Detecting structural damage from earthquakes is a vital aspect of disaster response for ensuring the continued safe use of affected building structures. In this paper, a method is proposed for detecting beam-end fractures after earthquake vibrations. In this proposed method, an index called local stiffness is used, which is defined as the ratio of the bending moment amplitude at a focused section in the first-mode vibration to the deformation amplitude of the structural frame. When a fracture occurs near the focused section, the local stiffness decreases significantly owing to the decrease of the moment transfer ability of the section. Thus, beam-end fractures are located by detecting drops in the local stiffness near a fracture. This method was applied to data measured in a shaking table test of a two-story steel moment frame, where beam-end fractures were observed after several excitations using earthquake ground motions. The time history of the local stiffness values obtained during the test demonstrated large decrease in values around the times of the fracture occurrences. Moreover, the local stiffness values could be calculated with adequate accuracy, even from the measured data without strict time synchronization. The local stiffness value was determined to be an effective tool for fracture detection based on simple time-series physical measurements.

检测地震造成的结构破坏是灾难响应的重要方面，以确保持续安全地使用受影响的建筑结构。本文提出了一种检测地震振动后梁端裂缝的方法。在此建议的方法中，使用了一个称为局部刚度的指标，该指标被定义为第一模态振动的聚焦部分处的弯矩幅度与结构框架的变形幅度之比。当在聚焦部分附近发生断裂时，由于该部分的矩传递能力的降低，局部刚度显着降低。因此，通过检测裂缝附近局部刚度的下降来定位梁端裂缝。将该方法应用于在两层钢制弯矩框架的振动台测试中测得的数据，在使用地震地面运动进行多次激励后，观察到梁端断裂。在测试过程中获得的局部刚度值的时间历程表明，在断裂发生时间附近的值大大降低。此外，即使没有严格的时间同步，也可以从测量数据中以足够的精度计算出局部刚度值。基于简单的时间序列物理测量，确定了局部刚度值是用于裂缝检测的有效工具。即使没有严格的时间同步也无法从测量数据中获取数据。基于简单的时间序列物理测量，确定了局部刚度值是用于裂缝检测的有效工具。即使没有严格的时间同步也无法从测量数据中获取数据。基于简单的时间序列物理测量，确定了局部刚度值是用于裂缝检测的有效工具。