Graphic courtesy of Tishman On one level of the World Trade Centers 16-acre, four-level basement, there are multiple and often competing stakeholders (each represented by a different color on the map). Courtesy Dig This LLC Dig This patrons can operate a Caterpillar D5 track-type bulldozer to create earthen mounds. Related Links: Editors' Picks: ENR's Top Stories of 2011 ENR readers kept many conversations alive this year—including and about types of innovation on major construction projects around the globe, a big iron playground in Vegas, tech trends on jobsites, trouble with BIM and viewpoints that struck more than a few nerves.Some
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.