大尺度平屋盖聚类最优风压分区研究

以大尺度平屋盖为研究对象，针对其风压分布变化梯度较大的问题和GB 50009-2012《建筑结构荷载规范》关于大尺度平屋盖风压分区规定的不完善，围绕大尺度平屋盖风压分区问题，在得到各种风向下风压测点最不利极值风压的基础上，利用最短距离聚类法对风压测点分区，得到不同分区类数下的分区方案，用基于质量系数的聚类有效性评价法确定最佳聚类数及最佳分区方案，并采用面积权重法给出大尺度平屋盖分区风压系数。研究结果表明：大尺度平屋盖聚类最优风压分区类数为3；大尺度平屋盖角部大致在10%屋盖跨度范围内，属于风敏感部位，设计、施工时需特别注意；整个屋面平均风压系数会导致大尺度平屋盖中部偏于保守设计，角部低估了风荷载；在进行大尺度平屋盖抗风设计时，应先确定极值风压分区，并针对不同部位分别进行设计和施工。通过与规范平屋盖分区方式、常用分区方式确定的分区风压系数对比显示，聚类最优风压分区较其他方式确定的分压风压系数结果更为合理。

Study on clustering optimal design zones of wind pressure on large-scale flat roof

As for the imperfection of design zoning for cladding design in current Chinese loading code, the optimal zoning law of area-averaged wind pressure for a large-scale flat roof cladding design by clustering algorithm is presented in this paper. The most unfavorable point peak pressure is derived considering all the inflow direction. Then different kinds of zoning laws are produced by the shortest distance of clustering algorithm and the optimal zoning law is found by the clustering validity assessment method based on quality coefficient. Finally, the area-averaged pressure is calculated by the optimal zoning law. Four conclusions can be drawn. Three classes of design zones for a large-scale flat roof are divided using the clustering algorithm. The most sensitive zone, 10% of the breadth, is located at the roof corner, which should be paid more attention in the design and construction. The averaged wind pressure coefficient of whole roof results in the conservative design for the middle part of flat roof and the underestimation of wind loads for the roof corner. The extreme wind pressure zones should be determined in advance and the different zones are designed and constructed respectively. Compared with the zoning law in current Chinese loading code and the most common zoning method for area-averaged pressure on large-scale flat roof, it is found that the optimal zoning law derived by clustering algorithm is more reasonable.