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CONTENTS
Volume 4, Number 6, December 2001
 

Abstract
This paper presents recent research on the experimental evaluation of wind loads on low buildings and the recommendations provided in the form of traditional codification. These mainly include the wind loads on buildings with geometries different from those examined in previous studies. This is followed by the evaluation of simulated wind loads on low building roofs. The overall application of a recently proposed simulation methodology for codification purposes is discussed in detail. The traditional codification provides for a group of roof geometries a single peak design pressure coefficient for each roof zone considering a nominal worst-case scenario; this may often lead to uneconomical loads. Alternatively, thernpresented methodology is capable of providing peak pressure coefficients corresponding to specific roof geometries and according to risk levels; this can generate risk consistent and more economical design wind loads for specific roof configurations taking into account, for instance, directional design conditionsrnand upstream roughnesses.

Key Words
codification; design loads; low buildings; pressure; wind.

Address
RWDI Inc., 650 Woodlawn Road West Guelph, Ontario, N1K 1B8, CanadarnCentre for Building Studies Department of Building, Civil and Environmental Engineering, Concordia University, 1455 de Maisonneuve Blvd. West Montreal, H3G 1M8, Canada

Abstract
The Leipzig Wind Profile is generally known as a typical neutral planetary boundary layer flow. But it became clear from the present research that it was not completely neutral but weakly stable. We examined whether we could simulate the Leipzig Wind Profile by using a (k- e) turbulence model including the equation of potential temperature. By solving analytically the Second Moment Closure Model under the assumption of local equilibrium and under the condition of a stratified flow, we expressed the turbulent diffusion coefficients (both momentum and thermal) as functions of flux Richardson number. Our (k- e) turbulence model which included the equation of potential temperature and the turbulent diffusionrncoefficients varying with flux Richardson number reproduced the Leipzig Wind Profile.

Key Words
a weakly stable atmospheric boundary layer; Mellor-Yamada model; (k- e) model; Second

Address
Division of Global Environment Engineering, Graduate School of Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan

Abstract
Wind tunnel pressure tests were conducted on a 1:100 scale model of a large industrial building with solar panels mounted parallel to the flat roof. The model form was chosen to have the same aspect ratio as the Texas Tech University test building. Pressures were simultaneously measured on the roof, and on the topside and underside of the solar panel, the latter two combining to produce a nett panelrnpressure. For the configurations tested, varying both the lateral spacing between the panels and the height of the panels above the roof surface had little influence on the measured pressures, except at the leading edge. The orientation of the panels with respect to the wind flow and the proximity of the panels to thernleading edge had a greater effect on the measured pressure distributions. The pressure coefficients are compared against the results for the roof with no panels attached. The model results with no panels attached agreed well with full-scale results from the Texas Tech test building.

Key Words
solar panels; wind loading; wind tunnel testing; pressure measurements.

Address
Department of Civil Engineering, University of Sydney, NSW 2006, AustraliarnOve Arup and Partners, Level 5 Festival Walk, Kowloon Tong, Hong KongrnDepartment of Civil Engineering, University of Sydney, NSW 2006, Australia

Abstract
With a newly developed multi-force-balance system(MFB), a twin-tower structure was studied for its wind-induced responses. The MFB system allowed the twin towers, which were linked structurally, to be treated as a single structural system with its corresponding modes of vibration involving coupled motions of the two towers. The towers were also studied using a more conventional force balance approach in which each tower was treated as an isolated structure, i.e., as though no structural link existed. Comparison of the results reveals how the wind loads between the towers are redistributed through the structural links and the modal couplings. The results suggest that although the structural links usually havernbeneficial impacts on wind-induced response, they may also play a negative role if the frequency ratios of pair modes are near 1.0.

Key Words
wind-induced twin-tower response; multi-force-balance (MFB); high-frequency force-balance

Address
Rowan Williams Davies & Irwin Inc., Guelph, Ontario, Canada

Abstract
Shantou Bay Bridge is the first long-span suspension bridge in China. Because of its location near the Shantou Seaport and its exposure to high typhoon winds, wind-resistant studies are necessary to be made. In this paper, critical flutter wind speeds and buffeting responses of this bridge at its operation and main construction stages are investigated. The Buffeting Response Spectrum method is first briefly presented. Then the sectional model test is carried out to directly obtain the critical flutter wind speed and to identify the flutter derivatives, which are adopted for the later analysis of the buffeting responses using the Buffeting Response Spectrum method. Finally the aeroelastic full bridge model is tested to further investigate the dynamic effects of the bridge. The results from the tests and the computations indicate that the flutter and buffeting behaviors of the Shantou Bay Bridge are satisfied.

Key Words
suspension bridge; sectional model; aeroelastic full bridge model, flutter; buffeting.

Address
State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, 200092 Shanghai, China


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