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Sustainability Sustainable Transportation Retaining Walls Denver RTD West Corridor By Warren Harrison Slong life of a well-designed structure. Thisustainability, to me, is the stingy use ofscarce resources (money) and the inherent thereby minimizes capital expenditures and increases the economic life of the facility, mini- mizing maintenance costs. The use in the last 40 years of geotechnical designed structures is a good example of sus- tainability. The use of the inherent strength of in-place rock and soil to build a structure is an excellent example of sustainable construc- tion practices. The original as-bid design of the new light rail station at the Jefferson County Justice Center had a 33 ft (10 m) high retaining wall supported with a double row of large-diameter drilled Fig. 1(a): Jefferson County Government station under construction. Full concrete caissons. The wall had to support the depth—33 feet (10 m)—supporting adjacent highway with permanent soil nearby US Highway 6 and also contend with nails and shotcrete (Photo courtesy of Harry Olsson) drainage from snow removal on the highway. As an alternate design, with the help of Bill Zietlow, we proposed a soil nail wall solution with a carved shotcrete facing. To ensure that the design was feasible, we invested in three additional soil borings and performed triaxial testing to determine our design assumptions. The idea of a carved wall came from a site visit during the ACI Convention in San Diego, CA, to the California Coastal Line Station near San Diego. The carved shotcrete was very impressive and made a very inviting station atmosphere. The final station walls consisted of approxi- mately 22,000 ft2 (2040 m2) of soil nail and shotcrete walls and 12,000 ft2 (1110 m2) of carved shotcrete walls, which were shot and finished by Boulderscape of California. The non-carved shotcrete was in the tunnel section Fig. 1(b): Wall under construction showing carved shotcrete facing, of the station. which is also structural member of final permanent wall structure The carving and architectural effect was the (Photo courtesy of Harry Olsson) main reason the design change was approved 32 Shotcrete • Spring 2015


2015SpringShotcreteEMag
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