Does anybody know where I could find a copy of the 1953 AASHO bridge design specifications?  

Sometimes you can find things like this at the local university, or the bridge office of the State DOT.  They usually keep these things around for comparisons.  As you've probably encountered, we aren't quite through replacing or widening all of our old bridges so there is reason to have these around.

If you have something specific to ask i may be able to help as our company keeps a good number of this old references around.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

Thanks Qshake, maybe you could help me.
I am looking for the standard loadings for vertical and horizontal earth pressures on cast in place box culverts under fill.  I am thinking that they may be in the range of 120 pcf for the soil density and 35 pcf as a horizontal equivalent fluid density.  If you could verify these values it would be helpful.

mtm161

mtm161,

I will be glad to help.  I'll take a look when I return to the office on Monday, December 6.  Should you need some actual copies of the material for reference please post a fax number.  Otherwise I will simply post the information you need in this thread.

Regards

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

The 1953 AASHO Specifications list:

Compacted sand, earth, gravel or ballast  120 lbs/cu. ft.

(a) Loads on Culverts

Earth pressures or load on culverts may be computed ordinarily as the weight of the earth directly above the slab.  In order to have the effect of increasing the allowable design dead load stresses 40 percent  more than allowed for live load, the effective weight of earth backfill may be taken as 70 percent of its actual weight.




3.2.18 - Earth Pressure

Structures which retain fills shall be proportioned to withstand pressure as given by Rankine's formula; provided, however that no structure be designed for less than an equivalent fluid pressure of 30 pounds per cubic foot.

Other comments are very much like our new specifications:
surcharge 2' of backfill.
For rigid frames one-half the moment caused by earth pressure may be used to reduce the positive moments in the beams, in the top slab or in the top and bottom slab.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

Thank you very much Qshake.  This information was very helpful.
mtm161