Technical Newsletter Issue 1Successful Projects Start by Using the Right Tools |
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High Pointe Commons, a large scale commercial project in Harrisburg,
PA, has 6 different walls totaling more than 24,000 ft² (2230
m²). With just one of the walls being over 700 ft (213 m) long
and a maximum height of 18 ft (5.48 m) tall, the project required
a plan, design and build approach that kept all parties informed.
K & M Dri-Lay was the wall installer and even with a few weeks
of difficult weather conditions that flooded the site, completed
the construction in 90 days.
All of the walls have either a slope or paved surface above, requiring special design and construction consideration. Keller Engineering used the AB Walls Design Software to engineer the walls, taking advantage of its design flexibility when modeling surcharges. Here is just one of the design considerations they examined for the project: |
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Manufacturer: Nitterhouse Masonry Products LLC Chambersburg, PA Contractor: K & M Dri-Lay Masonry Inc. Waynesboro, PA Product Used: AB Classic of the AB Collection |
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When to Lengthen the Top Geogrid LayersThe designer should consider lengthening the top layers of geogrid reinforcement for two reasons: |
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(1) Wall StabilityWhen slopes and/or surcharges are present above the retaining wall there are greater forces distributed to the top layers; especially those forces working to pull the geogrid out of the soil. Lengthening the top grids adds an immediate benefit to the pullout of soil calculations and the overall stability of the top of the wall. |
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(2) Performance EnhancementThe reason to lengthen the top grids with pavement above is to minimize the potential of future cracking, which can shorten the life of the paved surface as well as the life of the retaining wall by allowing water to migrate through the crack into the infill zone. An engineer should consider the reinforced soil mass and retained soil mass as separate structures working independently. Although there is no relative movement between the two zones, a defined construction joint remains. By bridging the construction joint with extended geogrid layers you disrupt any variations between them, such as settlement, and minimize the potential of future cracking of the paved surface and ultimately increasing the life of both the pavement and the retaining wall. For a further discussion on High Pointe Commons and other Allan Block projects see the Project Profiles. |
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Estimate Retaining Wall Projects AccuratelyAllan Block has developed many tools to help contractors do their jobs more efficiently including a variety of estimating tools. Accurate project estimates are key to ensure your project gets off to a good start. |
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Commercial Retaining Wall CalculatorThe AB Commercial Wall Calculator is a comprehensive estimating tool that allows the user to layout larger wall profiles by inputting top and bottom of wall elevations at various points along the wall. The estimating tool works in Microsoft Excel and has a maximum estimating height of 30 ft (9.1 m). The estimate will include quantities of Allan Block units, cap units, base and wall rock, geogrid, infill soil, drain piping and even cap adhesive. You can use it as a proposal sheet as well by inputting the material costs and your labor rates to determine a total project cost to present to your clients. It is an easy and powerful tool you can use to support your Allan Block business. |
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Residential Landscape Retaining Wall CalculatorFor smaller landscape walls up to 6 ft (1.8 m) tall you can user our Residential Retaining Wall Calculator. For these residential walls the user simply chooses the block type, the number of courses, the type of soils you are building on and the type of surcharge above the wall to get the estimate. |
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For more information on using these tools or general wall construction
and estimating questions contact the Allan Block Engineering Department
at engineeringinfo@allanblock.com
or call us at (800)899-5309, ext 3.
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Retaining Wall Tools and Accredited Training for EngineersAllan Block has always been an industry leader in the training of engineers and installers of segmental retaining walls.To compliment one most highly recognized contractor certification programs in North America, Allan Block is nationally certified by IACET to provide engineers with continuing education credits for tutorials and other training. Here are two industry advances that Allan Block has been involved with and can offer additional training for you: |
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Full Scale Seismic TestingAllan Block is the only SRW block to conduct full-scale seismic testing. The tests were run in Tsukuba, Japan, in conjunction with Columbia University, University of Delaware, Huesker Geosynthetics, the National Science Foundation and the National Research Institute of Agricultural Engineering of Japan. The outcome of these tests was an industry wide reevaluation of how seismic loads are modeled in segmental retaining walls. The entire industry has adopted a new method based on true results over the old theoretical model. |
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Design Changes to Include ICSIf you are familiar with AB Walls Design Software, you know its capabilities to design a full wall profile, plan view and multiple cross sections along the length of the wall at user defined locations. The engineer can design sections with slopes above, broken back slopes, live and dead load surcharges at user defined locations. What is new is that AB Walls is the only segmental retaining wall program calculating Internal Compound Stability (ICS). ICS calculations were developed by leading industry engineers and academics with Allan Block playing the leading role.This adds another level of check to your standard internal and external design calculations. ICS is not a substitute for global stability; however it uses calculations similar to a Simplified Bishop’s slope analysis. Unlike global stability programs that take large slip arcs entering well above and below the wall structure, ICS calculates multiple smaller circular slip arcs through a predefined area of retained soil, the infill reinforced mass and the facing units, but never goes below the leveling pad. This predefined area for ICS arc development is called the Wall Design Envelope. This wall design envelope can be used to define the rolls of responsibility for a project. |
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Check out these links for more information on
AB Walls Design Software,
ICS calculations
or contact the Allan Block Engineering Department at engineeringinfo@allanblock.com
or call us at (800) 899-5309, ext 3.
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Going Green with Allan Block Retaining Wall ProductsAllan Block Corporation is an environmentally conscious company that strives to be a leader in the future of "green" building products. Building with more environmentally useful products will increase efficiency and reduce the negative impact we have on the world we live in. As a leader in the industry, Allan Block provides environmental solutions to just about any landscape. Our efforts to provide green construction solutions coincide with the efforts of the U.S. Green Building Council’s LEED® (Leadership in Energy and Environmental Design) Program and other programs of its kind. See a detailed description of how Allan Block products can help your project achieve LEED® Credits. |
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