Sustainable Land Development Today - April 2008 - (Page 35) fit with the area’s New England heritage.” Since JGI met resistance from local officials, D.W. White decided to contact John Biondo, northeast regional manager for Tensar International Corporation (TIC), to see if he could suggest a cost-effective strategy for addressing the project’s newest set of requirements. “The SierraScape Retaining Wall System seemed like a good fit for several reasons,” Biondo said. “They’d be able to use it in retaining wall and pressure relief applications. The work would go in fast, which would help keep the construction on schedule. And it fit their budget.” Biondo also thought the system would address the aesthetic concerns raised by the town since the geogrid-reinforced, welded-wire facing units could be filled with onsite stone. It would provide a finished face that blended more naturally with the underlying blastrock structure, he said. Making the Grade After evaluating the system, JGI was satisfied that it would meet the project’s various requirements better than the alternative solutions, and the firm was soon able to present a new design to the owner and local officials. Ultimately, all the project participants agreed that the SierraScape Systems were the best option for balancing aesthetic, space, budget, and schedule issues. The revised design called for adding a 30-foot retaining wall to the project’s northern blastrock slope. Stacking the geogrid-reinforced, welded-wire forms above the 1H:1V blastrock fill slope provided the additional space the owner needed without adversely affecting the budget or schedule. A second wall would be used to create a grade separation for the new movie theatre. perience putting it together, the installation moved along quickly. It took a lot less time than the boulder walls which really helped us gain ground on our original schedule of the overall project.” Installation of the retaining wall structure involved placing the wire-formed facing units on top of the blastrock slope. Workers tied the adjoining facing units together and unrolled precut lengths of Tensar® Uniaxial (UX) Geogrids perpendicular to the wall face. They then used connection rods to mechanically connect the UX Geogrids to the facing units. At that point, heavy equipment was used to spread nine-inch lifts of onsite fill over the geogrids and place two- to fourinch stones in the wire-formed facing units. To establish a separation layer between the wall facing and the compacted fill, workers installed geotextile over the small stones. The process was repeated for each row until the structure attained the height specified in the design. “The mechanical connection between the geogrid and the facing units ensured facial stability and helped maintain alignment over the length of the row,” Biondo said. “That’s important when you’re building a structure with rows up to 1,500 feet long.” “It’s a good option for grade separations of more than 70 degrees,” Biondo said. “The positive, mechanical connection between the geogrids and facing units enables geotechnical engineers to design lower cost walls that are structurally equivalent to conventional methods.” Project Benefits From Cooperation With most of the project behind them, Ciance, York, and Biondo share the feeling that The Shoppes at Blackstone Valley project was very much a team effort. “We definitely had to work together to meet the owners needs,” York said. “We were thinking outside the box all the time and sharing ideas to keep the project moving along.” Ciance has a similar observation. “Collaboration was the key to this project going so smoothly. It also helped to have Tensar as a support group at every phase of work. We had a lot of design changes right through construction, but everyone worked together to make things go in easier.” “We all worked closely together,” Biondo agreed. “Everybody contributed to solving the design and constructability issues.” As for the system that played such a prominent role in helping the Shoppes at Blackstone Valley get off the ground: “The SierraScape Systems provided an easy-to-construct and cost-effective solution for the client,” Ciance said. “It was flexible enough to use for pressure relief and retaining. It’s a product I will look at again.” York reported that D.W. White has already used the system on a second project. This time the SierraScape Systems are supporting a big-box development being built in Reading, Mass., at the site of a former landfill. SLDT About the author: Steven Knapp is a freelance writer. He has written about engineering, telecommunications, computer hardware and software, satellite communication, and more. He can be reached at steve@knappcommunications.com. Savings on Theatre Construction Costs D.W. White’s crews followed the same installation steps for the pressure relief wall, which JGI designed to address the soil separation associated with constructing the new multiplex theatre. Using a SierraScape Pressure Relief Wall instead of a conventional cast-in-place structure enabled the owner to build the theatre’s rear wall using conventional masonry block—a much more affordable solution. “We considered a cast-in-place wall, but the cost would have been tremendous,” Ciance said. “Instead, we recommended using a 34-foot tall wall approximately three feet behind the theatre. The structure was strong enough to retain the lateral earth and building loads created by a single-story retail strip located at the top of the pressure relief wall.” Ease of Installation is Key With the project once again on track, D.W. White’s crews returned to the task of completing the site earthwork. Installation was easy according to York, even though his crews were new to the SierraScape Systems. “Once we gained ex- www.SLDTonline.com 35 http://www.SLDTonline.com
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