The prominence of bollards has dramatically increased during the past decade as a result of heightened concerns 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 popular for traffic direction and control, as well as in purely attractive applications. On the other hand, traffic bollards can serve many characteristics 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 allow 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 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, surveillance cameras, bicycle parking as well as seating. Decorative bollards are made in a number of patterns to harmonize with a variety of architectural styles. The prevalence of the very most 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 really a short vertical post. Early bollards were for mooring large ships at dock, plus they are still in use today. A typical 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 term bollard also describes a number of structures applied to streets, around buildings, and in landscaping. In accordance with 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. If the flow of former cannons was applied up, similarly shaped iron castings were designed to fulfill the same functions. Bollards have since evolved into many varieties that 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 simplest 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 many are cylindrical, sometimes using a domed, angled, or flat cap. They come in a number of metallic, painted, and durable powder coat finishes.
Removable bollards are used 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 so the bollard can be easily 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 count on how much they weigh rather than structural anchoring to remain in place. They are created to be moved rarely, then simply with heavy machinery for instance a fork-lift.
Bollards generally fall under three types 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 become an ornament. As standalone architectural or landscaping features, they could border, divide, or define a place. They may 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 one or more reveals near the top. Styles designed to match various historic periods normally have more elaborate shapes and surface details. Such as flutes, bands, scrolls as well as other ornamentation.The post-top is 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 using 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 steel, and concrete.
Ornamental designs with elaborate detail are often made from iron or aluminum casting. Aluminum bollards are desirable for applications where weight is a concern, such as a removable bollard. Aluminum units are usually a little more expensive than iron. For applications when a decorative bollard may be subjected to destructive impact, ductile iron is actually 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 usually manufactured by sand-casting – a traditional foundry technique which 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 appealing to the attention. If high-finish consistency is desired, seek a manufacturer that can machine 100% of the surface after casting to produce units having a uniform surface for maximum looks.
Finish is a vital consideration in a decorative bollard, from functional along with aesthetic standpoints. Bollards are, by their nature, susceptible to being scratched or nicked by pedestrians and vehicles. Those located near roadways are subjected to a reasonably aggressive environment; petrochemical residues and splashes of diluted road de-icing salts may compromise some painted finishes. Factory-applied powder coating – that is seen on iron, aluminum, and steel – is definitely an especially durable kind of painted finish. The applying 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 process that completes the finish gives it additional toughness and abuse resistance.
In applications where greater physical abuse is predictable, bollard covers made from aluminum can be a better choice than iron. In the event the finish coat is damaged, aluminum oxidizes to some color which is generally more acceptable compared to the red rust produced by iron. Aluminum and stainless-steel can also be found in a number of bare metal finishes. Functionality can be included in the otherwise decorative bollard. For instance, common choice is the chain eye – linking several bollards with chain, creating a simple traffic direction system. A large metal loop or arm on the side from the post allows parking and locking of bicycles, an increasingly popular choice as increasing numbers of 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 typical bollard applications are traffic direction and control, in addition to safety and security. The initial function is achieved from the visual presence in the bollards, and at some level by impact resistance, although, within these applications visual deterrence is definitely the primary function. Security and safety applications depend upon higher levels of impact resistance. The major difference between the 2 is safety designs are worried with stopping accidental breach of any 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 the two, as an example, allows easy passage for humans and human-powered vehicles – including wheelchairs or shopping carts – but prevents the passage of cars. Such installations are often seen before zcvjbu parking area entrance to some store, and also at the mouths of streets converted to outdoor malls or ‘walk streets’. In designing bollard installations for any site, care must be delivered to avoid locating them where they will turn into 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 type of bollards linked by a chain presents a visual cue never to cross the boundary, although it may be easy enough to get a pedestrian to travel over or beneath the chain when they choose. Bollards designed to direct traffic are often created to fold, deflect, or break away on impact.
Adding greater collision resistance allows a bollard to enforce traffic restrictions as opposed to 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 in the edge of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can actually redirect a vehicle back to the roadway when its wheels hit the bollard’s sloped sides.
These are employed where U-turns and tight-radius turns are frequent. This type of usage is particularly common at corners where vehicle drivers often misestimate turns, and pedestrians are especially close to the roadbed waiting to cross. In some cities, automatically retractable impact-resistant bollards are installed to manage the flow of traffic into an intersection. Internet videos of ‘bollard runners’ graphically demonstrate the strength of also a low post at stopping cars.