876Truck Mounted Impact Attenuators

876.01 Description

The work consists of providing, installing, operating, maintaining, and relocating truck mounted impact attenuators. This work also cons ists of providing, stockpiling, and moving repair packages.

876.02 Materials

Provide truck mounted impact attenuators with the following components:  Crushable cartridge encased in a shell,  Backup and support assembly to attach the backup to the truck, and  Truck with a minimum gross vehicle weight over 15,000 lb [6,800 kg], or  A trailer meeting all of the above specifications. Provide a truck chassis to mount the impact attenuator with a clearance from 11 in to 13 in [280 mm to 330 mm] between the bottom of the shell and the roadway. Provide truck mounted attenuators in accordance with the test requirements, procedures, and results in NCHRP 350 or MASH Test Level Three (TL -3) with letter of acceptance/eligibility from the FHWA. Submit certified test results meeting the test and performance criteria in accordance with NCHRP 350 or MASH. Provide the truck mounted impact attenuator cartridge with a standard trailer lighting system. Provide a minimum 90° tilt system with a mechanical locking device to secure the truck mounted attenuator cartridge in the 90° position.

876.03 Equipment — Vacant

876.04 Construction Methods

Do not park truck mounted impact attenuators against rigid objects, except as a temporary safety measure until installation of a permanent crash attenuator. Use this method for no longer than 72 hr or as shown on the Plans. Install the attenuator on the truck in accordance with the manufacturer’s recommendations. During truck mounted attenuator operations, stockpile the truck mounted impact atten uator replacement packages on the project or at another local site approved by the Resident Engineer. If repairing the truck mounted impact attenuator, ensure traffic safety through the construction area or suspend construction activities. Immediately rep air or replace damaged truck mounted attenuators.

876.05 Method of Measuremen T — Vacant

The Resident Engineer will measure Truck -Mounted Attenuator by the maximum number in use at any one time during the Project.

877.02 Portable Longitudinal Barrier

876.06 Basis of Payment

The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay Item: Pay Unit:

877.01 Description

This work consists of providing, placing, and relocating portable longitudinal ba rriers.

877.02 Materials

Provide materials in accordance with the following sections: Material: Section: Portland Cement Concrete, Class A 701 White Concrete 701.13 Reinforcing Steel 723 Submit alternative designs for approval by the Engineer before starting the manufacture of concrete barriers. The Engineer will consider alternative and special design features influencing the casting of a section, and attachments or holes that facilitate the handling and lifting of a section. Ensure alternative designs meet the exterior dimensions as shown on the Plans and perfor mance criteria in accordance with NCHRP 350 or MASH test level three (TL -3) guidelines. The Contractor may choose to use a steel barrier section instead of a concrete barrier section. The steel barrier system must be approved for use and listed on the QPL . Ensure the steel barrier system meets all performance criteria in accordance with NCHRP -350 or MASH test level three (TL -3) guidelines. Ensure all structural elements for the steel barrier system are fabricated from galvanized steel. Ensure all bolts, nuts and washers are galvanized.