International Symposium on Mitigative Measures against Snow ...

<strong>International</strong> <strong>Symposium</strong> on Mitigative Measures against Snow Avalanches
Egilsstaðir, Iceland, March 11–14, 2008
Table 1 shows basic information of Y towers.
Table 1. Y towers. Main dimensions, material and loading
Quantity
Average height
Height range
Weight of tower
Line angle
Base section
Foundation
connection
Base loading at
foundation
connection
Tower Type
Susp.
Towers
Tension
towers
[pcs.] 70 13
[m] 32 22,2
[m] 24 - 40 22 - 24
[ton] 27 - 54 55 - 65
[gone] 0 8 – 71
Material of steel plates - S355NL S355NL
Bottom dimension [m] 1,4 - 1,8 2,1 - 2,65
Thickness of steel [mm] 16 - 20 20
Flange bolt material - grade 8.8 grade 8.8
Quantity of flange bolts [pcs.] 24 24
Size of flange bolts - M45 - M60 M64 - M68
Material of anchor bolts - S355J2G3 S355J2G3
Qua. of anchor bolts [pcs.] 24 - 52 38 - 52
Size of anchor bolts - M64 M64
Max. overturning moment MN·m 8 - 31,3 20 - 34,5
Max. base shear force MN ,3 - 4,1 1 - 3,4
Two types of suspension insulator strings are used in the avalanche area; 1x300 kN and 2x210
kN. Tension insulator strings consist of triple or quad tension strings with breaking strength of
3x400 kN or 4x400 kN.
Figure 12: Avalanche towers in Áreyjardalur, spacing between lines is 60m.
174 Towers for snow avalanches in 420 kV transmission lines in Iceland