for Highway Construction Page 178 of 71 5 SECTION 215 – GEOSYNT HETIC REINFORCED ABUTMENT BACKFILL
215.01 Description.
Provide materials and construct geosynthetic reinforced abutment backfill .
215.02 Materials.
3/4 inch Aggregate for Untreated Base, Type A or B in accordance with 703.04. Subgrade Separation Geotextile , Type III in accordance with 718.07.
215.03 Construction Requirements.
Prepare the excavated area to a smooth, uniform condition without ruts, potholes, or protruding objects such as rocks or sticks. Excavate the existing roadway to the limits shown. Compact the bottom of excavated area with a minimum of 5 overlapping passes with an approved compactor. Remove and dispose of unsuitable foundation material below the bottom of the excavated area as directed. Replace material removed from below the designed elevation with approved material. Compact replacement material to Class A requirements as specified in 205.03.G. Place the geotextile in accordance with 640 with the roll direction perpendicular to the abutment bac k wall or wing walls. Install geotextile without wrinkles or folds, and tension the geotextile while placing the backfil l. Cover each geotextile layer entirely before starting the next lift. If geotextile from a different orientation overlaps the geotextile behind the abutment, maintain a minimum 4” vertical separation between geotextile layers. Place the abutment geotext ile in 16 inch lifts, or as specified. The geotextile does not have to be wrapped at the ends unless specified. Place backfill so as not to misalign or damage the abutment walls, wing walls or drainage system. Do not place backfill against newly constructed masonry or concrete structures until all 502.03 requirements have been fulfilled. Ensure that the backfill material maximum lift thickness after compaction is 8 in ches or less. Compact backfill in accordance with Class A compaction requirements. Field density testing will be performed at the same frequency as bridge abutments and approach slabs per the “Structure Backfill” construction type under I tem 210 – Compacting Backfill in the Quality Assurance Manual. Compact backfill within 3 feet of the structure by at least 5 passes of a lightweight mechanical tamper or roller. Density tests are not required within 3 feet of the walls. Slope the backfill away from all wall faces at the end of each day's operation to direct surface runoff away from the walls. Do not allow surface runoff from adjacent areas to enter the wall construction site .
215.04 Method of Measurement.
The Engineer will measure acceptably completed work by the cubic yard based on plan quantity .
215.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit price as follows: Pay Item Pay Unit Geosynthetic Reinforced Abutment Backfill ............................................ CY for Highway Construction Page 179 of 71 5 Subgrade Separation Geotextile , Type III and ¾” Aggregate for Untreated Base, Type A or B are incidental to the Geosynthetic Reinforced Abutment Backfill . Structure excavation within the limits for structure exca vation defined in Section 210 will be measured and paid under Section 210. Excavation outside the limits for structure excavation defined in Section 210 and within the G eosynt hetic Reinforced Abutment Backfill limits is incidental to this item . Compacting backfill within the Geosynthetic Reinforced Abutment Backfill limits is incidental to this item. The drainage system is incidental to this item. 216-250 for Highway Construction Page 180 of 715 SECTIONS 216 -250 - RESERVED for Highway Construction Page 181 of 71 5 SECTION 251 – MIGRATORY BIRD TREATY ACT (MBTA) COMPLIANCE
251.01 Description.
Manage the avoidance of migratory birds to comply with the Migratory Bird Treaty Act of 1918 (MBTA) and 36-11, Idaho Code.
251.02 Materials.
Not specified.
251.03 Construction Requirements.
Comply with the MBTA requirements, 36- 11, Idaho Code, and 107.17.
1.Provide an approved, qualified wildlife biologist.
2.Survey and monitor for migratory bird activity. During the nesting season, monitor vegetation or structures for nesting birds. Preemptive measures to avoid migratory bird species include clearing outside the nesting season, regular monitoring of bird activity, removal and disposal of unoccupied nests to prevent occupation, and exclusion devices (e.g., bird repellant spray, netting) that does not result in death or injury to adult birds.
3.Develop an avoidance plan, subm it the plans for review and approval 30 calendar days before performing any work. Show migratory bird nest location, avoidance plan, and visual markers for nest location in the plan.
4.Implement exclusion devices, bird repellent liquid, nesting prevention measures or remove and dispose of partially constructed and unoccupied nests of migratory or nongame birds regularly to prevent their occupatio n.
251.04 Method of Measurement.
MBTA compliance will be measured as specified in 109.03.C.5 or by invoice as agreed and approved before performing the work.
251.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit price as follows: Pay Item Pay Unit Migratory Bird Treaty Act Compliance .................................................... CA
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 214–216 of 768.