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Weak Post W-Beam Guardrail Attached to Culvert Headwall

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State IN
Description Text
 INDOT plans to add a Standard Drawing series that details the weak post, w-beam guardrail, attached to the outside of a culvert headwall.  We have read through MwRSF Research Report No. TRP-03-277-14 and have put together the attached standard drawing sheets.  Would it be possible for someone to review these standard drawings to make sure they are in accordance with the report?  Thank you


Bridge Rails
Road Closure Gates
Thrie Beam Guardrails


Date February 7, 2019
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Attachment Draft Standard Drawings for Side Mounted Headwall Weak Post.pdf
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(active)
I have reviewed the attached drawings.  Overall, they were great.  I only have a few minor clarifications of note:

1. you have the W-beam backup plate labeled on drawings E 601-MGSA-24, but it does not specify the length of the backup plate.  The original MGS bridge rail utilized 6" long backup plates, and I believe the drawings in report no. TRP-03-277-14 reflect this length.  However, after multiple instances of rail tearing due to contact with weak posts, the recommended length of the backup was increased to 12".  Since the 12" long plates will extend beyond the splice bolts, these elongated backup plates need to include additional slots to account for splice bolts.  Options and details for 12" backup plates are described on pages 146 and 147 of report no. TRP-03-322-15.  I have attached Figure 92 from that report herein as a reference.

2. Drawing no. E 601-MGSA-24 - Note 2.  2nd to last sentence reads "...for both the top and bottom slab reinforcement."  To avoid confusion, this may be better described as "...both the top and bottom reinforcement mats in the culvert slab."

3. Drawing no. E 601-MGSA-26: the mounting tube is called out as "Square Structural Tubing", but you may want to call it out as an HSS 4x4x3/8 similar to the way the post is labeled an S3x5.7 on drawings no. E 601-MGSA-27

4.  Drawing E 601-MGSA-28:  Note 6 reads "...combined height of the culvert headwall and culvert shall be 18 in."  This should read, "...combined height of the culvert headwall and top slab shall be 18 in."  Also, the arrows pointing to tube, plate, and bolt components in Section A-A are a little above the part they are pointing to.
Date February 7, 2019
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Attachment 12-in. backup plates.jpg
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(active) 		Thank you for your quick response!
Date February 10, 2019
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(active) 		No problem. 
Date March 14, 2019
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