# V. ACI 318-99 Circular Column

Determine the reinforced steel quantity for a circular column per ACI 318-99.

## Reference

Chu-Kia Wang and Charles G.Salmon, Reinforced Concrete Design, 5th Edition, Examples problem 13.15.1, p481 .

## Problem

 Pu = 1,050 kips

 Muz = Muy = 0 ft·kips

 f'c = 4,000 psi

 fy = 60,000 psi

Spiral lateral reinforcement used.

## Comparison

Table 1. Comparison of results
Result Type Reference STAAD.Pro Difference
Required steel area (in2) 10.45 10.505 none
Provided steel area (in2) 10.82 (7- #11) 10.82 (18- #7) none
Note: STAAD reports a more economical bar arrangement than the reference book.

## STAAD Input

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\10 Concrete Design\US\ACI 318-99 Circular Column.STD is typically installed with the program.

``````STAAD SPACE CIRCULAR CONCRETE COLUMN DESIGN PER ACI 318-99
START JOB INFORMATION
ENGINEER DATE 23-Sep-18
END JOB INFORMATION
*
* REFERENCE : REINFORCED CONCRETE DESIGN, 5TH EDITION BY CHU-KIA WANG
*             AND CHARLES G.SALMON, EX.13.15.1 PAGE 481
*
*  OBJECTIVE : TO DETERMINE THE REINFORCED STEEL QUANTITY FOR A
*              CIRCULAR COLUMN PER THE ACI 318-99 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 20
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 3150
POISSON 0.17
END DEFINE MATERIAL
CONSTANTS
MATERIAL MATERIAL1 ALL
SUPPORTS
1 FIXED
LOAD 1
JOINT LOAD
2 FY -1060
PERFORM ANALYSIS
START CONCRETE DESIGN
CODE ACI 1999
REINF 1 ALL
DESIGN COLUMN ALL
END CONCRETE DESIGN
FINISH
``````

## STAAD Output

```   ====================================================================
COLUMN  NO.     1  DESIGN PER ACI 318-99 - AXIAL + BENDING
FY - 60000  FC - 4000 PSI,  CIRC SIZE  20.00 INCHES DIAMETER  SPIR
AREA OF STEEL REQUIRED =  10.505  SQ. IN.
BAR CONFIGURATION       REINF PCT.   LOAD   LOCATION   PHI
----------------------------------------------------------
18 - NUMBER  7           3.438        1      END     0.750
(EQUALLY SPACED)
TIE BAR NUMBER    4 SPACING   2.00 IN
********************END OF COLUMN DESIGN RESULTS********************
```