Hello all,
I'm a student learning STAAD.Pro this semester.
I've done a beam model with two point loads applied. I've analyzed the model, but I haven't seen an output for what the actual value of max deflection in the beam is.
How does STAAD display this?
Thank you.
0753.Canopy.std
Hello. I've been following this deflection post and have tried to write in commands to print max displacements in the output. I am having difficulties executing the displacements properly; may be writing it wrongly in the code.
See below the STAAD output - the displacement given does not correspond with the max displ. shown in the outputs. Why are they not the same? And why is the L/DISP value so large? I have also attached the STAAD input. Please help.
By the way, I've also tried to follow this but have found it confusing. Not sure how to properly use the SECTION command and PRINT SECTION.
https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/9129/print-section-forces-in-staad-output
Thanks.
The section displacements that you see in the analysis output file are all global displacements and these are reported at 13 equally spaced sections along the length of a member (including the start and end). The L/DISP however is reported for the max local displacement only and not for the global section displacements because when checking the deflection in a member and satisfying the allowable deflection requirements ( L/240, L/360 etc) you should use the local displacements.
Thank you Sye. This explanation helps.
Sye, as you said the displacements are at 13 section locations. Therefore, the max displacement should be 0.2007 - (0.1755+0.1834)/2 = 0.02125 per your approximation and it is not equal to the printed MAX LOCAL DISPLACEMENT.
Also, I did a run on a structure and I compared the Report Table "Section Displacements" Max Disp, it does not match the printed (when using PRINT SECTION MAX DISPLACEMENT) Max Displacement which in turn does not match the approximation you mentioned above.
Which one is correct - the result table or the print? The table is helpful in getting the critical beam. Otherwise, one has to go through the result output one by one to get the maximum. The graphical deflection does seem to follow your approximation of the local deflection above. However, it would be difficult to know which member is critical. Using the Global Deflection to filter out maximums may not be that accurate.
To keep things simple here is a sample file ( EXAMP01_rev.STD) with respect to which I have explained the calculations. I have highlighted the max local displacement for member 6 for load case 1 obtained in different ways. If you look at the member section displacements output from the PRINT SECTION DISPL and PRINT SECTION MAX DISP output, both show the max local disp as 0.13606 inches as highlighted below
A rough calculation based on the section displacements reported in the output above also matches the value as shown next
Local Displacement at mid section = 1.0087 – (0.9048 + 0.8405)/2 = 0.13605 inches
The Maximum Relative Displacement table reports the same value as well as marked below
thanks for your help. I am implementing the review by deflection, I have managed to project it in the report, but some elements are reviewed by another parameter, is there a way to indicate that only the deflection parameter is projected???
PARAMETER 2 CODE AISCTRACK 0 MEMB 1 TO 32 37 TO 48CAN 1 MEMB 1 TO 32 37 TO 48DFF 250 ALLDJ1 1 1 17 24 47DJ2 3 1 17 24 47DJ1 9 13 20 27DJ2 10 13 20 27DJ1 11 MEMB 16 18 25DJ2 12 MEMB 16 18 25DJ1 4 MEMB 2 21 28 45DJ2 2 MEMB 2 21 28 45DJ1 3 MEMB 3 11 14 48DJ2 4 MEMB 3 11 14 48DJ1 13 MEMB 19 22 23DJ2 16 MEMB 19 22 23DJ1 17 MEMB 26 29 30DJ2 20 MEMB 26 29 30DJ1 1 MEMB 4 12 15 46DJ2 2 MEMB 4 12 15 46DJ1 7 MEMB 32 41DJ2 5 MEMB 32 41DJ1 8 MEMB 10 43DJ2 6 MEMB 10 43DJ1 7 MEMB 31 42DJ2 8 MEMB 31 42DJ1 5 MEMB 9 44DJ2 6 MEMB 9 44DJ1 7 MEMB 5 37DJ2 3 MEMB 5 37DJ1 8 MEMB 7 40DJ2 4 MEMB 7 40DJ1 6 MEMB 8 39DJ2 2 MEMB 8 39DJ1 5 6 38DJ2 1 6 38CHECK CODE MEMB 1 TO 32 37 TO 48
ALL UNITS ARE - KG METE (UNLESS OTHERWISE Noted)
MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/
FX MY MZ LOCATION
======================================================================
1 ST OR102X6.4 (MEXICAN_SECTIONS)
PASS DEFLECTION 0.671 11
104.12 T -25.92 -163.98 0.70
2 ST OR102X6.4 (MEXICAN_SECTIONS)
104.12 T 25.92 -163.98 0.70
3 ST OR102X6.4 (MEXICAN_SECTIONS)
PASS DEFLECTION 0.740 13
165.50 C -20.84 329.61 0.49
4 ST OR102X6.4 (MEXICAN_SECTIONS)
PASS DEFLECTION 0.736 13
154.54 C 13.28 368.92 0.49
5 ST OR102X6.4 (MEXICAN_SECTIONS)
PASS AISC- H2-1 0.800 13
2030.55 T -315.69 -382.37 0.00
6 ST OR102X6.4 (MEXICAN_SECTIONS)
PASS AISC- H2-1 0.854 12
2783.89 T 331.38 -394.35 0.00
Attach the model please.