在改革开放的新形势下,随着预应力高强钢材供应条件的好转,我国预应力技术也取得了突破性的进展,进入了一个由低强向高强、由低技术向高技术、由一般结构向现代结构发展的新阶段。这一阶段的特点主要表现在以下四个主要方面。一、部分预应力设计理论按照早期的设计理论,预应力混凝土是一种不容许出现拉应力的弹性材料。用它制作的梁板构件具有抗裂性高、不裂缝、刚度大等优点。但长期实践表明,这种按“无拉应力”或“零”应力准则设 Under the new situation of reform and opening up, with the improvement of the supply conditions of prestressed high-strength steel products, China’s prestressed technology has also made breakthrough progress, and has entered a transition from low-strength to high-strength, from low-tech to high-tech, and from general structures. A new stage in the development of modern architecture. The characteristics of this stage are mainly reflected in the following four major aspects. I. Partial Prestressed Design Theory According to the early design theory, prestressed concrete is an elastic material that does not allow tensile stress. The beam plate members made with it have the advantages of high crack resistance, no cracks, and high rigidity. However, long-term practice has shown that this type of criterion is based on the “no tensile stress” or “zero” stress criteria.