一、前言水泥混凝土是在建筑上用得最广、用量最大的一种建筑材料,它在力学性能上的主要缺点是:抗拉强度低和极限拉伸小,因而抗裂性差;抗冲击性低。为了克服这些缺点,在建筑上一个多世纪前就已开始采用钢筋混凝土,二十世纪二十年末开始采用予应力钢筋混凝土, I. INTRODUCTION Cement concrete is one of the most widely used and most used building materials in construction. Its main drawbacks in terms of mechanical properties are: low tensile strength and low ultimate elongation, and therefore poor crack resistance; impact resistance low. In order to overcome these shortcomings, reinforced concrete has been used for more than a century ago in buildings, and prestressed reinforced concrete has been used since the end of the 20th century.