I know this topic has been beaten to death...but I couldn't find something addressing my exact situation. I am designing a small pedestrian bridge. Steel I-beams with composite "wood" decking (2x8). The deck planks are bolted to the top flanges of the beams. Since the planks are discreet, I do not believe they brace the top flange. Any restraint provided by a particular deck plank cannot be transferred to the ends at the abutments. So I intend to prevent torsional rotation by means of a stiffener plate between the flanges. Question is this...how do I determine the depth/thickness? Actually wondering also if x-bracing is better than the plate idea.
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LTB of Bridge Beams
- Thread starter bpstruct
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Vertical stiffener plates between flanges don't help with LTB.
You need to prevent twist in the beams and the resulting lateral translation of the compression flange.
For a bridge like this with two beams, one idea is that you create a series of X-bridging between the beams to avoid twist. This is a relative brace (see AISC Specifications, Appendix 6).
Alternatively, you could create a horizontal series of diagonals, essentially creating a horizontal truss down the length of the bridge.
You need to prevent twist in the beams and the resulting lateral translation of the compression flange.
For a bridge like this with two beams, one idea is that you create a series of X-bridging between the beams to avoid twist. This is a relative brace (see AISC Specifications, Appendix 6).
Alternatively, you could create a horizontal series of diagonals, essentially creating a horizontal truss down the length of the bridge.
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