Design Of Flexible Subway Entrance Roof

The subway entrance roof is one of the most important parts in subway inlets and outlets. It is not only just a passageway, but also a hub which combines the underground space with the city culture. Nowadays, the subway entrance roof that the cities at home and abroad have adopted is in the form of stationary type. This kind of roof is simple and strong in structure and has the characteristics of high reliability in safety and tittle restrictions in shape design. The fixed type of roof could be classified into two kinds:(1) Covered Type which can help the passengers to keep out wind and rain in snowy or rainy weather.(2) Uncovered Type which could better provide the ventilation and lighting for the subway passages in sunny weather. Both of the two types have their own advantages, but it is quite difficult to integrate the two merits. This article would introduce a kind of flexible subway entrance roof which could own the advantages of covered and uncovered type roof. In bad weather, the roof would be opened up to provide the shelters for the coming and going passengers. In sunny weather, the roof will be put into the underground which would not affect the aesthesis of the underground passages and at the same time offer better ventilation and lighting in subway alleyway.This article designs two types of flexible roof based on the design requirement of flexible subway entrance roof. And they are suspended lifting roof and elastic lifting roof. The two types will meet the safety requirement and functionality about the flexible roofs. By the improvement in their appearance, these types of roofs would better fit in the culture of city.The design idea of suspended lifting roof is coming from large-scale suspended bridge. When the lifting roof is on working, it will drive the steel wire rope to provide impetus for the radius rod to turn. When the radius rod shifts certain angles, the steel rope fixed at the sides of crossbeam will help to make the crossbeam rise with the supporting and swinging about the strutting bar. After the roof rises, the motion devices set up at the beam of tail end will make the roof draw back by driving the chain. During the while working process, the motion devices in girders lift system and roof retraction system will realize the synchronism along the sides and when the roof is opened up, it could make use of the braking function to achieve the self-locking of mechanism at the same time reducing energy consumption. The elastic lifting roof realizes the promotion and demotion of beams at the two sides by hydraulic system and this system is controlled by flow distributing and collecting valve to achieve the synchronism of motions in the bilateral hydraulic cylinder. When the beams is up, three position fourway solenoid valve is in the middle position to keep the oil pressure unaltered and brings about the self-locking of mechanism.This article makes an illustration about the design of girders life system, roof retraction system and cleaning system in these two schemes. And then to have a motion simulation to the elastic lifting roof. At last the advantages and disadvantages of the two schemes are contrasted and analyzed with the provision of existed problems which need to be solved. All of these gather valuable experience for the design of flexible subway entrance roof...