CommScope ConQuest Conduit Construction - Manual (Page 69)

Tb = Ts * e fa
where:
Tb = pulling tension at end of bend in pounds
Ts = pulling tension at end of straight section entering
the bend in pounds
e = naperian log base (2.718)
f = coefficient of friction (if unknown use 0.500)
a = angle of bend (radians*)
*The bend angle in radians can be calculated by dividing the
angle in degrees by 57.3 (57.30 = 1 radian)
Calculated Pulling Tension – Bend Section of Conduit (HSWP)
This formula is used to determine the amount of tension placed on a cable at the end of pull in a bend section of
conduit. The formula is used in conjunction with the calculated pulling tension for a straight section of conduit to
calculate an estimated pulling tension for an entire conduit run. The tension through the straight section of conduit
entering into the bend must first be calculated as this formula uses that tension as part of the formula.
Example: QR 715
after 500 feet straight section 90
° bend
Ts = 36
e = 2.718
f = 0.500
a = 1.571
Tb = 36 * 2.718
0.500 * 1.571
Tb = 36 * 2.718 0.785
Tb = 36 * 2.192
Tb = 79
e fa Values for Common Angles
Angle of Coefficient of Friction Values
Bend in o f=0.7 f=0.6 f=0.5 f=0.4 f=0.3 f=0.15
15 1.20 1.17 1.14 1.11 1.08 1.04
30 1.44 1.37 1.30 1.23 1.17 1.08
45 1.73 1.60 1.48 1.37 1.27 1.13
60 2.08 1.87 1.68 1.52 1.37 1.17
75 2.50 2.19 1.92 1.69 1.48 1.22
90 3.00 2.57 2.19 1.87 1.60 1.27
Appendix 8.12
Calculated Sidewall Pressure