基于台风过程的建筑围护结构设计风压估算方法

A method for estimating design wind pressure on building envelopes based on typhoon process

为了降低基于台风过程的建筑围护结构设计风压估算方法——Storm passage方法的复杂性且不减弱其高精度,假定各次风暴引起的结构风荷载极值之间相互独立,得到了形式更加简洁更易于理解的用于Storm passage方法的结构风压年极值概率分布表达式。并从理论上将改进前后的Storm passage方法进行了对比,以证明两者在高重现期下的精度基本相同。在此基础上,结合一工程实例,将改进方法、原Storm passage方法、未考虑台风过程的Monte Carlo模拟方法以及三种工程上常用的简算方法进行了对比。研究结果表明,对于50年重现期设计风压,改进方法与原Storm passage方法之间误差极小,可忽略不计;不考虑台风过程将导致结构设计风压估值偏小,大部分结果的偏小程度在10%以内;工程中常用的最不利法过分保守,有时甚至可偏大100%;风向折减因子法可给出经济性和安全性都适当的结果,但应谨慎使用,不合理的风向折减因子取值可能导致估计结果的安全性不足。

In the purpose of reducing the complexity of the Storm passage method which can be used to estimate design wind pressure on building envelopes based on typhoon process, and without reducing the high accuracy of the original method, a more concise and easier-to-understand annual maximum wind pressure cumulative distribution expression for the Storm passage method was obtained by assuming that each storm extreme load was mutually independent. The improved and original Storm passage methods were compared in theory and proved that the precision of the two methods was almost the same for a high return wind period. Thereafter, using an example, the improved method, the original Storm passage method, the Monte Carlo method without considering typhoon process, and three commonly used simplified methods were compared. The results show that for the 50-year return period of design wind pressure, the error between the calculated results of the proposed improved method and the original Storm passage method can be negligible. The Monte Carlo method without considering typhoon process will underestimate the design wind pressure, but the maximum underestimation rate is within 10%. The worst-case method is generally too conservative, the overestimation of this method can reach up to 100% in some cases. The sector-by-sector method can produce results with reasonable economy and security, while the unreasonable directional factors may lead to the estimation with safety deficiency.