3 ms·
Sorry to sound stupid, but how is that exponential? Isn't it O(mn) where m = number of floors and n = number of shafts? EDIT: Unless there's some dependence be
by mindleyhilner 9y ago
Sorry to sound stupid, but how is that exponential? Isn't it O(mn) where m = number of floors and n = number of shafts?
EDIT: Unless there's some dependence between m and n, like if taller buildings always need more shafts or something.
- JumpCrisscross 9y ago> like if taller buildings always need more shafts or something The dependence is on keeping wait times reasonable. Taller buildings mean each shaft's elevator spends more time travelling, i.e. less time being available.
- masklinn 9y agoAt this point you start doing locals (multiple elevators per shaft traversing only a subset of the entire building) and express (elevators skipping floors, usually between ground floors and various "sky lobbies" at 30~40 floors interval).
- JumpCrisscross 9y agoWhich still involves adding shafts.
- ajarmst 9y agoThere's also a weight issue. The longer the shaft, the longer and heavier the cable must be, and the more tension and stretch. In some buildings, there may also be structural issues militating against an open shaft running the entire heightof the buldng.
- rtkwe 9y agoTaller buildings need more shafts because they'll spend more time in transit so unless the occupants have the patience of saints you need lots shafts to keep wait times down. Eventually most tall buildings setup sky lobbies and express lifts that only service a certain range of floors to keep wait times down during peak hours. It's really rough in convention center hotels when a huge convention comes to town a lot of the time it's practically impossible to get an elevator down from the middle floors because it's already full from the floors above you.