| dc.description.abstract | In recent years, the strength of rains and floods caused by typhoon are much stronger than ever, serial of bridge failure events made the bridge managements and researchers start to pay much attention to this problem. After the Kao-Ping Bridge broken, the Ministry of Transportation and Communications surveyed all the damaged bridges in Taiwan, than discovered that 82% bridges were damaged by scour. That is to say, scour is the primary threat to structure health of the bridges. When the pile foundation begin to expose, the bearing capacity of bridge structure will decrease. While the lateral force acts on the bridge structure is greater than the bearing capacity, the bridge pier will sink, tilt, and even collapse. Because there are several typhoons invading Taiwan every year, the government should pay more attention to the problem of bridge scour. The study subject is to develop a durable, reliable and cheap scour monitoring system- Piezoelectric Film Mounted Gravity Type Scour Monitoring System. This system improves the most existing problem and it has a cheap building cost, able to measure the back silting and installation without digging the river bed. A Piezoelectric Film Mounted Gravity Type Scour Monitoring System at least includes several piezoelectric films, a detection pole, two H beams, several fixing components, an encoder and a data logger. The detection pole is placed on river bed and links an encoder when finishing the installing. After the scour, the detection pole will go down with river bed, and then we can know the decreasing of elevation of river bed by the data from encoder. After the back silting, the piezoelectric films, which buried with silt or soil, will not send out the voltage because of the static situation. By this character, we can count how many piezoelectric films are buried with silt or soil. It can use the wireless network to achieve the real time monitoring. The manager can know the situation without going to the field in person and judge whether the bridge should do rush repair or not.
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