Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

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CHAPTER 16
Forms for
Concrete
Bridge Decks
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Wood Forms Suspended from Steel Beams
Figure 16-1 illustrates a method of suspending wood forms from steel
beams that support a concrete bridge deck. Coil bolts attach into
hanger frames resting on the tops of the beam flanges, and provide
support to the double stringers that span between the steel beams.
The single-span double stringers support the deck joists. The forms
are stripped by removing the coil bolts and lowering the stringers.
The decking and joists can be prefabricated in panels of convenient
widths, then erected and removed intact for additional uses. The following
example illustrates one method of designing the component
parts of the formwork.
Example 16-1
Design the component parts of the formwork for Figure 16-1 for the
following conditions:
Thickness of concrete slab, 8 in.
Center-to-center spacing of steel beams, 6 ft 6 in.
Clear span between steel beams, 5 ft 6 in.
Live load on forms, 75 lb per sq ft
Decking, ¾-in. Plyform Class I
Lumber will be No. 2 grade Southern Pine
Assume dry condition and load-duration less than 7 days
Permissible deflection, l/360
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