Study On Wind-induced Internal Pressure And Its Effects On Structures

Opening building is refere to the structure with wall opening due to destroy of windows or doors during hurricane, or unerected of enclosure under construction. The safety of a building structure in strong wind depends as much on internal pressure as it does on external pressure. Dynamic characteristics of wind-induced internal pressure and response of roof structure by exter-inter wind pressure combined action, is of great significance in wind resistance design. For the limiting case of a rigid non-porous building with a dominant windward wall opening, a number of experimental and analytical studyies in the past, have increased our under standing of internal pressure behaviour. This paper describes an stiffness model wind tunnel test to research on dynamic characteristics of wind-induced internal pressure and the relationship between external and internal pressure. Aeroelastic model wind runnel test was carried out to investigate the effect of internal pressure on roof response. The transient wind-induced internal pressures on rigid roofs were compared with computational fluid dynamics (CFD) numerical results by large eddy simulation, and then the conditions and mechanism of the resonant vibration of flexible roofs in the case of sudden opening were discussed. The main contents in this paper:1. The rigid model for windward opening building was designed. 21 work conditions of opening location, area, model volume and background porosity were carried out. Theory estimating equations of mean and root-mean-square of internal pressure coefficientswere presented by linearization of a transfer equation of external pressure to internal pressure. The affects of strutural parameters on mean and root-mean-square of internal pressure coefficients were analized by comparing the results of estimation and wind tunnel test.2. The affects of strutural parameters on roof response were studied by using aeroelastic model wind tunnel. An identification of aerodynamic damping method combined with the random decrement technique (RDT) and the Hilbert-huang transform (HHT) for long-span roof was presented. Aerodynamic damping in the case of sealing situation and opening situation is calculated respectively using thismethod and compared with the results of wind tunnel tests. The regular of aerodynamic damping depending on wind velocity and strutural parameters was discussed.3. Runge-Kutta method was utilized to solve the transfer equation. The influence of roof flexibility, opening area, wind speed and damping ratio on Helmholtz vibration was also obtained.4. Mean wind pressure coefficient was steady state computed by use of standard k-e dual-equation turbulence model. RMS of wind pressure coefficient was unsteady state computed by use of large eddy simulation. This paper describes an extension of the transient response study to utilise the transient response obtained from computational modelling in predicting the building internal pressure gain function. Based on the isentropic theory, the building volume should be enlarged in computational model. Good agreement obtained between the aeroelastic model test and the numerical simulation shows that the employment of the building volume enlargement in CFD can avoid the fluid-structure coupling analysis.5. Using the local mean wind pressure coefficients and time history of fluctuating pressures determined in CFD method, the wind-induced dynamic response for flat roof structure was calculated in time domain.6. To clarify the wind load distribution of industrial building during construction and research on its mechanism of wind-induced collapse, the numerical wind tunnel by Subgrid scale (SGS) model was performed to simulate the wind load on the wall of an industrial building during construction in Guang Dong province. To compare ventilation status of corridor double-skin facade with box facade, wind tunnel test and numerical simulation were carried out.