Keisoku Research Consultant Co., Ltd.
The Shimakawahara Tunnel was constructed in 1970s for flowing wasted water as a part of sewerage network. The tunnel was made of concrete with height of 4,740mm, width of 4,200mm and length of about 5km.
Even a number of cracks have appeared spreadly and have been sealed with appropriate treatments, a reliable monitoring system in which enable to grasp the structural health behavior is expected. To maintain the serviceability of tunnel a monitoring is pro-posed by utilizing SOFO sensory technology. The aim of monitoring is to monitor the structural health degradation due to environmental evolution and mechanical evolution such as dynamical stress of streaming water. In order to monitor the global deteriorated structural deformational properties, 5 of 10m long-gage optical fibers were installed.
Periodical monitoring was performed once a year.