The prominence of bollards has dramatically increased during the past decade as a result of heightened fears about security. They are an easy, 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, as well as in purely attractive applications. On the other hand, bollard post can provide many characteristics beyond security. They can be used as 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 they are often organized to allow pedestrian access while preventing entry of vehicles.
Removable and retractable bollards can allow different amounts of access restriction for a number of circumstances. They frequently inform 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 our own building exteriors and surrounding areas. Bollards can incorporate other functions including lighting, security cameras, bicycle parking as well as seating. Decorative bollards are made in a selection of patterns to harmonize with an array 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 designed 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 generally still being used today. A typical marine bollard is produced in cast iron or steel and shaped somewhat just like a mushroom; the enlarged top is made to prevent mooring ropes from slipping off.
Today, the word bollard also describes many different structures applied to streets, around buildings, and in landscaping. In accordance with legend, the very first street bollards were actually cannons – sometimes reported to be captured enemy weapons – planted in the earth as boundary posts and town markers. When the flow of former cannons was used up, similarly shaped iron castings were created to match the same functions. Bollards have since evolved into many varieties that are widely employed on roads, especially in urban areas, in addition to outside supermarkets, restaurants, hotels, shops, government buildings and stadiums.
The most frequent form of bollard is fixed. The simplest 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 numerous decorative designs. Some feature square or rectangular cross-sections, but most 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 utilized 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 therefore the bollard can be easily 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 how much they weigh as opposed to structural anchoring to stay in place. They are created to be moved rarely, and then only with heavy machinery such as a fork-lift.
Bollards generally fall into three types of applications:
Decorative Bollards – decorative bollards for architectural 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 be 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 latter lean toward visual simplicity – often straight-sided posts with a number of reveals near 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 contrary, they 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 often made of iron or aluminum casting. Aluminum bollards are desirable for applications where weight is a concern, such as a removable bollard. Aluminum units tend to be a little more expensive than iron. For applications in which a decorative bollard may 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 frequently manufactured by sand-casting – a traditional foundry technique which is economical and well-suitable for objects this size. However, sand-cast objects frequently bear surface irregularities that often leave the finished product less appealing 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 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 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 available on iron, aluminum, and steel – is surely an especially durable type of painted finish. The application form process builds up a coating with very consistent coverage. During coating, any bare metal is likely to attract the powder, eliminating pinholes in coverage. The baking method that completes the conclusion gives it additional toughness and abuse resistance.
In applications where greater physical abuse is predictable, plastic bollards made of aluminum can be a better option than iron. In the event the finish coat is damaged, aluminum oxidizes to a color that is certainly generally more acceptable compared to the red rust made by iron. Aluminum and stainless-steel can also be found in a variety of bare metal finishes. Functionality may be included in the otherwise decorative bollard. As an example, common choice is the chain eye – linking two 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, including motion sensors or cameras.
Traffic and Safety Bollards
The most common bollard applications are traffic direction and control, along with security and safety. The first function is achieved by the visual presence from the bollards, and at some level by impact resistance, although, within these applications visual deterrence is definitely the primary function. Security and safety applications rely on higher degrees of impact resistance. The major difference between both is safety designs are involved 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, for instance, 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 in front of zcvjbu parking area 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 come to avoid locating them where they will likely turn into 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 line of bollards linked with a chain presents a visual cue never to cross the boundary, although it might be easy enough to get a pedestrian to go over or underneath the chain if 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 rather than merely suggesting them. Plain pipe bollards are often placed in the corners of buildings, or flanking lamp-posts, public phones, fire hydrants, gas pipes and other installations that need to be shielded from accidental contact. A bollard in the fringe of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can actually redirect a vehicle back onto the roadway when its wheels hit the bollard’s sloped sides.
They are employed where U-turns and tight-radius turns are frequent. This sort 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 a few 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 also a low post at stopping cars.