Part of the Military deployment to the Border, that was ordered by President Trump, is a steady effort at emplacing concertina.
The ongoing Military deployment has been extended through the end of this fiscal year (30 September 2020), and seems likely to be renewed beyond then, as it was in past years under President Trump.
This year, the Military is expected to emplace several hundred miles of concertina. Typically, three or six miles of concertina goes for one mile of bollard barrier (3 or 6 rolls).
The Military will typically come along to string the concertina a few months after contractors have completed new bollards, and Government contracting Specialists have officially accepted the bollards as complete and to spec, closing out the contract deliverable. Then they can be sure that no re-working will be required, and the different crews don't get in each other's way.
Here is an example from Calexico, CA, where the first segment completed in the Trump Program (30 foot bollards) has been augmented with additional concertina. It is a very effective and long lasting, low maintenance upgrade, to deter and defeat ladder and rope climbing attempts. This segment in Calexico, which formerly led the Nation in assaults on Border Patrol officers, has been transformed by this new barrier. A secondary barrier (also 30 foot bollards) has already been contracted to run 150 feet behind this one, with a highly monitored, alarmed and policed "enforcement zone" between the barriers. Door closed.
Walls Work, and Super Walls, Super Work.