前言全部预应力钢筋混凝土构件由于刚度好,能代替一些大跨度钢结构建筑,故发展很快。但在发展中也发现全部预应力构件有反拱、纵裂、抗震性差等弱点,故近十几年,又发展了部分预应力构件。部分预应力构件兼有预应力与普通混凝土构件的优点,避免了各自的缺点。目前瑞典、芬兰、英国等十几个国家,已单独制订有部分预应力钢 Foreword All prestressed reinforced concrete components have developed rapidly due to their good rigidity and can replace some large span steel structures. However, in the course of development, all prestressed components were found to have weaknesses such as reversed arches, vertical cracks, and poor earthquake resistance. Therefore, in the past ten years, some prestressed components were developed. Some prestressed components combine the advantages of prestressed and ordinary concrete components, avoiding their own shortcomings. More than a dozen countries, including Sweden, Finland, and the United Kingdom, have separately developed partially prestressed steels.