# HL-93 Influence Line



## deviationz (Feb 2, 2010)

Folks,

Are there standard tables that can be referred to get the coefficients for shear/moment? I am referring to the examples in SERM 4th edition, chapter 8, where they are using coefficients times the axle load to determine the shear.

I believe the AISC publication on shears/moments is based on a HS-20 truck and not the HL-93.

I am a building guy who has never done bridges, so go easy on me.


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## McEngr (Feb 2, 2010)

deviationz said:


> Folks,Are there standard tables that can be referred to get the coefficients for shear/moment? I am referring to the examples in SERM 4th edition, chapter 8, where they are using coefficients times the axle load to determine the shear.
> 
> I believe the AISC publication on shears/moments is based on a HS-20 truck and not the HL-93.
> 
> I am a building guy who has never done bridges, so go easy on me.


There is not much different with HL-93. They reference where they get the loads, and I have it if you want to buy it from me.


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## MA_PE (Feb 2, 2010)

> There is not much different with HL-93



FWIW, the HL-93 loading represents two trucks:

1) the standard HS-20 truck and

2) the design tandem (aka the military or Interstate loading)

The HS-20 truck is 32kip axles spaced at 14 ft and the design tandem is two 25k axles spaced at 4 ft.

Therefore at shorter spans, the concentrated load at midspan of 32k will likely control but at longer spans the tandem load (50kips combined) may control.


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## McEngr (Feb 2, 2010)

http://www.pci.org/publications/bridge/index.cfm

If you look at the various loading chapter, you'll see equations that solve for these on simple spans. For multiple spans, they get more complicated. AISC has an old shears, moments, etc. diagrams and resulting reactions for bridge loads involving the HS20, which the SERM references. I don't need it anymore, so I could sell it to you at $20. I don't need it anymore since I'll never have to study it again. Thanks. )


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## deviationz (Feb 2, 2010)

McEngr said:


> http://www.pci.org/publications/bridge/index.cfm
> If you look at the various loading chapter, you'll see equations that solve for these on simple spans. For multiple spans, they get more complicated. AISC has an old shears, moments, etc. diagrams and resulting reactions for bridge loads involving the HS20, which the SERM references. I don't need it anymore, so I could sell it to you at $20. I don't need it anymore since I'll never have to study it again. Thanks. )


Thanks McEngr:

I was able to download the publication from AISC's website. I need to learn how to use it. I am sure to post up questions here if i have trouble understanding how to interpret it.


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## McEngr (Feb 4, 2010)

deviationz said:


> McEngr said:
> 
> 
> > http://www.pci.org/publications/bridge/index.cfm
> ...


No problem.


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