Civil Engineering Reference
In-Depth Information
As the external torque equals zero, there is no need to calculate the maximum
shear force factor and the maximum bending moment factor. The maximum shear
forces and bending moments in the bracing elements are obtained from formulae
(5.102), (5.103), (5.104) and (5.105) and their values are summarized in
Tables 6.8
and 6.9.
The efficiency of the bracing system has further improved compared to 'Layout
2'. The value of the global critical load increased by 333% and the smallest natural
frequency by 109%. The maximum horizontal displacements in directions
x
and
y
decreased by 65% and 83%, respectively, compared to the previous case. The
maximum displacements in both directions are now smaller than the recommended
maximum values:
The comparison of the values of the maximum shear forces and bending moments
with those of the previous cases also shows significant improvement: the maximum
values of the shear forces (in walls No. 3 and No. 4 for 'Layout 1' and in wall No. 4
for 'Layout 2') dropped by about 50-60%. There is also a similar reduction in the
values of the maximum bending moments. These favourable changes are due to
the fact that the elements of the bracing system with 'Layout 3' are arranged
optimally: the bending
and
torsional stiffnesses are maximum
and
the external
torque is minimum (=zero).
