The prominence of bollards has dramatically increased during the past decade as a result of heightened concerns about security. They are a basic, practical, and cost-effective method of erecting anti-ram perimeter defense without creating a visual sense of a fortified bunker. Bollards are commonly used for traffic direction and control, as well as in purely decorative applications. However, bollard post can provide many features beyond security. They can be used for purely aesthetic purposes, functioning as landscaping elements. Bollards can create visible boundaries of a property, or split 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 degrees of access restriction for many different circumstances. They frequently tell us where we are able to 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 like lighting, security 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 form 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 to the required function.
What Exactly Is A Bollard?
A bollard is actually 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 just like a mushroom; the enlarged top is designed to prevent mooring ropes from slipping off.
Today, the word bollard also describes a number of structures used on streets, around buildings, and in landscaping. According to legend, the very first street bollards were actually cannons – sometimes said to be captured enemy weapons – planted in the ground as boundary posts and town markers. When the supply of former cannons was applied up, similarly shaped iron castings were created to match the same functions. Bollards have since evolved into many varieties which can be widely employed on roads, especially in urban areas, along with outside supermarkets, restaurants, hotels, shops, government buildings and stadiums.
The most common form of bollard is fixed. The most basic 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 in addition a wide variety of decorative designs. Some feature square or rectangular cross-sections, but many are cylindrical, sometimes having a domed, angled, or flat cap. They come in a variety of metallic, painted, and sturdy powder coat finishes.
Removable bollards are employed where the necessity 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 and so the bollard can easily be 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 how much they weigh as opposed to structural anchoring to remain in place. They are made to be moved rarely, then only with heavy machinery like a fork-lift.
Bollards generally belong to three types of applications:
Decorative Bollards – decorative bollards for architectural and landscaping highlights;
Traffic and Safety Bollards – bollards which provide asset and pedestrian safety, in addition to 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 can also be accents, sentries, or supporting players to larger, more dramatic architectural gesture.
Decorative bollards are produced to harmonize with both traditional and contemporary architectural styles. The second 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. 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 feature a simple rounded or slanted top to deter passersby from leaving trash or utilizing them for impromptu seating. On the other hand, these are sometimes made flat and broad specifically to encourage seating. Common decorative bollard materials include iron, aluminum, stainless steel, and concrete.
Ornamental designs with elaborate detail are frequently manufactured from iron or aluminum casting. Aluminum bollards are desirable for applications where weight is a problem, such as a removable bollard. Aluminum units are usually a little more expensive than iron. For applications in which a decorative bollard might be subjected to destructive impact, ductile iron is really a safer choice than more brittle metals, as force will deform the metal rather than shatter and transforming it into possible hazardous flying projectiles.
Iron and aluminum bollards are frequently manufactured by sand-casting – a regular foundry technique that is certainly economical and well-fitted to objects this size. However, sand-cast objects frequently bear surface irregularities that tend to leave the finished product less attractive to the eye. If high-finish consistency is desired, seek a manufacturer that will machine 100% from the surface after casting to create units having a uniform surface for maximum visual appeal.
Finish is an important consideration in a decorative bollard, from functional in addition to aesthetic standpoints. Bollards are, by their nature, vulnerable to being scratched or nicked by pedestrians and vehicles. Those located near roadways are in contact with a reasonably 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 surely an especially durable form of painted finish. The applying process builds up 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 conclusion gives it additional toughness and abuse resistance.
In applications where greater physical abuse is predictable, bollard cover made of aluminum can be a better choice than iron. When 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 variety of bare metal finishes. Functionality could be added to the otherwise decorative bollard. For example, common choice is the chain eye – linking 2 or more bollards with chain, making a simple traffic direction system. A large 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 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 security and safety. The very first function is achieved from the visual presence of the bollards, and to some degree by impact resistance, although, in these applications visual deterrence is the primary function. Safety and security applications depend on higher amounts of impact resistance. The key difference between both is safety designs are concerned with stopping accidental breach of the 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 them, as an example, allows easy passage for humans and human-powered vehicles – like wheelchairs or shopping carts – but prevents the passage of cars. Such installations tend to be seen facing zcvjbu car park entrance to a store, as well as at the mouths of streets transformed into outdoor malls or ‘walk streets’. In designing bollard installations for a site, care has to be taken to avoid locating them where they will likely 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 a chain presents a visual cue not to cross the boundary, although it could be easy enough for a pedestrian to travel over or beneath the chain when they choose. Bollards made to direct traffic are occasionally designed 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 usually placed on 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 in the side of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can in fact 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 sort of usage is extremely 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 also a low post at stopping cars.