求翻译：以湖南某大桥引桥为研究对象。该引桥孔跨布置为3×30m，采用等高度预应力混凝土连续箱梁，上部结构混凝土强度等级C50，采用支架法现浇施工。是什么意思？

Approach for the study of a bridge in Hunan. The bridge opening span arrangement for 3x30m, use height prestressed concrete continuous box girder, upper structure concrete strength class C50, support law cast construction.