View Q&A

I was looking through previous tests in
order to find out how to best connect Temporary Jersey shape barrier to a
concrete jersey shape parapet and closest report to match this circumstance
that I could find is report TRP-03-208-10 Development of a Temporary Concrete Barrier to Permanent
Concrete Median Barrier Approach Transition.

We have quit a few
locations where this type of connection is made on older structures. Historically UDOT has made this
connection with two concrete barrier sections installed with stabilization pins
to help stiffen up the parapet to barrier connection.  Our Structures
division has a concern with how to make this connection without interfering
with the movement of the structure.

With larger structures we
are experiencing expansion and contraction causing deformation of the
connection pins at the parapet / barrier connection.

One thought is to install
a cast cast-in-place barrier section with an open joint between the CIP
barrier and parapet.  Maybe this is the best way to go. 

Are you aware of an option
for this type of connection? Or If not, what
are your thoughts for using the connection detail similar to report TRP-03-208-10? 

We here at MwRSF had a quick discussion on this topic this morning.  We agree that installing a short CIP/permanent parapet on the opposite site of an expansion joint before linking the PCB’s is an appropriate solution to eliminate issues with spanning across the joint. 

One note:  We have previously recommended that open joints in concrete barriers be limited to 4 inches (matching common PCB joints).  Open joints wider than 4” may lead to vehicle snag.  So, if your expansion/contraction joints will create openings greater than 4”, we would also recommend treating that gap with a cover plate to prevent snag.

Let me know if you have any further questions.

Thank you for your help.  Do you have a barrier foundation design that you could share that would work with a short CIP Jersey barrier design?  Also, if the barrier is cast on top of 9 inch thick concrete pavement would vertical steel epoxied into the pavement (P1 Bars) as shown on the attached drawing be acceptable?

You may have already looked at this drawing as it is part of our Standard Drawings that you are currently reviewing. 

I do not have a specific foundation for short installation lengths of concrete barriers.  However, a method of developing barrier foundations was previously put together in a TL-5 median barrier report – see TRP-03-210-07 Chapter 9 and Appendix C.  Anchoring to an existing 9” thick roadway slab should fine, assuming its much larger in footprint than the barrier.

Dowel bars epoxied into a concrete slab are common practice for anchoring concrete barriers.  That said, I do not think that 6” of embedment depth is adequate to develop a #8 bar (your P1 bars).  We have conducted previous testing that showed a #5 bar could be developed in 5.5” of embedment, but a #6 bar would pull out (concrete breakout failure).  For your 9” slabs and 6” embedment, I recommend utilizing a #5 dowel bar (which matches the stirrup steel size). Also, for short barrier installations (less than 20 ft) , I recommend placing the dowel anchorage bars adjacent to every barrier stirrup.  Thus, you would have the same bar size and spacing for both the dowel anchors and the barrier stirrups.