Abstract
The mechanism of wind-induced ovalling vibrations of cylindrical shells is numericallyrninvestigated by using a vortex method. The subject of this paper is limited to a two-dimensional structurernin the subcritical regime. The aerodynamic stability of the ovalling vibrations in the second to fourthrncircumferential modes is discussed, based on the results of a forced-vibration test. In the analysis, two modalrnconfigurations are considered; one is symmetric and the other is anti-symmetric with respect to a diameterrnparallel to the flow direction. The unsteady pressures acting on a vibrating cylinder are simulated and thernwork done by them for one cycle of a harmonic motion is computed. The effects of a splitter plate on thernflow around the cylinder as well as on the aerodynamic stability of the ovalling vibrations are also discussed.rnThe consideration on the mechanism of ovalling vibrations is verified by the results of a free-vibration test.
Address
Yasushi Uematsu, Department of Architecture and Building Science, Tohoku University, Sendai 980-8579, JapanrnNoboru Tsujiguchi, Yokohama Branch, Nishimatsu Construction Co. Ltd., Yokohama, JapanrnMotohiko Yamada, New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan
Abstract
This paper reports the field measurements concerning pressure equalization of rainscreenrnfacades carried out at the Technical University of Eindhoven (TUE) in the Netherlands. The field facilityrnincluding the details of test panel, meteorological tower, instrumentation, data collection and analysis isrnpresented. Results of investigations into cavity response for various leakage and venting configurations arerndiscussed. Frequency domain techniques have been utilized to show the influence of wind as well asrnfacade characteristics on the pressure equalization performance. Further, this paper presents an earlyrnattempt to synthesize the experimental results into existing building codes.
Key Words
field measurements; pressure equalization; rainscreen facade.
Address
K. Suresh Kumar, RWDI Inc., 650 Woodlawn Road West, Guelph, Ontario, N1K 1B8, CanadarnJ.A. Wisse, Faculty of Architecture, Building and Planning, FAGO, Technical University of Eindhoven (TUE), Postbus 513, 5600 MB Eindhoven, The Netherlands
Abstract
The paper addresses the suitability of wind pressure coefficients specified in contemporaryrndesign standards and codes of practice for gable roofs of intermediate slope (roof angle 10 o -30 o ). In arnrecent research study, a series of low building models with different roof slopes in this intermediate rangernwere tested in a boundary layer wind tunnel under simulated open country terrain conditions. This wasrndifferent from the original study in the 70
Key Words
building; code; design; load; pressure; roof; standard; wind.
Address
Theodore Stathopoulos and Kai Wang, Centre for Building Studies, Concordia University, Montreal, Quebec, CanadarnHanqing Wu, RWDI Inc., Guelph, Ontario, Canada
Abstract
A full-scale synchronized data acquisition system was set up on the roof of the experimentalrnbuilding at the Texas Tech University Wind Engineering Research Field Laboratory to simultaneouslyrncollect approaching wind data, conical vortex images, and roof corner suction pressure data. One-secondrnconditional sampling technique has been applied in the data analysis, which makes it possible to separatelyrnevaluate the influencing effects of the horizontal wind angle of attack, q, and the vertical wind angle ofrnattack, j. Results show a clear cause-and-effect relationship between the incident wind, conical vortices,rnand the induced roof-corner high-suction pressures. The horizontal wind angle of attack, q, is shown tornbe the most significant factor in influencing the overall vortex structure and the suction pressures beneath.rnIt is further revealed that the vertical wind angle of attack, j, plays a critical role in generating therninstantaneous peak suction pressures near the roof corner.
Address
F. Wu, P. P. Sarkar and K. C. Mehta, Wind Engineering Research Center, Department of Civil Engineering, Texas Tech University, Lubbock, Texas, 79409-1023, U.S.A.
Abstract
This paper presents an analytical method which takes into account the non-linearity of individualrnmembers, and discusses some case study results. It also discusses the relationship between member non-elasticrnbehavior and excitation duration, and the relationship between member fracture and overall structurernbehavior. It is clearly demonstrated that the frame already shows almost unstable behavior due to long-columnizationrnjust before the occurrence of a column fracture. Then, a column fracture immediately induces arnstructural collapse mechanism.
Key Words
across-wind force; non-elastic response; tall steel buildings; frame models; member cumulative ductility; member fracture; structural collapse mechanism.
Address
Yukio Tamura, Department of Architecture, Tokyo Institute Polytechnicsrn1583, Iiyama, Atsugi, Kanagawa, 243-0297, JapanrnHachinori Yasui and Hisao Marukawa, Urban Environment Research Center, Izumi Sohken Engineering Co., Ltd. 51 Minami-sode, Sodegaura, Chiba 299-0268, Japan
Abstract
Two 12 m high tubular steel lighting columns have been instrumented to determine the wind-inducedrnfatigue loading experienced by such columns. Each column supported a single luminaire mountedrnon a 0.5 m long bracket. One column was planted in soil, and the other bolted through a welded baseplaternto a substantial concrete base. The columns were strain gauged just above the shoulder weld which connectedrnthe main shaft to the larger base tube. Forced vibration tests were undertaken to determine the naturalrnfrequencies and damping of the columns. Extensive recordings were made of response to winds withrnspeeds from 4 m/s to 17 m/s. Selected records were analysed to obtain stress cycle counts and fatiguernlives. Mean drag coefficients were also derived from the strain data to investigate experimentally the effectrnof Reynolds Number.
Key Words
wind loading; fatigue; drag; lighting columns; street lights; lamp-posts.
Address
A.P. Robertson, R.P. Hoxey, J.L. Short and L.R. Burgess, Silsoe Research Institute, Wrest Park, Silsoe, Bedford, MK45 4HS, U.K.rnB.W. Smith, Flint & Neill Partnership, 21 Dartmouth Street, London, SW1H 9BP, U.K.rnR.H.Y. Ko, Highways Agency, Southwark, Street, London, SE1 OTE, U.K.
