偏转风场下高层建筑设计风速的风向折减因子

Wind Direction Reduction Factor for Design Wind Speed of High-rise Buildings Under Twisted Wind Field

摘要:

提出了超高层建筑设计风荷载估算过程中考虑风场偏转影响的强风风速风向折减因子修正方法。在风洞中模拟了一个方形截面超高层建筑刚性模型。在偏转风场和无偏风场工况下，根据提出的修正方法计算了北京地区和南京地区高层建筑设计风速的风向折减因子，分析了风场偏转对高层建筑气动力风向折减效应的影响。结果表明，偏转风场会使建筑风压存在偏移现象，最不利风压出现的风向角与无偏风场下不同，而在考虑风向折减效应的风荷载估算方法中，如果忽略风场偏转的影响就可能导致超高层建筑风荷载的低估，使得结构设计偏于危险，提出的修正方法能够有效解决这一问题。

Abstract:

In this paper， the calculation method of modified wind direction reduction factor of strong wind speed considering the influence of twisted flow in the design wind load estimation of super high-rise buildings is proposed. Wind tunnel tests of a square section high-rise building model under twisted and non-twisted wind fields are conducted. Using the proposed correction method， the wind direction reduction factors of design wind speeds of the Beijing and Nanjing regions are calculated. And the influence of twisted flow on the wind direction reduction effect of the aerodynamic force of the building is analyzed. The results show that there is a shift of wind pressures on the building under the twisted wind field， and the wind direction angles of the most unfavorable wind pressure under the twisted wind field are different from the cases under the non-twisted wind field. In the wind load estimation of the wind direction reduction effect， ignoring the influence of twisted flow may lead to a serious underestimate of the wind load of super high-rise buildings， making the structural design more dangerous. Moreover， the proposed correction method in this paper can effectively solve this problem.