1. 2K Cold Box Structural Analysis
Shirley Yang, Scott Kaminski
LCLS-II 2 K Cold Box FDR
March 9, 2017

2. Stress, Displacement and Buckling Center Column Design
Outline
Design Parameters
Mechanical
Seismic Loads
Stress, Displacement and Buckling
Center Column Design
Anchor & Shear Key Design
Documentation
Conclusion
LCLS-II 2 K CBX FDR, Mar 9, 2017

3. 2K Cold Box Structure
2K cold box structure is analyzed per PART 5 Design by Analysis Requirements of ASME Section VIII, Division 2.
12’1” OD 2” thick top plate; SA240, 304 SS.
12’ OD 1 1/4” thick top skirt; SA240, 304SS.
12’ OD 3/4” thick shell; SA516 Gr. 70, CS.
12’ OD 3/4” thick bottom head; SA516 Gr. 70, CS.
12’ OD 1/2” thick bottom skirt; A36, CS.
LCLS-II 2 K CBX FDR, Mar 9, 2017

4. Material Properties Young’s Modulus (psi) Poisson’s Ratio
0.29
Density (lb/in^3)
SA516 Gr. 70 CS RT
2.90E+07
0.26
0.28
RT = room temperature
LCLS-II 2 K CBX FDR, Mar 9, 2017

5. Allowable Stress Per BPVC S8
The table below lists the allowed stresses for each stress category as defined in the BPVC, S8, Div. 2, paragraphs (e) and (d).
Allowable Stresses for Each Stress Category (ksi) at Room Temp.
Material
Stress Category Pm PL
PL + Pb
PL + Pb + Q
SA240, 304SS 20 30 60
SA516 Gr. 70
Pm = primary membrane stress ≤ S (per BPVC S8D2 paragraph (e))
PL = primary local membrane stress ≤ 1.5×S (per BPVC S8D2 paragraph (e)
Pb = primary bending stress
Q = secondary stress
(PL + Pb) ≤ 1.5×S (per BPVC S8D2 paragraph (e))
(PL + Pb + Q) ≤ 3×S (per BPVC S8D2 paragraph (d))
LCLS-II 2 K CBX FDR, Mar 9, 2017

6. Seismic Load Cal – ASCE 7-10
LCLS-II 2 K CBX FDR, Mar 9, 2017

7. Seismic Load Cal – ASCE 7-10 Cont.
LCLS-II 2 K CBX FDR, Mar 9, 2017

8. Boundary Conditions – Worse Case Scenario
Vacuum is applied to the vessel
The standard earth gravity and the seismic acceleration are applied to the vessel
LCLS-II 2 K CBX FDR, Mar 9, 2017

9. Boundary Conditions – Worse Case Scenario Cont.
3. The moments from the AutoPipe on cold compressor nozzles and bayonets for worst cases are applied to the mounting plate.
4. The forces from the AutoPipe on cold compressor nozzles and bayonets are applied to the nozzle areas.
5. The seismic acceleration loads of cold compressors and motors are applied to the center of gravity of the CC system.
6. The bottom skirt surface is fixed.
LCLS-II 2 K CBX FDR, Mar 9, 2017

10. Von-Mises Stresses
The peak stress on the top plate is 15.7 ksi, less than the allowable stress, which is 20 ksi.
LCLS-II 2 K CBX FDR, Mar 9, 2017

11. Von-Mises Stress – Top Groove Weld
0.5” groove weld between the top plate and top skirt
LCLS-II 2 K CBX FDR, Mar 9, 2017

12. Von-Mises Stress – Middle Groove Weld
0.25” groove weld between the top skirt and the shell body.
LCLS-II 2 K CBX FDR, Mar 9, 2017

13. Von-Mises Stress – Bottom Groove Weld
0.375” groove weld between the shell body and bottom head are extracted
LCLS-II 2 K CBX FDR, Mar 9, 2017

14. Deformation
The maximum deformation is 0.176”, which is located in the compressors CC4 to CC6 area. But the “relative” deformation in each compressor area is less than the required tolerance, which is 1/16”.
LCLS-II 2 K CBX FDR, Mar 9, 2017

15. Vessel Buckling
Buckling modes were checked for the vessel since it is under the vacuum at the normal operation condition. The minimum buckling factor is Therefore, buckling is not a concern for the vessel.
LCLS-II 2 K CBX FDR, Mar 9, 2017

16. Thermal and Structure Consideration of the Center Column
6” Sch SS pipe
1/8” thick copper layer with a heat strap
Top and bottom plates as well as spider ribs
LCLS-II 2 K CBX FDR, Mar 9, 2017

17. Anchor Design
Twelve 3/4” F1554 Grade 36 anchors equally spaced on a ” diameter.
Hilti HIT-RE 500 V3 adhesive anchoring system with an effective embedment depth of 12.5”.
Anchors chairs with a top face 7” above the baseplate top face (gauge / stretch length of more than eight diameters).
LCLS-II 2 K CBX FDR, Mar 9, 2017

18. Operating weight of 41,000 lbs and a 7’-6” center of gravity
Anchor Design
Operating weight of 41,000 lbs and a 7’-6” center of gravity
ASCE Load Combination 7
( SDS) D + ρQE
Design Loads
Vertical = -20,700 lbs
ρQE (Mx) = 7,262,000 in-lbs
ρQE (My) = 2,178,600 in-lbs
The anchor bolts are suitable if the nominal bond and concrete breakout utilizations are less than 120% of the nominal steel utilization (the anchor embedment develops the steel strength of the anchor in tension) and the applied loads do not exceed the reduced steel, bond and concrete breakout strengths.
LCLS-II 2 K CBX FDR, Mar 9, 2017

19. 120% Nominal Steel Strength Nominal Concrete Breakout Strength
Anchor Design
120% Nominal Steel Strength
Nominal Bond Strength
Nominal Concrete Breakout Strength
Tension Utilizations
39.4%
23.3%
38.1%
Reduced Strength Steel
Reduced Strength Bond
Reduced Strength Concrete Breakout
63.3%
47.7%
78.1%
LCLS-II 2 K CBX FDR, Mar 9, 2017

20. Twelve 4” XXS A106 Grade B pipes equally spaced on a 150” diameter.
Shear Key Design
Twelve 4” XXS A106 Grade B pipes equally spaced on a 150” diameter.
7.625” long such that they extend 4” into the concrete slab
Two 1.5” diameter holes to facilitate the flow of grout
LCLS-II 2 K CBX FDR, Mar 9, 2017

21. ASCE 7-10 12.4.2.3 Load Combination 5
Shear Key Design
ASCE Load Combination 5
( SDS) D + ρQE + L + 0.2S
Design Loads
V = 168,600 lbs
Suitable if the bearing strength of the concrete exceeds the applied bearing load, the reaction shear load does not yield the shear key in shear, the resulting moment does not yield the shear key in bending and the attachment weld is sufficient for the shear / moment applied at the shear key-baseplate connection.
Concrete Bearing
Pipe Shear Stress
Pipe Bending Stress
Attachment Weld
Utilizations
48.6%
36.1%
69.8%
91.2%
LCLS-II 2 K CBX FDR, Mar 9, 2017

22. Anchor Structure – Boundary Condition
The normal operation weight is 41,000 lbf for the 2K CB g is applied to the X axial, and 0.59g is applied to the Z axial. Since the tensile load on anchors will be greater when there is less weight to resist overturning, -0.51g is applied to the Y axial. Thus a remote force of 80,700 lbf (41,000 lbf*1.968) in X axial, -20,700 (-41,000 lbf*0.51)lbf in Y axial and 24,200 (41,000lbf * 0.59)lbf in Z axial which is 90” above the baseplate is applied to the model.
LCLS-II 2 K CBX FDR, Mar 9, 2017

23. Anchor Structure – Stress
The peak von-Mises stress is 49.1ksi. But it is caused by singularity, which can be safely ignored. The average stress is far below the yield strength, which is 36 ksi.
LCLS-II 2 K CBX FDR, Mar 9, 2017

24. Anchor Structure – Stress cont.
LCLS-II 2 K CBX FDR, Mar 9, 2017

25. Nozzle Weldment and Reinforcement
LCLS-II 2 K CBX FDR, Mar 9, 2017

26. Nozzle Weldment and Reinforcement Cont.
LCLS-II 2 K CBX FDR, Mar 9, 2017

27. Nozzle Weldment and Reinforcement Cont.
LCLS-II 2 K CBX FDR, Mar 9, 2017

28. Documentation Document No. Title Author Status 79222-P0002
2K Cold Box Structure Analysis Report
S. Yang
In Development
79222-A0001
2K Cold Box Anchor-Shear Key Calculations
S. Kaminski
Submitted for Review
LCLS-II General Equipment Layout Cold Box Room
J. Tschirhart
Released
LCLS-II 2K Cold Box Shipped Assembly
D. Rath
In Progress
LCLS-II 2 K CBX FDR, Mar 9, 2017

29. Structural Analysis Conclusion
Structural design of the vessel meets the normal operation condition with the seismic effect.
The center column will be heat intercepted with copper layer to reduce the thermal shrinkage.
Double fillet lap joint will be used to weld nozzles to shell.
No reinforcement pad is required on openings.
Design acceptable using ASME B&PVC Sect VIII Div. I and Div. II.
LCLS-II 2 K CBX FDR, Mar 9, 2017