Effect of Strain Accumulation on Deformation Capacity of RC Flexural Members

探讨了钢筋混凝土构件受弯屈服后受反向循环加载的破坏机理。在反向循环荷载作用下，塑性铰区域在强度退化前出现了与单调荷载作用下相似的抗力消失和重建机制。当阻力机制暂时消失后无法重建时，发生强度劣化。认为塑性区的累积应变抑制了重建。应变积累发生在低荷载区，刚好在反向加载后进行重建。累积应变被认为是阻力机制重建的一个误差。当重构的误差积累到一定程度时，阻力机制的重构就变得不可能。这种破坏机制不同于增大弯矩或剪力所提供的阻力机制破坏而造成的破坏模式。另一方面，观察到的破坏模式不是由于阻力机制的破坏造成的，而是由于累积的重构误差所提供的重构不可能造成的。

Failure mechanism of RC members subjected to reversed cyclic loading after flexural yielding was discussed. Under reversed cyclic loading, a resistance mechanism similar to that under monotonic loading repeats temporary disappearance and rebuilding in the plastic hinge region before strength deterioration. Strength deterioration occurred when the resistance mechanism could not be rebuilt after the temporary disappearance. It was considered that accumulated strain in the plastic region inhibited the rebuilding. The strain accumulation occurred in the low load region just after the reversed loading where the rebuilding took place. The accumulated strain was considered to be an error of the rebuilding of the resistance mechanism. When the error of rebuilding was accumulated enough, it became impossible to rebuild the resistance mechanism.The failure mechanism is different from the failure mode that is caused by destruction of the resistance mechanism provided by increasing bending moment or shear force. On the other hand, the observed failure mode is not caused by destruction of the resistance mechanism but caused by impossibility of the rebuilding provided by accumulated errors of the rebuilding.