Strengthening of Columns for Confinement - Strengthening Design of Reinforced Concrete with FRP - page 192

P = 591.08 5kips, M = 64.49 kip-ft

nB , nB ,

Point C:

P = 343.01kips, M = 99.79 kip-ft

nC , nC ,

Point D:

P = 0kips, M = 59.036 kip-ft , ,

By comparing Figures 7.16 and 7.17, it is evident that the interaction diagram
according to ACI 440.2R-08 is conservative with respect to that of KDOT Column
Expert, especially in the compression-controlled region where confinement is
especially critical. This is attributed to ignoring the confinement by internal steel
in ACI 440.2R-08 while it is considered by KDOT Column Expert.

nD nD

Column by Saadatmanesh et al. (1996)

900

Saadatmanesh et al.
Column
Experimental

800

700

600

500

400

300

200

100

0

0 20 40 60 80 100 120

Bending Moment (kip-ft)

FIGURE 7.16 Confined interaction diagram according to ACI 440.2R-08 for column tested
by Saadatmanesh, Ehsani, and Jin (1996).

Moment (kN • m)

0

50 100 150

1200

5000

1000

4000

800

3000

600

2000

400

1000

200

0 0

0 20 40 60 80 100 120

Moment (k • ft)

FIGURE 7.17 Confined interaction diagram according to KDOT Column Expert for col-
umn tested by Saadatmanesh, Ehsani, and Jin (1996).