预应力混凝土梁极限破坏形式为混凝土压溃破坏，即破坏时梁顶缘混凝土达到其

Limit damage in the form of prestressed concrete beam concrete crushing damage, i.e. damage which the beam reaches the top edge of the concrete ultimate compressive strain cu = 0.0033 after crushing, non-prestressed tensile longitudinal reinforcement yield, the yield is not pressed steel;

The limit destruction form of pre-stressed concrete beam is concrete collapse damage, that is, when the top edge of the beam reaches its limit pressure strain concrete after the collapse, the non-pre-stressed pulled ribs yield, the pressure dispute;

The ultimate failure mode of prestressed concrete beam is concrete collapse, that is to say, when the concrete at the top edge of the beam reaches its ultimate compressive strain ∑ Cu = 0.0033, it will collapse, the non prestressed tensile longitudinal bar will yield, and the compression bar will not yield;<br>