EX. UK-3 Soil Springs for Portal Frame
A portal frame type steel structure is sitting on concrete footings. The soil is to be considered as an elastic foundation. The value of soil subgrade reaction is known from which spring constants are calculated by multiplying the subgrade reaction by the tributary area of each modeled spring.
This problem is installed with the program by default to C:\Users\Public\Public Documents\STAAD.Pro 2023\Samples\Sample Models\UK\UK-3 Soil Springs for Portal Frame.STD when you install the program.
Example Problem No. 3
Where:
- B = 6 m, H = 3 m, F1 = 1.2 m, F2 = 2.4 m
- P = 20 KN, w = 4.5 KN/m
- Soil Subgrade Reaction = 41,666.67 KN/m3
Springs of Joints | Spring Constant |
---|---|
1, 5, 10, & 14 (Edges) |
2.4 x 0.3 x 41,666.67 = 30,000 KN/m |
2, 3, 4, 11, 12, & 13 (Interior) |
2.4 x 0.6 x 41,666.67 = 60,000 KN/m |
Actual input is shown in bold lettering followed by explanation.
STAAD PLANE PORTAL ON FOOTING FOUNDATION
Every input has to start with the term STAAD. The term PLANE signifies that the structure is a plane frame structure and the geometry is defined through X and Y axes.
UNIT METER KNS
Defines the input units for the data that follows.
JOINT COORDINATES 1 0.0 0.0 0.0 5 2.4 0.0 0.0 6 1.2 3.0 0.0 ; 7 1.2 6.0 0.0 8 7.2 6.0 0.0 ; 9 7.2 3.0 0.0 10 6.0 0.0 0.0 14 8.4 0.0 0.0
Joint number followed by X, Y and Z coordinates are provided above. Since this is a plane structure, the Z coordinates are given as all zeros.
MEMBER INCIDENCES 1 1 2 4 5 3 6 ; 6 6 7 7 7 8 ; 8 6 9 9 8 9 ; 10 9 12 11 10 11 14
Defines the members by the joints to which they are connected.
MEMBER PROPERTIES BRITISH 1 4 11 14 PRIS YD 0.30 ZD 2.40 2 3 12 13 PRIS YD 0.60 ZD 2.40 5 6 9 10 TABLE ST JO254X203 7 8 TA ST UB305X165X40
The first two lines define member properties as prismatic (PRIS) followed by depth (YD) and width (ZD) values. The program will calculate the properties necessary to perform the analysis. See G.6.1 Prismatic Properties for additional information. Member properties for the remaining members are chosen from the British steel table. The term ST stands for standard single section.
UNIT MMS * E FOR STEEL IS 210 (KN/sq.mm.) AND FOR CONCRETE 21 (KN/sq.mm.) DEFINE MATERIAL START ISOTROPIC STEEL E 210 POISSON 0.3 DENSITY 76.977e-009 ALPHA 6e-006 DAMP 0.03 TYPE STEEL STRENGTH FY 0.24821 FU 0.399894 RY 1.5 RT 1.2 ISOTROPIC CONCRETE E 21 POISSON 0.17 DENSITY 23.534e-009 ALPHA 5e-006 DAMP 0.05 G 9.25 TYPE CONCRETE STRENGTH FCU 0.0275 END DEFINE MATERIAL CONSTANTS MATERIAL CONCRETE MEMB 1 TO 4 11 TO 14 MATERIAL STEEL MEMB 5 TO 10
The CONSTANT command initiates input for material constants like modulus of elasticity, Density, and Poisson's ratio. The length unit is changed from METER to MM to facilitate the input in familiar units.
SUPPORTS 2 TO 4 11 TO 13 FIXED BUT MZ KFY 60 1 5 10 14 FIXED BUT MZ KFY 30
The supports for the structure are specified above. The first set of joints are supports restrained in all directions except global moment-z (MZ). Also, a spring having a spring constant of 60 KN/mm is provided in the global Y direction at these nodes. The second set is similar to the former except for a different value of the spring constant.
UNIT METER
LOADING 1 DEAD AND WIND LOAD COMBINED
Load case 1 is initiated followed by a title.
SELF Y -1.0
The selfweight of the structure is specified as acting in the global Y direction with a -1.0 factor.
Since global Y is vertically upwards, the -1.0 factor indicates that this load will act downwards.
JOINT LOAD 6 7 FX 20.0
Load 1 contains joint loads also. FX indicates that the load is a force in the global X direction.
MEMBER LOAD 7 8 UNI GY -45.0
Load 1 contains member loads also. GY indicates that the load acts in the global Y direction. The term UNI stands for uniformly distributed load, and is applied on members 7 and 8, acting downwards.
PERFORM ANALYSIS
This command instructs the program to proceed with the analysis.
PRINT ANALYSIS RESULTS
The above PRINT command instructs the program to print analysis results which include joint displacements, member forces and support reactions.
FINISH
This command terminates the STAAD run.
Input File
STAAD PLANE PORTAL ON FOOTING FOUNDATION
UNIT METER KNS
JOINT COORDINATES
1 0.0 0.0 0.0 5 2.4 0.0 0.0
6 1.2 3.0 0.0 ; 7 1.2 6.0 0.0
8 7.2 6.0 0.0 ; 9 7.2 3.0 0.0
10 6.0 0.0 0.0 14 8.4 0.0 0.0
MEMBER INCIDENCES
1 1 2 4
5 3 6 ; 6 6 7
7 7 8 ; 8 6 9
9 8 9 ; 10 9 12
11 10 11 14
MEMBER PROPERTIES BRITISH
1 4 11 14 PRIS YD 0.30 ZD 2.40
2 3 12 13 PRIS YD 0.60 ZD 2.40
5 6 9 10 TABLE ST JO254X203
7 8 TA ST UB305X165X40
UNIT MMS
* E FOR STEEL IS 210 (KN/sq.mm.) AND FOR CONCRETE 21 (KN/sq.mm.)
DEFINE MATERIAL START
ISOTROPIC STEEL
E 210
POISSON 0.3
DENSITY 76.977e-009
ALPHA 6e-006
DAMP 0.03
TYPE STEEL
STRENGTH FY 0.24821 FU 0.399894 RY 1.5 RT 1.2
ISOTROPIC CONCRETE
E 21
POISSON 0.17
DENSITY 23.534e-009
ALPHA 5e-006
DAMP 0.05
G 9.25
TYPE CONCRETE
STRENGTH FCU 0.0275
END DEFINE MATERIAL
CONSTANTS
MATERIAL CONCRETE MEMB 1 TO 4 11 TO 14
MATERIAL STEEL MEMB 5 TO 10
SUPPORTS
2 TO 4 11 TO 13 FIXED BUT MZ KFY 60
1 5 10 14 FIXED BUT MZ KFY 30
UNIT METER
LOADING 1 DEAD AND WIND LOAD COMBINED
SELF Y -1.0
JOINT LOAD
6 7 FX 20.0
MEMBER LOAD
7 8 UNI GY -45.0
PERFORM ANALYSIS
PRINT ANALYSIS RESULTS
FINISH
STAAD Output File
PAGE NO. 1 **************************************************** * * * STAAD.Pro 2023 * * Version 23.00.02.*** * * Proprietary Program of * * Bentley Systems, Inc. * * Date= DEC 14, 2023 * * Time= 9:36:11 * * * * Licensed to: Bentley Systems Inc * **************************************************** 1. STAAD PLANE PORTAL ON FOOTING FOUNDATION INPUT FILE: D:\Documentation\STAAD.Pro\_Automated_Py\output\2023-12-14\SPro_Output_Input_Files\Sample .. .STD 2. UNIT METER KNS 3. JOINT COORDINATES 4. 1 0.0 0.0 0.0 5 2.4 0.0 0.0 5. 6 1.2 3.0 0.0 ; 7 1.2 6.0 0.0 6. 8 7.2 6.0 0.0 ; 9 7.2 3.0 0.0 7. 10 6.0 0.0 0.0 14 8.4 0.0 0.0 8. MEMBER INCIDENCES 9. 1 1 2 4 10. 5 3 6 ; 6 6 7 11. 7 7 8 ; 8 6 9 12. 9 8 9 ; 10 9 12 13. 11 10 11 14 14. MEMBER PROPERTIES BRITISH 15. 1 4 11 14 PRIS YD 0.30 ZD 2.40 16. 2 3 12 13 PRIS YD 0.60 ZD 2.40 17. 5 6 9 10 TABLE ST JO254X203 18. 7 8 TA ST UB305X165X40 19. UNIT MMS 20. * E FOR STEEL IS 210 (KN/SQ.MM.) AND FOR CONCRETE 21 (KN/SQ.MM.) 21. DEFINE MATERIAL START 22. ISOTROPIC STEEL 23. E 210 24. POISSON 0.3 25. DENSITY 76.977E-009 26. ALPHA 6E-006 27. DAMP 0.03 28. TYPE STEEL 29. STRENGTH FY 0.24821 FU 0.399894 RY 1.5 RT 1.2 30. ISOTROPIC CONCRETE 31. E 21 32. POISSON 0.17 33. DENSITY 23.534E-009 34. ALPHA 5E-006 35. DAMP 0.05 36. G 9.25 37. TYPE CONCRETE 38. STRENGTH FCU 0.0275 PORTAL ON FOOTING FOUNDATION -- PAGE NO. 2 39. END DEFINE MATERIAL 40. CONSTANTS 41. MATERIAL CONCRETE MEMB 1 TO 4 11 TO 14 42. MATERIAL STEEL MEMB 5 TO 10 43. SUPPORTS 44. 2 TO 4 11 TO 13 FIXED BUT MZ KFY 60 45. 1 5 10 14 FIXED BUT MZ KFY 30 46. UNIT METER 47. LOADING 1 DEAD AND WIND LOAD COMBINED 48. SELF Y -1.0 49. JOINT LOAD 50. 6 7 FX 20.0 51. MEMBER LOAD 52. 7 8 UNI GY -45.0 53. PERFORM ANALYSIS P R O B L E M S T A T I S T I C S ----------------------------------- NUMBER OF JOINTS 14 NUMBER OF MEMBERS 14 NUMBER OF PLATES 0 NUMBER OF SOLIDS 0 NUMBER OF SURFACES 0 NUMBER OF SUPPORTS 10 Using 64-bit analysis engine. SOLVER USED IS THE IN-CORE ADVANCED MATH SOLVER TOTAL PRIMARY LOAD CASES = 1, TOTAL DEGREES OF FREEDOM = 32 TOTAL LOAD COMBINATION CASES = 0 SO FAR. 54. PRINT ANALYSIS RESULTS ANALYSIS RESULTS PORTAL ON FOOTING FOUNDATION -- PAGE NO. 3 JOINT DISPLACEMENT (CM RADIANS) STRUCTURE TYPE = PLANE ------------------ JOINT LOAD X-TRANS Y-TRANS Z-TRANS X-ROTAN Y-ROTAN Z-ROTAN 1 1 0.0000 -0.1075 0.0000 0.0000 0.0000 -0.0003 2 1 0.0000 -0.1232 0.0000 0.0000 0.0000 -0.0002 3 1 0.0000 -0.1367 0.0000 0.0000 0.0000 -0.0002 4 1 0.0000 -0.1466 0.0000 0.0000 0.0000 -0.0002 5 1 0.0000 -0.1531 0.0000 0.0000 0.0000 -0.0001 6 1 0.5036 -0.1720 0.0000 0.0000 0.0000 -0.0032 7 1 1.0714 -0.1898 0.0000 0.0000 0.0000 -0.0045 8 1 1.0286 -0.2097 0.0000 0.0000 0.0000 0.0022 9 1 0.5240 -0.1901 0.0000 0.0000 0.0000 -0.0003 10 1 0.0000 -0.0897 0.0000 0.0000 0.0000 -0.0005 11 1 0.0000 -0.1210 0.0000 0.0000 0.0000 -0.0005 12 1 0.0000 -0.1504 0.0000 0.0000 0.0000 -0.0005 13 1 0.0000 -0.1759 0.0000 0.0000 0.0000 -0.0004 14 1 0.0000 -0.1969 0.0000 0.0000 0.0000 -0.0003 PORTAL ON FOOTING FOUNDATION -- PAGE NO. 4 SUPPORT REACTIONS -UNIT KNS METE STRUCTURE TYPE = PLANE ----------------- JOINT LOAD FORCE-X FORCE-Y FORCE-Z MOM-X MOM-Y MOM Z 2 1 0.00 73.95 0.00 0.00 0.00 0.00 3 1 0.09 82.00 0.00 0.00 0.00 0.00 4 1 0.00 87.96 0.00 0.00 0.00 0.00 11 1 0.00 72.58 0.00 0.00 0.00 0.00 12 1 -40.09 90.24 0.00 0.00 0.00 0.00 13 1 0.00 105.56 0.00 0.00 0.00 0.00 1 1 0.00 32.25 0.00 0.00 0.00 0.00 5 1 0.00 45.92 0.00 0.00 0.00 0.00 10 1 0.00 26.90 0.00 0.00 0.00 0.00 14 1 0.00 59.07 0.00 0.00 0.00 0.00 PORTAL ON FOOTING FOUNDATION -- PAGE NO. 5 MEMBER END FORCES STRUCTURE TYPE = PLANE ----------------- ALL UNITS ARE -- KNS METE (LOCAL ) MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z 1 1 1 0.00 32.25 0.00 0.00 0.00 0.00 2 0.00 -22.08 0.00 0.00 0.00 16.30 2 1 2 0.00 96.03 0.00 0.00 0.00 -16.30 3 0.00 -75.70 0.00 0.00 0.00 67.82 3 1 3 0.00 -103.39 0.00 0.00 0.00 -92.63 4 0.00 123.72 0.00 0.00 0.00 24.50 4 1 4 0.00 -35.76 0.00 0.00 0.00 -24.50 5 0.00 45.92 0.00 0.00 0.00 0.00 5 1 3 261.09 -0.09 0.00 0.00 0.00 24.82 6 -258.66 0.09 0.00 0.00 0.00 -25.09 6 1 6 132.10 -56.74 0.00 0.00 0.00 -73.59 7 -129.67 56.74 0.00 0.00 0.00 -96.64 7 1 7 76.74 129.67 0.00 0.00 0.00 96.64 8 -76.74 142.70 0.00 0.00 0.00 -135.72 8 1 6 -36.65 126.57 0.00 0.00 0.00 98.68 9 36.65 145.80 0.00 0.00 0.00 -156.40 9 1 8 142.70 76.74 0.00 0.00 0.00 135.72 9 -145.12 -76.74 0.00 0.00 0.00 94.51 10 1 9 290.93 40.09 0.00 0.00 0.00 61.89 12 -293.35 -40.09 0.00 0.00 0.00 58.38 11 1 10 0.00 26.90 0.00 0.00 0.00 -0.00 11 0.00 -16.74 0.00 0.00 0.00 13.09 12 1 11 0.00 89.32 0.00 0.00 0.00 -13.09 12 0.00 -68.99 0.00 0.00 0.00 60.58 13 1 12 0.00 -134.13 0.00 0.00 0.00 -118.97 13 0.00 154.46 0.00 0.00 0.00 32.39 14 1 13 0.00 -48.90 0.00 0.00 0.00 -32.39 14 0.00 59.07 0.00 0.00 0.00 0.00 PORTAL ON FOOTING FOUNDATION -- PAGE NO. 6 ************** END OF LATEST ANALYSIS RESULT ************** 55. FINISH *********** END OF THE STAAD.Pro RUN *********** **** DATE= DEC 14,2023 TIME= 9:36:11 **** ************************************************************ * For technical assistance on STAAD.Pro, please visit * * http://www.bentley.com/en/support/ * * * * Details about additional assistance from * * Bentley and Partners can be found at program menu * * Help->Technical Support * * * * Copyright (c) Bentley Systems, Inc. * * http://www.bentley.com * ************************************************************