Issue 54

A. Boulebd et alii, Frattura ed Integrità Strutturale, 54 (2020) 21-35; DOI: 10.3221/IGF-ESIS.54.02

B- C RACKED SECTION M CR

3

by











  f



2

2

2

 

 

y

'

'

'

 

 

n A y d n A d y  

I

n A d y

(10)

y

s

s

f

y

y

f

y

3

    

   

   

     

'

I I

M y cr 

'



  

I

I y y

(11)

1 1

  

M cr 



I y f 



M y

(12)





n d y f f y 

with σ f representing the tensile stresses of the strengthening.

2 M y



P y

(13)

L a

   2 24 P L y a E Ic y



2 3 4 

2

 

(14)

L L

y

a

C- P LASTICIZING SECTION M Y < M

   

 

d y u

  

s 





(15)

cu

y u

'



   

y d u

'  s



 

(16)

cu

  

y u

 

  

d y f

u

  

  







(17)

f

cu

y u

So, the formula of the moment can be expressed as follows from the balance of internal forces F s , F’ s of steel and F f for reinforcements:

31