Wind pressures on buildings with stepped roofs

1990 ◽  
Vol 17 (4) ◽  
pp. 569-577 ◽  
Author(s):  
T. Stathopoulos ◽  
H. D. Luchian
Keyword(s):  
Pressure Coefficient ◽  
National Standards ◽  
Building Code ◽  
Wind Loading ◽  
Positive Pressure ◽  
Code Design ◽  
Maximum Height ◽  
Basic Model ◽  
Wind Pressures ◽  
Flat Roof

The paper describes an experimental study for the evaluation of wind pressures on buildings with roofs of two different heights, such as one building with roofs at two levels or, more commonly, two flat-roofed buildings in a row. The study is experimental and consists of an extensive series of tests in a boundary layer wind tunnel simulating the flow over an open country terrain exposure. The basic model of the study has been designed and constructed in sections so that it can represent flat roofs in steps of different relative heights and widths. The maximum height of the model is variable and can represent a building up to 60 m high. The results of the study for buildings with a two-level flat roof are discussed in the paper. Data are presented in pressure coefficient form (both mean and peak values) measured locally on a number of pressure taps placed at strategic locations on the roof and wall sections of the model. The results of the study are compared with the flat-roof specifications described in the American National Standards Institute wind standard and the National Building Code of Canada. It has been found that some modifications of these standards are required to accommodate the wind loading of these building configurations. In particular, the inclusion of positive pressure coefficients must be considered for stepped roofs. Key words: building, code, design, loads, pressure, roof, wall, wind.

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.

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 The Wind Loading Characteristics of MAN Type Dry Gas Storage Tank

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Xinpeng Liu ◽  
Zhitao Yan ◽  
Zhengliang Li ◽  
Junfan Chen ◽  
Jingbo Liu
Keyword(s):  
Surface Roughness ◽  
Pressure Coefficient ◽  
Calculation Model ◽  
Wind Pressure ◽  
Wind Loading ◽  
Minimum Pressure ◽  
Spacing Ratio ◽  
Calculation Results ◽  
Wind Pressure Coefficient ◽  
Wind Pressures

The effects of Reynolds number (Re) and surface roughness on the wind pressure coefficient on a MAN type dry gas tank were analyzed in detail by wind tunnel tests. A wind load calculation model was then established, which is suitable for the wind resistant design of the gas tanks. The test results revealed that in the range of 7 × 105 < Re < 1.0 × 106 (supercritical regimes), the drag coefficient (Cd) and wind pressure coefficient remained constant, consistent with 2D cylinders in a uniform flow. However, in common with 2D cylinder flows, the surface roughness with the spacing ratio (λ) greater than 0.9 had a significant effect on the wind pressures coefficient. The minimum pressure coefficient (Cpmin) sharply increased from −2.3 to −0.65 with increasing surface roughness. The corresponding angle for the minimum pressure coefficient θmin was in between 140°and 90°, which was in a gradual decreasing trend with the increase in surface roughness of the model. The calculation method of the wind pressure coefficient with vary surface roughness was proposed, based on which, the calculation results were in good agreement with the test data.

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.

Comparisons of design wind pressures on roof-mounted solar arrays between wind tunnel tests and codes and standards

2020 ◽  
pp. 136943322096527
Author(s):  
Jingxue Wang ◽  
Qingshan Yang ◽  
Yi Hui
Keyword(s):  
Wind Tunnel ◽  
Experimental Results ◽  
Solar Panels ◽  
Wind Tunnel Tests ◽  
Pressure Equalization ◽  
Solar Arrays ◽  
Side Ratio ◽  
Design Values ◽  
Wind Pressures ◽  
Flat Roof

The current codes and standards concerning wind loads on roof-mounted solar panels are discussed and summarized. Wind pressures on flat- and slope-roof-mounted solar arrays obtained from wind tunnel tests are compared with the recommended design values in ASCE 7-16 and JIS C 8955: 2017. Different parameters, including building side ratio, aspect ratio and parapet height, are examined. Results show that the largest wind pressures on flat-roof-mounted solar panels of all zones in ASCE 7-16 tend to be 10% to 26% smaller than the experimental results when normalized tributary area An is larger than 103. Uplift wind forces on flat-roof-mounted solar panels in downstream regions obtained from experiments can be larger than the recommended values in JIS C 8955: 2017 for adverse wind, but downward force coefficients are basically smaller than those in JIS C 8955: 2017 for fair wind. 40% to 60% increase on the pressure equalization factor for slope-roof-mounted solar panels is suggested for the potential refinement of ASCE 7-16 based on this study. Meanwhile, proposed pressures of slope-roof-mounted solar panels in JIS C 8955: 2017 might be too conservative according of experimental results.

Mean Wind Pressure Field on the Typical Large-Span Roof Structures

2012 ◽  
Vol 166-169 ◽  
pp. 19-24
Author(s):  
Fang Hui Li ◽  
Ming Gu ◽  
Zhen Hua Ni ◽  
Shi Zhao Shen
Keyword(s):  
Pressure Field ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Pressure Data ◽  
Shape Factors ◽  
Local Shape ◽  
Wind Pressure Coefficient ◽  
The Mean ◽  
Urban Terrain ◽  
Wind Pressures

The wind tunnel tests of some typical large roofs, including a saddle roof, pitched roof and domes, are carried out with various terrains which cover suburban and urban exposures. The wind pressure data of roofs are obtained by using the synchronous multi-pressure scanning technique. The wind pressure coefficient and local shape factors of the wind load was investigated. The effects of various terrains on wind pressures of roofs are discussed. From the results, we can see mean pressures of these roofs exposed to the mean pressures exposed to the suburban terrain are 2 or 3 times those exposed to the urban terrain. And the terrains are no directly influence to the wind pressure shape factors.

Mean wind pressures on flat roof corners affected by parapets: field and wind tunnel studies

1999 ◽  
Vol 21 (7) ◽  
pp. 629-638 ◽  
Author(s):  
Theodore Stathopoulos ◽  
Rajan Marathe ◽  
Hanqing Wu
Keyword(s):  
Wind Tunnel ◽  
Wind Pressures ◽  
Flat Roof

Wind resistance of a narrow partially built house

1986 ◽  
Vol 13 (3) ◽  
pp. 375-381
Author(s):  
Ronald A. Macnaughton
Keyword(s):  
Key Words ◽  
Wind Load ◽  
Building Code ◽  
Wind Loads ◽  
Wind Loading ◽  
Critical Component ◽  
Wind Resistance ◽  
Early Stages ◽  
Resistance Analysis

This paper contains a wind load and resistance analysis for a type of structure that has frequently failed: partially built houses. The critical component of such structures is identified to be the first-storey shearwalls running across the house. The calculated racking strength of that storey is compared to the wind loading the structure would be expected to resist if it were engineered. Various methods are proposed for builders to provide these structures with more wind resistance during the early stages of construction. Differences between Canadian codes and codes in other jurisdictions with respect to this are pointed out. Key words: wind loads, houses, failure, wind bracing, temporary bracing, shearwalls, fibreboard, sheathing, permanent bracing, racking strength, construction procedures, nailing, building code.

Wind Load Characteristics of Tall Building with Atrium

2013 ◽  
Vol 639-640 ◽  
pp. 515-522
Author(s):  
Yong Gui Li ◽  
Q.S. Li
Keyword(s):  
Wind Tunnel ◽  
Critical Role ◽  
Pressure Coefficient ◽  
Tall Building ◽  
Wind Pressure ◽  
Wind Loads ◽  
Design Guideline ◽  
Pressure Coefficients ◽  
Opening Ratio ◽  
Wind Pressures

Wind tunnel test of 1:500 rigid model of tall building with atrium was carried out. Based on the experimental results, characteristics of wind pressures on atrium facades and wind loads on the structure were investigated in detail. The results show that the formation of flow separation on the building top plays a critical role in the generation of wind pressures on the atrium facades. Meanwhile, wind pressure coefficient distributions on the atrium facades are found to be relatively uniform. Moreover, the horizontal and vertical correlations of pressure coefficient exhibit high at most locations on atrium facades. With the increasing of the opening ratio, the mean wind pressure coefficients first decreased and then stabilized, and the fluctuating wind pressure coefficients first decreased and then increased. A design guideline for the wind-resistant design of atrium facades was proposed, and the results predicted by the proposed guideline were in good agreement with those from the wind tunnel tests, indicating that the proposed guideline can be used in engineering applications. When the opening ratio is no more than 5.33%, the effect of the facade pressures within the atrium on the wind loads on the structure can be ignored. For such cases, the wind-resistant design for a tall building with atrium can refer to that of a similar shape tall building without atrium.

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