PSI - Issue 13

Miroslav Strieška et al. / Procedia Structural Integrity 13 (2018) 1745–1750 Miroslav Strieška / Structural Integrity Procedia 00 (2018) 000 – 000

1747

3

Fig. 1. Factors affected the reliability of construction influenced by corrosion.

So, the ultimate resistance moment of cross-section in time M Rd (t), is given by following formulas. 2 4 (0 .ø .ø ) Rd Rd M M A B = − =

(8)

( ( (

)

( ) M k t t ( 0 . Rd 1

)

(

)

(

)

b

b

b

2.

4.

Rd M t

. k t t

. k t t − − −

20



=

+ − +

0

2

0

3

0

(9)

) )

=20 Rd M t

4 5 k k = −

(10)

( Rd M t

)

* + + 6 k t =20 .( (11) where (t*) is equal to (t-t 0 -20), t 0 is time of the passive stage, k 1 – k 9 are parameters depending on materials ’ and geometrical characteristic and A, B are parameters constant in time .( . ) ( ( ) . ) ) Rd M t = + + * * * 7 k t 8 k t 2 4 9 k t 3 >20