在建筑工程中,许多钢筋混凝土及混凝土结构,为减轻自重,降低成本,常常采用空心结构。空心或孔洞还可以做为各种不同用途的隐蔽管道使用。 近年来,国外不少地方,为在钢筋混凝土结构内形成空心或孔洞,采用了纸制芯模。 在苏联,借助于纸制芯模成型的空心钢 In the construction project, many reinforced concrete and concrete structures often use hollow structures to reduce their own weight and reduce costs. Hollows or holes can also be used as concealed pipes for various purposes. In recent years, in many places abroad, paper-made mandrels have been used to form hollows or holes in reinforced concrete structures. In the Soviet Union, hollow steel moulded with the aid of a paper core