The prominence of bollards has dramatically increased during the past decade due to heightened worries about security. They are a simple, practical, and cost-effective method of erecting anti-ram perimeter defense without developing a visual sense of a fortified bunker. Bollards are commonly used for traffic direction and control, and in purely decorative applications. On the other hand, plastic safety bollards can provide many characteristics beyond security. They can be used purely aesthetic purposes, functioning as landscaping elements. Bollards can make visible boundaries of any 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 degrees of access restriction for a variety of circumstances. They frequently tell 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 or perhaps seating. Decorative bollards are made in a selection of patterns to harmonize with a wide range of architectural styles. The prevalence of the very most common form 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 towards 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 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 a variety of structures used on streets, around buildings, and then in landscaping. Based on 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 used up, similarly shaped iron castings were designed 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 kind of bollard is fixed. The simplest 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 in addition a wide variety of decorative designs. Some feature square or rectangular cross-sections, but a majority of are cylindrical, sometimes having a domed, angled, or flat cap. They are offered in a variety 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 and so the bollard can easily be 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 rather than structural anchoring in which to stay place. They are designed to be moved rarely, and after that only with heavy machinery for instance a fork-lift.
Bollards generally belong to three types of applications:
Decorative Bollards – decorative bollards for architectural and/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 become an ornament. As standalone architectural or landscaping features, they could border, divide, or define a space. 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 one or more reveals close to the top. Styles created to match various historic periods usually have more elaborate shapes and surface details. These include 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 include a simple rounded or slanted top to discourage passersby from leaving trash or making use of them for impromptu seating. On the contrary, 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 tend to be 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 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-suited 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 eye. If high-finish consistency is desired, seek a manufacturer that will machine 100% in the surface after casting to produce units having a uniform surface for max 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 exposed to a relatively 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 definitely an especially durable form of painted finish. The application process builds 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 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 option than iron. In the event the finish coat is damaged, aluminum oxidizes to your color that is generally more acceptable compared to red rust made by iron. Aluminum and stainless are also available in a number of bare metal finishes. Functionality can be added to the otherwise decorative bollard. For example, common option 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 from the post allows parking and locking of bicycles, a progressively popular choice as increasing numbers of people seek alternative green transportation. Bollards may also contain lighting units or security devices, such as motion sensors or cameras.
Traffic and Safety Bollards
The most typical bollard applications are traffic direction and control, together with safety and security. The very first function is achieved from the visual presence from the bollards, and to some degree by impact resistance, although, in these applications visual deterrence will be the primary function. Safety and security applications depend upon higher degrees of impact resistance. The key distinction between the 2 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, 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 in front of zcvjbu car park entrance to some store, and at the mouths of streets transformed into outdoor malls or ‘walk streets’. In designing bollard installations for a site, care has to be come to avoid locating them where they are going to turn into a navigational hazard to authorized vehicles or cyclists.
Some applications for traffic guidance depend on the cooperation of drivers and pedestrians and do not require impact resistance. A type of bollards linked by way of a chain presents a visual cue to not cross the boundary, even though it may be easy enough to get a pedestrian to travel over or underneath the chain when they choose. Bollards made to direct traffic are sometimes designed 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 usually placed at the corners of buildings, or flanking lamp-posts, public phones, fire hydrants, gas pipes as well as other installations that ought to be protected from accidental contact. A bollard at the fringe of a roadway prevents cars from over-running sidewalks and harming pedestrians. Bell-shaped bollards can in fact redirect a car back onto 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 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 control the flow of traffic into an intersection. Internet videos of ‘bollard runners’ graphically demonstrate the effectiveness of a low post at stopping cars.