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V. GB 50011-2001 Static Seismic - Case1

Calculate the base shear and its distribution along the height using the equivalent lateral force method in GB 50011-2001 using the default equivalent gravity load factor for horizontal seismic action.

Details

Structure to be modelled:
  • height = 3× 4m = 12m
  • plan dimension X = 4m
  • plan dimension Z = 5m
Input parameters:
  • Frequency of seismic event: Frequent
  • Classification of seismic design: Group 2
  • Seismic design intensity: 8
  • Site class: II
  • Period in the X direction: T = 0.467s
  • Equivalent gravity load factor for horizontal seismic action: 0.85 (default in STAAD.Pro)
  • Damping ratio, ζ = 0.05 (default in STAAD.Pro)

The section of all members is HW300X300, and the seismic weight for each floor is assumed as 280 kN applied as joint weight of 70 kN to nodes 2, 3, 5, 6, 8, 9, and 11 to 16. S

Validation

The effective weight of the structure:

G Eq = 0.85 × 280  kN × 3  floors = 714  kN

The max value of the horizontal seismic influence for a "frequent" earthquake with intensity of 8, ɑmax = 0.16 (Table 5.1.4-1)

The characteristic period, Tg = 0.4s (Table 5.1.4-2)

The power index of the curvilinear decrease section:

γ = 0.9 + 0.05 - ζ 0.5 + 5 ζ = 0.9

The damping adjustment factor:

η 2 = 1 + 0.05 - ζ 0.06 + 1.7 ζ = 1.0

Tg < T < 5Tg

The horizontal seismic influence coefficient corresponding to the fundamental period of the structure:

ɑ 1 = ( T g T ) γ η 2 × ɑ max = ( 0.4 0.467 ) 0.9 1.0 × 0.16 = 0.139

The characteristic value of the total horizontal seismic action of the structure:

F Ek = ɑ 1 × G Eq = 0.139 × 714 = 99.25  kN (Eq. 2.5)

T = 0.467 < 1.4Tg = 0.56

Additional seismic action factors at the top of the building δn = 0

Additional horizontal seismic action applied at top of the building ΔFn = δn × FEk = 0

Characteristic value of horizontal seismic action applied at the ith mass:

F i = G i H i j = 1 n G j H j F E k ( 1 - δ n )
Story Level Gi

(kN)

Hi

(m)

GiHi

(kN·m)

GiHi/ΣGiHi Fi

(kN)

ΔFn

(kN)

Vi

(kN)

3rd 280 12 3,360 0.5 49.623 0 49.623
2nd 280 8 2,240 0.333 33.082 82.705
1st 280 4 1,120 0.167 16.541 99.246
Σ 840 6,720 1
Story Level Lateral Load

(kN)

Gravity Load

(kN)

λ

(%)

λmin

(%)

Adjustment

Factor

3rd 49.623 280 17.72 3.2 1
2nd 82.705 560 14.77 3.2 1
1st 99.246 840 11.82 3.2 1

Results

Table 1. Comparison of results
Result Type Reference STAAD.Pro Difference Comments
Story Shear, Fi (kN) 1st 16.541 16.563 negligible  
2nd 33.082 33.126 negligible  
3rd 49.623 49.689 negligible  
Base Shear, V (kN) 99.246 99.377 negligible  

STAAD.Pro Input File

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\06 Loading\GB 50011\GB 50011 2001 Static Seismic - Case1.std is typically installed with the program.

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 18-May-15
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
       1 0 0 0
       2 0 4 0
       3 4 4 0
       4 4 0 0
       5 0 8 0
       6 4 8 0
       7 0 0 5
       8 0 4 5
       9 4 4 5
      10 4 0 5
      11 0 8 5
      12 4 8 5
      13 0 12 0
      14 4 12 0
      15 0 12 5
      16 4 12 5
MEMBER INCIDENCES
       1         1         2
       2         2         3
       3         3         4
       4         2         5
       5         5         6
       6         6         3
       7         2         8
       8         3         9
       9         5        11
      10         6        12
      11         7         8
      12         8         9
      13         9        10
      14         8        11
      15        11        12
      16        12         9
      17         5        13
      18         6        14
      19        11        15
      20        12        16
      21        13        14
      22        13        15
      23        14        16
      24        15        16
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 2.17185e+07
POISSON 0.17
DENSITY 23.5616
ALPHA 1e-05
DAMP 0.05
TYPE CONCRETE
STRENGTH FCU 27579
ISOTROPIC STEEL
E 2.05e+08
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-05
DAMP 0.03
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY CHINESE
1 TO 24 TABLE ST HW300X300
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 4 7 10 FIXED
DEFINE REFERENCE LOADS
LOAD R1 LOADTYPE Dead  TITLE DL
JOINT LOAD
2 3 5 6 8 9 11 TO 16 FY -70
END DEFINE REFERENCE LOADS
DEFINE GB50011 2001 LOAD
INTENSITY 8 FREQUENT GROUP 2 SCLASS 2 PX 0.467
REFERENCE LOAD Y
R1 1.0 
LOAD 1 LOADTYPE Seismic  TITLE EL-X DIR
GB50011 LOAD X 1
PERFORM ANALYSIS PRINT LOAD DATA
PRINT ANALYSIS RESULTS
FINISH

STAAD.Pro Output

   LOADING     1  LOADTYPE SEISMIC  TITLE EL-X DIR                            
   -----------
   *****************************************************************************
   *                                                                           *
   * EQUIV. SEISMIC LOADS AS PER SEISMIC DESIGN CODE FOR BUILDINGS             *
   *                              (GB50011:2001) OF CHINA ALONG X              *
   *  T CALCULATED =  0.685 SEC.      T USER PROVIDED =  0.467 SEC.            *
   *  T USED =  0.467 SEC.                                                     *
   *  MAX. HORIZONTAL SEISMIC INFLUENCE COEFFICIENT =  0.160                   *
   *  CHARACTERISTIC PERIOD =  0.400 SEC.                                      *
   *  DAMPING RATIO =  0.050    POWER INDEX (GAMMA) = 0.900                    *
   *  DAMPING ADJUSTMENT FACTOR (ETA2) =  1.000                                *
   *  ADJUSTING FACTOR (ETA1) =  0.020                                         *
   *  HORIZONTAL SEISMIC INFLUENCE COEFFICIENT (ALPHA1) =  0.139  (13.918%)    *
   *  MINIMUM SHEAR FACTOR AS PER SEC. 5.2.5 (LAMBDA) =   0.032  (  3.200%)    *
   *  EQUIVALENT GRAVITY LOAD FACTOR FOR HORIZONTAL SEISMIC ACTION =  0.850    *
   *  TOTAL HORIZONTAL SEISMIC ACTION =                                        *
   *          =  0.139 X      0.850 X    840.000 =       99.377  KN            *
   *  DESIGN BASE SHEAR =  1.000 X       99.377                                *
   *                    =       99.377  KN                                     *
   *  ADDITIONAL SEISMIC ACTION FACTOR (DELTAN) =  0.000                       *
   *****************************************************************************
    CHECK FOR MINIMUM LATERAL FORCE AT EACH FLOOR [GB50011:5.2.5]
                                                           LOAD -    1    FACTOR -   1.000
    FLOOR            LATERAL          GRAVITY         LAMBDA   LAMBDA   ADJUSTMENT
    HEIGHT (METE)    LOAD (KN  )      LOAD (KN  )      (%)     MIN (%)   FACTOR
    -------------    -----------      ------------    ------   ------   -----------
        12.000           49.689          280.000       17.75     3.20     1.00
         8.000           82.814          560.000       14.79     3.20     1.00
         4.000           99.377          840.000       11.83     3.20     1.00
    JOINT            LATERAL          TORSIONAL            VERTICAL      LOAD -    1
                     LOAD (KN  )      MOMENT (KN  -METE)   LOAD (KN  )    FACTOR -   1.000
    -----            -------          ---------           -----------
       2     FX        4.141    MY        0.000           FY        0.000
       3     FX        4.141    MY        0.000           FY        0.000
       8     FX        4.141    MY        0.000           FY        0.000
       9     FX        4.141    MY        0.000           FY        0.000
                 -----------        -----------           ----------------
          TOTAL =     16.563              0.000                     0.000    AT LEVEL     4.000 METE
      STAAD SPACE                                              -- PAGE NO.    5
       5     FX        8.281    MY        0.000           FY        0.000
       6     FX        8.281    MY        0.000           FY        0.000
      11     FX        8.281    MY        0.000           FY        0.000
      12     FX        8.281    MY        0.000           FY        0.000
                 -----------        -----------           ----------------
          TOTAL =     33.126              0.000                     0.000    AT LEVEL     8.000 METE
      13     FX       12.422    MY        0.000           FY        0.000
      14     FX       12.422    MY        0.000           FY        0.000
      15     FX       12.422    MY        0.000           FY        0.000
      16     FX       12.422    MY        0.000           FY        0.000
                 -----------        -----------           ----------------
          TOTAL =     49.689              0.000                     0.000    AT LEVEL    12.000 METE
   ************ END OF DATA FROM INTERNAL STORAGE ************
    85. PRINT ANALYSIS RESULTS
  ANALYSIS RESULTS                    
      STAAD SPACE                                              -- PAGE NO.    6
   JOINT DISPLACEMENT (CM   RADIANS)    STRUCTURE TYPE = SPACE
   ------------------
 JOINT  LOAD   X-TRANS   Y-TRANS   Z-TRANS   X-ROTAN   Y-ROTAN   Z-ROTAN
      1    1     0.0000    0.0000    0.0000    0.0000    0.0000    0.0000
      2    1     0.6474    0.0138    0.0000    0.0000    0.0000   -0.0014
      3    1     0.6474   -0.0138    0.0000    0.0000    0.0000   -0.0014
      4    1     0.0000    0.0000    0.0000    0.0000    0.0000    0.0000
      5    1     1.4829    0.0215    0.0000    0.0000    0.0000   -0.0012
      6    1     1.4829   -0.0215    0.0000    0.0000    0.0000   -0.0012
      7    1     0.0000    0.0000    0.0000    0.0000    0.0000    0.0000
      8    1     0.6474    0.0138    0.0000    0.0000    0.0000   -0.0014
      9    1     0.6474   -0.0138    0.0000    0.0000    0.0000   -0.0014
     10    1     0.0000    0.0000    0.0000    0.0000    0.0000    0.0000
     11    1     1.4829    0.0215    0.0000    0.0000    0.0000   -0.0012
     12    1     1.4829   -0.0215    0.0000    0.0000    0.0000   -0.0012
     13    1     2.0484    0.0240    0.0000    0.0000    0.0000   -0.0007
     14    1     2.0484   -0.0240    0.0000    0.0000    0.0000   -0.0007
     15    1     2.0484    0.0240    0.0000    0.0000    0.0000   -0.0007
     16    1     2.0484   -0.0240    0.0000    0.0000    0.0000   -0.0007
      STAAD SPACE                                              -- PAGE NO.    7
   SUPPORT REACTIONS -UNIT KN   METE    STRUCTURE TYPE = SPACE
   -----------------
 JOINT  LOAD   FORCE-X   FORCE-Y   FORCE-Z     MOM-X     MOM-Y     MOM Z
      1    1    -24.84    -83.72      0.00      0.00      0.00     64.44
      4    1    -24.84     83.72      0.00      0.00      0.00     64.44
      7    1    -24.84    -83.72      0.00      0.00      0.00     64.44
     10    1    -24.84     83.72      0.00      0.00      0.00     64.44
      STAAD SPACE                                              -- PAGE NO.    8
   MEMBER END FORCES    STRUCTURE TYPE = SPACE
   -----------------
   ALL UNITS ARE -- KN   METE     (LOCAL )
  MEMBER  LOAD  JT     AXIAL   SHEAR-Y  SHEAR-Z   TORSION     MOM-Y      MOM-Z
      1    1     1    -83.72     24.84    -0.00     -0.00      0.00      64.44
                 2     83.72    -24.84     0.00      0.00      0.00      34.94
      2    1     2     -0.00    -37.23    -0.00      0.00      0.00     -74.45
                 3      0.00     37.23     0.00     -0.00      0.00     -74.45
      3    1     3     83.72     24.84    -0.00     -0.00      0.00      34.94
                 4    -83.72    -24.84     0.00      0.00      0.00      64.44
      4    1     2    -46.49     20.70    -0.00     -0.00      0.00      39.51
                 5     46.49    -20.70     0.00      0.00      0.00      43.30
      5    1     5      0.00    -31.16    -0.00      0.00      0.00     -62.31
                 6      0.00     31.16     0.00     -0.00      0.00     -62.31
      6    1     6     46.49     20.70    -0.00     -0.00      0.00      43.30
                 3    -46.49    -20.70     0.00      0.00      0.00      39.51
      7    1     2     -0.00     -0.00     0.00      0.00     -0.00      -0.00
                 8      0.00      0.00    -0.00     -0.00     -0.00      -0.00
      8    1     3      0.00      0.00     0.00      0.00     -0.00       0.00
                 9     -0.00     -0.00    -0.00     -0.00     -0.00       0.00
      9    1     5      0.00     -0.00     0.00      0.00     -0.00      -0.00
                11     -0.00      0.00    -0.00     -0.00     -0.00      -0.00
     10    1     6     -0.00      0.00     0.00      0.00     -0.00       0.00
                12      0.00     -0.00    -0.00     -0.00     -0.00       0.00
     11    1     7    -83.72     24.84    -0.00     -0.00      0.00      64.44
                 8     83.72    -24.84     0.00      0.00      0.00      34.94
     12    1     8      0.00    -37.23    -0.00      0.00      0.00     -74.45
                 9      0.00     37.23     0.00     -0.00      0.00     -74.45
     13    1     9     83.72     24.84    -0.00     -0.00      0.00      34.94
                10    -83.72    -24.84     0.00      0.00      0.00      64.44
     14    1     8    -46.49     20.70    -0.00     -0.00      0.00      39.51
                11     46.49    -20.70     0.00      0.00      0.00      43.30
     15    1    11      0.00    -31.16    -0.00      0.00      0.00     -62.31
                12      0.00     31.16     0.00     -0.00      0.00     -62.31
      STAAD SPACE                                              -- PAGE NO.    9
   MEMBER END FORCES    STRUCTURE TYPE = SPACE
   -----------------
   ALL UNITS ARE -- KN   METE     (LOCAL )
  MEMBER  LOAD  JT     AXIAL   SHEAR-Y  SHEAR-Z   TORSION     MOM-Y      MOM-Z
     16    1    12     46.49     20.70    -0.00     -0.00      0.00      43.30
                 9    -46.49    -20.70     0.00      0.00      0.00      39.51
     17    1     5    -15.34     12.42    -0.00     -0.00      0.00      19.01
                13     15.34    -12.42     0.00      0.00      0.00      30.68
     18    1     6     15.34     12.42     0.00     -0.00     -0.00      19.01
                14    -15.34    -12.42    -0.00      0.00     -0.00      30.68
     19    1    11    -15.34     12.42    -0.00     -0.00      0.00      19.01
                15     15.34    -12.42     0.00      0.00      0.00      30.68
     20    1    12     15.34     12.42     0.00     -0.00     -0.00      19.01
                16    -15.34    -12.42    -0.00      0.00     -0.00      30.68
     21    1    13     -0.00    -15.34    -0.00      0.00      0.00     -30.68
                14      0.00     15.34     0.00     -0.00      0.00     -30.68
     22    1    13      0.00     -0.00     0.00     -0.00     -0.00      -0.00
                15     -0.00      0.00    -0.00      0.00     -0.00      -0.00
     23    1    14     -0.00      0.00     0.00     -0.00     -0.00       0.00
                16      0.00     -0.00    -0.00      0.00     -0.00       0.00
     24    1    15      0.00    -15.34    -0.00      0.00      0.00     -30.68
                16      0.00     15.34     0.00     -0.00      0.00     -30.68
   ************** END OF LATEST ANALYSIS RESULT **************