Section B-B is intended to illustrate the 4” layer of aggregate and the filter fabric as identified in the special provisions and Standard Specifications. Page 28 of the spec states: "A 4" layer of clean aggregate, as specified by the manufacturer, is required for bedding." Please note that this is required by the EOR and is not specified by Contech. The 4” layer of aggregate may be omitted, if not required by the manufacturer. Please confirm that material must be produced at a G2 Certified Precast Concrete facility. Yes, the producer is required to be on the IDOT list of Certified Precast Concrete Producers and be qualified to produce Precast Articulated Block Revetment Mats (category G2). (04/13/2023)

Regarding Articulated Concrete Block: In order to size the block per HEC-23 DG8, we need maximum depth of flow on the revetment and slope of the energy grade line. Only velocity is provided. Depth of flow and slope isn't available. The contractor should bid according to the Standard Specifications for Road and Bridge Construction, Highway Standards, and the plans and specifications available online. The coverage area on sht 38/71 of the plans is not clear, and there is no scale shown. Could you please clarify the area? Otherwise, we will need to approximate based on what is specified as the "visible" area (1280 SY) The “visible” area of 1280 Sq. Yd. matches the quantity shown on sheet 39 of 71 and is the area of anticipated coverage for the articulated block revetment mat. (04/13/2023)