I need to check that the Service III stress for the bent cap is under 24 ksi.
From RC-Pier's Cap Design Report, I get the following:
CRACKING/FATIGUE CHECK:=======================Cracking check as per AASHTO LRFD (6th Edition, 2012)
...
Span 9: From 66.00 ft To 75.00 ft <------ Cracking ------> <------ Fatigue ------> Loc AbsLoc H Comb fs-t dc Srqt Sprt fs-t ratio fs-t Comb Loc AbsLoc H Comb fs-b dc Srqb Sprb fs-b ratio fs-b Comb ft ft in ksi in in in ksi ------------------------------------------------------------------------------ 0.00 66.0 42.0 8 18.1 4.1 25.2 6.8 0.0 0.00 0 0 0.0 4.3 48.0 13.5 0.0 0.00 0 1.00 67.0 42.0 8 11.6 4.1 43.9 6.8 0.0 0.00 0 0 0.0 4.0 48.0 4.6 0.0 0.00 0 2.75 68.8 42.0 8 0.5 4.1 48.0 6.6 0.0 0.00 0 1 1.7 4.0 48.0 4.4 0.0 0.00 0 6.25 72.3 42.0 0 0.0 4.1 48.0 6.6 0.0 0.00 0 1 24.8 4.0 16.6 4.4 0.0 0.00 0 6.73 72.7 42.0 0 0.0 4.1 48.0 6.6 0.0 0.00 0 1 29.1 4.0 12.9 4.4 0.0 0.00 0 8.00 74.0 42.0 0 0.0 4.1 48.0 6.8 0.0 0.00 0 1 25.1 4.0 16.3 4.6 0.0 0.00 0 9.00 75.0 42.0 1 1.0 4.1 48.0 6.8 0.0 0.00 0 0 0.0 4.3 48.0 13.5 0.0 0.00 0
I understand that the 29.1 stress is based upon the spacing required per AASHTO 5.7.3.4, but I'm not understanding where the required spacing comes from. Is the reported stress a function of the required spacing or vice versa? Is the stress reported just a limit, per AASHTO 5.7.3.4? How is RC-Pier determining the required spacing?
Even though this is an old request, I also am looking for the equations RCPier uses for calculating fss.
i'm trying to give a generic answer but if you are still unable to find the right information then please do let me know I shall further look into it.
Once you have designed the Pier cap then please click on PRINT and then click on Detailed Design Report.
Then select the required Report you want to generate and then click SUBMIT.
Then at every POI the program will show the equation, Article number and units the program is using to calculate the Spacing.
I hope it helps.
Please see the attached screen shot.
Thank you for the screenshots. This is very nearly what I am looking for. However, I can't see in the design report what the equation is for fss.
I have the same question as Brandon, which is:
Brandon Neill said:Is the fss calculated from fs = Ms/(As j d)?
If that is the case, is it possible to see the values for Ms, As, j, and d that result in 1.49 (from your example). I can understand that answering in a broad sense helps the most people, but in this case, I am wondering what the specific values in the equation for fss, as well as how (and where) the program chooses those values. Could you send a screenshot of the Analysis tables for Service Load State 3, if the result is pulled from there, or the moment diagram?
For crack check considers the Envelope Service moment value which can be obtained from the Analysis TAB.
Asb_eff from Flexure Design should be used for calculation of crack stresses.
Generally I follow the procedure mentioned in the RCPier Tutorial Manual Page HC-32.
Please see the attached screenshot.