随着现代科学技术的迅猛发展，我国许多城市中心区60～70年代建造的大批6层以下砖混结构建筑，由于其规模小、功能简单等因素，已远不适应现代工作及城市发展的要求。使用单位迫切希望对原有建筑进行改扩建，这已成为今后一个时期城市建设的重要课题之一。对此，我们在多年实践 With the rapid development of modern science and technology, a large number of 6-storey or less brick-concrete buildings constructed in the central area of ​​many cities in the 1960s and 1970s are far from the requirements of modern work and urban development because of their small scale and simple functions. . The use unit desperately wants to reconstruct and expand the original building, which has become one of the important issues for urban construction in the coming period. In this regard, we practice for many years