crane span structures的用法和样例：
例句
- It is demanding to fabricate crane bridge as large welded structure, so the upgrade to change its span is very challenging.
摘要起重机桥架作为大型焊接结构件，制造要求高，其改制具有典型意义。 - Crane makers are usually happy to give details of the dimensions of their cranes and bridges to structural engineers.
吊车制造厂商一般乐于将他们生产的吊车和桥架的详细尺寸提供给结构工程师。
