606Guardrail

Guardrail

Description

606.01This work consists of the construction of guardrail per these specifications and in

conformity with the lines and grades shown on the plans or established. The construction of the various types of guardrail shall include the assembly and erection of all component parts and materials complete at the locations shown on the plans or as directed.

The types of guardrail are designated as follows:

Type 3 Guardrail – Midwest Guardrail System (MGS) W-Beam 31 Inches Type 6 Guardrail – Thrie Beam Type 7 Guardrail – F-Shape Concrete Barrier (Precast) (Temporary) Type 9 Guardrail – Single Slope Concrete Barrier Use of Type 4 Precast Concrete Barrier not permitted.

Materials

606.02Materials shall meet the requirements specified in the following subsections:

“W” Beam Rail and Thrie Beam Rail 710.05 Guardrail Hardware 710.09 Guardrail Posts 710.08

Paint for field painting of guardrail shall conform to subsection 708.03, Structural Steel Bridge Paint.

Concrete for precast or cast-in-place barrier shall be made with an approved Class D Concrete and shall conform to the requirements of Section 601. The Contractor may elect to use an approved self-consolidating Class D concrete. Reinforcing steel, unless otherwise noted, shall be epoxy coated and conform to the requirements of Section 602.

Concrete for bridge rail shall be Class DF Concrete and conform to the requirements of Section 601.

Construction Requirements

606.03Post and Rail Elements

plumb, grades and lines as staked. All fittings and metal plates shall be placed securely in position to conform to designated dimensions and requirements. Posts shall be set by one of the following methods:

606.04

Driving of posts shall be accomplished by methods and equipment that will leave the posts in their final position free from any distortion, burring, or any other damage.

Excavated post holes shall have a firm bottom and be backfilled with acceptable material placed in layers and thoroughly compacted.

Dissimilar metal-to-metal or aluminum-to-concrete post or rail installations shall have contact surfaces separated by a protective coating approved by the Engineer.

Wood posts cut in the field shall have the cut surfaces protected with two coats of a preservative approved by the Engineer. When the cut surface is above ground, the treating solution to be used shall be the same type as was used in the original treatment.

installation. All bolts in the finished rail shall be drawn tight. Bolts shall be of sufficient length to extend beyond the nuts. Rail shall be shop bent for installations on horizontal curves having a radius of 150 feet or less.

element shall closely follow the setting of posts to keep the number of posts without rail at a minimum. When necessary to minimize potential hazards, the Engineer will specify the direction that the rail installation is to advance, and the number of posts installed ahead of rail installation. At the end of the Contractor’s workday, the Contractor shall treat the ends of the installed guardrail as follows:

installed with one end attached to the rail already in place and the free end resting on the ground. The free end on the ground shall be restrained by tying the rail to the posts by ropes or cables. The guardrail shall not be left in this configuration for more than 24 hours unless protected by an approved attenuating device.

606.04Concrete. Where paving is removed or damaged due to the Contractor’s

operations, the Contractor shall furnish an approved mix and shall repair the paving as required, at the Contractor’s expense.

In construction zones not closed to traffic, the Contractor shall treat the ends of the installed concrete guardrail at the end of the workday as follows:

attenuator or provide treatment as shown in the Contract.

by cast-in-place or slipform methods. The trench for the base of the cast-in-place reinforced barrier end anchorages shall be excavated to the lines and grades shown on the plans or established. The bottom of the trench shall be compacted to the density specified in subsection 203.07(a). The compacted trench bottom shall be watered and approved before placing concrete.

606.04

Concrete finish for all cast-in-place barriers shall be Class 1 per subsection 601.14. Slipform barriers shall not receive additional finishing unless permitted by the Engineer. Exposed vertical surfaces of slipformed barrier shall receive a vertical broom finish. When hand finishing is allowed, it shall be performed in conformance with subsection 601.12(a). The Engineer may determine that the exposed surfaces of the guardrail shall be tested with a 10-foot straightedge laid along the exposed surface in a longitudinal direction. The Contractor shall furnish an approved 10-foot straightedge and provide an operator to aid the Engineer in testing the exposed surfaces. All surface tolerances shall be measured in a longitudinal direction. Deviation of any exposed surface in excess of the tolerance specified shall be corrected at the Contractor’s expense. Longitudinal surface tolerances for the top of the barrier and the sides of the barrier from the top to a line 7 inches below the top of the barrier are:

inch from the edge of the straightedge.

inch from the edge of the straightedge with allowance made for curve deflection. Longitudinal surface tolerances for the remaining surfaces of the barrier are:

inch from the edge of the straightedge.

inch from the edge of the straightedge with allowance made for curve deflection. The Contractor will be allowed a maximum of three days of slipform production if the barrier being placed does not meet the specified tolerances. After the third day of placement of out-of-tolerance slipform barrier, the Contractor shall stop production. The Contractor shall submit a corrective action plan to the Engineer for review. The plan shall address corrective actions to the equipment and materials and a time frame for completion of the corrective actions. The plan shall address methods and materials to be used to correct out-of-tolerance barrier. Patching will not be allowed to correct out-of-tolerance barrier. Further placement of barrier will not be allowed until all previously placed barrier that failed to meet tolerances is corrected or removed. Each occurrence of out-of-tolerance slipform barrier shall be subject to the same corrective cycle.

Standard Plan M-606-14) may be formed upside down to minimize air pockets and improve surface finish. Concrete finish for precast barriers shall be Class 1 per subsection 601.14. Each segment of the precast barrier shall not have spalls, corner breaks, and bottom spalls totaling more than 5 square feet of surface area, which includes the base. All required hand finishing shall be performed in conformance with subsection 601.12(a). Connecting loops shall not be frayed, stretched, or deformed. Gaps between units shall not exceed the dimensions shown on the plans. Precast barrier units shall not be lifted or stressed in any way before they have developed the strength of the concrete specified. Units shall be supported at designated pickup points. Connecting loops shall not be used as pickup points. Care shall be taken during fabrication, storage, handling, and transporting to prevent cracking, twisting, or other damage. Minor chips on edges may be patched with the approval of the Engineer. Breakage and chipping may be cause for rejection. Units damaged in such a way as to impair their appearance or suitability, in the opinion of the Engineer, shall be replaced at the Contractor’s expense. Units rejected by the Engineer shall be marked on both sides with an orange painted “R” approximately 12 inches high and 6 inches wide.

606.05 The base for placing precast barrier shall be prepared to the lines and grades shown on the plans or established. When it becomes necessary to connect cast-in-place barrier sections to precast barrier installations during construction, the cast-in-place sections shall be constructed complete with connecting hardware per Standard Plan M-606-14 to join the cast-in-place sections to the abutting precast sections. A fifteen-foot transition section shall be provided when attaching barriers of differing shapes.

Method of Measurement

606.05Guardrail will be measured by the linear foot along the centerline of the rail from

end to end of completed and accepted rail as shown on the plans, excluding end anchorages, median terminals, and transitions.

End anchorages, median terminals, and transitions will be measured by the actual number placed and accepted. Each end anchorage, median terminal, or transition shall include all concrete, reinforcing steel, anchor bolts, cable, rods, turnbuckles, backing rail, plates, bolts, nuts, washers, and all other work and material necessary to complete the item.

Posts will be included in the quantities of guardrail of the specified type and not measured separately. Additional posts required for guardrail adjacent to bridges and obstructions, as shown on the plans, will not be measured and paid for separately but shall be included in the work.

Basis of Payment

606.06The accepted quantities of guardrail will be paid for at the contract unit price for

the type specified.

Payment will be made under:

Pay Item Pay Unit Guardrail, Type___ Linear Foot End Anchorage, Type___ Each Guardrail, Type___ (____Post Spacing) Linear Foot Median Terminal Each End Anchorage (_____) Each Transition, Type _____ Each

All work and materials necessary and incidental to the temporary treatment of guardrail ends will not be measured and paid for separately but shall be included in the work.

Partial payments will not be made for partially completed guardrail runs that do not conform to the end treatments specified in subsections 606.03(c) or 606.04.

Polyolefin fiber reinforcement will not be measured and paid for separately but shall be included in the work.

607.01