冷弯型钢檩条屋面增设光伏板的下撑式檩条结构加固受力性能分析及改造方案

轻钢厂房屋面檩条在加铺光伏板后进行荷载验算时通常会出现承载能力不足的问题,对此提出了一种下撑式檩条结构对原有檩条进行加固改造。为研究加固后下撑式檩条结构的受力性能以及提出符合经济性原则的改造加固方案,利用ANSYS建立了下撑式檩条的有限元模型,并采用控制变量法研究了撑杆长度、撑杆截面、拉条截面和撑杆间距对下撑式檩条结构受力性能的影响。结果表明：撑杆长度是整体结构受力的主要影响因素,撑杆长度增加,檩条及撑杆应力均会大幅减小,拉条应力则呈先增大后减小趋势；拉条截面变化对整体结构受力影响较小,随拉条截面直径增加,檩条及撑杆应力曲线保持平缓下降,拉条应力则更为敏感,曲线下降斜率较大；撑杆截面与撑杆间距对整体结构受力影响程度较低。最终,提出了满足改造用钢量最小的改造加固方案,且针对部分常见截面、跨度及设计荷载的屋面檩条,给出了对应的改造方案推荐表以便实际工程快速选用。

Study on Mechanical Property and Retrofitting Scheme of Down-stayed Purlin Structure for Reinforcing Cold-formed Steel Purlin Roof with Photovoltaic Panels

The problem of insufficient bearing capacity usually appears in the load checking calculation of light steel mill roof purlin after the photovoltaic panels are added. Therefore, a down-stayed purlin structure was proposed to reinforce the original purlin. To study the mechanical property of reinforced down-stayed purlin structure and put forward a reinforcement scheme conforming to the principle of economy, ANSYS was used to establish the finite element model of down-stayed purlin, and control variable method was used to study the influence of the strut length and strut cross section, brace cross section and distance between struts to mechanical property of down-stayed purlin structure. The results show that the strut length is the main influencing factor of the whole structure stress. With the strut length increasing, the purlin and strut stress will decrease greatly and the brace stress will increase first and then decrease. The change of brace section has little influence on the stress of the whole structure. As the diameter of brace section increases, the stress curve of purlin and strut declines gently, however the brace stress is more sensitive and the slope of the curve is large. The influence of strut section and strut spacing on the stress of the whole structure is little. Finally, the reinforcement scheme meeting the minimum amount of steel was put forward. And in order to facilitate the rapid selection of practical projects, the corresponding reconstruction scheme recommendation table was given for some common section, span and design load of roof purlin.