630.01 Description. This item shall consist of the construction
of a rock buttress as shown on the plans or as dire cted by the Engineer according to these specifications and to t he lines, grades, and dimensions shown on the plans or as directed by the Engineer.
630.02 Materials. Stone used for construction of the rock
buttress shall be obtained from an approved source and shall consist of sandstone, limestone, syenite, novaculite, or ot her hard and durable stone. Shale, slate, or similar materials shall not be used. The stone shall be greater than 1½" (40 mm) and les s than 30" (750 mm) in any dimension. The stone shall be reas onably well graded and angular, with fractured faces on at leas t 75% of the surface and shall not contain more than 10% overbur den or fines less than 1½" (40 mm) in maximum cross-section. The sto ne shall weigh not less than 150 pounds per solid cubic foot (2400 kg per solid cu m) and shall have a percent of wear not gr eater than 45 by the Los Angeles Test (AASHTO T 96) and when subject ed to 5 cycles of the Soundness Test (Sodium Sulfate, AASHT O T 104) shall have a loss not to exceed 12 percent. The st one shall have an absorption rate (AASHTO T 85) of less than 3 percen t. Relatively thin, layered rock shall not be used for the mass o f the rock buttress, but may be used to face the outside surfaces of the buttress.
630.03 Construction Methods. Before placing the rock buttress,
a trench shall be excavated and shaped as indicated on the plan drawings or as directed. The rock shall be dumped or placed 513 substantially to the shape indicated on the plan dr awings. During stone placement operations, larger rock shall be pu shed to the lower portion of the rock buttress. Objectionable voids between large rocks shall be filled with smaller stones or suitab le granular material to provide adequate bearing surfaces for adjacent r ocks. Care shall be exercised to place rock along the out side face that will present a reasonably pleasing appearance. Backfill shall be according to Subsection 210.09.
630.04 Method of Measurement. Rock Buttress completed and
accepted will be measured by the cubic yard (cubic meter) in place. The volume will be computed by the average end area method.
630.05 Basis of Payment. Work completed and accepted and
measured as provided above will be paid for at the contract unit price bid per cubic yard (cubic meter) for Rock But tress, which price shall be full compensation for furnishing and hauli ng material; for placing and compacting the rock; for backfilling; a nd for all labor, equipment, tools, and incidentals necessary to comp lete the work. Required excavation for the trench will be measured and paid for as provided in Section 210 for the appropriate clas sification of excavation. Payment will be made under: Pay Item Pay Unit Rock Buttress Cubic Yard (Cubic Meter)