What is Wobble Coefficient in post tensioning system?

Lets us answer this question from scratch,
the word wobble means unsteady jerking movement from one end to other or move
unevenly while coefficient is a symbol or number that defines the relation
between two or more variables.
While post tensioning we use strand wire
that is being joined by twisting around one and other to make a tendon, this
tendon is to be inserted within a profile pipe called sheathing or duct after
the concrete will achieve a specified compressive strength.
What is Wobble Coefficient in post tensioning system?
Sometimes the jacking force is applied from
one end or both ends. The duct or profile pipe is to be inserted as per the
designed curvature and location. The strand wire or tendon can’t be completely
set as per the designed curvature and profile due to field restrictions and faulty
workmanship.
Due to these reasons the curvature is bit
shifted from the designed curvature and thus causes some loss in tensioning
force. When jacking force is applied at one end, it decreases as we moves to
the farther end due to friction between the tendon and the profile pipe or
duct, this friction losses is of two types,
1)     
Curvature friction loss
2)     
Wobble friction loss
Curvature friction loss is basically the loss in tensioning or
jacking force due to design curvature while wobble friction or wobble coefficient
is a function of unintended deviation due to faulty workmanship or field
restrictions.
Wobble coefficient is usually denoted by K and is measured
in units of per length. It is found by multiplying the jacking force at any
distance from jacking end with the average of the intended angular deviation
from the design profile.

Usually having value of 0.0088. 
Saad Iqbal
Hi there, I am Saad Iqbal from Pakistan. I am an enthusiastic blogger, passionate content creator, construction geek, and a creative graphic designer. Connect with me at my social channels.