Characterizing wind-structure interaction for performance-based wind design of tall buildings
Characterizing wind-structure interaction for performance-based wind design of tall buildings
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DOI：
10.1016/j.engstruct.2023.115812
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发表时间：
2023-08
影响因子：
5.5
通讯作者：
S. P. Hareendran;A. Alipour;B. Shafei;Partha Sarkar
中科院分区：
文献类型：
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作者：
S. P. Hareendran;A. Alipour;B. Shafei;Partha Sarkar
基于性能的风设计（PBWD）已受到风界和结构工程界的广泛关注。ASCE PBWD预标准（2019）的发布特别强调了这一点。高层建筑的PBWD需要一系列步骤，其中一个步骤是相互作用参数，即表征高层建筑与风场的相互作用。在涉及细长结构（如高层建筑）的研究中，必须考虑这一随时变气动载荷的相互作用参数。气动载荷包括由脉动风引起的湍流载荷，称为抖振载荷，以及由结构运动与风相互作用引起的自激载荷，称为气动弹性载荷。柔性结构在临界风速下会变得不稳定，即所谓的颤振速度，其中结构会发生发散运动。自激载荷引起的气动失稳通常不会在高层建筑的设计风速范围内发生，但在风-结构相互作用分析中确实需要考虑，特别是当高层建筑变得越来越细长并允许进入后弹性区域时。本研究旨在通过将自激荷载纳入高层建筑顺风、横风和扭转三自由度响应运动的响应分析中，来表征高层建筑PBWD中的相互作用参数。为此，首先从结构的比例截面模型的风洞试验中获得用于表示频域自激载荷的颤振导数，然后将其转换为称为有理函数系数（RFC）的近似系数，作为拉普拉斯或时域自激载荷的有理函数近似（RFA）的一部分。在时域上，将与计算的RFC相关的抖振荷载和自激荷载结合起来计算结构上的风荷载。利用非线性动力时程分析方法研究了44层和60层高层建筑在极端风条件下的非线性结构行为，并观察了任何类似颤振的不稳定性。PBWD概念的应用考虑了与乘员舒适度和结构或非结构损伤相关的性能目标。
Performance-based wind design (PBWD) has been receiving a great deal of attention from the wind and structural engineering communities. This is specifically highlighted with the release of the ASCE pre-standard for PBWD (2019). The PBWD of tall building requires a series of steps one of which is the interaction parameter, i.e. characterizing the interaction of the tall building with the wind field. In the studies involving slender structures-such as tall buildings, it is essential to consider this interaction parameter which is a function of the time-varying aerodynamic loads. The aerodynamic loads consist of the turbulent loads due to fluctuating wind, known as buffeting loads, and the self-excited loads resulting from the interaction of the structural motions with wind, referred as aeroelastic loads. Flexible structures can become unstable at a critical wind speed, known as flutter speed, wherein a diverging motion of the structure occurs. Aerodynamic instability that is caused by self-excited loads generally doesn’t occur in tall buildings within their design wind speeds but certainly needs to be considered in a wind-structure interaction analysis, particularly when tall buildings become increasingly slender and are allowed to enter post-elastic region. This study aims to characterize the interaction parameter in the PBWD of tall buildings by including the self-excited loads in its response analysis corresponding to the three-degree-of-freedom response motions of the building in along-wind, across-wind, and torsional directions. For this purpose, the flutter derivatives that are used to represent the self-excited loads in frequency domain are first obtained from wind tunnel tests of scaled section models of the structure and then converted into approximate coefficients known as Rational Function Coefficients (RFC) as part of Rational Function Approximations (RFA) of the self-excited loads in Laplace or time domain. The wind loads on a structure in time domain are calculated by combining both the buffeting loads and self-excited loads associated with the calculated RFC. The non-linear structural behavior of a 44-story and a 60-story tall building each is studied using nonlinear dynamic time-history analysis in extreme wind conditions and then observed for any flutter-like instabilities. The concept PBWD is applied considering the performance objective involving those associated with occupant comfort and structural or non-structural damages.