In 1993, the longest cable-stayed bridge in Finland to date, the Tähtiniemen Silta, or Tähtiniemi Bridge, was opened to traffic. It was built, at a cost of approximately 200 million euro, to carry Finnish Highway 4 (E75) across Lake Ruotsalainen, one of the many lakes in southern Finland.
The bridge has an overall length of 924 m, and includes a cable-stayed (harp-form) structure with main spans of 165 m either side of its 105-metre pylon. The width of the deck varies between 22 m and 30 m.
For this project, mageba supplied two TENSA-MODULAR expansion joints of type LR10. With 10 individual movement gaps per joint, they facilitate longitudinal movements of 800 mm each. They also facilitate significant transverse and vertical movements, and rotations about every axis. A TENSA-GRIP (type RS) single-gap joint was also required, for smaller movements at one axis.
In addition, mageba supplied 26 RESTON-POT bearings to support the bridge’s deck. These have a maximum load capacity of 15,500 kN, and accommodate deck movements of up to +/-450mm.
TENSA-MODULAR expansion joints, TENSA-GRIP joint and RESTON-POT bearings
924m (main span 165m)
Pekka Pulkkinen, WSP