Companies working on the $670-million Mississippi River Bridge in St. Louis have shattered geotechnical records with a 36,067-ton load test on one of the bridge's drilled-shaft, concrete foundations. Photo: MTA Joint Venture Record-breaking load cell makes its final descent. Related Links: St. Louis Link Will Be Tough, Diverse, Green Osterberg Cell Transformed Testing Award of Excellence Winner Clyde Baker The test, performed this past June, consisted of drilling an 11.5-ft-dia shaft 43.5 ft under the riverbed, then cutting an 11-ft-dia socket more than 23 ft into the underlying limestone bedrock. An Osterberg hydraulic load cell was then lowered to the
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.