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2017SpringShotcreteEMag

| SUSTAINABILITY Form-and-Pour to Shotcrete By Ross King In today’s increasingly competitive and challenging structural concrete marketplace, the need for innovative solutions to challenging forming issues is greater than ever. Old standbys aren’t the answer for increasingly complex requirements. These challenging issues require new and better solutions. Not too long ago, form-and-pour methodology completely dominated the forming marketplace, but that’s changing. Today, the marketplace is seeing structural shotcrete gain far greater acceptance as a more logical and efficient option for structural concrete applications. And with today’s increased emphasis on sustainability and environmental responsibility, structural shotcrete is well-positioned to make further inroads and experience increased demand and growth. Shotcrete for structural needs was first adopted on the west coast of North America beginning in California and then eventually moving north to Washington state. Until relatively recently, however, shotcrete was rarely used in thick, heavily reinforced structural concrete applications east of the Rockies in the United States or in any parts of Canada. Over the last 5 years, however, recognition and acceptance of structural shotcrete in thick, heavily reinforced sections has now extended to the east coast and across Canada as well. This growth has been driven by the efficiency of one-sided shotcrete formwork panels for buildings and civic structures and the ability to produce high-quality concrete in place using wet-mix shotcrete placement. The greatest barrier to acceptance in the early stages of adoption was a resistance by structural engineers, architects, and project owners to consider shotcrete as a viable alternative. The hard work and persistence of structural shotcrete pioneers on a prove-it-as-you-go basis, however, has steadily helped dispel concerns that existed in the past. Today, the acceptance of structural shotcrete as an option to concrete poured into two-sided forms built to contain high fluid pressures is commonplace. Structural shotcrete placement is now routinely included in project specifications for a wide variety of high-quality concrete structures. Structural shotcrete offers several compelling advantages that are now coming to light and driving its growth in the construction marketplace: • Substantially less formwork is required; • The formwork that is required is substantially lighter in weight; Fig. 1: Tall segmented radius, one-sided “shoot panels” for curved wall forming Fig. 2: Architectural reveals and recessed panels on single reskinned shoot panels for curved wall prior to reinforcing bar placement 52 Shotcrete | Spring 2017 www.shotcrete.org


2017SpringShotcreteEMag
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