Issue 50

A. Tijani et alii, Frattura ed Integrità Strutturale, 50 (2019) 141-148; DOI: 10.3221/IGF-ESIS.50.13

Corroded section calculation According to Val et Al [21], the section consumed by corrosion A p (t) is expressed in formula 1. It uses a probabilistic analysis of experimental data to determine the maximum corrosion depth p(t) and the geometrical shape of the corroded wire section .

D

 

0



A A

P t

if

( )

       

1

2

2

2

D

D

0

0





 

( )   P t

p A t

A A

D

( )

if

(1)

1

2

0

4

2

2

D

0





P t

D

if

( )

0

4

With:

  

   

2

2

0 2 D D P t b D     0 ( )

1 



A

0.5

2     

1

0

  

  

2

P t

( )

2





2  0.5 ( ) P t

A

b

2

D

0

2

 

  

P t

( )

b P t 

 

2 ( ) 1

D

0

     

0 2 arcsin b D



1 

  

  

2 ( ) b P t



2 

2arcsin

The residual surface of the wire is then:

2

0 p D A t A t 

 

( )

( )

(2)

a

4

Tensile strength reduction of the corroded wires Structures are designed to withstand permissible loads. When attacked by corrosion, the decrease of wires’s cross-section induces a reduction in their strength. Thus, irreversible damage can occur leading to the collapse of the structure. It is therefore important to take into account the reduction of the resistance of the corroded elements if it is desired to keep them in service. The model described by Stewart et al. [20] expresses the strength of the corroded wires f py (t) as a function of the strength of the undamaged wires f py0 :

p A t A t a

( ) ( )

 

  

( ) 1  



(3)

py f t

f

y

py

0

145