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Shotcrete in Qatar By Lars Balck, Robert (Bobby) Oyenarte, Buddy Williams, and T. J. Williams Ctwo large shotcrete storage tank projects in embarked on a remarkable transformationper capita in the last decade. Since Qatar gainedindependence from the British in 1971, it hasrom International LLC (Crom), a subsidiaryof The Crom Corporation, recently completed Qatar totaling over 144 million gal. (545,000 m3) recently labeled the “National Vision 2030,” of usable potable water storage. In both projects, where the nation will continue to invest billions Crom was responsible for constructing four large- of dollars in infrastructure to promote tourism and diameter cast concrete membrane floors and develop a diverse economy not solely reliant on cylindrical composite walls of shotcrete with petrochemicals and hydrocarbons. embedded galvanized corrugated steel diaphragm, In 2012, nearly all the available potable water and circumferential single wire-wrapped pre- was being supplied from desalination facilities stressing with shotcrete cover. Throughout the with no peak demand production capabilities, course of both projects, Crom placed over which reduced reserves to less-than-desirable 21,000 yd3 (16,000 m3) of shotcrete and 2165 levels. As of December 31, 2013, Qatar had a total miles (4012 km) of galvanized high-tensile- population of 2.05 million people, of which strength prestressing wire for the walls of the approximately 300,000 are Qatari nationals. This storage tanks. total far exceeds the originally projected popula- Qatar, a sovereign Arab emirate, shares its only tion for 2016. With low reserves and actual land border with Saudi Arabia to the south, with population growth rate exceeding the projected the rest of its territory surrounded by the Persian rate, the government instituted aggressive measures Gulf. Doha, Qatar’s capital and only major city, to boost their potable water storage capacity by has approximately 1.6 million residents. Qatar is building out a number of reservoir pump stations. estimated to have 1% of the world’s oil and the third-largest natural gas reserve, which has helped Challenges the nation to become the world’s richest country The combination of weather, silica fume, high- cement content mixture, water availability, and high levels of traffic congestion all presented challenges to having an efficient shotcrete operation. Weather Working around the weather was a constant and significant struggle. Sandstorms and fog would occur unexpectedly and would completely “whiteout” the site and access roads, causing a complete shutdown of work. Because of the inherent dangers and recorded incidents in sand- storms and fog, all truck traffic, by law, must pull off the road until the event has passed or face steep traffic violations and even jail time. With the concrete delivery trucks having an average commute of 45 minutes, even a short event would result in the load of concrete being rejected. After a sand- storm, the crew would often need an entire shift to remove the dust, clean up, and start over. Even welcomed fog during the spring months caused delivery delay problems, which resulted in many loads being rejected. In the summer, nearly all concrete was placed Fig. 1: Night finishing exterior at night due to constant daily high temperatures 8 Shotcrete • Spring 2014


2014SprShotcreteEMag
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