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一、前言预应力混凝土是1928年由法国的弗来西奈首先研究成功的。预加应力的目的是使混凝土预先受压以消除使用条件下混凝土的裂缝。所以他的设计准则是结构于使用荷载下,混凝土应永远处于受压状态而不容许出现拉应力。他认为没有裂缝的混凝土使用性能好、质量高。实践表明,这种在使用状态下混凝土永远处于受压状态的所谓“全”预应力结构既非必要,也不经济,而且在很多情况下仍然会出现裂缝,与之相
I. INTRODUCTION Prestressed concrete was first studied in France in 1928 by Fresna Sinai. The purpose of prestressing is to pre-stress the concrete to eliminate cracks in the concrete under conditions of use. Therefore, his design criteria is that the structure should be under load and the concrete should always be under pressure without allowing tensile stress. He believes that crack-free concrete has good performance and high quality. Practice has shown that this kind of so-called “all-prestressed” structure in which the concrete is in a state of pressure forever under use is neither necessary nor economical, and cracks still occur in many cases.