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Mow Strips

Question
State VA
Description Text

We are working on our miscellaneous installation details for
our new MGS standard.  After discussions during our pooled fund meeting
last week, it is apparent that the paving details under the rail are
critical.  We currently do not have a leave-out detail for our 27 ¾”
w-beam guardrail. 



 



How is your state handling this issue?  It appears that
some states are saw cutting or coring a leave-out and adding a low strength
sealant after the post is installed to prevent weed growth.  This seems to
be a labor intensive process.



 



Other states specify a 2” thick asphalt mow strip without
any leave-outs.  Does anyone have any in-service data on this method?



 



Bob:  Any thoughts?



 



Thanks 

Keywords
  • Guardrail
Other Keywords Mow Strips
Date April 27, 2017


Response
Response

1.      Do you currently have a separate pay item(s) for w-beam to thrie beam stiffness transitions at bridges? Yes

2.      Will you be using a separate pay item(s) for w-beam to thrie beam stiffness transitions at bridges after MASH implementation? Yes

3.      If you answered yes to question 1 or 2 above, what are your separate pay items called? Do you use a separate pay item for approach and trailing ends?

2505-4008300

STEEL BEAM G'RAIL

2505-4008410

STEEL BEAM G'RAIL BAR TRANS SECT, BA-201

2505-4021010

STEEL BEAM G'RAIL END ANCHOR, BOLTED

 

4.      Are you now or in the future (due to MASH implementation) using a separate pay item(s) for stiffening the guide rail where a fixed object (IE: utility pole, pier, sign structure, etc) is less than 4 feet from face of rail element?  If yes, what are your separate pay items called. We do not currently use a separate bid item for that.  Locations are just noted in the plans.

 

Date April 27, 2017


Response
Response

Dave/ All,

1.      … Pay item(s) … for w-beam/ thrie beam @ bridges? NDOR pays for a “Bridge Approach Section” (25’) which includes the W-THRIE BEAM TRANSITION SECTION & nested thrie bean leading to the bridge rail – Standard plan 740.

2.      … using a separate pay item(s w-beam/ thrie beam trans. @ bridges after MASH implementation?  Yes:

3.      (a) … what are your separate pay items called? “Bridge Approach Section” & “Special Bridge Approach Section” for thrie beam Plan 741.

When not part of a “Bridge Approach Section” we use “W-THRIE BEAM TRANSITION SECTION

(b) … separate pay item for approach and trailing ends? Yes; Approach: End Treatments Type I (parallel) or II (taper 4’ away) these are listed in the contract as to what is allowed, Trailing: “END ANCHORAGE ASSEMBLY” includes; 2 – posts, cable assembly, strut & yoke assembly, etc.

4.      (a) … stiffening the guide rail when object is less than 4 feet from face ? we pay for extra posts; using 3’1.5” post spacing. 

(b) … separate pay items called. “Guardrail posts”

 

Average Unit Prices: http://www.roads.nebraska.gov/business-center/business-opp/hwy-bridge-lp/item-history/

Standard plans: http://www.roads.nebraska.gov/business-center/design-consultant/stand-spec-manual/

Standard plans 700 ‘s

Special plans: 7000 ‘s

 

 

Date April 27, 2017


Response
Response

We have provided guidance on this topic in the past. We have typically referred to FHWA Memo B64b (see attached). The memo encapsulated previous research done at MwRSF, TTI, and CALTRANS regarding leave outs and fill materials.

 

I have attached the memo and the previous related research reports.

 

In addition, we did work on a weak post version of the MGS for installation in mow strips. This would be an alternative that would not require leave outs.

 

The link to a zip file with that research and the information above can be accessed at the link below.

 

https://unl.box.com/s/yn8spztfk6whv3qke2acenz5kyn37rw4

 

Thanks  

Date April 27, 2017
Attachment b64b.pdf
Attachment 0-4162-2.pdf
Attachment crmcrete_final_report.pdf
Attachment Guardrail_Posts_Alternative_Mow_Strips_405160-14-1.pdf
Attachment Rec for Placement of Posts in Rock.pdf
Attachment TRP-03-119-03_GR_Posts-in-Rock_5-30-03_FINAL.pdf


Response
Response

David,

 

See Illinois responses below in RED.

 

_______________________________________________________________________

Midwest States Pooled Fund members,

NJDOT currently does not use a separate pay item for the W-beam to thrie beam transitions at bridges.  The cost for these transitions are included in the price of the guide rail.  Now that NJDOT will be switching to the 31” MGS after 12/31/2017, these transitions are significantly longer than the NCHRP 350 transitions and we are considering separate pay items.

 

Can you please answer the following questions on the practice in your state:

 

1.     Do you currently have a separate pay item(s) for w-beam to thrie beam stiffness transitions at bridges?  YES

2.     Will you be using a separate pay item(s) for w-beam to thrie beam stiffness transitions at bridges after MASH implementation? YES

3.     If you answered yes to question 1 or 2 above, what are your separate pay items called? Do you use a separate pay item for approach and trailing ends?

Connection to a concrete parapet or other concrete structure is TRAFFIC BARRIER TERMINAL, TYPE 6.  This is Highway Standard 631031.

Connection to a steel bridge rail is called TRAFFIC BARRIER TERMINAL, TYPE 6A.   This is Highway Standard 631032.

Connection to a concrete structure and not using a curb is called TRAFFIC BARRIER TERMINAL, TYPE 6B.  This is Highway Standard 631033.

 

You can review these at our Highway Standards: http://www.idot.illinois.gov/doing-business/procurements/engineering-architectural-professional-services/Consultants-Resources/highway-standards-and-district-specific-standards

You can find the coded pay items here: https://www.google.com/url?q=http://www.idot.illinois.gov/Assets/uploads/files/Doing-Business/Specialty-Lists/Highways/Design-%26-Environment/Coded-Pay-Items/January-16-2015-Letting/CodedPayItemsHwy20150116.pdf&sa=U&ved=0ahUKEwjPrcOY6f7SAhXh5oMKHQhxDuEQFggHMAE&client=internal-uds-cse&usg=AFQjCNE8bvrnXfiy4U8l7oWNqlnH6-j74Q

 

4.     Are you now or in the future (due to MASH implementation) using a separate pay item(s) for stiffening the guide rail where a fixed object (IE: utility pole, pier, sign structure, etc) is less than 4 feet from face of rail element?  If yes, what are your separate pay items called.

Yes, guardrail with 6’-3” post spacing is STEEL PLATE BEAM GUARDRAIL, TYPE A. Guardrail with 3’-1 ½” post spacing is called STEEL PLATE BEAM GUARDRAIL, TYPE B. We do not have guardrail post spacing of 1’ 6 ¾” depicted on a Standard, but it could be included as a plan detail with a unique pay item. Both Type A and Type B are shown on Highway Standard 630001 at the same link referenced above.

 

Date April 28, 2017


Response
Response

1.      Yes, WisDOT has separate bid items.

2.      Yes, WisDOT will use separate bid items.

3.      614.2500 MGS Thrie Beam Transition

4.      Yes, we use separate bid items when there is a need for reduced working width.  We use to not have separate bid items.  Low and behold contractors and field staff were not stiffening the beam guards when they should have or not providing enough of it.

 

Bid items are:

614.2300 MGS Guardrail 3 (normal post spacing)

614.2310 MGS Guardrail 3 HS  (Half post Spacing)

614.2320 MGS Guardrail 3 QS  (Quarter post Spacing)

 

We tell designer they are responsible for providing appropriate working width.  If they don’t it is Errors and Omissions on their part.

 

We use a different bid items for a number of situations (e.g. areas with reduced grading, long spans…).

 

 

Date April 28, 2017


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