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Steel Designers' Manual - 6th Edition (2003)
136 Bridges
(a)
(b)
•••••:__
suspended span
(c)
(d)
(e)
Fig. 4.8 Girder type bridges. (a) Single span; (b) simply-supported spans; (c) cantilever and
suspended span; (d) continuous; (e) continuous – curved soffit
are similarly suited to a half-through form so as to reduce the length of staircases
and ramps, which can often exceed the length of the span itself. Highway, railway
and pedestrian bridges of girder type for short and medium spans are further
described below.
4.3.6.1 Highway bridges – composite deck construction
(see also Chapter 17)
Composite deck construction (Fig. 4.9) should be used wherever the construction
depth will permit. If possible, multiple spans should be made continuous over the
intermediate supports, so reducing the number of bearings and expansion joints.
Continuity gives economies throughout the structure and reduces traffic disruption
arising from the maintenance needs of these vulnerable elements. A number of
options are available for maintaining continuity over intermediate supports. If
ground conditions are poor such that the predicted differential settlement of the