References

TERRASOL with its branch TERRASOL TUNISIA has been the geotechnical consultant for the Japanese company TAISEI CORPORATION during the construction of the Rades – La Goulette bridge.

This bridge includes a main cable-stayed bridge, as well as access viaducts with their access
embankments.

Its outstanding character lies specially in the geotechnical context, with compressible muds of a hundred meters thick.

• The two main piers of the viaduct are founded on 9 piles (diameter 2000 mm), which were originally planned to 100 m depth; due to the difficulties to drill such piles and after two full-scale load tests, the depth of these piles could be reduced to 80 m.
• The multiple piers of the access viaducts are founded on precast piles (reinforced concrete) 25 m deep, driven downto a thin sand layer.
• Access embankments, whose heights reach 8 m with pre-loading, could be built without any instability ; vertical drains installed in the first more compressible layer have enabled to achieve consolidation in 3 to 4 months approximately, with settlements reaching 1.50 m!

Adequate soil testing, complemented by design studies accounting for the specific soil behaviour encountered on site, allowed anticipating this unusual behavior in a satisfying way, which could be confirmed by on-site monitoring.

Terrasol’s achievements: