The popularity of bollards has dramatically increased during the past decade because of heightened fears about security. They are an easy, practical, and cost-effective way of erecting anti-ram perimeter defense without creating a visual sense of a fortified bunker. Bollards are widely used for traffic direction and control, as well as in purely decorative applications. However, security bollards can offer many characteristics beyond security. They can be used as purely aesthetic purposes, functioning as landscaping elements. Bollards can make visible boundaries of a property, or split areas within sites. They can control traffic and are often arranged to permit pedestrian access while preventing entry of vehicles.
Removable and retractable bollards can allow different degrees of access restriction for many different circumstances. They frequently inform us where we can and cannot drive, park, bike, or walk, protect us from crime, shield vehicles and property from accidents, and add aesthetic features to the building exteriors and surrounding areas. Bollards can incorporate other functions including lighting, surveillance cameras, bicycle parking or even seating. Decorative bollards are created in a selection of patterns to harmonize with a wide range of architectural styles. The prevalence of the very common type of security bollard, the concrete-filled steel pipe, has encouraged the manufacturing of decorative bollards created to fit as covers over standard steel pipe sizes, adding pleasing form for the required function.
What Is A Bollard?
A bollard is a short vertical post. Early bollards were for mooring large ships at dock, and they are still in use today. A normal marine bollard is produced in cast iron or steel and shaped somewhat just like a mushroom; the enlarged top was created to prevent mooring ropes from slipping off.
Today, the word bollard also describes a variety of structures applied to streets, around buildings, as well as in landscaping. In accordance with legend, the initial street bollards were actually cannons – sometimes reported to be captured enemy weapons – planted in the ground as boundary posts and town markers. Once the availability of former cannons was applied up, similarly shaped iron castings were designed to fulfill the same functions. Bollards have since become many varieties that are widely employed on roads, especially in urban areas, as well as outside supermarkets, restaurants, hotels, shops, government buildings and stadiums.
The most common kind of bollard is fixed. The most basic is definitely an unaesthetic steel post, about 914 to 1219 mm (36 to 48 in.) above-grade. Specially manufactured bollards include not only simple posts, but in addition a multitude of decorative designs. Some feature square or rectangular cross-sections, but most are cylindrical, sometimes using a domed, angled, or flat cap. They are offered in a variety of metallic, painted, and durable powder coat finishes.
Removable bollards are used where the requirement to limit access or direct traffic changes occasionally. Both retractable and fold-down styles are employed where selective entry is frequently needed, and therefore are designed therefore the bollard can easily be collapsed to ground level and quickly re-erected. Both retractable units may be manually operated or automated with hydraulic movements. Movable bollards are large, heavy objects – frequently stone or concrete – that rely on their weight rather than structural anchoring to remain in place. They are made to be moved rarely, and then only with heavy machinery for instance a fork-lift.
Bollards generally fall under three types of applications:
Decorative Bollards – decorative bollards for architectural and/or landscaping highlights;
Traffic and Safety Bollards – bollards that offer asset and pedestrian safety, as well as traffic direction; and
Security Bollards and Post Covers – decorative, impact-resistant bollard enhancements
Some bollards are intended purely to become an ornament. As standalone architectural or landscaping features, they could border, divide, or define a place. They can be accents, sentries, or supporting players to larger, more dramatic architectural gesture.
Decorative bollards are manufactured to harmonize with both traditional and contemporary architectural styles. The latter lean toward visual simplicity – often straight-sided posts with several reveals nearby the top. Styles made to match various historic periods usually have more elaborate shapes and surface details. These include flutes, bands, scrolls and other ornamentation.The post-top is a distinctive feature; traditional bollard design often includes elaborate decorative finials, whereas contemporary versions frequently feature a simple rounded or slanted top to discourage passersby from leaving trash or utilizing them for impromptu seating. On the contrary, these are sometimes made flat and broad specifically to encourage seating. Common decorative bollard materials include iron, aluminum, stainless, and concrete.
Ornamental designs with elaborate detail are frequently made of iron or aluminum casting. Aluminum bollards are desirable for applications where weight is a problem, for instance a removable bollard. Aluminum units tend to be a little more expensive than iron. For applications when a decorative bollard could be subjected to destructive impact, ductile iron is a safer choice than more brittle metals, as force will deform the metal instead of shatter and transforming it into possible hazardous flying projectiles.
Iron and aluminum bollards are frequently manufactured by sand-casting – a conventional foundry technique that is certainly economical and well-fitted to objects this size. However, sand-cast objects frequently bear surface irregularities that often leave the finished product less appealing to the eye. If high-finish consistency is desired, seek a manufacturer which will machine 100% in the surface after casting to produce units having a uniform surface for maximum appearance.
Finish is a vital consideration in a decorative bollard, from functional as well as aesthetic standpoints. Bollards are, by their nature, prone to being scratched or nicked by pedestrians and vehicles. Those located near roadways are exposed to a fairly aggressive environment; petrochemical residues and splashes of diluted road de-icing salts may compromise some painted finishes. Factory-applied powder coating – which is seen on iron, aluminum, and steel – is definitely an especially durable type of painted finish. The application process increases a coating with very consistent coverage. During coating, any bare metal has a tendency to attract the powder, eliminating pinholes in coverage. The baking method that completes the finish gives it additional toughness and abuse resistance.
In applications where greater physical abuse is predictable, plastic bollard made of aluminum might be a better choice than iron. In the event the finish coat is damaged, aluminum oxidizes to your color that is certainly generally more acceptable compared to the red rust created by iron. Aluminum and stainless-steel can also be found in a variety of bare metal finishes. Functionality may be put into the otherwise decorative bollard. For example, common option is the chain eye – linking 2 or more bollards with chain, developing a simple traffic direction system. A sizable metal loop or arm on the side in the post allows parking and locking of bicycles, an increasingly popular choice as more people seek alternative green transportation. Bollards may also contain lighting units or security devices, like motion sensors or cameras.
Traffic and Safety Bollards
The most frequent bollard applications are traffic direction and control, together with security and safety. The first function is achieved through the visual presence of the bollards, and at some level by impact resistance, although, in these applications visual deterrence is definitely the primary function. Safety and security applications rely on higher degrees of impact resistance. The major distinction between both is safety designs are worried with stopping accidental breach of any defined space, whereas security is all about stopping intentional ramming.
Closely spaced lines of bollards can form a traffic filter, separating motor vehicles from pedestrians and bicycles. Placing the posts with 1 m (3 ft) of clearance between the two, as an example, allows easy passage for humans and human-powered vehicles – such as wheelchairs or shopping carts – but prevents the passage of cars. Such installations are frequently seen facing zcvjbu car park entrance to some store, as well as at the mouths of streets changed into outdoor malls or ‘walk streets’. In designing bollard installations to get a site, care has to be taken to avoid locating them where they will be a navigational hazard to authorized vehicles or cyclists.
Some applications for traffic guidance depend on the cooperation of drivers and pedestrians and never require impact resistance. A line of bollards linked by way of a chain presents a visual cue to not cross the boundary, even though it might be easy enough to get a pedestrian to travel over or beneath the chain when they choose. Bollards designed to direct traffic are often made to fold, deflect, or break away on impact.
Adding greater collision resistance allows a bollard to enforce traffic restrictions instead of merely suggesting them. Plain pipe bollards are often placed at the corners of buildings, or flanking lamp-posts, public phones, fire hydrants, gas pipes along with other installations that need to be shielded from accidental contact. A bollard at the fringe of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can certainly redirect a vehicle back to the roadway when its wheels hit the bollard’s sloped sides.
They may be employed where U-turns and tight-radius turns are frequent. This kind of usage is especially common at corners where vehicle drivers often misestimate turns, and pedestrians are specifically close to the roadbed waiting to cross. In certain cities, automatically retractable impact-resistant bollards are installed to regulate the flow of traffic into an intersection. Internet videos of ‘bollard runners’ graphically demonstrate the potency of a low post at stopping cars.