View Q&A

Temporary Barrier Rail and 6'' curb

Question
State	IA
Description Text	As shown in the attached detail, there will be 6’’ sloped curve adjacent to a paved shoulder with a permanent concrete barrier on top of it. The MSE wall in the detail will be under construction this winter and the Finished Grade Shoulder Pavement and the Barrier will not be in place. The plan right now is to place temporary barrier rail in front of the 6’’ sloped curb. This will be in a workzone with a 45mph speed limit and be in place for 5-6 months. We are assuming the temporary must be anchored. Are there any other concerns with the barriers potential interaction with the 6’’ sloped curb? Thanks,

Question

State

Description Text

As shown in the attached detail, there will be 6’’ sloped curve adjacent to a paved shoulder with a permanent concrete barrier on top of it. The MSE wall in the detail will be under construction this winter and the Finished Grade Shoulder Pavement and the Barrier will not be in place. The plan right now is to place temporary barrier rail in front of the 6’’ sloped curb. This will be in a workzone with a 45mph speed limit and be in place for 5-6 months. We are assuming the temporary must be anchored. Are there any other concerns with the barriers potential interaction with the 6’’ sloped curb?

Thanks,

System Performance Evaluation

System Types
Portable Barriers

Applications

System Features

Date November 6, 2018
Previous Views (122) Favorites (0)

Attachment 20181105161127008.pdf

Response
Response (active)	Typically we do not recommend installation of PCBs in front of curbs or other obstructions that limit translation of the back face of the barrier. The concern is that restraining the back of the barrier will cause the barrier to rotation rather than translation when impacted. This will tend to induce increased vehicle climb and stability on the toe and the sloped face of the barrier. Anchoring of the barrier will help reduce this significantly depending on the type of anchorage used. It is also less of a concern at the 45 mph speed you are using which corresponds to TL-2 speeds as compared to TL-3. We would generally recommend anchoring in this case to prevent the rotation. If you had the room, you could provide 24” between the back of the PCB and the curb to allow for translation and redirection prior to interaction with the curb. However, I don’t know what your space limitations are. Thanks

Response

Response
(active)

Typically we do not recommend installation of PCBs in front of curbs or other obstructions that limit translation of the back face of the barrier.

The concern is that restraining the back of the barrier will cause the barrier to rotation rather than translation when impacted. This will tend to induce increased vehicle climb and stability on the toe and the sloped face of the barrier.

Anchoring of the barrier will help reduce this significantly depending on the type of anchorage used.

It is also less of a concern at the 45 mph speed you are using which corresponds to TL-2 speeds as compared to TL-3.

We would generally recommend anchoring in this case to prevent the rotation.

If you had the room, you could provide 24” between the back of the PCB and the curb to allow for translation and redirection prior to interaction with the curb. However, I don’t know what your space limitations are.

Thanks

Date November 6, 2018
Previous Views (122) Favorites (0)