Amendment 1_PHASE IV_Spec 255.02.6_Page_29.doc

Amendment 1

Atch 3 AG-0355-S-09-0004

April 15, 2009

Recovery - West Fork Rock Creek Road #2071 Phase 4

255.02.4 Rock

Rock for the facing section of gabion units shall be hard, angular to round, durable and of such quality that they shall not disintegrate on exposure to water or weathering during the life of the structure, in accordance with ASTM D6711. The rocks shall range between 4 inches (100 mm) and 8 inches (200 mm). Each range of sizes may allow for a variation of 5% oversize rock by number of particles, or 5% undersize rock by number of particles, or both. The size of any oversize rock shall allow for the placement of minimum of three layers of rock must be achieved when filling the 3 feet (1 m) high units and a minimum of two layers for the 1.5 feet (0.50 m) high units.

255.02.5 MSE Wall Select Backfill

Mechanically stabilized earth structures shall be made of a good quality, well graded, free draining, and granular material. Backfill to consist of the following gradation or approved alternate:

Select Granular Backfill Gradation

Submittal: Submitt laboratory test results conforming to Table 255-07

255.02.6 Geotextile & Drain Pipe

Place 4” diameter perforated pipe within 18” x18” drainage fill wrapped with geotextile filter fabric. Slope pipe at 1/8” per foot minimum and discharge every 100’ maximum at low points.

Geotextile to be utilized between Gabion Baskets and MSE wall backfill shall be a Non-woven drainage geotextile conforming to the following specification: