product representative, Falkner selected EPS 22Geofoam, which offers a compressive strength of 7.3 psi at one percent deformation. Shop drawings of the block configuration pattern were produced to validate structural soundness before placement. Atlas packaged pre-numbered blocks and followed a specified delivery sequence to ensure easy, pre- cise installation of each block according to plans. Once the Geofoam arrived, laborers were easily able to move the 40” x 48” x 96” blocks by hand. Most of the blocks required no modifica- tions, but where needed, a hand-held hot wire cutter was used to quickly customize the Geofoam to fit around the bridge's superstructure. “With the embankment built, it was time to lay the road, and that went a lot different than expected,” continued Falkner. The road plan called for a crushed limestone base subgrade, covered with a hot asphalt mix to be topped with ten inches of concrete paving. “On the aggregate side, everything was kind of squishy and it took a lot longer than we expected to get a smooth surface. I was worried about the Geofoam side, but it was rock solid under the equipment as we pushed the base out with a dozer.” Just as civil infrastructure challenges come in a variety of flavors, so do the possibilities for solutions innovation. For general contractor, WW Clyde, of Springville, Utah, one such opportunity presented itself on a road and bridge project in Pocatello, Idaho. Known as the Cheyenne South Valley Connector, the project involved a new two-lane roadway connecting the east and west sides of Pocatello. The main feature of the project was a 430-foot long bridge traversing the Portneuf River that also crosses six sets of active railroad tracks, South 2nd Avenue in Po- catello, and several bike and pedestrian paths. Minimizing community impact during construction was a key consideration for WWClyde and project manager, Bryson Clyde, a licensed Professional Engineer, and fourth-generation builder in the Clyde family. “In almost every construction project cost, schedule, and resources are the three primary variables,” shared Clyde. “As the project manager, it’s my responsibility to balance the allocation of each, which often requires some innovative thinking.” Molded polystyrene was used as removable concrete formwork in Pocatello, Idaho by heavy civil industrial contractor, WW Clyde.
On the Cheyenne South Valley Connector, innovation came in the form of an unusual application of Atlas Molded Products’ molded polysty- rene Geofoam. Regularly used as a structural fill, in the case of the Pocatello bridge, WW Clyde’s structures manager suggested that the Geofoam could be used to create the formwork for the bridge’s three concrete piers. “We never used Geofoam as concrete formwork before, but this project opened our eyes to the possibilities of this dynamic product and its abil- ity to help solve construction challenges in the future,” Clyde continued. Typically, builders use wood or metal to construct concrete forms, which in custom applications like bridge piers can be very time consuming and expensive. Clyde calculated that using Geofoam as the concrete formwork saved the project an estimated $7,800 in formwork material costs alone. Add to that some 200 manhours saved in not having to build wooden forms by hand and the benefits were measurably obvious. Once the shop drawings for the formwork were approved, the foam blocks were cut and shaped to the engineering specifications. Curved fillets were attached to the foam blocks to add an artistic fluted flair to the finished surface. The foam blocks were then delivered to the site, secured in place, and the concrete was poured from the top to fill the carefully constructed void of each pier. “Using molded polystyrene geofoam not only saved money but is also save a lot of time,” finished Clyde. “We shaved more than a week off a very tight construction schedule by using Geofoam to make the con- crete forms. Truthfully, most of the work was done by Atlas in shaping the product to our specifications. When it arrived on site, putting it in place was quite easy and things were very efficient.” Though much of what is accomplished with Geofoam goes largely un- noticed by the everyday public, builders, engineers, and owners across the country have long realized the benefits of this strong, lightweight, adapt- able material and know they have a trusted ally inAtlas Molded Products. Eliminating the need to hand-build the formwork with wood shaved an estimated 200 manhours and $7,800 of non-tangible costs off the overall project budget.
SEAN O’KEEFE is an architecture and construction writer who crafts stories and content based on 20 years of experience and a keen interest in the people who make projects happen. He can be reached at sean@sokpr.com.
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csengineermag.com
october 2020
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