Civil Engineering Reference
In-Depth Information
(b)
Shear centre
The shear centre is an important geometrical characteristic of the bracing system. By
definition, an external force passing through the shear centre only develops translation
but not rotation.
The shear centre is the centroid of the translational stiffnesses and is also called
centre of stiffness. Its location is calculated using the rules of determining the centroid.
The distance of the shear centre from an arbitrary axis is obtained by dividing the
'static moment' of the translational stiffnesses related to the axis with the sum of the
stiffnesses. The
x
coordinate of shear centre
O
of the system of parallel walls in the
coordinate system
¯ —¯
(Fig. 4.4) is obtained from
(4.14)
where
¯
i
is the distance of the
i
th wall from axis
¯, k
i
is the translational stiffness of the
i
th wall defined by formula (4.12) and
n
is the number of walls.
Fig. 4.4
Shear centre for parallel walls.
When all the walls are of the same material and height, the above formula
simplifies to
