CLIFTON STRAIGHT Clifton blocks feature a rear lip system for quick installation with no mortar or pins needed, and its hollow core design for core filling makes it perfect for large retaining wall projects. Professional engineering quotes are available online.
RETAINING WALL INSTALLATION BEFORE INSTALLATION BEGINS 1. Confirm lot lines, wall location, wall length, set back requirements and elevations. 2. Confirm the on-site soils. For walls built in clay or poor soils, consult an engineer to confirm the wall design and the required soil reinforcement. See Midwest Manufacturing Engineering for more details. 3. Call the local utility companies to confirm the location of underground utilities. 4.
BASIC INSTALLATION - GRAVITY WALLS Segmental Retaining Walls that rely on their own weight, core fill, friction between units and setback are called gravity walls. Conventional segmental retaining walls are generally effective as gravity structures for most non-critical wall applications. Don’t assume shorter walls never require the services of a soils engineer. The heights listed by the manufacturer are used as a rule of thumb when ideal wall conditions are present.
Step 2 - Leveling Pad Installation Place a minimum of 6" of compacted base material and compact to 95% Standard Proctor density. Verify that the base is level with a transit or hand level. Be aware that the base material (commonly referred to as road base or base aggregate) will vary from region to region. The base material should consist of crushed material: ¾" crushed concrete with fines or ¾" crushed rock or limestone with fines. Your material must be angular, nothing round.
Step 5 - Successive Course Installation Before adding successive courses, each block needs to be clean and free of foreign material. Center the block and pull it forward until the rear lip abuts the two blocks below it. Place core and drainage fill as in Step 4. Place the backfill material behind the drainage rock in maximum 3" to 6" lifts based on the rating of your compaction equipment and compact to 95% Standard Proctor Density. Repeat this process for each successive course.
Step 6.3 - Stepping a Wall/Another Option Another option for walls that step-up is to cut to fit a 6" wide section of a Step/Cap for the Denver or an 8" wide section of a Step/Cap for the Clifton and lay the Step/Cap vertically to finish the end. To ensure the vertical cap maintains a straight line from the face to the back of the block, a 2" chip is installed near the back of the block (see illustration below).
SPECIAL APPLICATIONS AND WALL DETAILS Convex/Outside Curves and Concave/Inside Curves & Corners Step 1 - Base Course Preparation for a Convex Curve Place the blocks on the leveling pad so there are no gaps between them. Consider using PVC Flex Pipes to create smooth and accurate curves. When possible, start building a curve from the center and work left and right through the curve.
RADIUS OF CONVEX CURVES ON SUCCESSIVE COURSES Top Course Radius Center Stake Base Course Radius Convex Curve Chart 1 2 3 4 5 6 7 Block Rows Radius (Min.) 1 24½" 2 263/32" 3 2711/16" 4 299/32" 5 2929/32" 6 32½" 7 343/32" 8 3511/16" 8 CONCAVE/INSIDE CURVE Step 1 - Base Course Preparation for a Concave Curve Place the blocks on the leveling pad so there are no gaps between them. Consider using PVC Flex Pipes to create smooth and accurate curves.
Step 2 - Successive Course Installation for a Concave Curve Build each course of units by starting at the same place and the same bond as the last course. Keep in mind, for Concave Curves, the taller the wall the smaller the first course needs to be. The radius of each additional course will be slightly larger than the lower course.
DENVER OR CLIFTON INSIDE CORNERS To build inside corners with the Denver or Clifton, corner units are not needed. Step 1 - Base Course Preparation Begin an inside corner from the corner of the wall and install the blocks from the corner out, when possible. Place the second unit at a right angle and centered to the first base unit. Only half of a whole block installed on the corner will be exposed. Also, always core fill each unit to ensure proper interlock.
Before excavation can begin, the rise and run of the stair treads must be determined and codes must be met. Stairs can be built by stacking two Clifton units and a Step/Cap on top of each other for more stability. A more economical option is stacking one Clifton and a Step/Cap. Stairs can be built in front of the wall or into the wall with radius turns or outside 90º corners (see illustrations below).
Steps Built Into the Wall Using Corner Units Riser Cross-Section of Steps Built Into a Wall, Stacking Two Blocks and a Step/Cap CLIFTON STRAIGHT
TIERED WALLS Tiered Denver and Clifton walls offer a visually pleasing and less obtrusive alternative to conventional wall construction. On sites that provide sufficient land area for this application, these walls are typically designed with green space between the tiers.
GEOGRID REINFORCED WALLS All installation instructions are the same as for gravity retaining walls except for the addition of geogrid. Geosynthetic reinforcement is an engineered product that is typically comprised of polypropylene, polyester or other high tensile material. Used in conjunction with segmental retaining wall blocks, it helps stabilize the soil mass behind a wall. Depending on the wall design, the length and the number of grid layers will vary.
BASIC GEOGRID REINFORCEMENT Step 1 - Preparation for Grid The area behind the wall on the grid layer needs to be level with the top of the block (after compaction) and compacted to 95% of the Standard Proctor density (ASTM D698). Step 2 - Grid Placement Place the grid as close to the face of the wall without exposing it after successive placement of blocks. Ensure the grid is placed with the strength direction perpendicular to the wall.
BASIC GEOGRID REINFORCEMENT - CONVEX CURVE Step 1 - Grid Placement Cut geogrid to required lengths and place the grid as close to the face of the wall without exposing it when following the contour of the curve. Place the next course of SRW block, taking care that the grid sits flat and is secured between the units. Each geogrid length should be laid perpendicular to the wall face and pulled tight to remove any slack. The geogrid should never overlap on top of the Clifton or Denver Units.
BASIC GEOGRID REINFORCEMENT - CONCAVE CURVE Step 1 - Grid Placement Cut geogrid to required lengths and place the grid as close to the face of the wall without exposing it when following the contour of the curve. Place the next course of SRW block, taking care that the grid sits flat and is secured between the units. Each geogrid length should be laid perpendicular to the wall face and pulled tight to remove any slack. The geogrid should never overlap on top of the Clifton or Denver Units.
GEOGRID - OUTSIDE 90° CORNER Step 1 - Grid Placement On an outside 90° corner, it is important that grid layers do not overlap at the corner. Place the first grid layer at the correct elevation and length. Each geogrid length should be perpendicular to the wall face. Lay the first geogrid corner section perpendicular to one side of the corner. Lay the second geogrid section perpendicular to the other side of the corner but not overlapping the first geogrid section.
ESTIMATES FOR DRAIN PIPE, ADHESIVE AND GEOGRID Drain Pipe The length of the wall will in most cases determine the amount of drainpipe needed. Check the plan for exact specifications and locations of the drainpipe. Concrete Adhesive Use one 10.5-ounce tube of adhesive for every 14 ft. of wall length where Step/ Caps and Corners are installed. Use one 29-ounce tube of adhesive for every 39 ft. of wall length where Step/Caps and Corners are installed. ø=34 deg.
