弦弓式预应力柱面网壳结构风洞试验及风致效应研究

弦弓式预应力柱面网壳结构是一种新颖的结构形式，通过对网壳下部拉索施加预应力使结构成为自平衡体系，某火电厂干煤棚为弦弓式预应力柱面网壳结构在干煤棚结构中的首次应用，风荷载是其主要荷载之一，目前规范对该类网壳结构的体型系数未作明确规定，因此需要进行风洞试验来确定其体型系数，试验考虑了网壳周边环境的作用，严格模拟了规范规定的大气边界层风场，分析研究了网壳表面风压分布规律及其影响因素，给出了可供设计采用的体型系数，同时进行了风致效应的研究，研究表明，周边环境对网壳表面风压分布的影响较大而煤堆的影响较小，大气边界层风场中风速脉动导致的风压改变在设计时已不容忽视，风荷载对网壳下部预应力拉索应力起着卸载作用，各索的最大应力减少比例在20％左右。

Wind tunnel test and wind-induced response of string-bow prestressed cylindrical latticed shell

String-bow prestressed cylindrical latticed shell is a novel structure, which is self-balanced by pretensioned cables below the shell grid. It has first been used as the dry-coal-shed of a power station. Such structures are usually under strong wind load. The current design codes do not provide the shape coefficients for this kind of structures, hence, it is necessary to carry out a wind tunnel test to acquire the shape coefficients of the wind load. This test attempted to simulate the boundary layer wind field accurately in which the influence of environment has been considered. The paper summarized the behavior of wind pressure on shell surface and the influence factors, arrived at the shape coefficient for design and investigated the wind-induced response. It is shown that the influence to wind pressure distribution due to surrounding environment is important and the influence by coal is less significant. The influence on wind pressure by turbulence in boundary layer wind field can not be ignored in design. Wind load decreases the stress of the cables below the shell grid, with the maximum decrement in each cable being about 20%.