원형 개폐식 돔 지붕의 외장재용 풍압 계수 분석)

  • Lee, Jong-Ho;Kim, Yong-Chul;Cheon, Dong-Jin;Yoon, Sung-Won
    • Journal of the Korean Association for Spatial Structures
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    • v.20 no.1
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    • pp.49-59
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    • 2020
  • This study investigates the wind pressure characteristics of elliptical plan retractable dome roof. Wind tunnel experiments were performed on spherical dome roofs with varying wall height-span ratios (0.1~0.5) and opening ratios (0%, 10%, 30% and 50%), similar to previous studies of cirular dome roofs. In previous study, wind pressure coefficients for open dome roofs have been proposed since there are no wind load criteria for open roofs. However, in the case of Eeliptical plan retractable dome roof, the wind pressure coefficient may be largely different due to the presence of the longitudinal direction and transverse direction. The analysis results leads to the exceeding of maximum and minimum wind pressure coefficients KBC2016 code.