Experimental study on temperature distribution of key structural components of double-deck bridges during fire affected by wind and deck height

Abstract

This study delves into the influence of deck height and ambient wind speed on the temperature distribution of key structural components in a double-deck bridge during fire, utilizing scaled-down fire experiments. The experimental results were analyzed to pinpoint the maximum temperature of the upper bridge deck in a windy environment, corresponding to each of the three scenarios: buoyant plume, intermittent flame, and continuous flame. Additionally, a temperature rise prediction equations for the upper bridge deck was derived. It was observed that the maximum temperature of the truss diminishes as the deck height escalates. A model predicting the maximum temperature rise of trusses was formulated through dimensionless analysis. For the majority of operational conditions, the truss temperature initially increases and then decreases with an increase in vertical height. A temperature jump is noted at the peak of the truss, which becomes less pronounced as the deck height increases. By fitting the experimental data, the prediction formulas for the dimensionless temperature rise at the peak of the truss were obtained. The findings presented in this paper offer a theoretical framework and temperature range criteria that can inform the fire protection design and fire risk evaluation of critical structural elements in double-deck bridges.