Effect of cracks on air-tightness of vacuum tube bridge structures

Abstract

Air resistance is a very important consideration for any kinds of vehicles that travel at high speed. The vacuum tube transportation system is therefore considered as one of the most effective transportation system, which can maintain the high speed of the train by minimizing the air resistance. The air resistance can be minimized by reducing and maintaining air pressure inside the tube. For bridges with vacuum tube structures, the impact of externally applied loads on the air-tightness performance level should be taken into consideration. Therefore, the aim of this work is to study the effect of load-induced cracks on the air-tightness of concrete vacuum tube structures. To achieve this aim, a predictive model that describes the crack width is adopted and the cracking pattern on the vacuum tube structure is analyzed. The leakage rate of air through the cracks is then assessed and finally, the relationship between the crack behaviour and its effect on the air-tightness of vacuum tube structure is established.