Design of frame structure with Indian Standard IS 13920
I designed a RCC frame structure with Indian code IS 456. The design result was alright. As the structure was in high seismic zone, I reperformed the design with IS 13920. The structure even though has been designed by the software but the design result is full of unheard warnings, mostly of the same character, particularly as under:
Warning: ‘ UDL loading is not defined for member 85, 86, 89 ……….etc etc
Default value will be used’
Almost all the beam members are in the list of warning. There was no such warning when I ran the file with IS 456. Now I have to submit that when there is no UDL on the beam members in the structure how can I load them with UDL.
Please clarify whether Staad pro V8i is not inbuilt for designing the structure with IS 13920 – Ductile detailing or there is a bug in the software. As the design has been performed with default value for UDL, may I know what default value has been considered by the software.
I could remove the warnings and tackle the problem. Hence no further clarifications are required.
You could have explained in detail how did you eliminate the warnings so that others like me can learn from your experience.
Thanks in advance.
With warm regards,
The error can be removed by using EUDL or GLD parameters in the design component...
I am not sure how or when to use the EUDL parameter... I am using GLD parameters only...
Usage of GLD parameter:
After setting Design Code as IS13920 and before setting Design beam command, enter
GLD <load comb no> <list of beams>
The load comb number should refer to a load combination in the staad file that is set to 1.0(DL+LL) and list of beams should be full set of beams being designed by IS13920 code...
Hope that helps...
I have doubts whether the load assigned to GLD will be Combined Load case No. or Repeat Load case No. I am inclined to go in for Repeat Load case keeping in view the brief idea that I got from studying the case. I would request some Senior Members to throw light in the matter and enlighten us as we are now very close to actual solution of the case.
I found this detail in STAAD.Pro 2004 software release report (build 1002.India) about GLD parameter:
<Quoted from the report in description of GLD parameter for IS13920 design>
Gravity load number to be considered for calculating equivalent udl on span of the beam, in case no EUDL is mentioned in the input. This loadcase can be any static loadcase containing MEMBER LOAD on the beam which includes UNI, CON, LIN and TRAP member loading. CMOM member loading is considered only when it is specified in local direction. FLOOR LOAD is also considered.
The load can be primary or combination load. For combination load, only load numbers included in load combination is considered. The load factors are ignored. Internally, the unfactored load is multiplied by a factor 1.2 during design
If both EUDL and GLD parameters are mentioned in the input mentioned EUDL will be considered in design
No dynamic (Response Spectrum, 1893, Time History) and moving load cases are considered.
CMOM member loading in global direction is not considered
UMOM member loading is not considered.
<End of Quoted text>
So, load combination can be used as per above detail.
your reply is quite clear and many many thanks to you for your quick response. I have analysed my model both with Load Combination and Repeat Load. There is no difference in analysis result and design result. The result is same for both the cases.
I have used GLD parameter for beam design in staad file. But while analyzing the file, it quits unexpectedly. How can it be solved.
There has been a problem with IS:13920 code design. One can ask the program to compute Equivalent UDL for the design of beams by using GLD parameter. The program is facing problem with GLD parameter in STAAD.Pro V8i version 20.07.09.31. This has already been logged in problem tracking system. This problem has even been fixed and the fix will be available in the next elease of STAAD.Pro which is expected to be released officially in few weeks.
Workaround: You can use EUDL parameter instead of GLD parameter