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.

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.

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.

A MATHEMATICAL MODEL OF THE PHYSICAL GROWTH MECHANISM AND GEOMETRICAL CHARACTERIZATION OF GROWING FORMS

2011 ◽  
Vol 04 (01) ◽  
pp. 35-53 ◽  
Author(s):  
YURI K. SHESTOPALOFF
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Growth Mechanism ◽  
Growth Suppression ◽  
Physical Growth ◽  
Geometrical Parameters ◽  
Growth Equation ◽  
Software Application ◽  
Multicellular Organisms

The article introduces a mathematical model of the physical growth mechanism which is based on the relationships of the physical and geometrical parameters of the growing object, in particular its surface and volume. This growth mechanism works in cooperation with the biochemical and other growth factors. We use the growth equation, which mathematically describes this mechanism, and study its adequacy to real growth phenomena. The growth model very accurately fits experimental data on growth of Amoeba, Schizosaccharomyces pombe, E.coli. Study discovered a new growth suppression mechanism created by certain geometry of the growing object. This result was proved by experimental data. The existence of the growth suppression phenomenon confirms the real workings and universality of the growth mechanism and the adequacy of its mathematical description. The introduced equation is also applicable to the growth of multicellular organisms and tumors. Another important result is that the growth equation introduces mathematical characterization of geometrical forms that can biologically grow. The material is supported by software application, which is released to public domain.

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.

THE MIXING OF A JET OF CARBON DIOXIDE FROM SMASHING SUBSONIC FLOW

2018 ◽  
Vol 8 (2) ◽  
pp. 142-145
Author(s):  
Olga A. BALANDINA
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Numerical Calculation ◽  
Temperature Distribution ◽  
Subsonic Flow ◽  
Gas Jet ◽  
Geometrical Parameters ◽  
Aspect Ratios ◽  
Calculation Results ◽  
Jet Blowing

Presents the results of a numerical calculation of the interaction of the jet of carbon dioxide from smashing subsonic air fl ow. Were identifi ed and analyzed pressure values, the trajectories of the jet, the velocity profi les at small blowing intensities. The comparison of calculation results with experimental data of other authors. The obtained curves of the temperature distribution for carrying air fl ow and the jet issued from a slit-like holes with aspect ratios 1:2; 1:3; 1:4. Analysis of the results showed that the geometrical parameters of the jet blowing holes does not signifi cantly aff ect the temperature distribution in the region behind the jet. The research results can be used in the design of the jet bodies of the gas burners of boilers. Will conduct further modeling to enhance the process of formation of the gas-air mixture in the gas jet type burners.

scholarly journals Unbalanced snow distributions for the design of arch-shaped roofs in Canada

1980 ◽  
Vol 7 (4) ◽  
pp. 651-656 ◽  
Author(s):  
D. A. Taylor ◽  
W. R. Schriever
Keyword(s):  
Building Code ◽  
Large Radius ◽  
Design Loads ◽  
Snow Loads

This note examines in some detail the design snow loads on simple arches and curved roofs recommended in the 1977 Commentary on Snow Loads of the National Building Code of Canada. Empirical modifications that give more appropriate unbalanced snow loads for large-radius arches and that will alleviate the problems caused by some overconservative aspects of the 1977 design loads are presented. They have been accepted for inclusion in the 1980 commentary.

Computational Fluid Dynamics Modeling of Gas–Liquid Cylindrical Cyclones, Geometrical Analysis

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Juan Carlos Berrio ◽  
Eduardo Pereyra ◽  
Nicolas Ratkovich
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Cfd Modeling ◽  
Nozzle Geometry ◽  
Geometrical Parameters ◽  
Experimental Setup ◽  
Dynamics Modeling ◽  
Two Phase ◽  
Mean Square Errors

The gas–liquid cylindrical cyclone (GLCC) is a widely used alternative for gas–liquid conventional separation. Besides its maturity, the effect of some geometrical parameters over its performance is not fully understood. The main objective of this study is to use computational fluid dynamics (CFD) modeling in order to evaluate the effect of geometrical modifications in the reduction of liquid carry over (LCO) and gas carry under (GCU). Simulations for two-phase flow were carried out under zero net liquid flow, and the average liquid holdup was compared with Kanshio (Kanshio, S., 2015, “Multiphase Flow in Pipe Cyclonic Separator,” Ph.D. thesis, Cranfield University, Cranfield, UK) obtaining root-mean-square errors around 13% between CFD and experimental data. An experimental setup, in which LCO data were acquired, was built in order to validate a CFD model that includes both phases entering to the GLCC. An average discrepancy below 6% was obtained by comparing simulations with experimental data. Once the model was validated, five geometrical variables were tested with CFD. The considered variables correspond to the inlet configuration (location and inclination angle), the effect of dual inlet, and nozzle geometry (diameter and area reduction). Based on the results, the best configuration corresponds to an angle of 27 deg, inlet location 10 cm above the center, a dual inlet with 20 cm of spacing between both legs, a nozzle of 3.5 cm of diameter, and a volute inlet of 15% of pipe area. The combination of these options in the same geometry reduced LCO by 98% with respect to the original case of the experimental setup. Finally, the swirling decay was studied with CFD showing that liquid has a greater impact than the gas flowrate.

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.

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