The Top-Pinning, Hole-to-Slot Advantage

In VERSA-LOK's unique system, pins are inserted in the holes of an upper unit and tapped into receiving slots of two lower units. Top-pinning makes installation easy because the units do not have to be lowered onto pins. Instead, pins are placed in units after the units are set near their final position.

VERSA-LOK’s unique hole-to-slot pinning allows variable bond, which is a structurally preferable installation method. Variable bond eliminates the gaps between units that are necessary with wall systems that require exact half-bond installation. The hole-to-slot pinning system allows units to be adjusted horizontally as needed during construction, and it allows vertical joints to wander in relation to joints in courses above and below.

Hole-to-slot pinning also better accommodates curves because there are no protrusions or lips to cut or modify around tight curves. This creates more accurate, consistent alignment and setback. There is no need to maintain a strict half-bond around curves and corners.

Cut-away view at right shows pins occupying holes in top course and set into slots in bottom course.

Pin Advantages for Geogrid-Reinforced Walls

A pinned interlock between courses eliminates the need for wall units to have protrusions, lips or tongues. As a result, geogrid lays flat between courses of units. This simplifies installation of geogrid and avoids damage to the grid that can occur when it is wrapped around or otherwise forced to conform to a protrusion. Pin connections also provide a positive mechanical connection to geogrids, even when there is little friction between units, such as in seismic events. Without modifications, unit protrusions and lips can change setback in curved walls. Pinned VERSA-LOK wall units can maintain consistent setback in both straight and curved sections of walls without modification.

VERSA-LOK’s Pinned and Frictional Interlock Advantage

While some retaining wall systems offer only one type of connection, VERSA-LOK’s interlock system delivers a premium combination of both a frictional and a mechanical (pinned) connection. VERSA-LOK’s original pinning system provides a mechanical interlock between retaining wall units and a mechanical connection to geogrid soil reinforcement. The mechanical connection ensures excellent interlock even when there is little weight above, and therefore little frictional force, as during construction before units are stacked on the connection and at the tops of finished walls, where there is little weight on the top course of units.

In summary, VERSA-LOK's top-down, hole-to-slot pinning delivers these advantages:

  • Improved performance and shear strength, resulting from both frictional interlock and a positive mechanical interlock between units and geogrid layers
  • Quick and easy installation, because units can be slid into position first and then pinned
  • Minimal gaps between adjacent units, improving the appearance of corners and curves
  • Easier placement of units and geogrid due to flat surface of units
  • Variable bond
  • More uniform setback around curves

VERSA-TUFF Pin Properties

VERSA-TUFF® pins are made from fiberglass-reinforced nylon. VERSA-TUff pins vary in size depending on which VERSA-LOK unit is being used.

VERSA-TUFF pins are used with VERSA-LOK Standard, Cobble and Square Foot retaining wall units. They are 6.8 in. tall and 0.48 in. in diameter. Two pins are used per unit.

VERSA-TUFF Snap-Off Pins are used with VERSA-LOK Accent retaining wall units and in VERSA-LOK Mosaic®retaining walls. VERSA-TUFF Snap-Off pins are designed to accommodate the varying heights of units within Mosaic panel. The full-length of these pins is used for the 6-inch-high Standard and Cobble units. When pinning through the shorter 4-inch-high Accent units, the top two inches of the VERSA-TUFF Snap-Off Pin above the unit is easily snapped off. VERSA-TUFF Snap-Off pins are 6.8 in. tall, 4.63 in. at snap-off height, and 0.48 in. in diameter.

VERSA-LOK Brute® Pins are used with VERSA-LOK Brute®retaining walls. (Brute wall units are available in select markets only.) Brute pins are 8.75 in. tall and 0.87 in. in diameter.

VERSA-LOK Data For Engineers

In an installed wall, the friction between VERSA-LOK wall units and the pin connection combine to provide unit interlock and a mechanical connection to geogrids. These properties—unit-to-unit shear strength and unit-to-geogrid connection strength—are used for wall design calculations. For each VERSA-LOK unit, shear and connection strength have been determined by independent, product-specific laboratory testing, per ASTM standards.

If you are a licensed professional engineer (P.E.) doing a final wall design, you can download this VERSA-LOK unit interface data in a VDF (vendor data file) format, for use in NCMA's SRWall 4.0 wall engineering design software. For VERSA-LOK shear and connection data in printed form or in a file format for use in other wall design software, contact VERSA-LOK at 800-770-4525. See our Engineering page for more information.