514Permanent Concrete Traffic Barrier

3.1 General . Perform excavation and embankment work in accordance with Item 400, “Excavation and Backfill

for Structures,” except for measurement and payment. Place reinforcing steel in accordance with Item 440. Welding of additional bars to the reinforcing cage is allowable, if approved, when slipform placement is used. Weld in accordance with Item 448, “Structural Field Welding.” Cast barrier in place, slipform barrier, or construct barrier using precast concrete sections unless otherwise shown on the plans. Use forms meeting the requirements of Item 424 for precast sections. Wood forms are allowable for curves and transitions. Construct formwork in accordance with Item 420, “Concrete Substructures.” Multi-project fabrication plants (as defined in Item 424) that produce concrete traffic barrier must be qualified in accordance with DMS -7350 , “Qualification Procedure for Multi -Project Fabrication Plants of Precast Concrete Traffic Barrier.” See the Department’s MPL for approved fabricators. Construct drilled shaft foundations in accordance with Item 416, when required. Construct barrier in accordance with Item 420. Form -cure or water -cure concrete, except for precast sections, for at least 4 days, or cure with Type 1- D or Type 2 membrane curing compound. Cure precast sections in accordance with Item 424. Remove concrete, mortar, oil, and other substances leaked onto the roadway.

3.2 Cast -in-Place Barrier .

3.2.1 Conventionally Formed Barrier . Accurately set forms for conventionally formed barrier. Secure the forms in

a manner that is not detrimental to roadway pavement and will maintain barrier in a true position during concrete placement. Remove forms after the concrete has reached sufficient strength to prevent physical damage to the barrier. 2024 S pecifications 514 799 3.2.2. Slipformed Barrier . Ensure slipformed barriers are within a vertical and horizontal alignment tolerance of ±1/4 in. in 10 ft. Construct barrier with a smooth and uniform appearance. Remove and replace unsatisfactory barrier at the Contractor’s expense. Consolidate concrete so it is free of honeycomb. Provide concrete with a consistency that will maintain the shape of the barrier without support. Minimize starting and stopping of the slipform operation by ensuring a continuous supply of concrete. Provide a wire line to maintain vertical and horizontal alignment of the slipform machine. Attach a grade line gauge or pointer to the machine so a continuous comparison can be made between the barrier being placed and the established grade line. Do not exceed the manufacturer’s recommended speed for the slipform machine. Rails or supports at the required grade are allowed instead of sensor controls.

3.3 Precast Sections. Notify the Engineer of the location of the casting site and date on which work will begin if

precast sections are used. Form cure concrete until the concrete has reached sufficient strength to permit handl ing without visible cracks or other damage to the sections. Produce precast barrier sections to the tolerances shown in Table 1 unless otherwise shown on the plans. Table 1 Precast Barrier Tolerances Dimension Tolerance Length ±1 in. Insert placement ±1/2 in. Horizontal alignment ±1/8 in. per 10 ft. of length Deviation of Ends Horizontal skew ±1/4 in. Vertical batter ±1/8 in. per foot of depth Repair or replace concrete traffic barrier damaged during fabrication, curing, handling, or placing, as directed.