DelDOT Standard Specifications Section 720: Guardrail

720.1Description.

This work consists of constructing guardrails.

720.2Materials.

A.PCC, Class B Section 1022

B.Steel Posts, Steel Shapes Section 1070

C.Galvanized Beam Guardrail Section 1070

D.Guardrail Hardware Section 1070

E.Guardrail Reflectors Section 1070

F.Timber Posts Section 1070

G.Offset Blocks

1.Wood Section 1070

2.Recycled Composite Materials

a.As specified by the manufacturer

b.Selected from the Approved Products List (https://www.deldot.gov/Business)

H.Galvanized Steel Pipe Section 1070

720.3Construction.

A.Conduct a pre-installation field meeting prior to placement of guardrail systems if required by the

engineer or noted in the contract.

B.Before installation, provide shop drawings for guardrail components not provided in the contract

including the associated manufacturer’s installation instructions.

C.Provide and install guardrail and components in accordance with the Contract.

720.3.1 Post Installation.

A.Dig test pits to determine utility and storm sewer conflicts before post placement in accordance

with Section 204. Repair damage to subsurface facilities caused by post installation.

B.The Department will allow the driving method for post placement. Seal posts with material

approved by the engineer.

C.If the driving method is not used, excavate post holes of sufficient diameter to allow tamping of

backfill around the posts. Backfill with approved material. Place backfill in compaction lifts not exceeding 6-inches of uncompacted material.

D.Align the posts to within 1/4-inch of line and grade before installing rail elements. Install posts

plumb. Repair bituminous concrete that cracks or breaks resulting from post installations in accordance with Section 401.

720.3.2 Rail Assembly.

A.Lap rails in the direction of traffic flow for the closest lane. Draw tight all bolts except those

through expansion joints. Tighten bolts through expansion joints as tight as possible without preventing the beams from sliding past one another longitudinally. Extend bolts at least 1/4-inch beyond the nuts. Do not extend bolts necessary for adjustment more than 1/2-inch beyond the nuts. Burr the last thread of post railing bolts to prevent removal.

B.Do not field cut holes in rails unless otherwise directed in the contract. If holes must be field cut,

mechanically punch or drill them. Remove all burs created by field cutting activities from the rail. Galvanize holes with a method approved by the engineer. 720.3.3 Offset Blocks.

A.Install new guardrail, using either wood or approved recycled composite offset blocks. Do not mix

different types of manufactured composite blocks or mix composite and wood blocks. Do not install composite offset blocks at wood posts.

B.Notch wood offset blocks in accordance with the Standard Construction Details only when

installing on steel posts. When installing wood offset blocks on wood posts, toenail the wood offset block in place using a 3-inch long ceramic coated screw. Place the screw so that it penetrates both the wood offset block and wood post.

C.Install approved recycled composite offset blocks in accordance with the manufacturer’s

recommendations with no modifications. 720.3.4 Guardrail Reflectors.

A.Install guardrail reflectors in accordance with the Standard Construction Details.

720.3.5 Relocating Guardrail.

A.Remove existing guardrail in a manner that prevents damage. Replace hardware with new

hardware.

B.Reinstall and reset the guardrail system at the locations designated in the contract and in

accordance with Section 720.3, and the Standard Construction Details. If the existing guardrail has steel offset blocks, replace the offset blocks with offset blocks meeting the requirements of Section 1070 and the Standard Construction Details. Install new guardrail reflectors in accordance with Section 720.3.4. 720.3.6 Guardrail Over Culvert. Provide and install guardrail over culvert in accordance with the Standard Construction Details.

720.4Method of Measurement.

A.The Department will measure:

1.Guardrail from the center of end post to the center of end post, excluding barrier connections

and end treatments;

2.guardrail components as the number of each component provided, placed, and accepted by

limit of payment;

3.guardrail over culverts as the number of each provided, placed, and accepted by limit of

payment;

4.relocated guardrail as the number of linear feet of guardrail relocated and accepted.

720.5Basis of Payment.

A.The Department will pay the quantity of guardrail installations, guardrail components, replacing

individual components, relocating guardrail, or guardrail over culverts at the contract unit price. New beam guardrail installation includes all posts, beams, hardware, and components. Price and payment will constitute full compensation for:

1.Pre-installation field meeting;

2.test pits;

3.providing and placing materials and components;

4.fabricating;

5.excavating;

6.required transition sections;

7.guardrail reflectors;

8.burring bolts;

9.backfilling;

10.grading;

11.compacting;

12.disposing of surplus materials and components; and

13.patching material around posts.

B.The Department will not pay for repairing damaged subsurface facilities caused by post

installation. ITEM DESCRIPTION UNIT 720001 GALVANIZED STEEL BEAM GUARDRAIL (WOOD POST) LF 720002 GUARDRAIL TO BRIDGE GUARDRAIL TRANSITION LF 720004 STEEL RAIL ELEMENT, STRAIGHT LF 720005 STEEL RAIL ELEMENT, CURVED LF 720006 GALVANIZED STEEL POSTS EACH 720007 SHORT WOOD BREAKAWAY POST, TREATED EACH 720008 OFFSET BLOCK EACH 720009 TERMINAL CONNECTOR, BRIDGE AND BARRIER EACH 720010 GALVANIZED RAIL ELEMENT, THRIE BEAM EACH 720011 GALVANIZED TRANSITION SECTION, THRIE BEAM EACH 720012 GALVANIZED STEEL POST, THRIE BEAM EACH 720013 GALVANIZED STEEL BRACKET, THRIE BEAM EACH

ITEM DESCRIPTION UNIT 720017 GALVANIZED RAIL ELEMENT EACH 720018 GALVANIZED STEEL POST, 7' EACH 720019 GALVANIZED STEEL POST, 8' EACH 720020 GUARDRAIL REFLECTOR EACH 720021 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 1-31 LF 720022 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 2-31 LF 720023 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 3-31 LF 720025 GUARDRAIL OVER CULVERTS, TYPE 2-31 EACH 720026 GUARDRAIL OVER CULVERTS, TYPE 3-31 EACH 720028 CURVED GUARDRAIL SECTION LF 720030 RELOCATING GUARDRAIL LF 720032 REMOVE AND RESET GALVANIZED STEEL POST AND OFFSET BLOCK EACH 720033 OFFSET BLOCKS EACH 720034 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 1-27 LF 720035 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 2-27 LF 720036 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 3-27 LF 720037 GALVANIZED STEEL BEAM GUARDRAIL, TYPE 1-31, STEEP SLOPE LF 720038 LONG WOOD BREAKAWAY POST, TREATED EACH

Referenced in this section

Sections that cite this one

GUARDRAIL in other states

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Source: Delaware Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 397–0 of 786. View official source ↗

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