minimum offset for concrete traffic barrier

[evett]

What is the minimum offset for concrete traffic barrier in a work zone application?
I have a 6 lane divided interstate bridge replacement project where the traffic will be shifted on to a single existing bridge while the proposed bridge is constructed and the opposing lanes will be separated by concrete traffic barrier. The work zone speed limit is 55 mph and the ADT is 50000. In the lane shift area the existing lanes will be narrowed from three 12-foot lanes in each direction to three 10-foot lanes in each direction. My question is how close to the outside lane line can I place the concrete traffic barrier?

 

[dicksewerrat]

Check with the DOT. They will have specs for this.

 

[wolfhnd]

Make sure you consider the fact that distance to barrier effect accident rates and capacity.

 

[ACtrafficengr]

The shy distance will be about 2'.

If you want to look at safety, the new RSAP software will help calcuate expected crash costs. It's on the Transportation Research Board website

 

[wolfhnd]

Why the shy distance may be about 2' the barrier will effect capacity up to 6' of clearance. I have always used Barrier which shipped with the roadside package to calculate crash rates. You will have to get the accident cost data for you institution it varies substatially from area to area. In construction zones I have used as little as 10' between barriers. If you go less than that heavy trucks will have to be detoured. Please give us more information about what you are doing. Traffic volume lane widths etc.

 

[ACtrafficengr]

Also don't forget that temporary barrier will deflect when hit, unless it's pinned and grouted down.

 

[wolfhnd]

Jim do you have details for anchoring the barrier and what type barrier. We just upgraded from the old cable joints to a pinned joint.

 

[ACtrafficengr]

When minimal deflection is required, NYSDOT grouts between sections, and pins the barrier to the deck or ground. NYSDOT spec's holes on the lower slopes to pin the barrier to the deck, and I-beam joints.

Their standard sheets are on-line here:

http://dotweb2.dot.state.ny.us/caddinfo/design/stdsheets/stdsht.html#S606

 

[wolfhnd]

Thank You