Working stress conc. design
Working stress conc. design
(OP)
Can anyone please tell me approximately when the industry made the switch from designing reinforced concrete using the working stress method to using LRFD? Also, where I might find decent literature on the working stress method. The existing building I am looking at was built in 1965-66.
Thank you.
Thank you.






RE: Working stress conc. design
I would guess that it would have been designed by working stress given the age that you have, but if you are analyze it using the provisions of Chapter 20 of the current ACI 318 you should be all right.
RE: Working stress conc. design
RE: Working stress conc. design
RE: Working stress conc. design
The limit states concrete code development came along in the 70's and 80's.
RE: Working stress conc. design
Take a look at the early Chapter 1 commentary in ACI 318. They have a discussion there about this topic. - I think they provide some history as well.
Note that the ASD method is no longer in the current versions of ACI 318 but the commentary in Chapter 1 allows the use of the ASD method based upon the 1999 ACI 318.
RE: Working stress conc. design
Mike McCann
MMC Engineering
RE: Working stress conc. design
RE: Working stress conc. design
So far as theory, one could go to Google Books and download any number of public domain texts on the subject.
I would think a "structural" designer should be able to do WSD without needing a review, be competent to derive the theory, and have a few texts in addition to ACI and AASHO readily on hand.
Just a thought...
RE: Working stress conc. design
That's why it's called WSD.
Mike McCann
MMC Engineering
RE: Working stress conc. design
While you should use the old codes and design handbooks to figure out what was done, rework or reuse with modification have to meet current design practices. A resource like older editions of the CRSI Design Handbook (1952 to present) can be used to determine the expected load capacity for members.
There were many proprietary slab systems using very odd reinforcing patterns, including 3-way, 4-way, and 5-way straight bar systems, truss bar layouts, and concentric hoops in slabs. If you can't figure out the bar layout because nothing is where it is expected, look into those. These were primarily for flat slabs or flat plates. Also, beams may use truss bars and frequently had little or no shear reinforcement.