No abstract

Shifting the threshold zone of road tunnels with semitransparent tension structures has shown itself to be an effective way of saving energy in regards to electricity consumption, maintenance, and construction materials used in the electrical lighting, thus lessening negative environmental impacts. Even though the shape of the tension structure has a major influence on energy savings, the optimal type of structure for each tunnel is often difficult to determine, because experiments using real tunnels are extremely expensive. It is thus necessary to find methods of doing this that are both reliable as well as economical. In this research study, three candidate structures were set up at the portal of a scale model of a real tunnel. The energy savings in each case were analyzed and compared. As a result, it was possible to formulate a new equation that calculates the energy savings in the threshold zone.

Abstract.After the successful introduction of transparent tension structures in the portal of road tunnels as an effective measure for energy savings, optimization of such savings has been sought. A computational method based on graphical design capable to simulate the optical properties of the sun, any transparent tension structure and any road tunnel whatever its orientation, has been developed and presented in this paper. A comparison with measurements in a real tension structure placed in the entrance portal of one real tunnel is performed and discussed.

Placement of semi-transparent tension structures in the portal gate of road tunnels to shift their threshold zone and use sunlight, has been proved to be an interesting procedure to save electrical energy. However, in order to obtain the maximum performance, the shape of the structure has to be established for each tunnel, depending on its geographic location, orientation and surroundings. In previous works, computational methods and a scale model have been used to determine the optimal shape of these structures without expensive and time costing trials. In this work, comparison of the results is presented and it shows that the virtual modeling combined with the previously derived ESTS equation can be used to choose of the most convenient structure.