S-12 Live Loading from the 50's - Any help?

[3Fan]

Hi folks. We are in the process of load rating some old pony trusses and welded gusset connections. The original plans for one particular truss state the design live loading as S-12. Could someone shed some light on what this loading entailed. The plans are from either 1951 or 1957 (bad photo copy).

Not that this has any impact on how we rate the truss, but I am just curious on how our rating compares to the orignal design loading.

 

[crossframe]

Shortened version of H15-S12-44? (HS-15 in modern parlance.)

The "S" designation was the "semi-trailer" part of the load, and was taken to be 80% of the "truck" portion.

 

[cap4000]

The H15-S12 loads are as follows. Concentrated load for Moment = 24kips, for Shear = 30kips. The uniform lane load per foot of lane = 480#/ft.

The three axle loads are 6kips, 24kips and 24kips spaced out at 14 feet each.

This is all taken from the 3ed edition AASHTO 1941.

 

[cap4000]

AASHTO 1953 6th edition. H15-S12-44 loads are as follows. 13.5 kips for moment, 19.5 kips for shear and the lane load = 480#/ft. The axle loads are the same as above but the rear spacing varies from 14ft to 30ft.

 

[bridgebuster]

Now, there are three of us here with the '53 AASHO. I had the '44 and the '49 but they grew legs.