Civil Engineering Reference
In-Depth Information
below the top slab, reacting against hardwood timber packs placed between the top
fl anges, Figure 15.28.
The force in the bars and the shape and size of the timber packs must be designed
to provide stability to the new double cantilever. The disturbing moments that must
be resisted are due to the overturning moment of the new double cantilever when
nominally in balance (
15.4.4
), to the friction in its bearings as the bridge deck changes
in length, and to the weight of the mid-span stitch. The bars must also resist the direct
tension due to the bearing friction. Furthermore, it is necessary to check that the
Figure 15.28
Building the mid-span stitch
