Reinforced concrete bridges - Computational Analysis and Design of Bridge Structures - page 103

f c

Confined concrete

f c ′ c

Unconfined concrete

f c ′

Assumed for
cover concrete

ε c

ε 0 2ε 0 ε sp ε cc ε cu

Figure 4.2 Stress-strain relation for monotonic loading of confined and unconfined
concrete. (Data from Mander, J.B., Priestley, M.J.N., and Park, R., J Struct Eng .,
114(8), 1804-1826,1988b.)

confinement reinforcement used. The equations are listed here and shown
in Figure 4.2.

f
f

n ( )

ε ε

ε ε

c c cc

c

(4.2a)

=

′ n

( n − 1 ) + ( )

cc

cc

in which

E
E E

c

n = (4.2b)

−

c sec

′

E = 5000 f (both in a unit of MPa) (4.2c)

c

c

f cc
cc

′

E

sec =

(4.2d)

ε

where ε cc is the strain at the maximum compressive strength of confined
concrete f c ′

f
f

′
′

cc

ε = ε 1 5 + − 1 (4.2e)

cc co

c

and f c ′ , the compressive strength of confined concrete, is given as

7 94 . f

′

f
f

′
′

′ ′ t t

f = f − 1 254 2 254 1 . + . + − 2 (4.2f)

cc c ′

f

c c