本研究主要為運用智能骨材感測器進行振動台實驗之RC構架與宜蘭牛鬥橋橋墩之健康診斷,所使用的智能骨材壓電感測器為利用壓電陶瓷材料所製成,利用波動力學及壓電材料可發射應力波亦可接收應力波之特性,進行混凝土結構物之健康診斷研究。結構健康診斷為將智能骨材壓電感測器埋入RC結構物內,當試體受到破壞時,由智能骨材壓電感測器發射應力波以及不同位置的感測器來擷取應力波,利用應力波振幅隨著結構破壞程度、裂縫增加而減少振幅的特性,可知RC結構物之損壞程度,利用數值分析得到損壞指標,即可判斷出結構物損壞程度,其量測結果隨著結構物的損壞程度越嚴重,損壞指標也越高,當結構物達到嚴重破壞程度時,所量測到的損壞指標也相當接近最大值。本次研究為壓電感測器第一次應用於現地橋墩結構,除了可驗證壓電材料用於實際結構物檢測的可行性,判斷混凝土結構之健康程度,另實為土木結構非破壞檢測上之一種新的檢測方法。
In this research, the smart piezoelectric sensors have been applied to the damage detections of RC frame to shake table excitations and the in-situ test of the Niu-Dou Bridge in Yi-Lan. The adopted smart sensors of this research are fabricated by piezoceramic materials. Base on the wave propagation theory and the sensor can be used as actuator and receiver for sending and receiving stress waves to monitor the health state of the concrete structures. The smart piezoelectric sensors have been pre-embedded or post-embedded in the concrete structures to form a smart sensing system. The first test was a shake table test of a reinforced concrete frame. A piezoceramic-based device, called “smart aggregate”, was pre-embedded and adopted for the structural health monitoring of the concrete frame under earthquake excitations. The second test of this study was the on-situ health monitoring of RC piers of Niu-Dou Bridge in Taiwan, under seismic loading. RC piers instrumented with the post-embedded piezoceramic-based sensors were tested using reversed cyclic loading. During the shake table test and the on-situ reversed cyclic loading test, one sensor was used as an actuator to generate propagating waves, and the other sensors were used to detect the waves. By analyzing the wave response, the existence of crack can be detected and the severity can be estimated. The experimental results demonstrate the sensitiveness and the effectiveness of the piezoceramic-based approach in the structural health monitoring of concrete structures under earthquake loading.