The popularity of bollards has dramatically increased during the past decade because of heightened concerns about security. They are a simple, practical, and cost-effective means of erecting anti-ram perimeter defense without developing a visual sense of a fortified bunker. Bollards are widely used for traffic direction and control, and in purely decorative applications. However, decorative bollards can serve many features beyond security. They can be used purely aesthetic purposes, functioning as landscaping elements. Bollards can create visible boundaries of any property, or separate areas within sites. They can control traffic and are often organized to permit pedestrian access while preventing entry of vehicles.
Removable and retractable bollards can allow different levels of access restriction for a number of 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 such as lighting, surveillance cameras, bicycle parking as well as seating. Decorative bollards are produced in a variety of patterns to harmonize with a variety of architectural styles. The prevalence of the very common kind of security bollard, the concrete-filled steel pipe, has encouraged the manufacturing of decorative bollards designed to fit as covers over standard steel pipe sizes, adding pleasing form to the required function.
What Exactly Is A Bollard?
A bollard is really a short vertical post. Early bollards were for mooring large ships at dock, and they are generally still in use today. An average marine bollard is manufactured 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 used on streets, around buildings, and in landscaping. Based on legend, the very first street bollards were actually cannons – sometimes said to be captured enemy weapons – planted in the earth as boundary posts and town markers. Once the supply of former cannons was applied up, similarly shaped iron castings were created to fulfill the same functions. Bollards have since become many varieties which are widely employed on roads, specifically in urban areas, along with outside supermarkets, restaurants, hotels, shops, government buildings and stadiums.
The most frequent form of bollard is fixed. The easiest is surely an unaesthetic steel post, about 914 to 1219 mm (36 to 48 in.) above-grade. Specially manufactured bollards include not merely simple posts, but additionally a multitude of decorative designs. Some feature square or rectangular cross-sections, but many are cylindrical, sometimes with a domed, angled, or flat cap. They are offered in a variety of metallic, painted, and sturdy 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 often needed, and therefore are designed so the bollard can be simply 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 count on their weight as opposed to structural anchoring to remain in place. They are created to be moved rarely, and after that only with heavy machinery for instance a fork-lift.
Bollards generally fall under three varieties of applications:
Decorative Bollards – decorative bollards for architectural or landscaping highlights;
Traffic and Safety Bollards – bollards that provide asset and pedestrian safety, along with 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 an area. They may also 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 near the top. Styles created to match various historic periods will often have more elaborate shapes and surface details. Such as flutes, bands, scrolls and other ornamentation.The post-top is actually a distinctive feature; traditional bollard design often includes elaborate decorative finials, whereas contemporary versions frequently come with a simple rounded or slanted top to discourage passersby from leaving trash or making use of them for impromptu seating. On the contrary, they may be 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 from iron or aluminum casting. Aluminum bollards are desirable for applications where weight is an issue, like a removable bollard. Aluminum units are generally slightly more expensive than iron. For applications in which a decorative bollard might be subject 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 economical and well-fitted to objects this size. However, sand-cast objects frequently bear surface irregularities that have a tendency to leave the finished product less attractive to the eye. If high-finish consistency is desired, seek a manufacturer which will machine 100% from the surface after casting to generate units having a uniform surface for optimum visual appeal.
Finish is an important consideration in a decorative bollard, from functional as well as aesthetic standpoints. Bollards are, by their nature, vulnerable 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 an especially durable type of painted finish. The application form process builds a coating with very consistent coverage. During coating, any bare metal has a tendency to attract the powder, eliminating pinholes in coverage. The baking process that completes the finish gives it additional toughness and abuse resistance.
In applications where greater physical abuse is predictable, bollard covers 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 than the red rust created by iron. Aluminum and stainless-steel can also be found in a quantity of bare metal finishes. Functionality can be added to the otherwise decorative bollard. For instance, common choice is the chain eye – linking 2 or more bollards with chain, making 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 increasing numbers of people seek alternative green transportation. Bollards might 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, along with safety and security. The initial function is achieved through the visual presence in the bollards, and at some level by impact resistance, although, in these applications visual deterrence will be the primary function. Safety and security applications depend on higher degrees of impact resistance. The major distinction between the 2 is safety designs are involved with stopping accidental breach of the defined space, whereas security is 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 them, for instance, 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 in front of zcvjbu car park entrance to some store, and at the mouths of streets changed into outdoor malls or ‘walk streets’. In designing bollard installations to get a site, care must be delivered 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 you should not require impact resistance. A type of bollards linked with a chain presents a visual cue never to cross the boundary, even though it might be easy enough to get a pedestrian to go over or under the chain should they choose. Bollards created to direct traffic are sometimes created to fold, deflect, or break away on impact.
Adding greater collision resistance allows a bollard to enforce traffic restrictions rather than merely suggesting them. Plain pipe bollards are frequently placed in the corners of buildings, or flanking lamp-posts, public phones, fire hydrants, gas pipes as well as other installations that need to be protected from accidental contact. A bollard on the edge of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can actually redirect an automobile back to the roadway when its wheels hit the bollard’s sloped sides.
They are employed where U-turns and tight-radius turns are frequent. This type 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 a few 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 even a low post at stopping cars.