Nanami ASHIZAWA’s research while affiliated with Tokyo Institute of Technology and other places

Structures receive thermal energy from solar radiation, and temperature differences occur between structural members due to differences in solar exposure and heat capacity. This study attempted to generate electricity from this structural thermal energy, particularly targeting the temperature difference between the pavement and decks of steel deck bridges. The thermal environment of a full-scale steel deck bridge specimen was measured, and a thermal conduction analysis using a finite element model was conducted to explore the structural design for efficiently transferring heat to thermoelectric modules. The installation position that is advantageous for power generation in steel deck bridges was investigated through experiments and heat conduction analysis, followed by power generation simulations. Finally, prototype thermoelectric energy harvesters were installed on the target steel deck bridge and verification experiments demonstrated the potential for utilizing thermal energy in structures.

p>In this study, an influence line of the girder displacement of the bridge was estimated by Bridge- Weigh-In-Motion using an accelerometer. Displacement was calculated by two times of integration of the measured acceleration. The data has the problem of low sensitivity due to a single sensor, and it contains measurement noise. To compensate for these problems, two correction methods were applied to the integration result. They were the baseline correction method and the drift correction method using boundary conditions of traffic-induced vibrations. It was shown that the result of integration was improved by using these methods. A calibration process to estimate the influence line of the bridge was proposed using iterative calculation method to optimize the result using local buses. It was shown that by using this method, vehicle detection and weight estimation can be performed with high accuracy, especially for large vehicles.</p