AASHTO 4.6.2.1.3 - Width of equivalent strip for the Design Tandem

[gonutsdonuts]

Hey all,

I'm a bridge EIT stuck on a little deck design question that I can't really find explicitly said anywhere in AASHTO (or anywhere else online).

If the entire design tandem is to be included in the deck design it presumed to be distributed over a larger equivalent strip. Is this strip supposed to be double the strip width calculated by 4.6.2.1.3, except for in the case of overlapping strips where it would become the width of one strip +4ft (tandem axel spacing)?

Thanks! (Bridge Forum is a bit of a wasteland)

 

[TehMightyEngineer]

I always calculated the equivalent strip based on the two axles and removed the overlapping widths.

Maine Professional and Structural Engineer
American Concrete Industries

http://www.americanconcrete.com

 

[BridgeEI]

I haven't had time to really dig into this but I believe you use the equivalent strip width you calculate even if it "overlaps". It's very possible for the strip width to overlap on the HL93 truck.

The only time I account for the overlap is calculating the wheel load pressure that is being distributed to a RCB.