A short post being used to protect a perimeter called the bollard. The term bollard basically indicates a post on a ship which is being used for mooring boats .These are of wide variety of shapes and styles ,and can be made of almost any material, depending on the need, including metal, stone, cement, or plastic.
Bollards are being installed to control road traffic, mainly prevent automotive vehicle collision, guiding traffic away from pedestrians and property. It is one crucial part for the building perimeter planning for engineers as part of their security plans. Greater vehicle activity can make an area prone to accident. Higher speeds tend to reduce driver reaction times and in turn increases vehicle momentum, thus increases the damage potential.
The advanced crash- or k-rated bollards are being used to protect against criminal attacks. Vehicle ram-raids are a big concern, where to gain access the thieves crash a vehicle directly into a building that threatens the safety of employees and customers. The damage can be fatal if the building is occupied. The terrorist attacks can happen to government or financial buildings, or buildings that accommodate a large number of people The use of explosives or vehicle ramming attacks are common methods for this where we need this crash rated bollards .
These are special types advanced bollards being used for designing of the protection of high-target buildings from criminal vehicular attack.
It is being installed at a secured distance that it can prevent any criminal terrorist attack, in such a way that it can save the building from getting damaged. They are often placed to ensure a wide safe zone around a vulnerable perimeter. A staggered or unpredictable pattern of installation makes them more effective to prevent such attack.
They are becoming an ever growing market as an element of city and security planning, and are mandatory for many government or military installations. For some city the anti-terrorist crash-rated bollards are quintessential for “High and Medium Tier” buildings that are vulnerable of exceptional threat, vulnerability and impact characteristics.
It is very important for the bollards to pass live testing. They need to resist a payload of 15,000-lb without exceeding set penetration .Depending on the distances based on the vehicle speeds they can stop they have been categorized ,such as K12, K8, and K4 for 50 mph, 40 mph, and 30 mph respectively.
Crash-rated bollards are generally made of steel pipes filled with concrete and are often quite a bit expensive and require specialized installation teams and methods.
Here if the steel pipes used are plain, it can be covered to fit its architectural surroundings. Bollard covers can be of various materials, such as ductile iron, cast iron, steel, concrete, and plastic depending on the location and the look. Here the plastic or steel are mostly used in crash-rated covers.
These security bollards are being usually grounded several feet below grade and fixed in place with concrete. It often comes with additional sub grade footings which are made of steel.
For the areas where the underground utilities or structures that prevent deep mounting, shallow mounted crash-rated bollards can be used. These are being installed with a beam system to connect multiple bollards in an underground lattice. These can be spread widely like the roots of a tree, such a way that it provides impact stability.
Errant vehicles can cause fatal and sometimes irreversible damage upon impact not only with a building but also to pedestrians and occupants. So it is crucial to safeguard the surrounding driving environment to understand how a building and its occupants may be threatened.
There are generally two referenced rating systems for crash rated bollards K-ratings and ASTM standards.
- Government Building
- Defense Facility