H20 and H20-44

[Yihan]

any difference between H20 and H20-44?
thanks

 

[Yihan]

sorry, I meant "difference between HS20 and HS20-44"

 

[msquared48]

-44. Sorry. Couldn't resist.

If my memory serves me correctly...

With HS20, you have a 20 ton vehicle with 4 tons on the front axle, and 16 tons on the rear dual or single axle combination. I would have to look at the sketch to see the distance between axles.

With the HS20-44, you have a 44 foot overall length, 14 foot tractor and a 30 foot trailer, with 4 tons on the front axle and 8 tons on the rear of the tractor at the hitch, and 8 tons on the rear axle. There are tweeks to this arrangement too.

You can verify this either with AASHTO or the 1963 California Highway Design Manual. I know - dating myself here.



Mike McCann
MMC Engineering

 

[bridgebuster]

There's H20-44 and HS20-44.

In both cases the "44" stands for 1944, the year the loading was adopted.

H20 truck is a 20T truck; two axles, 4T & 16T, spaced at 14'.

HS20 is a 36T truck It's the H20 truck with an additional 16T axle with a variable spacing of 14' to 30', whichever produces maximum stress.

 

[SteelPE]

Never really done bridge work before but here is a question.

Is this the loading used to design bridges today? If I remember correctly, you can increase and decrease the load proportionally to allow for larger vehicles. Is H20-44 and HS20-44 the load used most often to design bridges today?

 

[tumbleleaves]

1) H20 and H20-44 maybe the same thing. But you'd better check because H20-44 looks like a typo where "HS20-44" was meant.

2) HS20 was the standard AASHTO loading that consisted of the truck or the lane load. The LRFD HL-93 is the LRFD AASHTO loading.

 

[msquared48]

Then there is this thread from 07:

AASHTO H-20, HS-20. . .

thread165-182712

Or, you could relent and just Google it.

Mike McCann
MMC Engineering