Backfilling Backfill structures with granular material Class II up to the subgrade elevation, or to an elevation determined by the Engineer. Place backfill in layers no greater than 10 inches thick and compact each layer to at least 95 percent of the maximum unit weight. Maintain at least 3 feet of cover during construction, unless trimming for final grades. Structure Covers / Access Provide and install covers, including any frames on or in the new structures as required by the manufacturer. Place casting in a full motor bed in accordance with manufacturer specifications or as directed by Engineer.. After final adjustment of the structure to the proposed elevation, the void area around the structure shall be completely backfilled with sand-aggregate-water-cement mixture as directed by the Engineer, to provide a stable base around the structure. A minimum 24 hours cure time shall be provided prior to beginning paving operations in these areas. A direct access route, as approved by the Engineer, allowing a minimum of HS20 loading requirements or greater must be provided to the treatment system to facilitate maintenance. The cost of direct access shall be paid for separately as shown on the plans. Measurement and Payment The completed work, as described, will be measured and paid for at the contract unit price for the following pay item: Pay Item Pay Unit Hydrodynamic Separator Structure, ___ cfs Each Payment for Hydrodynamic Separator Structure, __ cfs includes all equipment, labor, hydrostatic testing and materials to complete this item in accordance with the plans and specifications. The Hydrodynamic Separator Structure, __ cfs shall be cleaned, per the manufacturer's guidelines prior to final acceptance and is included in the contract unit price. Actual sizes of structures are not shown on the plans and all earthwork related items required to install the structure and associated piping shall be included in the contract unit price. The cost of piping and pipe connections between the external bypass structure(s) and the hydrodynamic separator structure shall be included in the unit price. Dewatering shall be considered as part of the necessary work, and will not be paid separately.
Backfilling Backfill structures with granular material Class II up to the subgrade elevation, or to an elevation determined by the Engineer. Place backfill in layers no greater than 10 inches thick and compact each layer to at least 95 percent of the maximum unit weight. Maintain at least 3 feet of cover during construction, unless trimming for final grades. Structure Covers / Access Provide and install covers, including any frames on or in the new structures as required by the manufacturer. Place casting in a full motor bed in accordance with manufacturer specifications or as directed by Engineer.. After final adjustment of the structure to the proposed elevation, the void area around the structure shall be completely backfilled with sand-aggregate-water-cement mixture as directed by the Engineer, to provide a stable base around the structure. A minimum 24 hours cure time shall be provided prior to beginning paving operations in these areas. A direct access route, as approved by the Engineer, allowing a minimum of HS20 loading requirements or greater must be provided to the treatment system to facilitate maintenance. The cost of direct access shall be paid for separately as shown on the plans. Measurement and Payment The completed work, as described, will be measured and paid for at the contract unit price for the following pay item: Pay Item Pay Unit Hydrodynamic Separator Structure, ___ cfs Each Payment for Hydrodynamic Separator Structure, __ cfs includes all equipment, labor, hydrostatic testing and materials to complete this item in accordance with the plans and specifications. The Hydrodynamic Separator Structure, __ cfs shall be cleaned, per the manufacturer's guidelines prior to final acceptance and is included in the contract unit price. Actual sizes of structures are not shown on the plans and all earthwork related items required to install the structure and associated piping shall be included in the contract unit price. The cost of piping and pipe connections between the external bypass structure(s) and the hydrodynamic separator structure shall be included in the unit price. Dewatering shall be considered as part of the necessary work, and will not be paid separately.
RCOC12SP403D_HydrodynamicSeparator.docx