View Q&A

MGS Box Culvert Mounting on Tall Headwall

Question
State	WY
Description Text	We are rehabbing some box culverts and attempting to incorporate the recently developed MGS Low Cost Box Culvert/Bridge Rail Design as a replacement railing. The particular box culvert in question will require adding a taller headwall to provide a 1V:10H slope into the face of the side mounted MGS Railing. Our Bridge Personnel would like to know if it is better to design the sockets so that the bottom connection is into the top of the box, rather than the headwall since it is rather tall. This design is shown in the attached drawing. Or is it O.K. just to stay with the standard design? In any case we would like to standardize the length of the posts.

Question

State

Description Text

We are rehabbing some box culverts and attempting to incorporate the recently developed MGS Low Cost Box Culvert/Bridge Rail Design as a replacement railing. The particular box culvert in question will require adding a taller headwall to provide a 1V:10H slope into the face of the side mounted MGS Railing. Our Bridge Personnel would like to know if it is better to design the sockets so that the bottom connection is into the top of the box, rather than the headwall since it is rather tall. This design is shown in the attached drawing. Or is it O.K. just to stay with the standard design? In any case we would like to standardize the length of the posts.

System Performance Evaluation

System Types
Road Closure Gates
Thrie Beam Guardrails

Applications

System Features

Date May 19, 2014
Previous Views (126) Favorites (0)

Attachment Question to Pooled Fund.docx Attachment Preliminary Design.pdf

Response
Response (active)	Your proposed design, shown in the PDF "Preliminary Design", should work great as a retrofit to the original weak-post guardrail to culvert attachment system. By extending the length of the socket with the height of the headwall, you will limit/reduce the lateral load transferred into the headwall by the top anchor rod (longer moment arm between tension at top of socket and compression at bottom of socket equals lower loads with same bending strength in post). Since it sounds like you are retrofitting the headwall to an existing box culvert, limiting the loads imparted to the headwall and the connection to the culvert is probably the best course of action.

Response

Response
(active)

Your proposed design, shown in the PDF "Preliminary Design", should work great as a retrofit to the original weak-post guardrail to culvert attachment system. By extending the length of the socket with the height of the headwall, you will limit/reduce the lateral load transferred into the headwall by the top anchor rod (longer moment arm between tension at top of socket and compression at bottom of socket equals lower loads with same bending strength in post). Since it sounds like you are retrofitting the headwall to an existing box culvert, limiting the loads imparted to the headwall and the connection to the culvert is probably the best course of action.

Date May 23, 2014
Previous Views (126) Favorites (0)