View Q&A

We are evaluating a proposal submitted by one of our
District offices regarding placement of temporary concrete barrier (TCB) across
and on both ends of a bridge deck. We have some questions about options for
transitioning the TCB once it leaves the bridge deck.

1.      
Section B-B in the attachment complies with
internal guidance to provide 2.0’ between the back of TCB and the curb on the
bridge deck. This scenario could be for freestanding TCB, or at most, short
pins (approximately 4.5” embedment into the bridge deck) could be provided.

2.      
Section A-A does not comply with internal
guidance since we indicate that the face of the TCB should be between 2” and 1’
from the face of the guardrail; and the underlying surface on which the TCB
rests needs to be paved and in the same plane extending to the face of the
guardrail.

We feel that the TCB could be shortened by using a taper of
not steeper than 1:12 once the installation is off of the bridge deck. At that
point a section or two could be placed parallel to the guardrail and the end
units could be anchored to the underlying paved shoulder using anchor pins in
all six holes. Placement of a Test Level 3 (the posted speed on the roadway is
55 mph) temporary narrow, redirective impact attenuator would be required at
both ends.

A.     
Are there any transition devices available that would
allow another option for realigning the guardrail to attach to the TCB on both
ends? We could anchor the end unit of the TCB into the underlying paved
shoulder (or we could anchor multiple units, provided that they are not on the
bridge deck, since our Bureau of Bridges and Structures does not allow
anchoring on bridge decks). Such an arrangement would not require temporary
impact attenuators on both ends; however, we are unaware of potential
performance issues for TL 3 connecting guardrail to TCB.

B.     
Are there other options that we might consider?

Any thoughts or guidance that you could provide would be appreciated.