Elevator Systems for Tall Buildings Part II: Mixed-Mode Elevator Systems

Models of two types of mixed-mode elevator systems are presented; in the first, elevators in a tall building operate partly in an express mode and partly in a local mode. The second system contains both express-mode and local-mode elevators, but any one elevator is either an express or a local. It is found that the general strategies to be followed in elevator design, with the objective of conserving the useful floor area, are (in order indicative of the increasing positive effect): (a) keep the service zone of an elevator as small as possible, (b) separate express from local elevators, (c) use only express elevators, and (d) split express elevators on all long runs.