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EX. US-10 Finite Element Model for a Rectangular Tank

A tank structure is modeled with four-noded plate elements. Water pressure from inside is used as loading for the tank. Reinforcement calculations have been done for some elements.

This problem is installed with the program by default to C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\Sample Models\US\US-10 Finite Element Model for a Rectangular Tank.STD when you install the program.

Tank Model

Deflected Shape

Actual input is shown in bold lettering followed by explanation.

    STAAD SPACE FINITE ELEMENT MODEL OF TANK 
    * STRUCTURE

Every input has to start with the term STAAD. The word SPACE signifies that the structure is a space frame (3-D) structure.

    UNITS FEET KIPS

Defines the input units for the data that follows.

    JOINT COORDINATES
    1  0.  0.  0.  5  0.  20.  0.
    REPEAT 4  5.  0.  0.
    REPEAT 4  0.  0.  5.
    REPEAT 4  -5.  0.  0.
    REPEAT 3  0.  0.  -5.
    81  5.  0.  5.  83  5.  0.  15.
    REPEAT 2  5.  0.  0.

Joint number followed by X, Y and Z coordinates are provided above. The REPEAT command generates joint coordinates by repeating the pattern of the previous line of joint coordinates. The number following the REPEAT command is the number of repetitions to be carried out. This is followed by X, Y and Z coordinate increments. See TR.11 Joint Coordinates Specification .

    ELEMENT INCIDENCES
    1 1 2 7 6 TO 4 1 1
    REPEAT 14 4 5 
    61 76 77 2 1 TO 64 1 1
    65 1 6 81 76
    66 76 81 82 71
    67 71 82 83 66
    68 66 83 56 61
    69 6 11 84 81
    70 81 84 85 82
    71 82 85 86 83
    72 83 86 51 56
    73 11 16 87 84
    74 84 87 88 85
    75 85 88 89 86
    76 86 89 46 51
    77 16 21 26 87
    78 87 26 31 88
    79 88 31 36 89
    80 89 36 41 46

Element connectivities are input as above by providing the element number followed by joint numbers defining the element. The REPEAT command generates element incidences by repeating the pattern of the previous line of element nodes. The number following the REPEAT command is the number of repetitions to be carried out and that is followed by element and joint number increments. See TR.12 Member Incidences Specification .

    UNIT INCHES
    ELEMENT PROPERTIES
    1 TO 80 TH 8.0

Element properties are provided by specifying that the elements are 8.0 inches THick.

    DEFINE MATERIAL START
    ISOTROPIC CONCRETE
    E 3000.
    POISSON 0.17
    DENSITY 8.7e-005
    ALPHA 5e-006
    DAMP 0.05
    G 1346.15
    TYPE CONCRETE
    STRENGTH FCU 4
    END DEFINE MATERIAL
    CONSTANTS
    MATERIAL CONCRETE ALL

The DEFINE MATERIAL command is used to specify material properties and the CONSTANT is used to assign the material to all members.

    SUPPORT 
    1 TO 76 BY 5 81 TO 89 PINNED

Pinned supports are specified at the joints listed above. No moments will be carried by these supports. The expression 1 TO 76 BY 5 means 1, 6, 11, etc. up to 76.

    UNIT FT
    LOAD 1
    ELEMENT LOAD
    4 TO 64 BY 4 PR 1.
    3 TO 63 BY 4 PR 2.
    2 TO 62 BY 4 PR 3.
    1 TO 61 BY 4 PR 4.

Load case 1 is initiated. It consists of element loads in the form of uniform pressure(indicated by PR)  acting along the local z-axis.

    PERFORM ANALYSIS

This command instructs the program to proceed with the analysis.

    UNIT INCHES
    PRINT JOINT DISPLACEMENTS LIST  5  25  45  65  

The joint displacement values for the listed nodes will be reported in the output file as a result of the above command.

    PRINT ELEM FORCE LIST 13 16
    PRINT ELEM STRESS LIST 9 12

Two types of results are requested for elements. The first one requests the nodal point forces in the global axes directions to be reported for elements 13 and 16. The second one requests element centroid stresses in the element local axes directions to be reported for elements 9 and 12. These results will appear in a tabular form in the output file.

    START CONCRETE DESIGN

The above command initiates concrete design.

    CODE ACI
    DESIGN SLAB  9  12

Slabs (i.e., elements) 9 and 12 will be designed and the reinforcement requirements obtained. In STAAD, elements are typically designed for the moments MX and MY at the centroid of the element.

    END CONCRETE DESIGN

Terminates the concrete design operation.

    FINISH

This command terminates the STAAD run.

Input File

STAAD SPACE FINITE ELEMENT MODEL OF TANK STRUCTURE
UNITS FEET KIPS
JOINT COORDINATES
1 0. 0. 0. 5 0. 20. 0.
REPEAT 4 5. 0. 0.
REPEAT 4 0. 0. 5.
REPEAT 4 -5. 0. 0.
REPEAT 3 0. 0. -5.
81 5. 0. 5. 83 5. 0. 15.
REPEAT 2 5. 0. 0.
ELEMENT INCIDENCES
1 1 2 7 6 TO 4 1 1
REPEAT 14 4 5
61 76 77 2 1 TO 64 1 1
65 1 6 81 76
66 76 81 82 71
67 71 82 83 66
68 66 83 56 61
69 6 11 84 81
70 81 84 85 82
71 82 85 86 83
72 83 86 51 56
73 11 16 87 84
74 84 87 88 85
75 85 88 89 86
76 86 89 46 51
77 16 21 26 87
78 87 26 31 88
79 88 31 36 89
80 89 36 41 46
UNIT INCHES
ELEMENT PROPERTIES
1 TO 80 TH 8.0
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 3000.
POISSON 0.17
DENSITY 8.7e-005
ALPHA 5e-006
DAMP 0.05
G 1346.15
TYPE CONCRETE
STRENGTH FCU 4
END DEFINE MATERIAL
CONSTANTS
MATERIAL CONCRETE ALL
SUPPORT
1 TO 76 BY 5 81 TO 89 PINNED
UNIT FT
LOAD 1
ELEMENT LOAD
4 TO 64 BY 4 PR 1.
3 TO 63 BY 4 PR 2.
2 TO 62 BY 4 PR 3.
1 TO 61 BY 4 PR 4.
PERFORM ANALYSIS
UNIT INCHES
PRINT JOINT DISPLACEMENTS LIST 5 25 45 65
PRINT ELEM FORCE LIST 13 16
PRINT ELEM STRESS LIST 9 12
START CONCRETE DESIGN
CODE ACI
DESIGN SLAB 9 12
END CONCRETE DESIGN
FINISH

STAAD Output File

                                                                  PAGE NO.    1
             ****************************************************        
             *                                                  *        
             *           STAAD.Pro CONNECT Edition              *        
             *           Version  22.04.00.**                   *        
             *           Proprietary Program of                 *        
             *           Bentley Systems, Inc.                  *        
             *           Date=    APR 21, 2020                  *        
             *           Time=    15:41:36                      *        
             *                                                  *        
             *  Licensed to: Bentley Systems Inc                *        
             ****************************************************        
     1. STAAD SPACE FINITE ELEMENT MODEL OF TANK STRUCTURE
INPUT FILE: US-10 Finite Element Model for a Rectangular Tank.STD
     2. UNITS FEET KIPS
     3. JOINT COORDINATES
     4. 1 0. 0. 0. 5 0. 20. 0.
     5. REPEAT 4 5. 0. 0.
     6. REPEAT 4 0. 0. 5.
     7. REPEAT 4 -5. 0. 0.
     8. REPEAT 3 0. 0. -5.
     9. 81 5. 0. 5. 83 5. 0. 15.
    10. REPEAT 2 5. 0. 0.
    11. ELEMENT INCIDENCES
    12. 1 1 2 7 6 TO 4 1 1
    13. REPEAT 14 4 5
    14. 61 76 77 2 1 TO 64 1 1
    15. 65 1 6 81 76
    16. 66 76 81 82 71
    17. 67 71 82 83 66
    18. 68 66 83 56 61
    19. 69 6 11 84 81
    20. 70 81 84 85 82
    21. 71 82 85 86 83
    22. 72 83 86 51 56
    23. 73 11 16 87 84
    24. 74 84 87 88 85
    25. 75 85 88 89 86
    26. 76 86 89 46 51
    27. 77 16 21 26 87
    28. 78 87 26 31 88
    29. 79 88 31 36 89
    30. 80 89 36 41 46
    31. UNIT INCHES
    32. ELEMENT PROPERTIES
    33. 1 TO 80 TH 8.0
    34. DEFINE MATERIAL START
    35. ISOTROPIC CONCRETE
    36. E 3000.
    37. POISSON 0.17
    38. DENSITY 8.7E-005
      FINITE ELEMENT MODEL OF TANK STRUCTURE                   -- PAGE NO.    2
    39. ALPHA 5E-006
    40. DAMP 0.05
    41. G 1346.15
    42. TYPE CONCRETE
    43. STRENGTH FCU 4
    44. END DEFINE MATERIAL
    45. CONSTANTS
    46. MATERIAL CONCRETE ALL
    47. SUPPORT
    48. 1 TO 76 BY 5 81 TO 89 PINNED
    49. UNIT FT
    50. LOAD 1
    51. ELEMENT LOAD
    52. 4 TO 64 BY 4 PR 1.
    53. 3 TO 63 BY 4 PR 2.
    54. 2 TO 62 BY 4 PR 3.
    55. 1 TO 61 BY 4 PR 4.
    56. PERFORM ANALYSIS
            P R O B L E M   S T A T I S T I C S
            -----------------------------------
     NUMBER OF JOINTS         89  NUMBER OF MEMBERS       0
     NUMBER OF PLATES         80  NUMBER OF SOLIDS        0
     NUMBER OF SURFACES        0  NUMBER OF SUPPORTS     25
           Using 64-bit analysis engine.
           SOLVER USED IS THE IN-CORE ADVANCED MATH SOLVER
   TOTAL      PRIMARY LOAD CASES =     1, TOTAL DEGREES OF FREEDOM =     459
   TOTAL LOAD COMBINATION  CASES =     0  SO FAR.
    57. UNIT INCHES
    58. PRINT JOINT DISPLACEMENTS LIST 5 25 45 65
  JOINT    DISPLACE LIST     5        
      FINITE ELEMENT MODEL OF TANK STRUCTURE                   -- PAGE NO.    3
   JOINT DISPLACEMENT (INCH RADIANS)    STRUCTURE TYPE = SPACE
   ------------------
 JOINT  LOAD   X-TRANS   Y-TRANS   Z-TRANS   X-ROTAN   Y-ROTAN   Z-ROTAN
      5    1   -0.00403   0.00027  -0.00403   0.00021   0.00000  -0.00021
     25    1    0.00403   0.00027  -0.00403   0.00021   0.00000   0.00021
     45    1    0.00403   0.00027   0.00403  -0.00021   0.00000   0.00021
     65    1   -0.00403   0.00027   0.00403  -0.00021   0.00000  -0.00021
   ************** END OF LATEST ANALYSIS RESULT **************
    59. PRINT ELEM FORCE LIST 13 16
  ELEM     FORCE    LIST     13       
      FINITE ELEMENT MODEL OF TANK STRUCTURE                   -- PAGE NO.    4
   ELEMENT FORCES    FORCE,LENGTH UNITS= KIPS INCH
   --------------
     GLOBAL CORNER FORCES
 JOINT     FX          FY          FZ          MX          MY          MZ
               ELE.NO.     13 FOR LOAD CASE     1
    16 -2.3570E+01 -1.8550E+01 -3.9109E+00 -1.3649E+02  2.4437E+02  1.3427E+02
    17 -7.0147E+00 -1.5328E+01 -1.6950E+01 -8.5004E+01 -4.0990E+01 -2.1558E+02
    22  4.0892E+01  5.9984E+00  1.8154E+01 -1.4891E+02  5.4757E+02  2.6486E+02
    21 -1.0308E+01  2.7879E+01  2.7070E+00  2.9817E+02  5.0071E+02 -1.8356E+02
               ELE.NO.     16 FOR LOAD CASE     1
    19 -3.7438E+01  3.4537E+00 -2.8252E+01 -2.4192E+02  1.9474E+02  2.4055E+02
    20 -3.6565E+01  6.0104E-01 -2.7049E+01  2.5567E+02  2.1788E+02 -4.0380E+02
    25  3.2510E+01  1.7764E-15  2.6260E+01 -4.9347E+02  1.4400E+03  4.9347E+02
    24  4.1493E+01 -4.0547E+00  2.9041E+01  5.2703E+02  1.4655E+03 -3.3022E+02
    60. PRINT ELEM STRESS LIST 9 12
  ELEM     STRESS   LIST     9        
      FINITE ELEMENT MODEL OF TANK STRUCTURE                   -- PAGE NO.    5
   ELEMENT STRESSES    FORCE,LENGTH UNITS= KIPS INCH
   ----------------
            STRESS = FORCE/UNIT WIDTH/THICK, MOMENT = FORCE-LENGTH/UNIT WIDTH
  ELEMENT  LOAD       SQX        SQY          MX          MY          MXY
                      VONT       VONB         SX          SY          SXY
                      TRESCAT    TRESCAB
      9      1         0.15        0.01       -5.43        5.56        5.60
                       1.35        1.20        0.02        0.08        0.03
                       1.55        1.39
       TOP : SMAX=       0.83 SMIN=      -0.72 TMAX=       0.78 ANGLE= 67.3
       BOTT: SMAX=       0.74 SMIN=      -0.65 TMAX=       0.69 ANGLE=-22.8
     12      1        -0.02       -0.04       -0.11       20.01       -0.21
                       2.05        1.72       -0.00        0.16       -0.01
                       2.05        1.72
       TOP : SMAX=       2.04 SMIN=      -0.01 TMAX=       1.03 ANGLE=-89.3
       BOTT: SMAX=       0.01 SMIN=      -1.71 TMAX=       0.86 ANGLE=  0.4
          **** MAXIMUM STRESSES AMONG SELECTED PLATES AND CASES ****
             MAXIMUM       MINIMUM       MAXIMUM       MAXIMUM       MAXIMUM
            PRINCIPAL     PRINCIPAL       SHEAR       VONMISES       TRESCA
             STRESS        STRESS        STRESS        STRESS        STRESS
          2.040916E+00 -1.712074E+00  1.026498E+00  2.046982E+00  2.052995E+00
 PLATE NO.      12            12            12            12            12
 CASE  NO.       1             1             1             1             1
   ********************END OF ELEMENT FORCES********************
    61. START CONCRETE DESIGN
      FINITE ELEMENT MODEL OF TANK STRUCTURE                   -- PAGE NO.    6
 CONCRETE DESIGN 
    62. CODE ACI
    63. DESIGN SLAB 9 12
      FINITE ELEMENT MODEL OF TANK STRUCTURE                   -- PAGE NO.    7
    **WARNING** - ELEMENT DESIGN to ACI 318-14 is not available in this version 
 of STAAD.Pro
    64. END CONCRETE DESIGN
    65. FINISH
             *********** END OF THE STAAD.Pro RUN ***********         
               **** DATE= APR 21,2020   TIME= 15:41:36 ****
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