Guardrail Leaveouts 606 special provision July 6, 2016

Section 606: Metal and Concrete Wall Barrier How many of you are familiar with section 606 of the NMDOT Standard Specifications 2014 edition? What you should know is that we have not been using this section since May of 2014.

Special Provision Modifying Section 606 All projects that let after May 2014 has a Special Provision modifying section 606 in its entirety. The latest revision was October 2014 and we are currently working on a new revision to focus on Guardrail post leaveouts.

Section 606.3.1.1 October 2014 Revision In the meantime, all guardrail posts on w-beams that are restrained by rock, asphalt, or concrete must have a leaveout constructed if the pavement surface thickness is between 3” to 8”. If the asphalt thickness is greater than 8”, Standard Drawing section 606-GR31-05/20 Guardrail post detail in rock formation shall apply. The leaveout cavity must be fill with grout material similar to flowfill but with a 28 day compressive strength of 120 psi or less. The Department will allow the contractor to drive the steel posts through asphalt surfacing but a leaveout must be constructed… It’s probably easier to drive the posts before driving the posts. October 2014 Revision

Section 606.3.9 October 2014 Revision In the past, Department have used guardrail pads for vegetation and erosion control purposes. The current standard drawings is referred as mow strips. The revised special provision will eliminate mow strip terminology. October 2014 Revision

Section 606 Leaveout ≥0” 3” to 8” Leaveouts shall be constructed when asphalt is equal to 3” not to exceed 8” If the pavement surface is greater than 8”, the detail for installation of posts in rock foundation shall apply. If the posts are installed by driving, the offset between the front edge of the leaveout and the front face of the post is not required.

Section 606 Leaveout Grout 120 PSI or less. 7” Min. 1’ 3”” Min. Recommended material for grout is a two-sack grout mixture. Other leaveout materials may be accepted (e.g. foams) as alternatives to the two-sack grout provided their compressive strength does not exceed 120 psi. 1’ 3”” Min. 1’ 3”” Min.

Section 606.5.1 October 2014 Revision

Section 606 Latest Revision NMDOT is currently working on a July 2016 revision. An addendum will be issue to the projects letting in July 2016.

Section 606 Latest Revision All of the October 2014 revision applies with the following exceptions: Every w-beam post installed on pavement surface must have a leaveout constructed regardless of surface thickness. Installation of guardrail shall be done by a personnel certified by the guardrail manufacture. Wood posts will no longer be an option with the exception of end treatments if recommended by the manufacture.

Section 606 Conclusion Leaveouts shall be constructed for every w-beam post that is restrained by rock, asphalt, or concrete. End treatment posts shall be installed in accordance with manufacture’s recommendations and approved shop drawings. Posts on thrie beams are not required unless restrained by rock or concrete.

Questions?