V. ACI 318-02 Square Column

Determine the reinforced steel quantity for a square column per ACI 318-02.

Reference

Notes on ACI 318-02 Building Code Requirements for Structural Concrete, Example 7.8, p7-46, Design of Square Column for Biaxial loading.

Problem

P = 1,200 kips

M_uz = 300 ft·kips

M_uy = 125 ft·kips

f'_c = 5,000 psi

f_y = 60,000 psi

Comparison

Table 1. Comparison of results
Result Type	ACI Notes	STAAD.Pro	Difference
Provided steel area per ACI 318-02(in²)	5.93 (4- #11)	5.93 (4- #11)	none

STAAD Input

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\10 Concrete Design\US\ACI 318-02 Square Column.STD is typically installed with the program.

STAAD SPACE SQUARE COLUMN DESIGN PER ACI 318-02
START JOB INFORMATION
ENGINEER DATE 21-Sep-18
END JOB INFORMATION
*
* REFERENCE : NOTES ON ACI 318-02 BUILDING CODE REQUIREMENTS
*             FOR STRUCUTURAL CONCRETE EXAMPLE 7.8 (PAGE # 7-46)
*
*  OBJECTIVE : TO DETERMINE THE REINFORCED STEEL QUANTITY FOR A
*              SQUARE COLUMN PER THE ACI 318-02 CODE
*
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 0 12 0;
MEMBER INCIDENCES
1 1 2;
UNIT INCHES KIP
MEMBER PROPERTY AMERICAN
1 PRIS YD 24 ZD 24
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 3150
POISSON 0.17
END DEFINE MATERIAL
CONSTANTS
MATERIAL MATERIAL1 ALL
SUPPORTS
1 FIXED
UNIT FEET KIP
LOAD 1
JOINT LOAD
2 FY -1200
2 MZ 300
2 MX 125
PERFORM ANALYSIS
START CONCRETE DESIGN
CODE ACI 2002
UNIT INCHES KIP
FC 5 ALL
MINMAIN 11 ALL
MAXMAIN 11 ALL
TRACK 2 ALL
DESIGN COLUMN ALL
END CONCRETE DESIGN
FINISH

STAAD Output

   ====================================================================
        COLUMN  NO.     1  DESIGN PER  ACI 318-02 - AXIAL + BENDING
   FY - 60000  FC - 5000 PSI,  SQRE SIZE - 24.00 X 24.00 INCHES, TIED
           ONLY MINIMUM STEEL IS REQUIRED.
           AREA OF STEEL REQUIRED =   5.760  SQ. IN.
   BAR CONFIGURATION       REINF PCT.   LOAD   LOCATION   PHI-Z  PHI-Y
   -------------------------------------------------------------------
     4 - NUMBER 11           1.083        1      END     0.650  0.650
   (PROVIDE EQUAL NUMBER OF BARS ON EACH FACE)
   TIE BAR NUMBER    4 SPACING  22.56 IN
       COLUMN INTERACTION: MOMENT ABOUT Z -AXIS (KIP-FT)
    --------------------------------------------------------
      P0        Pn max    P-bal.    M-bal.   e-bal.(inch)
    2795.88   2236.70   1043.87    793.30    9.12
       M0       P-tens.   Des.Pn    Des.Mn     e/h
     294.69   -374.40   1846.15    461.54    0.02083
    --------------------------------------------------------
       COLUMN INTERACTION: MOMENT ABOUT Y -AXIS (KIP-FT)
    --------------------------------------------------------
      P0        Pn max    P-bal.    M-bal.   e-bal.(inch)
    2795.88   2236.70   1043.87    793.30    9.12
       M0       P-tens.   Des.Pn    Des.Mn     e/h
     294.69   -374.40   1846.15    192.31    0.00868
    --------------------------------------------------------
                            Pn       Mn       Pn       Mn    (@ Z )
            |             2064.65   486.58  1032.32   793.01
         P0 |*            1892.60   580.71   860.27   780.26
            | *           1720.54   652.53   688.22   755.81
      Pn,max|__*          1548.49   709.10   516.16   677.87
            |   *         1376.43   749.65   344.11   565.14
      Pn    |    *        1204.38   776.44   172.05   435.29
     NOMINAL|     *         Pn       Mn       Pn       Mn    (@ Y )
       AXIAL|      *      2064.65   486.58  1032.32   793.01
 COMPRESSION|       *     1892.60   580.71   860.27   780.26
          Pb|-------*Mb   1720.54   652.53   688.22   755.81
            |      *      1548.49   709.10   516.16   677.87
 ___________|____*_______ 1376.43   749.65   344.11   565.14
            |  * M0   Mn, 1204.38   776.44   172.05   435.29
            | *   BENDING
      P-tens|*     MOMENT
            |            
   ********************END OF COLUMN DESIGN RESULTS********************