This questions stems from one of the biggest misconceptions out there regarding bollards. Most people fill the bollards with cement. Why? Does anyone have the answer? Mostly because it has always been done that way. Does it provide more strength?
Throughout my career, I have sold upwards of 25,000 bollards. That’s a lot of bollards. I have spoken to many engineers and have asked them this very question: Is a bollard stronger with or without cement? Every engineer I have spoken with told me that the bollard is stronger WITHOUT cement. Yet, bollards are being filled with cement every day. Mostly because it has always been done that way.
Filling a bollard with cement causes at least two problems. First, cement is wet. What happens when steel is exposed to wetness? It rusts. Second, if an impact occurs, you want the bollard to absorb the impact. With cement, it doesn’t absorb the impact, it breaks off at its weakest point, usually at the bottom of the bollard. Why? Because that is where it has rusted. We have all seen a bollard that has been hit and uprooted from the ground. The break is always at its weakest point, which is at grade.
Most bollard installations are core drilled. That means they are installed like a fence post. Dig a hole, drop in the bollard, fill it with cement, and fill in the hole with cement. That works well with a chain link fence post. It doesn’t work well with bollards. Chain link fences are not designed to stop a car. They are designed to keep people out of an area. How many times have we seen a car run through a chain link fence on TV? That’s not Hollywood magic. It easily happens.
When protecting your most valuable assets, hopefully you wouldn’t simply dig a hole and drop in any old piece of pipe, fill it with cement, and call it a bollard. You may as well have nothing there for the good it would do. You need to have a solid footing with the proper pipe diameter and wall thickness to be able to actually stop a car.
No one has ever filled a removable bollard with cement. That’s because cement makes the bollard too heavy to remove easily. And yet, I have not seen a removable bollard fail in the field yet. Coincidence? I think not. I have crash tested bollards NOT filled with cement, which have stopped a 15,000 lb. vehicle traveling at 50 mph. The vehicle is stopped dead in its tracks. Would filling it with cement stopped it better? I doubt it. Does it matter? No. The vehicle stopped.
Try this experiment. Take a wooden dowel 1/8” thick and push it into a plastic straw. Seems pretty robust, correct? Now break it in half. What happens? Not only does the dowel snap, so does the straw. If you bend the straw by itself, it will not break in two. With the dowel inside the straw, the straw has nowhere to bend, so it snaps. The theory and principles are the same with steel. Of course, the steel is bigger and thicker, but so is a 2500 lb. vehicle traveling at 10 mph. or more.
When placing bollards in the ground, you are typically protecting something, such as electrical panels, sides of buildings, loading docks, or front doors. And most importantly, you’re protecting people or customers that frequent your stores and pay your bills. Don’t place a perfectly good bollard in front of your store to protect your valuable assets only to fill it with cement. Not only will it weaken the bollard, in a couple of months, the rust that forms will leave ugly stains on your front sidewalk.
>Have you ever sat at an outside patio drinking your 5.00 cup of coffee and the only protection is a bolted down wrought iron fence? Have you ever looked at the bolts on that wrought iron? Most are rusted out and can be pulled up by hand. Is that protection?
Those of us that work in this industry owe it to each other to do the right thing. Nothing is worse than the feeling of implied safety when in fact there is little to no safety at all. We owe it to ourselves to protect our people and assets by being educated when it comes to security measures. Pouring cement into bollards just because it is what we always did is not being responsible. If that were the case in all scenarios, perhaps we should still use leeches to ward off disease.
Stop putting cement into bollards. It will save money on unnecessary cement and labor costs, and most importantly, it will save lives.
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