1)structural steelwork [public works category],结构钢筋工程(公共工程类别)2)specialized operations for highway structures [public works category],专门公路结构运作(公共工程类别)3)prestressed concrete works for highway structures [public works category],公路结构的预应力混凝土工程(公共工程类别)4)fabrication of steel pipe specials [public works category],特别钢管的制造(公共工程类别)5)electrical installations [public works category],电器装置(公共工程类别)6)land piling [public works category],土地打桩(公共工程类别)