DESCRIPTION
640.01.01 General. This work consists of constructing masonry block retaining walls.
MATERIALS
640.02.01 General. Material shall conform to the following Sections and Subsection:
Portland Cement Concrete ................................ ..................................................................................................................... Section 501 Reinforcing Steel ................................ .................................................................................................................................... Section 505 Portland Cement ................................ .................................................................................................................................... Section 701 Grout and Mortar Aggregate .................................................................................................................................... Subsection 706.03.04 Water ..................................................................................................................................................................................... Section 722 Unless otherwise specified, use Class A or Class AA concrete. Class D may be substituted for Class A concrete or Class DA may be substituted for Class AA concrete. Masonry block shall be slump block or split face block of the dimensions shown on the plans and conforming to ASTM C90, Type I. Add an integral color pigment to all concrete block and mortar, except the grout used in filling cells. The color pigment shall consist of a synthetic mineral oxide specifically manufactured for coloring masonry products and mortar. Obtain the integral coloring by mixing the pigment material with the other ingredients in a sequence and by methods that will result in a uniform color. Unless otherwise indicated on the plans, the color of the concrete blocks and mortar shall approximate Federal Standard No. 37875 as shown in Table VIII of Federal Standard No. 595B. The final color selections will be subject to approval. The polyvinyl chloride premolded joint filler shall conform to Subsection 707.03.03 (c). CONSTRUCTION
640.03.01 General . Give not less than 10 days notification in advance of shipment of concrete blocks to the
jobsite for testing before shipment. Provide a separate storage area for concrete blocks which have been tested and accepted but are stockpiled for later delivery to the jobsite. Construct footings according to Section 502. Compose mortar for masonry wall s of 1 part Portland cement to not more than 3 parts surface dry mortar aggregate by volume, to which hydrated lime may be added in the quantity of 25% by volume of cement. Treat hydrated lime as an addition to and not as replacing any cement. Hydrated lim e shall conform to ASTM C207, Type S. Prepared mortar mix may be substituted if approved. All grout used to fill cells shall attain a minimum compressive strength of 17 MPa (2,500 psi) in 28 days when tested according to Test Method No. Nev. T427. Constr uct the masonry wall true and plumb. Lay straight uniform courses in common bond with vertical joints aligned over center of unit below as shown on the drawings. Align all vertical cells. Mortar joints shall be 9.5 mm (0.375 in.) thick. Lay all blocks wit h horizontal and vertical mortar joints buttered along face edges for a depth equal to thickness of face shells, also on the webs surrounding the cells to be filled. Shove vertical joints tight. Concave tool joints smooth. Keep all wall surfaces clean and free from mortar blotches. Place reinforcement as shown on the plans. Solidly fill cells with grout according to the details shown on the plans. 640 RETAINING WALLS At the conclusion of the masonry work, remove mortar daubs and smears and clean down the walls. Take precaut ions when constructing the masonry walls when the temperature is below 4 °C (40 °F). Provide suitable materials to heat materials, protect the work from cold and frost, and to insure that mortar or grout will harden without freezing. METHOD OF MEASUREMENT
640.04.01 Measurement. Masonry retaining walls will be measured by the square meter (square foot),
measured along the face of the wall, on the masonry block portion placed above the top of the footing. Concrete in footings for masonry retaining walls wi ll be measured and paid for according to Section 502. Reinforcement in masonry block walls and masonry block wall footings will be measured and paid for according to Section 505. Structure excavation and granular backfill will be measured and paid for ac cording to Sections 206 and 207. BASIS OF PAYMENT
640.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract
price per unit of measurement for the pay items listed below that are shown in the proposal. Payment will be full compensation for the work prescribed in this Section. Payment will be made under: Pay Item Pay Unit Masonry Retaining Wall ................................ ................................ ................................................................ Square Meter (Square Foot) SECTION 641 VEHICULAR IMPACT ATTENUATORS DESCRIPTION
641.01.01 General. This work consists of furnishing and installing impact attenuator systems.
MATERIALS
641.02.01 General. Select approved impact attenuators from the manufacturers listed in the QPL. Use the
impact attenuator selected for the entire project and do not use a combination of types of impact attenuators. Impact Attenuator (Special) shall meet all the requirements of this Section except the type and configuration of the unit will be s pecified in the Special Provisions. Concrete used in the foundation slabs shall have a minimum compressive strength of 28 MPa (4,000 psi) and shall conform to Section 501. Reinforcing bars used in the concrete base slabs shall be Grade 420 (60) conforming to Section 505. Submit for approval the manufacturer’s shop drawings, foundation details, installation recommendations, and any other pertinent information for the impact attenuator. Receive approval for the exact model of impact attenuator proposed, pri or to installation. Furnish and install the units with all parts and materials necessary for them to perform as designed. CONSTRUCTION
641.03.01 General. Excavate any material encountered for the construction of base slabs according to
Section 206. Furnish and install aggregate base, reinforcing steel, concrete, backfill, asphalt pavement, anchor bolts, miscellaneous hardware, epoxy, reflectors on the nose sections, and any other incidentals required for construction of the attenuators. Construct concrete and metal reinforcement items according to Sections 502 and 505. Install impact attenuators according to the plans and the manufacturer’s recommendations. METHOD OF MEASUREMENT
641.04.01 Measurement. Impact attenuators will be measured by the eac h.
BASIS OF PAYMENT
641.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract
price per unit of measurement for the pay items listed below that are shown in the proposal. Payment will be full compensation for the work prescribed in this Section. Payment will be made under: Pay Item Pay Unit Impact Attenuator ................................ ................................ .............................................................................................................. Each Impact Attenuator (Special) ............................................................................................................................................................... Each