Richard Hammond reveals how engineers made one of the longest bridges in the world earthquake-proof, with solutions inspired by incense and a tobbogan.
Richard Hammond reveals how engineers made one of the longest bridges in the world earthquake-proof. Building a structure almost 3 kilometres long in water 65 metres deep was almost the least of the engineering challenges of bridging the Gulf of Corinth in Greece. The construction would cross one of the most active seismic fault lines in Europe. Defying disaster called for solutions inspired by fragrant Indian incense, the ring-pull in a soda can, a tobbogan, a hammock, and some shiny steel chimneys.
The bottom of the Gulf of Corinth is a 500 metre deep layer of soft silt. In a tremor it would turn to quicksand and the bridge would sink. The solution - long steel rods which act like the roots of sweet-smelling Vetiver grass.
Preventing the bridge from toppling over meant allowing it to toboggan from side to side on a thick layer of gravel that acts like ball bearings. And stopping the bridge deck from buckling if it moved meant slinging it like a sailor's hammock and then restraining the movement with the biggest viscous dampers in the world. The system safely passed a real test in a 6.5 earthquake in June 2008.
But earthquake protection left the bridge potentially vulnerable to other natural hazards, which the engineers had to tackle.
The result is an engineering masterpiece, completed just in time for the 2004 Athens Olympics, and realising a century-old dream of connecting two towns 300 kilometres apart by land, but separated by a mere two kilometres of water.