1920s concrete beam analysis - working stress design
1920s concrete beam analysis - working stress design
(OP)
When analyzing an existing structure for new loads, where the original design was "working stress" with the allowable working stress of the concrete reinforcing steel at 16ksi, how would you convert that to a value that could be used with strength design and factored loads?
Or would the more appropriate thing to do be to analyze it using the working stress method?
Or would the more appropriate thing to do be to analyze it using the working stress method?
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
However, that being said, you still have to be concerned with bond and check it as many of the bars of the time were not the deformed shapes we use today.
Mike McCann
MMC Engineering
RE: 1920s concrete beam analysis - working stress design
Msquared48, do you have the number/name on that PCA article? I'd like to read it.
RE: 1920s concrete beam analysis - working stress design
Mike McCann
MMC Engineering
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
The info from boo1 is great and hokie's point about shear brought up another issue to consider as well.
Of the many past old beam designs I have checked - besides shear giving me headaches I also found that the longitudinal flexural rebar rarely was detailed to properly develop moments like we do today.
Generally top steel was insufficiently developed past inflection points, or were turned down (the old "crank" bars) too soon.
Makes for some dicey interpretation of how much capacity you actually have....even though the beams have stood for decades.
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
RE: 1920s concrete beam analysis - working stress design
http://www.concrete.org.uk/fingertips_nuggets.asp?...
There is also a book by J. Stanley Rabun "Structural Analysis of Historic Buildings", that you can preview on google books. He gives 3700 psi for a 1:2:4 mix at 6 months.
RE: 1920s concrete beam analysis - working stress design
A useful book!
RE: 1920s concrete beam analysis - working stress design
http://www.crsi.org/index.cfm/vintagesteel
RE: 1920s concrete beam analysis - working stress design