The prominence of bollards has dramatically increased during the past decade as a result of heightened fears about security. These are an easy, practical, and cost-effective method of erecting anti-ram perimeter defense without developing a visual sense of a fortified bunker. Bollards are widely used for traffic direction and control, as well as in purely decorative applications. On the other hand, safety bollards can serve many functions beyond security. They can be used purely aesthetic purposes, functioning as landscaping elements. Bollards can create visible boundaries of a property, or separate areas within sites. They can control traffic and are often set up 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 tell us where we could and cannot drive, park, bike, or walk, protect us from crime, shield vehicles and property from accidents, and add aesthetic features to our building exteriors and surrounding areas. Bollards can incorporate other functions including lighting, security cameras, bicycle parking or perhaps seating. Decorative bollards are produced in a number of patterns to harmonize with a wide range of architectural styles. The prevalence of the very common form of security bollard, the concrete-filled steel pipe, has encouraged the manufacturing of decorative bollards made to fit as covers over standard steel pipe sizes, adding pleasing form towards the required function.
What Exactly Is A Bollard?
A bollard is a short vertical post. Early bollards were for mooring large ships at dock, and they are generally still in use today. A normal marine bollard is manufactured in cast iron or steel and shaped somewhat such as a mushroom; the enlarged top is designed to prevent mooring ropes from slipping off.
Today, the phrase bollard also describes many different structures applied to streets, around buildings, and then in landscaping. According to legend, the initial street bollards were actually cannons – sometimes reported to be captured enemy weapons – planted in the earth as boundary posts and town markers. When the supply of former cannons was applied up, similarly shaped iron castings were made to fulfill the same functions. Bollards have since become many varieties which are widely employed on roads, especially in urban areas, in addition to outside supermarkets, restaurants, hotels, shops, government buildings and stadiums.
The most frequent type of bollard is fixed. The easiest is an unaesthetic steel post, about 914 to 1219 mm (36 to 48 in.) above-grade. Specially manufactured bollards include not merely simple posts, but also a wide variety of decorative designs. Some feature square or rectangular cross-sections, but a majority of are cylindrical, sometimes using a domed, angled, or flat cap. They come in a selection of metallic, painted, and durable powder coat finishes.
Removable bollards are used where the need to limit access or direct traffic changes occasionally. Both retractable and fold-down styles are employed where selective entry is often needed, and are designed therefore the bollard can be simply collapsed to ground level and quickly re-erected. Both retractable units might be manually operated or automated with hydraulic movements. Movable bollards are large, heavy objects – frequently stone or concrete – that depend on their weight rather than structural anchoring to remain in place. They are created to be moved rarely, then just with heavy machinery for instance a fork-lift.
Bollards generally fall under three varieties of applications:
Decorative Bollards – decorative bollards for architectural and 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 be an ornament. As standalone architectural or landscaping features, they are able to border, divide, or define a space. They can be accents, sentries, or supporting players to larger, more dramatic architectural gesture.
Decorative bollards are made to harmonize with both traditional and contemporary architectural styles. The latter lean toward visual simplicity – often straight-sided posts with several reveals close to the top. Styles designed to match various historic periods will often have more elaborate shapes and surface details. Such as flutes, bands, scrolls along with 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 deter passersby from leaving trash or utilizing them for impromptu seating. On the other hand, 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 usually made from iron or aluminum casting. Aluminum bollards are desirable for applications where weight is a problem, such as a removable bollard. Aluminum units tend to be slightly more expensive than iron. For applications where a decorative bollard could be subject to destructive impact, ductile iron is a safer choice than more brittle metals, as force will deform the metal as opposed to shatter and transforming it into possible hazardous flying projectiles.
Iron and aluminum bollards are usually manufactured by sand-casting – a traditional foundry technique that is certainly economical and well-suited to objects this size. However, sand-cast objects frequently bear surface irregularities that tend to leave the finished product less attractive to the attention. If high-finish consistency is desired, seek a manufacturer that will machine 100% of the surface after casting to produce units with a uniform surface for maximum visual appeal.
Finish is a crucial consideration in a decorative bollard, from functional along with aesthetic standpoints. Bollards are, by their nature, prone to being scratched or nicked by pedestrians and vehicles. Those located near roadways are subjected to a fairly aggressive environment; petrochemical residues and splashes of diluted road de-icing salts may compromise some painted finishes. Factory-applied powder coating – that is on iron, aluminum, and steel – is an especially durable kind of painted finish. The application form process builds up a coating with very consistent coverage. During coating, any bare metal tends 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, bollard cover manufactured from aluminum may be a better choice than iron. In the event the finish coat is damaged, aluminum oxidizes to a color which is generally more acceptable compared to the red rust produced by iron. Aluminum and stainless are also available in a variety of bare metal finishes. Functionality may be put into the otherwise decorative bollard. As an example, common option is the chain eye – linking 2 or more bollards with chain, creating a simple traffic direction system. A sizable metal loop or arm on the side of the post allows parking and locking of bicycles, an increasingly popular choice as more people seek alternative green transportation. Bollards could 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 safety and security. The initial function is achieved through the visual presence from the bollards, and to some degree by impact resistance, although, in these applications visual deterrence is the primary function. Security and safety applications rely on higher levels of impact resistance. The key difference between the 2 is safety designs are involved with stopping accidental breach of any defined space, whereas security is approximately 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 tend to be seen facing zcvjbu parking area 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 must be taken to avoid locating them where they are going to become 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 collection of bollards linked by way of a chain presents a visual cue never to cross the boundary, even though it might be easy enough to get a pedestrian to visit over or under the chain when they choose. Bollards made to direct traffic are often designed 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 in the corners of buildings, or flanking lamp-posts, public phones, fire hydrants, gas pipes along with other installations that need to be protected against accidental contact. A bollard on the fringe of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can in fact redirect an automobile 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 particularly common at corners where vehicle drivers often misestimate turns, and pedestrians are specifically near to the roadbed waiting to cross. In certain cities, automatically retractable impact-resistant bollards are installed to control the flow of traffic into an intersection. Internet videos of ‘bollard runners’ graphically demonstrate the effectiveness of even a low post at stopping cars.