LICENTIATE THESIS - Luleå tekniska universitet

Dead Loads:
Slab: 0.320 m á 24 kN/m 2 = 7.68 kN/m 2
Ballast: 0.600 m á 20 kN/m 2 = 12.00 kN/m 2
Traffic loads:
If the load from one bogie pair is spread over 1.70 + (1.5 / 2 + 0.75) = 3.20 m (in the
longitudinal direction of the bridge, see Figure 1.1), we will have:
2 ⋅ 22.5
2
P = 22.5 tons ⇒ q = = 45.36 kN/m
3.20 ⋅ 3.10
2⋅25 2
P = 25 tons ⇒ q = = 50.40 kN/m
3.20 ⋅ 3.10
2⋅30 2
P = 30 tons ⇒ q = = 60.48 kN/m
3.20 ⋅ 3.10
Load combination
Fatigue load according to Load Combination C in section 22:23
“Bärighetsbestämmelser”, Banverket (1995) [Design handbook for Railway Bridges]:
The partial factors, which must be used, are:
Dead loads = 1.0 (ψγ)
Ballast = 1.2 (ψγ)
Traffic load: For iron ore load, 1.2 (a dynamic factor)
Summation of loads:
Dead Loads
Slab: 7.68 · 1.0 = 7.68 kN/m 2
Ballast: 12 · 1.2 = 14.40 kN/m 2
Total = 22.08 kN/m 2
Traffic loads
P = 22.5 tons ⇒ q = 45.36 · 1.2 = 54.43 kN/m 2
P = 25 tons ⇒ q = 50.40 · 1.2 = 60.48 kN/m 2
P = 30 tons ⇒ q = 60.48 · 1.2 = 72.58 kN/m 2
The critical section for the bridge, regarding the load q above, is the connection
between the slab and the longitudinal beams.
The traffic load, V dim, on one half of the bridge, i.e. B / 2 = 3.1 / 2 = 1.55 m, results
in:
- 4 -