Inside Curve with Gravity Extenders

Curves, Gravity, Inside Curve

Inside Curve with Gravity Extenders

Key Considerations for Gravity Inside Curves

STEP

First Course of MagnumStone outside Curve units

Quick Steps

The MagnumStone blocks should begin at a fixed point in the retaining wall. This should be the lowest point of elevation, or if it’s a flat surface begin at the 90-degree corner, curve or an abutment to another structure.
If possible, start building a curve from the center and work outward to the left and right, through the curve.
Use PVC Flex Pipes along the base leveling pad to create a smooth and accurate concave (outside) curve. For alignment purposes, the PVC Flex pipe will be positioned along the back of where the base blocks will be placed.
Properly measure the concave curve and place the first MagnumStone base block on the leveling pad where the center of the concave curve will be located.
The back of the MagnumStone base block should be tight to, but not touching, the PVC Flex Pipe to provide an accurate, consistent alignment.
The blocks should be tight together, level and the back of the blocks should be aligned along the PVC Flex Pipe.
Continue to lay the MagnumStone base course on either side of the concave curve until the base course is complete.
At the discretion of the project engineer, impermeable materials can be placed and compacted at the toe of the wall. If this is specified, the amount of impermeable material should reach the desired height of the perforated drainpipe.
Once the concave curve’s base course is confirmed to be the correct radius and position outlined in the approved engineering design, the PVC Flex Pipe used for alignment can be removed from behind the wall.
If no gravity extender units are required, proceed to install adequate drainage, fill the hollow core blocks with clear crush drainage gravel, then add and compact layers of backfill behind the blocks as outlined here in these steps of the MagnumStone Unit Installation section.

STEP

Gravity Extenders Units for First Course of Inside Curve

Quick Steps

If MagnumStone gravity extender units are part of the approved engineering design, they can be added once the first course of MagnumStone base blocks are properly installed.
The size of gravity extender units required will vary depending on the retaining wall design.
Similar to the beginning of the base course, start by attaching gravity extender units to base blocks at the center of the curve, and work outward, left and right along the retaining wall.
Follow the retaining wall’s approved design to install 2 ft. (0.61 m.) or 4 ft. (1.22 m.) gravity extender units to MagnumStone base blocks along the rest of the first course.
At the discretion of the project engineer, impermeable materials can be placed and compacted at the toe of the wall. If this is specified, the amount of impermeable material should reach the desired height of the perforated drainpipe.
Once gravity extender units are installed, proceed to install adequate drainage, fill the hollow core blocks and surround the gravity extenders with clear crush drainage gravel, then add and compact layers of backfill behind the extender units as outlined here in these steps of the MagnumStone Unit Installation section.

STEP

Laying Second Course of Inside Curve

Quick Steps

Similar to the first course, begin the second course at the center of the concave curve.
Maintain the running bond pattern by centering the block so it overlaps above the two blocks below (with SecureLugs pressed tight to the front of the hollow cores of the blocks beneath it).
The second course will naturally have a setback of 1”/ft. (25 mm. per block).
Continue to place MagnumStone standard blocks along the second course, on both sides of the concave curve’s initial block of the second course until the full course is complete.
If no gravity extender units are required, proceed to install adequate drainage, fill the hollow core blocks with clear crush drainage gravel, then add and compact layers of backfill behind the blocks as outlined here in these steps of the MagnumStone Unit Installation section.

STEP

Gravity Extender Units for Second Course of Inside Curve

Quick Steps

Similar to the gravity extenders of the first course’s concave curve, attach gravity extender units according to the approved engineering design.
Continue placing 2 ft. (0.61 m.) or 4 ft. (1.22 m.) gravity extender units as required by the retaining wall’s design plans for the remainder of the second course.
Once gravity extender units are installed, proceed to install adequate drainage, fill and compact the hollow core blocks and surround the gravity extenders with clear crush drainage gravel, then add and compact layers of backfill behind the blocks as outlined here in these steps of the MagnumStone Unit Installation section.

STEP

Higher and Top Courses of Inside Curves

Quick Steps

Properly install layers of clear crush gravel and approved backfill materials for each course as outlined in the previous steps.
For the final course of the retaining wall, install MagnumStone top blocks for a clean finish and more versatility for top of wall details.
Add and compact gravel in the hollow core’s top block and install approved backfill materials behind the wall, until both are level with the back of the top block.
Lay soil separation fabric from the back of the top block’s facing over the block and approximately 12” (0.3 m.) over the backfill area.
Atop the remaining 8” (0.2 m.) behind the block facing, install planting soil to cover the soil separation fabric and backfill zone.