Should Protective Bollards be Concrete Filled?
One question often asked when established a protected area from vehicles, should my bollards be concrete filled? Many times this question isn’t even asked, the simple assumption is that bollards should be filled with concrete to make them stronger.
The real answer to this question isn’t that simple, however. One of the most common bollard installations are concrete filled bollard barriers used in conjunction with an HDPE bollard cover. While concrete does strengthen the post to a degree; making it stiffer and less likely to bend during a light impact it can actually make it more likely to fail during a significant vehicle incursion.
TrafficGuard® representatives theorized that if a schedule 40, 4” bollard was struck hard enough, not only would it fail but would fail totally, snapping at its base and allowing a vehicle to run through almost unabated. In 2017, TrafficGuard® installed the 4”, concrete filled bollard at the test track at the Texas A&M Transportation Institute. Utilizing the 5,000 lb. re-useable test vehicle, a test was run to determine the security bollards ability to stop it at 20 MPH. The result was a complete failure as can be seen in the test video below:
What TrafficGuard® has come to learn through crash testing various bollards a various speeds is that a hollow bollard is allowed bend and absorb impact, while a filled bollard is not, with dramatically different results. That is not to say all concrete filled bollards are not viable for particular applications, such as protecting building corners from low speed glancing contact. However, for applications where a direct run up may occur, they can be completely ineffective if struck.