Model Test Study of Change Mechanism of Temperatures and Humidity in Main Cable of Suspension Bridge

To study the distribution and change laws of the temperatures and humidity in the main cable of suspension bridge that has been in the humid and corrosive environment for of long time, the scale-down model of the main cable of the suspension bridge was designed and the indoor test for the model was made. In the room of the simulated special environment, the model of the main cable (4 m in length and 30 cm in diameter) was placed. The environment of 4 conditions was simulated, the temperature and humidity sensors were arranged and the temperatures and humidity ratios in the main cable were monitored. The distribution and change laws of the temperatures and humidity in the main cable were acquired and the thermal conductivity and thermal exchange coefficients of the main cable were calculated. The results indicate that the distribution and change laws of the humidity ratios are similar to those of the temperatures. At the rise of the ambient temperatures, the temperatures and humidity ratios in the main cable rise with the passing of the time. The higher the external temperatures are, the faster the temperatures and humidity ratios will come to the stability. When the cable is locally heated, the obvious temperature gradient distribu-tion appears in the section of the main cable and the distribution and changes of the humidity ratios are not uniform. When the water gathers in the main cable, the distribution and changes of the temperatures and humidity in the section of the main cable become even more non-uniform as compared to those in the section of the cable in the dry state and the temperature gradient distribution is more obvious. © 2017, Journal Press, China Railway Bridge Science. All right reserved.