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Sustainability Top Ten Sustainability Benefits 1. Formwork savings of 50 to 100% over conventional of Shotcrete cast-in-place construction. The United States Green Concrete Council’s (USGCC) book, 2. Formwork does not have to be designed for internal The Sustainable Concrete Guide—Applications, includes a list pressures. of the top 10 sustainability benefits of shotcrete in its chapter 3. Complex shapes require very little—if any—formwork. on shotcrete. Over the next 10 issues of Shotcrete magazine, 4. Crane and other equipment savings or elimination. this Sustainability column will elaborate on each one of the 5. Labor savings of at least 50% in repair applications. listed advantages. Previous discussion of advantages from past 6. New construction speed savings of 33 to 50%. issues can be viewed on the ASA website at www.shotcrete. 7. Speed of repair reduces or eliminates downtime. org/sustainability. 8. Better bonding to the substrate enhances durability. U.S.GREEN 9. with other processes (see below).Adaptability to repair surfaces that are not cost-effective CONCRETE COUNCIL 10. Ability to access restricted space and difficult-to-reachareas, including overhead and underground. Adaptability to Repair Surfaces That Are Not Cost-Effective with other Processes t 7122 ft (2170 m) and supported by 86 piers, with 43 in eachhe Abraham Lincoln Memorial Bridge, located in LaSalle,IL, is the longest bridge in the state, with a total length of direction. The bridge is elevated approximately 70 ft (21 m) above the Illinois River, numerous local roads, lakes, wetlands, and railroads. The piers range from 50 to 100 ft (15 to 30 m) high, 41 ft (12 m) wide, and 4 ft (1.2 m) thick at the caps while increasing to 6 ft (1.8 m) at the base. The piers span between 135 and 165 ft (41 and 50 m). (Refer to Fig. 1.) Bridge deck access to the piers below was severely limited to a 10 ft (3.048 m) area adjacent to live traffic. Access on the ground was limited to only a handful of piers but they were virtually inaccessible, as they were surrounded by the Illinois River, Fig. 1: The Abraham Lincoln Memorial Bridge wetlands, lakes, and the historic Illinois-Michigan Canal. For the piers that were surrounded by land, 70 ft (21 m) tall boom lifts segmentally. On several piers that were severely deteriorated, were placed over the side of the bridge with cranes. Platforms set one-third of the pier was prepared and then shotcreted to under the deck were constructively engineered as a safe way to structurally replace the removed concrete. Once the shotcrete in be used at all finger-joint piers over the river, lakes, and wetlands the repaired section reached 70% of its required strength, the crew that were otherwise inaccessible. (Refer to Fig. 2.) remobilized and repeated the procedure on the next one-third of The adaptability of shotcrete provided a superior solution to the pier. This eliminated any concern for destabilization of the undertake the repairs. All of the shotcrete work was done from the structure. (Refer to Fig. 3.) bridge deck; and the use of shotcrete and its versatility had many Using a packaged, preblended shotcrete material mixed on site advantages compared with other processes, such as form and cast. as needed allowed a fresh, quality-controlled mixture with a One example was the ability to remove concrete on the piers consistent water-cementitious material ratio (w/cm). Ready mixed 42 Shotcrete • Spring 2013


2013SprShotcreteEMag
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