开孔结构风致内压研究

Study on wind-induced internal pressure of opening structure

为研究迎风面单一开孔建筑的内压特性,分析了开孔建筑的结构特征参数和来流风速因素对内压的影响.采用Davenport水平脉动风速谱,利用三角级数对开孔处的来流风速时程进行模拟.根据准定常假设,由模拟得到的风速时程计算出开孔处的外压系数时程,并通过内压传播方程计算出内压系数时程.参数分析结果表明,内压能量随开孔尺寸、来流风速的增大而增大,随建筑容积、结构柔度的增大而减小,Helmholtz频率仅受建筑本身结构参数影响,同来流大小无关,由于开孔后结构刚度降低,容易落入暴风雨中的低频能量区发生二次破坏.

To clarify the properties of internal pressure of single opening structure, the effects of opening building＇s characteristics and wind speed on internal pressure were analyzed. By adapting Davenport spectrum for horizontally fluctuating wind, wind velocity time history at the opening was simulated by using trigonometric series. On the basis of quasi-steady theory, external pressure coefficient time history was calculated from the external wind velocity time history at the opening, and internal pressure coefficient time history was computed by utilizing an internal pressure transmission equation for a single opening. The parametric analysis results show that large opening size and wind speed can provoke high internal pressure, and that the increase of building bulk and flexibility can decrease the internal pressure. Helmholtz resonance frequency is merely affected by the structural parameters and is independent of the wind velocity. Secondary damages that are easily caused in low-frequency storm field due to stiffness degradation of structure in the case of opening structure.