一、前言钢筋混凝土有一个很大的弱点,就是当钢筋混凝土构件处于受弯状态时,由于混凝土的抗拉能力较小,构件的受拉区往往会出现裂缝,使构件的刚度大为降低。若对构件的受拉区预先施加一个压应力,当构件受到的外荷载在其受拉区产生的拉应力超过预先施加的压应力时,才能使混凝土产生裂缝。这样就可延缓构件开裂时间,使混凝土构件在使用阶段不开裂,从而克服普通钢筋混凝土构件的弱点。这种在钢筋混凝土构件受到外荷载作用之前(或在构件使用阶段之前),就预先对其受拉区施加一个压应力而获得的钢筋混凝土,就简称预应力混凝土。预应力混凝土保留了普通钢筋混凝土的 I. Preface Reinforced concrete has a great weakness, that is, when the reinforced concrete components are in the bent state, due to the small tensile capacity of the concrete, cracks in the tension zone of the components tend to occur, and the rigidity of the components is greatly reduced. If a compressive stress is applied in advance to the tension zone of the component, cracks can occur in the concrete when the tensile stress of the component subjected to the external load in the tension zone exceeds the pre-applied compressive stress. In this way, the cracking time of the component can be delayed so that the concrete component does not crack during use, thereby overcoming the weakness of the ordinary reinforced concrete component. Before the reinforced concrete member is subjected to the external load (or before the use of the member), the reinforced concrete obtained by applying a compressive stress to the tensioned region in advance is referred to as prestressed concrete. Prestressed concrete retains ordinary reinforced concrete