所谓预应力混凝土技术,就是人为地预先对混凝土构件引入一个内应力,并使其作用方向和分布情况与使用应力相反,从而使得构件在使用过程中所受外力要首先抵消其预加应力之后,混凝土才开始产生拉伸变形。这样,预应力构件在裂缝时的承载能力就比普通构件的大得多,就使 The so-called prestressed concrete technology is to artificially introduce an internal stress to the concrete member in advance, and make its direction of action and distribution opposite to the use of stress, so that the external force received by the member during use must firstly offset its prestressing force. Concrete begins to stretch and deform. In this way, the load-carrying capacity of the prestressed member in the crack is much greater than that of the ordinary member, so that