20吨/5吨箱型结构的桥式起重机,跨度为31.5米。按设计标准要求,应具有千分之一跨度的上拱度(即挠度),两主梁同一截面处高低差不得大于4毫米。但由于常年频繁作业,致使上拱度产生下降变形,必须及时进行修复。以往的修复方法是将起重机分部件拆卸 20 t / 5 t box structure overhead crane, span of 31.5 meters. According to the design standards, it should have a one-thousandth span camber (that is, deflection), two girders at the same cross-section height difference of not more than 4 mm. However, due to frequent perennial operations, resulting in declining crown deformation, must be promptly repaired. The previous repair method is to dismantle the crane subassembly