Throughout the winter and spring of 2010 Freyssinet constructed a remarkable structure in Middlesbrough – Temenos, Britain’s largest sculpture. The 105m long construction is nearly 50m high and consists of five miles of stainless steel wire in a cable net, strung between two steel hoops, 32m and 28m in diameter, one of which is hanging in the air from a 45m tall mast. The structure as a whole weighs 156 tonnes and cost £2.7million.
Freyssinet’s package involved the supply and erection of the cable net and back-stays and the secret to winning the contract was Freyssinet’s innovative approach to the erection method. With the rings lying flat on the ground beneath their final positions, the cable net was loosely woven at ground level. This maximised safety by avoiding working at height whenever possible. The circular ring was then craned into position and temporarily propped. Then the mast and elliptical ring were raised and proped so that the elliptical ring rested in a temporary cradle on the ground. The final cable connections were made using aerial access company Alps so that the cable net hung loosly between the two rings. A winch cable system, designed by Tony Gee, was then attached to the elliptical ring, between the winch at the mast base and snatch blocks at the top of the mast. Once the cable was tensioned, the temporary supports were removed and the ring winched into a position where the permanent stays between the top of the ring and the mast could be connected. The cable net was then completed and the circular hoop rotated back into its final position by tensioning its back stays and thus tensioning the whole system.