f_ck

-

characteristic strength of concrete in compression

f_cd

-

design strength of concrete in compression

f_ctk

-

characteristic strength of concrete in tension

f_ctd

-

design strength of concrete in tension

f_yk

-

characteristic strength of steel

f_yd

-

design strength of steel

f_ctm

-

design strength of steel in tension

where:

α_cc = 1

α_ct = 1

γ_c = 1,5

-

for reinforced concrete structures

γ_c = 1,8

-

for concrete strustures

b

-

cross-section width

h

-

cross-section depth

d

-

effective depth of cross-section

z

-

lever arm (arm of internal forces)