駅前デッキの広場機能とマネジメントに関する研究

－柏駅東口ダブルデッキの変遷と活用実態－

抄録

 An elevated pedestrian deck that has been constructed over a station plaza is a facility to connect a station with surrounded area in order to achieve smooth traffic. Approximately 230 decks has been constructed along with railway station in Japan, and the aging of the decks becomes a problem recently. With the case study of Kashiwa Station East Deck “Double Deck” which is the oldest deck in Japan, the purpose of this paper is to examine process and system of the deck management as a plaza with achieving revitalization of the decks as urban open spaces.
 The reason why the Double Deck had been built was not only to create a pedestrian friendly space within downtown in Kashiwa, but also to provide a traffic plaza space that was lacked at this moment. Applying the Urban Redevelopment Project provided for the Urban Renewal Act, one third of the station square floor was built with the deck in 1973. At the time of its completion, the deck space was the road under a law, but it became popular place as a symbol plaza and event space because of the first elevated car-free space. In fact, the number of music performances on the deck has increased since 1990s, and then Kashiwa city made the rule about performance on the deck, “Kashiwa Rule” in 2005, to support their activity. It allows performers to do their activities throughout a year with easy and low-cost registration procedure.
 After 40 years from construction, in 2012, its seismic repair was accomplished. Along with this repair, the deck also increased plaza floor for event space. In the same period of deck repair, private sector which is composed of 4 shopping street organizations redeveloped the space below the deck as pedestrian plaza in order to create a pedestrian friendly environment at the ground level. After its redevelopment, the private sector handed over an arrangement to the Kashiwa city about management of the plaza.
 These two redevelopments make the station square more friendly for pedestrians, and it became more fascinating space. Moreover, the station square leads the public private partnerships in public space management on the Double Deck. The Kashiwa Rule is also the part of its management system. Logistical management work are taken by NPO and local private organization under an arrangement with Kashiwa city. On the other hand, from 2016 April, the Kashiwa Machidukuri Kosha Public Corp. started a comprehensive management including the Double Deck and its ground pedestrian plaza, following private sector's management. This total management aims to increase diversity of activities in the station square, with deregulating road occupancy permission by the Act on Special Measures concerning Urban Reconstruction.
 The Kashiwa east station square including the Double Deck is still “road” in law. However, through spatial regeneration and formation of management by public private partnership, it has become almost “plaza” spatially and functionally. Many of the pedestrian decks built in Japan are still planed only as a part of transportation hub. In order to promote the revitalization of downtown around the railroad station in the future, it is necessary to reconsider the function of a station square and its deck, and also to establish a guideline to design a station square as a more vibrant and more pedestrian friendly space.