URBAN TRAFFIC DISTRIBUTION AND ELEVATOR CAPACITY IN SUPER HIGH BUILDINGS

Abstract

In recent years, very high buildings have been extensively constructed to utilize the narrow urban grand space. Most of those buildings are used for offices, and some for hotels or hospitals. But, there are some plans to build a super high building to form a "compact city" which brings residence, office, and some urban facilities close together. It is expected that the people in the building can satisfy their daily needs at hand so that the amount of traffic should be reduced. In this "city type" building, the trips occur for a variety of reasons, for example, employment, school, shopping etc., which are of different types compared to those in traditional buildings. In this paper, we will discuss those traffic problems in the city type buildings. When we consider the traffic problem in a high building, the major difficulty appears in the vertical movement. Insufficient elevator area causes the complaint of the passengers for long waiting time, on the other hand, wide elevator area causes the dissatisfaction of the owner of the building having small area left for rent. For simplicity, we assume that the rest of the floor area not used for elevator are all used for residence, where people distribute uniformly. And, as for the traffic distribution, we adopt the "gravity model" in the theory of urban transportation distribution theory, in other words, a trip occurs by the interaction of a pair of people in the building, and the trip occurrence probability for the pair is equal to a constant multiplied by the deterrence factor. The deterrence factor is based on the distance between the origin and destination. We derive the equation to determine the elevator area distribution in the following way. The transportation capacity c per unit area of elevator passage is assumed to be constant irrespective of the building height. The number of trips passing through a floor is the sum of the trip occurrence probabilities for such pairs that one located above the floor and the other located below. The product of the capacity c and t,he elevator area on the floor should be equal to this amount. The equation is derived from the condition that this relation should be satisfied at each floor in the building. When the size of the building and the deterrences factor are given, the equation can be solved numerically to obtain the elevator area distribution. We solve the equations for several cases and consider the relation between the population P in the building and the number of trips T travelling through the elevator area. When the deterrence factor is small and the number of trips per person is at a high level, then population P or amount of trips per person T/P can be raised only at a very slow rate by enlarging the height, of the building. If one expects to get substantial gain in T/P or P by constructing a higher building, the deterrence factor should be made large by carefully designing the facility layout in the building. We also draw the graphs which show the suitable population size and amount of trips for the building of each height.