Calculating deflections of the Indian River Inlet Bridge using rotations from a structural health monitoring system

Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
As the age of bridges worldwide increase, and their structural integrities decrease, the need for ways to evaluate and monitor the ever changing structural health of bridges has become more crucial. One monitoring method that has recently gained popularity worldwide is the use of structural health monitoring systems. Structural health monitoring systems allow bridge owners to continuously monitor parameters that can be used to assess a bridge’s structural health. Two such parameters are strain and rotation. While structural health monitoring systems have advanced over the years, bridge owners still lack simple methods for analyzing certain types of structural health monitoring data in order to evaluate the structural integrity of their bridges. One example is the monitoring and evaluation of bridge rotations. While rotations can offer insight into a bridge’s deflections, they have not been thoroughly investigated and introduced to the bridge industry. ☐ In this research, rotation data from a structural health monitoring system on the Indian River Inlet Bridge, and two additional surface mounted tilt meters, was analyzed and used to calculate bridge deflections. The methodology behind calculating bridge deflections from rotation data is based on elastic beam theory and the double integration method. In order to obtain the rotation data for the analyses, a controlled load test was conducted on the Indian River Inlet Bridge in May of 2016. During that load test, a survey crew was onsite to measure the deflection of the bridge. The deflections that were calculated using structural health monitoring system rotation data were compared to the measured defections. The final calculated Load Pass 0_1 midspan deflection was off from the survey midspan deflection by about 16%. The final calculated Load Pass 0_2 midspan deflection was off from the survey midspan deflection by about 14%. Through these comparisons of calculated deflections to survey deflections, the methodology used to calculate deflections from rotation data was validated. The deflections that were predicted by a validated finite element analysis (FEA) of the bridge were also compared to measured survey deflections. The FEA model midspan deflection was off from the survey midspan deflection by about 9%, which suggests that FEA can be used to produce both rotations and deflections.
Description
Keywords
Applied sciences, Deflections, Indian river inlet bridge, Rotations, Structural health monitoring
Citation