First of all, does the results vary if I use SMALLDELTA instead of PDELTA and also how can I get results for LARGE PDELTA. In case of load combinations do I have to use the text PDELTA ANALYSIS & CHANGE after each combination. I have attached a model here, can anyone revise it for LARGE PDELTA analysis for all the load combinations & is the variation in results prominent from SMALL PDELTA analysis & analysis without PDELTA. Also I would like to know about the theory taken into consideration for large PDELTA analysis & SMALL PDELTA analysis.
Arch FOB_Single Span(BNBC).std
The PDELTA ANALYSIS and PDELTA ANALYSIS SMALLDELTA is the same as by default PDELTA ANALYSIS includes the effect of LARGE + small delta. If you need just the LARGE DELTA you need to explicitly specify the commands as show next PDELTA 15 ANALYSIS LARGEDELTA … where 15 stands for the number of iterations asked for. Section 5.37.2 of the technical reference manual has more explanation on this. You do NOT need to use PDELTA and CHANGE after every load case or REPEAT LOAD case. By the way, you cannot use LOAD COMBINATION when using PDELTA. You have to use REPEAT LOADs instead. The following wiki explains how to quickly convert LOAD COMB to REPEAT LOADs communities.bentley.com/.../30456.how-to-convert-a-load-combination-to-a-repeat-load In the attached model I have changed your load combination 50 to REPAT LOAD. You need to do the same for the other ones
Arch FOB_Single Span(BNBC)_modified.std You can refer to the following page for more information on PDELTA analysis. communities.bentley.com/.../2047.staad-pro-pdelta-analysis-faq
Sir
I applied a concentrated compressive load and moment at free end of a cantilever column.
I calculated deflection at free end due to moment and found out compressive load * deflection due to moment.
I repeated the steps for 5 iterations manually and got a converged solution.
But in Staad Different results were obtained for p small delta and p large delta analysis.
How to perform combined P small delta + P large delta analysis?
Kindly help me.
PDELTA ANALYSIS command will include bot small and large delta effects. If you wish to consider a large delta effect only, use a command PDELTA ANALYSIS LARGEDELTA.