PHOTO BY ArcelorMittal Steel structural tower rises in London at Olympic Games site. The U.K.'s tallest sculpture—at 114.5 meters—reached structural completion on Oct. 28, when crews placed the top section of steel-tube diagrid. Designed as a permanent observation platform over London's emerging Olympic Park, the tower contains some 2,000 tonnes of steelwork. It was designed by local artist Anish Kapoor, along with structural engineer Cecil Balmond, former chairman of Arup Group Ltd., London. Steelcraft Erection Services Ltd., Dalton, is building the ArcelorMittal Orbit tower with tubular modules fabricated by the company's affiliate Watson Steel Structures Ltd., Bolton. The tower is
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.