假定，厂房位于8度区，采用轻屋面，屋面支撑布置见图，支撑采用Q235钢材。试问，屋面支撑采用下列何种截面最为合理（满足规范要求且用钢量最低）？ <br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/24131024_0.png"><br/> 屋面支撑布置图各支撑截面特性如表：<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/24131024_0_1.png">