Hi Sir/Madam,
There is unexpected high out of plane bending UC based on API22 by using SACS 13.2, see attached screenshot and Detailed Calculation as below.
Manual computation of UC based on actual / allowable bending stress is small but SACS is giving unreasonable large UC.
Please advise.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Detailed review report of member 3410 - 3406
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Units: Length -(cm) Force -(kN) Stress -(N/mm2)
Design Code - API RP2A,22nd ------------------------------------------------------------------------
****** Member Infomation ******
Group 41
Section Name Tubular
Total Length 13.82 (m)
Location 0.00 (m)
Segment 1 of 2
LC Option Single
Critical LC OP17
AMOD 1.00
------------------------------------------------------------------------
****** Basic Properties ******
Section Type Tubular
Outer Diameter 55.88
Wall Thickness 1.27
Elastic Modulus 210.00 1000(N/mm2)
Shear Modulus 80.00 1000(N/mm2)
Yield Strength 345.01 (N/mm2)
Axial Area A 217.88
Mom. of Inertia Iy 8.1E+004
Mom. of Inertia Iz 8.1E+004
Shear Area Y 108.94
Shear Area Z 108.94
Tors. Constant J 1.6E+005
****** Member's Properties ******
Slenderness Ratio (KL/r)y 64.09
Slenderness Ratio (KL/r)z 142.59
Radius of Gyration ry 19.31
Radius of Gyration rz 19.31
Eff. Length Factor Ky 0.90
Eff. Length Factor Kz 0.90
Overall Buck. Length Ly 13.80 (m)
Overall Buck. Length Lz 30.70 (m)
Final (K*L)y 12.42 (m)
Final (K*L)z 27.63 (m)
- Segmented Member: Overall buckling length is re-calculated from apprximate buckling load effectively at this segment. Leffy 13.77 (m) Leffz 13.77 (m) TUB Ring Spacing 13.82 (m)
Reduction Factor Cmy 0.85
Reduction Factor Cmz 0.85
------------------------------------------------------------------------ ****** End Forces and Moments ((kN), (kN-m)) ******
Tor. Moment Mx -3.3895
Bending Moment My 38.3418
Bending Moment Mz 9.2645
Axial force fx -1148.9885
Shear force fy -0.9487
Shear force fz -7.5851
****** Actual Stresses ******
Axial stress fa -52.7339
Bending Major fby 13.1821
Bending Minor fbz 3.1852
Resultant Shear fv 0.7017
Torsional Shear fvt -0.5827
****** Allowable Stresses ******
--- Allowable Stresses without Hydrostatic Pressure
Axial Tension Ft 207.0001 (6.1)
Shear Fv 138.0001 (6.12)
Axial Compression Fa 53.1890 (6.2~5)
Bending about Y Fby 246.4070 (6.6~8)
Bending about Z Fbz 246.4070
Euler Buckling Y Fey 263.2328 (6.3)
Euler Buckling Z Fez 53.1890
Elastic Loc Buckling Fxe 2863.6379 (6.4)
INelast Loc Buckling Fxc 345.0002 (6.5)
--- Allowable Stresses with Hydrostatic Pressure
Axial 53.1890
Major Axis Bending 246.4070
Minor Axis Bending 246.4070
Shear in Local Y 138.0001
Shear in Local Z 138.0001
Euler Buckling 53.1890
******** Unity Ratios ********
Critical Unity Ratio 2.2769 (6.20 ) Cmp>.15A
Combined Unity Ratio 2.2769 (6.3.2~5)
Axial Component 0.9914
Bending Major Y-Y 0.0025
Bending Minor Z-Z 1.2829
Shear in Y 0.0093
Shear in Z 0.0042
Euler Buckling Y-Y 0.2003
Euler Buckling Z-Z 0.9914
****** Hydrostatic Pressure Analysis ******
--- Parameters
Safety Fac. Tension SFxt 1.6700
Safety Fac. Compression SFxc 2.0000
Safety Fac. Bending SFb 1.4001
Safety Fac. Hoop Comp SFh 2.0000
Crit Hoop Buck. Coeff. Ch 0.0100
Geometric Parameter M 232.0019
Imperf. Reduc. Fac Alpha 0.8000
Water Depth d 78.2360 (m)
Water Depth at Member z 30.5356 (m)
Wave Height Hw 0.0000 (m)
Wave Length L N/A
--- Stresses
Hoop Stress fh 6.7856 (6.14)
Axial Stress fa -52.7339
Result Bending Stress fb 13.5614
Elastic Hoop Buck Stress Fhe 95.4546 (6.16)
Crit Hoop Buck Stress Fhc 95.4546 (6.18) 'NOTE: Marine Method selected'
--- Hydrostatic UC Ratios
MAX Hydro Collapse UC 0.3804
Combined Tension and Hydro UC 0.0000 (6.26)
Combined Comp and Hydro UC 0.3804 (6.27)
Hoop Compression UC 0.1422 (6.28)
Large Compression UC 0.0528 (6.29)
What is the UC reported in the SACS listing file? Does it match what is being displayed in Precede? It looks like there may be some sort of reporting bug occurring in SACS.
I'd recommend submitting a service request with the analysis so that a technical representative can take a look at this issue:
https://communities.bentley.com/products/electrical___instrumentation/w/electrical_and_instrumentation__wiki/40369/how-to-log-service-request
Regards,
Geoff