Temporary Movable (“Zipper”) Barrier systems in work zones
Michigan has used the movable barrier wall on 4 or 5 projects in work zones. The state has used these on freeways where traffic is switched from one side of the road to the other. The zipper wall is placed between the lanes of traffic and is moved two times a week to give the motorists more lanes in one direction or the other. For a 8 mile project the wall is moved from one lane to the other in 45 minutes.
These were used once where the freeway was shut down for the weekend. Permanent median barrier wall was removed and during the week, the zipper sat in its place. When the freeway was closed, the contractor moved the zipper out of the way and started working.
The “zipper” barrier systems are layed out just like the temporary concrete barrier wall. The Special Provision for Movable Concrete Traffic Barrier, which can be found in the given website, utilized when using the zipper wall on a project.
Special devices that are used with the barrier installations:
– Refer to the special provisions (on the web site below). The reflectors are sometimes broken off by the transfer machine when placed as barrier systems suggest. By using the reflectors specified, especially the Bunzl Extrusion PCBM T-12, there is almost 100 percent retention through the life of a construction season.
– The other device needed is an impact attenuator. The Barrier System Absorb 350 works well with the zipper wall.
– The barrier system provides a special device that is hooked to a crane to help unload the segments of wall from a truck and put the segment in place.