Wire Ropes Under Bending and Tensile Stresses - Wire Ropes: Tension, Endurance, Reliability - page 304

With these, the rope tensile forces are

S S ¼ 1,450 9 : 81
6

1 : 1 1 1 : 25 1 : 06 ¼ 3,455 N :

Number of bending cycle:
With these forces for the traction sheave and with the endurance factor
f N3 = 0.1 for the undercut groove a = 100, the discard numbers of bending
cycles are

N A10 ; T ¼ 0 : 1 3,719,000 ¼ 371,900

and for the deflection sheave with a normal steel groove r = 0.53 d and practically
no side deflection

N A10 ; S ¼ 5,990,000 :

Number of trips:
Then, according to ( 3.92 ), the number of trips from or to the ground floor is

1

Z A10 ¼ ¼ 350,000 :

1 1

5,990,000 371,900 þ

According to Fig. 3.82 for residential buildings with seven floors, the number of
trips from or to the ground floor is expected to be 80 % of the total number of trips.
Then the total number of trips, at which not more than 10 % of the wire ropes have
to be discarded, is

Z A10 ; tot ¼ Z A10

0 : 8 ¼ 437,000

It is not necessary to consider the force limits for elevators.

Example 3.12 Elevator for high office building

Data:
Nominal load Q = 1,600 kg

s

Car mass F = 2,500 kg

F

Counterweight G = 3,300 kg

G

Tension sheave mass G t = 400 kg

Q

Hoisting distance H = 150 m

s b

Warrington 8 9 19 - FC - sZ .

G T

R 0 = 1,570 N/mm 2

Nominal strength

Nominal rope diameter d = 16 mm

Number of ropes n = 5

Rope mass s = 653 kg