一种新型光伏农业大棚结构设计研究

Reserch on structure design of a new photovoltaic agricultural greenhouse system

使用结构有限元软件SAP 2000和结构分析软件PKPM分别建立了新型光伏农业大棚的三维空间和二维平面模型,根据桩柱嵌固点位置设置固定约束,三维空间模型中屋架支撑和桩间支撑采用索模拟,其余结构采用框架单元模拟,据此分析不同荷载工况下结构体系的受力性能,并将三维及二维模型计算结果进行了对比.结果表明:桩柱受力向最后1跨端桩柱集中,南坡横梁受力向最前1跨横梁集中,这是光伏农业大棚结构体系与常规光伏结构的最大区别;支撑体系具有一定的作用,桩间支撑及屋架支撑将边列有效约束形成整体受力系统,减少荷载作用下桩身变形,从而降低桩身受力,中间列在系杆体系平面外约束及整体空间效应下,桩身变形和弯矩也较平面模型有所减少;大棚结构的空间效应改变了横梁体系的受力性能,根据平面模型计算选取截面时,局部会造成安全隐患,局部也会造成材料浪费;屋脊系杆受力大于桩顶系杆的受力,屋脊系杆的设计截面可稍大于桩顶系杆的设计截面.

The three-dimension(3-D)spatial model and two-dimension(2-D)plane model of a new photovoltaic(PV)agricultural greenhouse system are built by using structural design software SAP 2000 and PKPM respectively.The embedded place of pile-pillar is fixed;the roof support system and pile support system are simulated by cable element;the others are simulated by frame element.Then the 2D and 2D structure performances in different load conditions are analyzed and compared.It is shown that the pile-pillar force is concentrated to the last span;but the force of beam in the south slope is concentrated to the first span,which is the biggest difference between PV agricultural greenhouse system and traditional PV system.The roof support system,pile support system and tie-rod system bind the whole model together effectively,which reducing the pile-pillar deformation and bearing-force.The performance of beam system is changed by the space effect of greenhouse,which causing safety risk or material waste in some regions referring to the results of plane model.The roof tie-rod section should be larger than the pile top tie-rod.