10. 2. Drag forces on stay cables
2.1 Drag coefficient
2.2 Importance of drag forces. Experience of
the Normandy Bridge
2.3 Conclusion on the importance of drag
forces
13. The drag coefficients of the different ducts tested in 1991 for the Normandie Bridge by the CSTB
14. A recent pipe for a Freyssinet stay cable,
with the two imbricated helical filets
Drag coefficients of three HDPE pipes;
a typical cylinder, a cylinder equiped with
one helical filet and the last with two.
17. Drag forces on the deck : proportional to the span
and depending of shapes.
Drag forces on the stay cables: proportional to
the square of the span.
Drag forces on the stay cables : proportional to
the diameter.
Capacity of the stay cables : proportional to the
square of the diameter.
18.
19. 3 – Stay cable quality
3.1 Corrosion protection.
3.2 Strenght and fatigue resistance.
3.3 Prefabrication against constitution in situ.
20. Corrosion protection.
Two complementary nested barriers
SETRA – fib – PTI
example : galvanisation
+ oil wax
+ HDP extrusion
No role for the external duct (or pipe)
21. Strength and fatigue resistance
Tests on wires and strands.
Tests on anchorage bending effects.
Anchorage by Wedges