目前,世界各国发展了不少高层建筑,有的达到一百多层,高层建筑的承重骨架大都采用钢结构。由于我国长期以来钢产量供不应求,钢材价格高于钢筋混凝土,使建筑中采用钢结构受到很大限制,过去只在一些冶金和机械工业的大、重型厂房中,当采用钢筋混凝土作主承重结构有困难时,才采用钢结构。近年来,随着我国四化事业的发展,我国一些大城市,如北京、上海、广州等地随着高层建筑的兴起,有些同外资合营 At present, many countries in the world have developed a number of high-rise buildings, some of which reach more than a hundred layers. Most of the load-bearing structures of high-rise buildings use steel structures. As China’s steel output has been in short supply and steel prices are higher than those of reinforced concrete, the use of steel structures in construction has been greatly limited. In the past, only large and heavy-duty factories in metallurgical and mechanical industries used reinforced concrete as the main bearing structure. When difficult, steel structures are used. In recent years, with the development of China’s four modernization projects, some major cities in China, such as Beijing, Shanghai, and Guangzhou, have risen with the rise of high-rise buildings, some of which have joint ventures with foreign companies.