Civil Engineering Reference
In-Depth Information
Figure 11.8
Modelling of portal node
The uprights have to carry the same bending moment as the haunch, but with the
benefi t of a compression force due to the weight of the roof. Thus they may be slightly
thinner than the haunches.
The modelling of the node between slab and upright must be carefully considered.
The theoretical span for the calculation of the bending moments in the portal should
be taken to the point of intersection of the centre lines of members. The peak bending
moment beyond the face of the upright will be rounded as described in
6.13.5
, whereas
the depth of the slab will be increased at an angle of 35°. The maximum hogging
reinforcement will be the greater of that calculated using the moment
M
1
at the face
of the wall with the depth of the haunch
h
, or the rounded moment
M
2
at the axis of
