Indian river inlet bridge (part A): Description of the bridge and the structural health monitoring system

Abstract

Delaware’s Indian River Inlet Bridge opened to traffic in May of 2012. The cable-stayed bridge has a main span of 289 m and back spans of 121 m. It was constructed using a combination of cast-in-place and pre-cast reinforced concrete. In an effort to enhance the long-term maintenance and management of this significant infrastructure, a comprehensive structural health monitoring (SHM) system was installed on the bridge. To the authors knowledge, this is the first long-span, cable-supported bridge in the U.S. to have a permanent long-term structural health monitoring system installed during initial construction. The fiber-optic SHM system that was installed has 144 sensors distributed throughout the structure. These sensors measure strain, acceleration, tilt, bearing displacement, temperature, wind speed and direction, and chloride ingress at key locations on the bridge. The SHM system provides valuable quantitative data which can be utilized by the bridge owner in their management and maintenance the bridge for years to come. This paper will review the design of the bridge and provide an overview of the SHM system, including the types and layout of the sensors, and the fiber-optic network.