Column Schedule from ETABS — Bars, Ties and Hoops for Every Column, Drawn and Exported to DXF

Design checks

Calculation

1. 1Steel required
   A_{s,req} = \max_{\text{stories}} A_s
   A_{s,req} = 11.00 \ \text{at 2ND}
   A_{s,req}=11.00 in²

   ETABS's As over 3RD, 2ND; its minimum there 3.75 in².

2. 2Bars chosen
   A_{s} = \textstyle\sum n \, \pi d_b^2 / 4
   A_s = 10 imes 0.954 + 2 imes 0.761 = 11.07
   A_s=11.07 in²

   10-Ø28 + 2-Ø25: 5 bars along each 25 in face and 3 along each 15 in face, corners included (3x5 short × long); Ø28 at the corners and the bars nearest them.

3. 3Required/provided against your max
   \text{DCR} = A_{s,req} / A_s \le \text{your max}
   \text{DCR} = 11.00 / 11.07 = 0.994 \ (\text{max } 1.00)
   \text{DCR}=0.994

   Within your max of 1.00: the bars give at least As required ÷ 1.00.

4. 4Bar spacing along the 25 in face
   s = \dfrac{L - 2(c_c + d_t) - d_b}{n - 1}
   s = \dfrac{25.0 - 2(1.50 + 0.394) - 1.102}{5 - 1} = 5.03
   s_{B}=5.03 in

   Centre to centre; your limits 4.0–8.0 in.

5. 5Bar spacing along the 15 in face
   s = \dfrac{L - 2(c_c + d_t) - d_b}{n - 1}
   s = \dfrac{15.0 - 2(1.50 + 0.394) - 1.102}{3 - 1} = 5.06
   s_{H}=5.06 in

   Centre to centre; your limits 4.0–8.0 in.

6. 6Steel ratio
   \rho_g = A_s / A_g
   \rho_g = 11.07 / (25.0 \times 15.0) = 0.0295
   \rho_g=0.0295
7. 7Length ℓo at each endACI 318-08, document reference
   \ell_o \ge \max(\ell_n / 6,\ c_{max},\ 18\text{ in})
   \ell_o = \max(102.0 / 6,\ 25.0,\ 18) \to 25
   \ell_o=25 in

   ℓn = 102.0 in, the tallest story of the group (120.0 in) less the beam; rounded up to the inch.

8. 8Tie set A (within ℓo)ACI 318-08, document reference
   s_A \le \min(8 d_b,\ 24 d_t,\ c_{min}/2,\ 12\text{ in},\ \text{your cap})
   s_A = 4.0 \ (\text{your 4 in limit})
   s_A=4.0 in

   Ø10 hoops, 2/3 legs (long / short): 2 running along the 25 in side and 3 along the 15 in side; the code limit 7.50 in, rounded down to 0.50 in.

9. 9Tie set B (middle zone)ACI 318-08, document reference
   s_B \le \min(16 d_b,\ 48 d_t,\ c_{min},\ d/2,\ \text{your cap})
   s_B = 6.0 \ (\text{your 6 in limit})
   s_B=6.0 in

   The code limit 6.28 in: d/2 for shear, d = 12.56 in across the 15 in side.

Assumptions

• The steel each column needs at each story is ETABS's concrete frame design As (the larger of the P-M demand and the minimum); a group of stories takes the largest of its stories.
• Bars: 16 mm first; the next size up mixed in at the corners, then at the face bars nearest the corners (the bars farthest from both axes add most to the column's strength), before that size is used throughout. A larger size is taken only when the smaller can't give the steel, or when it saves more than 5 % of it. Of the layouts that fit, the least steel wins, giving at least the steel required ÷ your max required/provided of 1.00.
• Bars 4.0 in to 8.0 in apart centre to centre along each face, and at least the code's clear spacing; each bar's centre the clear cover, the tie and half the bar in from the face.
• Ties: every corner and alternate bar held by a tie corner, none more than 6 in clear from a held bar; two neighbouring held bars share a closed inner tie, a lone one takes a crosstie. Every tie a closed hoop with 135° hooks.
• Going down a column, a group keeps at least the bars of the group above — as many, each as large; where the column gets bigger below, fewer bars are allowed there, with as much steel and the largest bar no smaller.
• IMRF: hoops at tie set A within ℓo at each end and tie set B between; ℓn is the tallest story of the group less a 18 in beam. Your caps: 4.0 in within ℓo, 6.0 in in the middle zone.
• Below plinth (FDN TO GF): 2.5 in clear cover, the column drawn 2.0 in bigger each way than its ETABS section. The bars and ties are designed on ETABS's section with the 1.5 in cover above — the extra cover carries nothing (ACI 318-08 §10.8.4) — so the cage runs on unchanged.