Issue 60

Osman S et al., Frattura ed Integrità Strutturale, 60 (2022) 1-12; DOI: 10.3221/IGF-ESIS.60.01

       1 1.5 s b

2 2 . . . . t s s b



f

f

e

(3)

L ystrip

where: ( f L ) when failure due to yield in strips



  

M

16.

2 1 .

p

 

f

(4)





L

 b s s

f

 

 2

c

where: ( f L ) when failure due to yield in angles. Badalamenti et al. [7]

Badalamenti et al. [7] proposed a design equation for determining the ultimate load that is carried by the RC column strengthened with steel angles and strips based on the effect of concrete confinement and load carried by the steel angles. The formula is expressed as the following equation :             campione 1 1 8 cc s ys a yL p b d f A f n L t f (5)

where, f cc = compressive strength of confined concrete; n a = Maximum axial force in angles; n a and fcc are calculated by using the following formula.

0.87

 

  

f

1 4.74 l

   f

f

(6)

cc

co

f

co

  

  2

max q s

2

 t f 1

 t f 1





L

 

yl

yl

1

3





n

(7)

1

a

  L t f 1 1

2

yl

Campione [1 8 ] Campione [18] proposed an equation for calculating the capacity of the strengthened column using steel jacketing. To determine the confinement pressure, it is assumed that the confinement pressure is reduced in steel strips suddenly while it remains constant along the steel angle. The effect of concrete confinement and composite action between the concrete column and steel jacketing is taken into consideration, as the following equation :

 p n b d f . . .





1 1 . 8. . . n L t f a

. A f

(8)

ult

c

ys

L yL

where, n is the dimensionless load capacity of confined concrete core and n a is the maximum axial force available indirectly loaded angles in the dimensionless as the following equation :

0.87

  

   

   1.5 s

  

f

 

      1 1.42 cc s

b

f

e

(9)

cc

f

cd

s b

  

   1.5

s

1

1

 

     1 0.63



n

e

(10)





a

 

b L

0.5

t

b

L

1

1



1



 s t

s

t

2 2

4