Today's barriers are capable of stopping and destroying a truck weighing up to 65,000 pounds and traveling at 50 mph. Such barricades can be raised or lowered at will to stop traffic or let it through. In an emergency, the thick steel plates or bollards pop out of the ground within one second.
A mobile barrier can be towed and set up in only 15 minutes. Nonetheless, it will stop a 15,000-pound (22.2 kN) vehicle going 40 mph (80 mph). For instance, deployable vehicle crash barriers helped the 4,000 police and military officers protecting participants at the Pittsburgh G-20 Summit. The totally self-contained barriers were towed into position and controlled vehicle access within 15 minutes. No excavation or sub-surface preparation was required. Once positioned, the mobile barricades unpacked themselves by using hydraulics to raise and lower themselves off their wheels. DC-powered pumps then raised or lowered the barriers.
In designing a barrier system, consider whether to use a passive or active system. Normally, an active system keeps the barrier in the active or up position. It must be deactivated to permit access. Active systems are preferable to ones that must be activated to prevent access because they are more secure.
One final area that should not be overlooked is aesthetics. With today's smart designs, it is no longer necessary to choose between form and function — end-users can have them both. Designers are creating secure environments with more compatible and aesthetically pleasing architectural elements.
Virtually unlimited in styles and aesthetics, safety consultants can specify having ornamental steel trim attached directly to a bollard or select cast aluminum, iron or bronze to slip over the crash tube. If damaged, the old sleeve simply slides off and a new one slips on. Designer bollards are available in stainless steel, cast stone, ceramics and epoxy-based stones. They can be fitted with an internal warning light for increased visibility and engineered to suit high traffic volumes.
In addition, highly customized designs can be added to the tops of bollards. For instance, those that protect California’s state capitol facilities in Sacramento include the Great Seal of the State of California, the Governor’s Seal, the Assembly Seal and the Senate Seal.
Bollard systems operate individually or in groups up to ten and are used for intermediate-level security applications. Individual bollards are up to 12.75 inches in diameter, up to 35 inches high and are usually mounted on 3-5 foot centers. Hydraulic versions can be operated by a variety of control systems. Manual versions are counter balanced and lock in the up or down position. They lower to allow passage of authorized vehicles. Bollards will stop vehicles dead in their tracks as they have been tested to stop and destroy an attacking vehicle weighing 10,000 pounds moving at 65 miles per hour or a 20,000-pound vehicle moving at 46 miles per hour.
High-security sliding gates, which will match the materials used in the perimeter fence, have been successfully full-scale tested to ASTM M50 and K12 standards, allowing no penetration of a 15,000 pound truck traveling 50 mph. Most customers want a shallow foundation to avoid underground utilities conflicts and significantly lower the time and cost of implementation.
For those organizations striving to create as green of an environment as possible, barriers, barricades, bollards and crash gates can be operated either manually or hydraulically on FDA-approved vegetable oils. There is also a growing trend to use electro-mechanical barricades.
David Dickinson is Senior Vice President, Delta Scientific