Placement of ACBs
The articulating concrete blocks must be placed on the geotextile in such a manner as to produce a smooth plane surface in intimate contact with the geotextile. Joint spacing between adjacent blocks is to be maintained so that binding of blocks does not occur and block-to-block interlock is achieved. In curvature and grade change areas, alignment of the individual block and the orientation of the neighboring adjacent block must provide intimate block to fabric contact and block-to-block interlock. Care shall be taken to avoid damage to the geotextile or subgrade during the block installation process. When a geotextile is used, the ACB system placement should begin at the upstream end and proceed downstream. If an ACB system is to be installed from downstream up, a contractor option is to place a temporary toe on the front edge of the ACB system to protect against undermining when flows are anticipated. On sloped sections, where practical, placement shall begin at the toe of the slope and proceed up the slope. Block placement shall not bring block-to-block interconnections into tension. Individual blocks within the plane of the finished system shall not exceed the protrusion tolerance beyond that used in the stability design of the system. The maximum protrusion tolerance for any given block is 0.5 inches (13 mm) (See Diagram 6).
Spreader Bar | Subgrade Preparation | Geotextile Installation | Loading and Unloading Cabled Mattresses
Placement of ACBs | Cabling, Anchoring and Crimping | Grouting | Bibliography