建于1971～1972年间的贵州某厂,其中有4个车间跨度为15m、柱距6m、长度38～72m不等,上有三角形屋架。1990年厂方在维修吊车时发现屋架下弦、中立杆节点及支座附近等处混凝土有裂缝,宽度为0.3～0.05mm(长度有的贯穿整个断面,有的仅在表面)。经我院分析鉴定认为上述裂缝需要进行 Built in 1971 ~ 1972 in a factory in Guizhou, of which four workshops span 15m, column spacing 6m, length 38 ~ 72m range, there are triangular roof truss. In 1990, when the crane was repaired, the factory found the lower chord of the roof truss, cracks in the concrete near the neutral pole joints and in the vicinity of the support, etc., with a width of 0.3 ~ 0.05mm (the length of the whole section, some only on the surface). By our hospital analysis identified that the cracks need to be carried out