LICENTIATE THESIS - Luleå tekniska universitet

As0
ρ =
b ⋅ d , not higher than ρ=0.02 (reinforcement content)
w
A s0 is the smallest amount of reinforcement due to bending in the tension zone, in
actual beam section, between the zero-point of the bending moment and its maximum
point. As an alternative the amount of reinforcement that has a length of (d+l b) and that
passes the actual section can be used. l b is the length that is required to anchor the
design tension force.
4.3 Shear force capacity for the Lautajokki Bridge
From the example we will get the following input data:
Width: bw = 1.0 m
Effective depth: d = 0.295 m
Factor, effective depth: ξ = 1.6 – d = 1.6 - 0.295 = 1.305 m
As0 201
Reinforcement content: ρ = = = 0.0068 (φ16 s100)
b ⋅d100 ⋅295
f = 1.305 1 + 50 ⋅0.0068 ⋅0.3 ⋅ f
Formal shear strength: ( )
v ctd
The shear force capacity, V c, for different strength classes can now be calculated and the
result is displayed in Table 4.1.
Table 4.1 The shear force capacity, V c according to Swedish Code BBK94
for different strength classes.
A) Strength Class
C30 C40 C50 C60 C80
f ck 30 40 50 60 80
f ctk:0.05 2.0 2.5 2.9 3.1 3.4
Swedish Code BBK94
f cd = f ck· 0.85 / 1.5 / 1.2 = 14.17 18.89 23.61 28.33 37.78 MPa
f ctd = f ctk;0.05 /1.5/1.2 = 1.11 1.39 1.61 1.72 1.89 MPa
fv = 1.305(1 + 50 ⋅0.0068
)
⋅0.3⋅ f =
V = 1.0 ⋅0.295 ⋅ f =
ctd
c v
0.58
A) Strength classes according to EC2-draft (1999).
- 9 -
0.73
0.85
0.90
0.99
MPa
172.0 214.9 249.3 266.5 292.3 kN
Note: The calculation in this section is not made strictly according to the Swedish code
BBK94, since the strength classes are taken from the Eurocode. As mentioned earlier in
this chapter it is difficult to compare the codes since there are several factors that are