Impact Attenuators Art. 643.03 CONSTRUCTION REQUIREMENTS
642.03 General. The rumble strips shall be cut to the dimensions shown on
the plans. Guides shall be used to ensure consistent alignment, spacing, and depth. In portland cement concrete shoulders, rumble strips may be formed according to the details shown on the plans immediately after the application of the final finish. Rumble strips shall be omitted within the limits of structures, entrances, side roads, entrance ramps, and exit ramps. In portland cement concrete shoulders, rumble strips shall not be placed within 6 in. (150 mm) of transverse joints. Cuttings resulting from this operation shall be disposed of according to
Article 202 — 03 and the shoulders shall be swept clean.
642.04 Method of Measurement. This work will be measured for payment in
feet (meters) along the edge of pavement. Measurement will include both the cut and uncut (formed and unformed) sections of the shoulder rumble strips with exceptions for bridge decks, approach slabs, turn lanes, entrances, and other sections where shoulder rumble strips have been omitted.
642.05 Basis of Payment. This work will be paid for at the contract unit price
per foot (meter) for SHOULDER RUMBLE STRIPS, 8 INCH (200 MM) or SHOULDER RUMBLE STRIPS, 16 INCH, (400 MM). SECTION 643. IMPACT ATTENUATORS
643.01 Description. This work shall consist of furnishing and installing impact
attenuators.
643.02 Materials. Materials shall be according to the impact attenuator
manufacturer’s specifications and the following. Item Article/Section
a.Fine Aggregate (Note 1) ..................................................................... 1003.01
b.Steel Posts, Structural Shapes, and Plates ........................................ 1006.04
c.Rail Elements, End Section Plates, and Splice Plates ........................ 1006.25
d.Bolts, Nuts, Washers and Hardware ................................................... 1006.25
e.Hollow Structural Tubing ................................................................. 1006.27(b)
f.Wood Posts and Wood Blockouts......................... 1007.01, 1007.02, 1007.06
g.Preservative Treatment ...................................................................... 1007.12 Note 1. Fine aggregate shall be FA 1 or FA 2, Class A quality. The sand shall be unbagged and shall have a maximum moisture content of five percent. CONSTRUCTION REQUIREMENTS
643.03 General. Impact attenuators shall meet the testing criteria contained
in either NCHRP Report 350 or MASH and shall be on the Department’s qualified Art. 643.04 Impact Attenuators product list. Fully redirective and partially redirective attenuators shall be designed for bi-directional impacts.
643.04 Installation. Impact attenuators shall be installed according to the
manufacturer’s specifications and include all necessary transitions between the impact attenuator and the item to which it is attached. Regrading of slopes or approaches for the installation shall be as shown on the plans. The design for sand module impact attenuators (orientation and number of modules, sand weights, etc.) shall be as shown on the plans. Bases for sand module impact attenuators will be required. The bases shall be constructed of either portland cement concrete or hot-mix asphalt (HMA). Portland cement concrete bases shall be 6 in. (150 mm) thick and be according to the applicable requirements of Section 424. HMA bases shall be 8 in. (200 mm) thick and be according to the applicable requirements of Section 408. The surface of the base shall be slightly sloped or crowned to facilitate drainage. The perimeter of each module and the specified weight (mass) of sand in each module shall be painted on the surface of the base. Bases for impact attenuators, other than sand modules, shall be installed when required by the manufacturer. The bases shall be constructed according to the manufacturer’s specifications, on a prepared subgrade. The surface of the base shall be slightly sloped or crowned to facilitate drainage.
643.05 Method of Measurement. This work will be measured for payment as
each, where each is defined as one complete installation. Contract quantities for sand module attenuator bases may be accepted according to Article 202.07(a). When measured, sand module attenuator bases will be measured in place and the dimensions used to calculate square yards (square meters) will not exceed those as shown on the plans.
643.06 Basis of Payment. This work will be paid for at the contract unit price
per each for IMPACT ATTENUATORS (FULLY REDIRECTIVE, NARROW); IMPACT ATTENUATORS (FULLY REDIRECTIVE, WIDE); IMPACT ATTENUATORS (FULLY REDIRECTIVE, RESETTABLE); IMPACT ATTENUATORS (SEVERE USE, NARROW); IMPACT ATTENUATORS (SEVERE USE, WIDE); IMPACT ATTENUATORS (PARTIALLY REDIRECTIVE); or IMPACT ATTENUATORS (NON- REDIRECTIVE), of the test level specified. Sand module impact attenuator bases will be paid for at the contract unit price per square yard (square meter) for ATTENUATOR BASE. Regrading of slopes or approaches will be paid for according to Section 202 and/or Section 204 of the Standard Specifications. High Tension Cable Median Barrier Art. 644.06 SECTION 644. HIGH TENSION CABLE MEDIAN BARRIER
644.01 Description. This work shall consist of furnishing and installing a high
tension cable (HTC) median barrier with terminals/end anchorages.
644.02 Materials. Materials shall be according to the following.
Item Article/Section
a.Reinforcement Bars ....................................................................... 1006.10(a)
b.Portland Cement Concrete (Note 1) ....................................................... 1020
c.Wire Rope (Cable) and Fittings (Note 2) Note 1. The portland cement concrete shall be Class SI. Note 2. The wire rope (cable) shall be according to AASHTO M 30, Type 1 with Class A coating, of the diameter shown in the manufacturer’s specifications. Additionally, the wire rope shall be prestretched and shall have a breaking strength of 39,285 lbs (175 kN) for 3/4 in. (19 mm) wire rope (individual wire strength equivalent to 174,000 psi (1200 N/sq mm)) and the prestretched wire rope shall have a minimum modulus of elasticity of 11,805,000 psi (8300 kg/sq mm).
644.03 Equipment. Equipment shall be according to the median barrier
manufacturer’s specifications and the following. Item Article/Section
a.High Tension Cable Median Barrier ............................................... 1106.02(n) CONSTRUCTION REQUIREMENTS
644.04 General. The HTC median barrier shall be constructed to the lines
and grades shown on the plans and according to the manufacturer’s specifications, except as modified by the contract documents.
644.05 Line Post Foundations. Line posts for the HTC median barrier shall
be placed in concrete socket foundations. The minimum depth of the foundations shall be as shown on the plans. The minimum diameter for the foundations shall be 12 in. (300 mm) and the tops of the foundations shall be crowned 1/2 in. (13 mm). When the barrier is to be placed within paved shoulders or mow strips, the paved area(s) shall be constructed first and the concrete foundations placed in cored or formed holes.
644.06 End Anchorages. The Contractor shall submit to the Engineer shop
drawings detailing the required end anchorage foundation system at each location. The system shall utilize drilled shaft foundations and the number, diameter, depth, reinforcement, and cable connection of each shall be determined by the supplier. As a minimum, single shaft anchorage systems, with all cables terminating at one shaft, shall be at least 24 in. (600 mm) in diameter and 12 1/2 ft (3.8 m) deep while multiple shaft systems, with one cable per shaft, shall be at least 18 in. (450 mm) in diameter
Referenced in this section
Sections that cite this one
IMPACT ATTENUATORS in other states
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Source: Illinois Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 588–590 of 1,217. View official source ↗