CIVIL ENGINEERING FORMULAS

BRIDGE AND SUSPENSION-CABLE FORMULAS 267

(10.60)

Then

(10.61)

(10.62)

Span length then is L 2 c, with the previous same symbols.

GENERAL RELATIONS FOR SUSPENSION CABLES

Catenary

For any simple cable (Fig. 10.3) with a load of qoper unit length of cable, kip/ft
(N/m), the catenary length s, ft (m), measured from the low point of the cable
is, with symbols as given in Fig. 10.3, ft (m),

(10.63)

Tension at any point is

T 2 H (10.64)

(^2) q 2
os
(^2) Hq
oy
s

H

qo

sinh

qox

H

x

1

3!

qo

H

2

x^3 

Sagdc ft (m)

c(dc)^2 

S

2 

2



0.5

dc

T

w

(a)

Cable

P

(b)

C

M

VL

TL

L

L

H s

yM y

h

fR

RH

TR

VR

L

2

ab

L

y

x

x

L

2

h/ 2

FIGURE 10.3 Simple cables: (a) shape of cable with concentrated load; (b) shape of

cable with supports at different levels.