Allan Block’s new website is up and running! With the new update, we will have all of our resources within our literature to help you construct and design your walls properly. Most notably are all the design charts we have included in our Commercial and Residential Design Manual. The design charts provide essential guidance for building segmental retaining walls under typical conditions. These charts are meant to help contractors, designers, and engineers quickly determine the correct wall components, heights and configurations.

Some key charts to highlight:

• Gravity Wall Max Heights
• Reinforced Wall Design
• Soils Bearing Min Capacities
• Block Setback Max Heights
• No-Fines Concrete Design
• Max Radius Charts for Building

To find these charts on our website please navigate to allanblock.com, Select “Contractor” or “Design Pros”, and on the left-hand side under “Allan Block Books” – select Commercial Installation Manual. Use the table of contents to find the chart you need. You have the option to view our resources and literature online or download our books to a .pdf format and save them to your computer. If you have any questions regarding the design charts, don’t hesitate to reach out to us at 800-899-5309 x3 or email us at engineering@allanblock.com.

• Not enough space for geogrid reinforcement behind the wall
• Utility relocation costs that would make the project prohibitively expensive
• Seasonal drainage from adjacent farm field runoff
• Permanent obstacles in front of the wall location

Traditional reinforced retaining wall systems simply wouldn't fit.

The Innovation: No-Fines Concrete Backfill

Duffy Engineering and Associates found the answer in an innovative material combination: Allan Block units with No-Fines Concrete backfill. This solution created a smaller footprint gravity wall system that met all the site constraints.

What makes No-Fines Concrete special?

• Contains only Portland cement and coarse aggregate – no sand
• Creates interconnected voids for superior drainage
• Forms a solid, permeable mass when cured
• Combines with block facing to create an effective gravity wall system

No-Fines Concrete has been in the industry for over 25-years and is used extensively in various parts of the world.

When site constraints eliminate conventional solutions, innovative materials can open new possibilities. The Woodland Heights project proves that No-Fines Concrete backfill systems can deliver durability and performance even in the tightest spaces – solving problems that stumped previous wall installations.

Facing a challenging retaining wall project with space constraints? Contact our technical team at 800-899-5309 x 3 to explore whether No-Fines Concrete solutions could work for your specific site conditions.

It's not unusual to encounter sites where standard geogrid-reinforced walls are not a feasible application. This could be due to tight property boundaries, underground utilities, or shallow bedrock. When there's a need to reduce the reinforcement depth, no-fines concrete (NFC) offers an ideal alternative. While the segmental retaining wall (SRW) industry generally requires geogrid lengths to be at least 60% of the wall height, NFC solutions can typically be designed with reinforcement depths as little as 30 to 40% of the total wall height.

No-fines concrete, as the name suggests, is a type of concrete mix that excludes sand or other fine particles. It was initially developed as a cost-effective alternative by reducing the amount of cement and fine materials needed. The presence of cement in the mix increases the friction angle between the aggregate particles. Once it cures, the resulting material acts like a permanently bonded or "stabilized aggregate," providing long-term cohesion.

The concrete backfill consists of cement, fly ash, water, and coarse aggregate. The quantity of cement material is approximately 500 lb./yd³ (297 kg/m³) with a water/cement ratio of approximately 0.30 – 0.40. A typical NFC backfill design mix consists of 3/8 in. to 3/4 in. (9.5 mm to 19 mm) aggregate with an aggregate/cement ratio of 6:1.

Independent testing was conducted by Allan Block, to find out more information, see excerpts from Tech Sheet #417 or request a copy of the testing report - contact us via email at engineering@allanblock.com.

At Allan Block, we understand the challenges that come with designing segmental retaining walls, tight timelines, evolving site data, and complex wall configurations. That’s why we offer free preliminary design services to engineers, architects, and other design professionals.

Our in-house engineering team uses AB Walls 3D+Terraces retaining wall design software to generate comprehensive retaining wall design packets at no cost to you. Also included in our preliminary services are fence overturning calculations, global stability analysis, and MathCAD hand calculations.

How Our Preliminary Design Services Work

If you have a project with retaining walls, send us the following:

• A site civil plan or wall plan with wall elevations and lengths
• A geotechnical report or description of onsite soils
  • Accurate soil information plays a crucial role in your design

Once we receive the necessary materials, our engineering team will start working on a design. The preliminary design packet that we create with AB Walls to provide to you includes:

• Specifications and Notes
• Plan/Layout view
• Elevation/profile view
• Cross-section calculations
• Typical Details
• Preliminary material estimate

Each packet is clearly marked as preliminary and is intended for review by your firm. The final review and engineer’s stamp remain your responsibility, but we’ll handle the legwork!

If revisions are needed, let us know, we’re happy to make adjustments. Alternatively, you can use our free design software to edit the layout yourself. Don’t have the software yet? We’ll provide a copy and help you get started. Our team also offers free technical support and tutorials to help you make the most of it.

Get started today, streamline your workflow and ask our experienced team for assistance. Send your project information to email to request preliminary design assistance. Designing smarter by letting us assist you!