A bollard is a short post used to create a protective or architectural perimeter. They come in a wide variety of shapes and styles to accentuate or visually stand out in their settings. Bollards can be made from almost any material, depending on their needed function, but the most common bollards are metal, stone, cement, or plastic.
Types of Bollards
The differentiation of bollards is made on its nature of use-
1. Traffic Line or Street Bollards
Traffic bollards are used to guide traffic toward appropriate areas while ensuring clear sightlines and allowing pedestrian access. They can guide cars by creating roadway demarcation, or prevent access to restricted areas like bike lanes, public squares, and traffic islands.
2. Pedestrian Bollards
In many landscapes and properties, decorative bollards are used to define distinct pedestrian areas. A line of bollards around a building may define its perimeter and add architectural flair. Bollards can be used to contain a playground or park, allowing easy access but discouraging its use as a throughway.
When linked with chain, a line of bollards can encourage pedestrians to stay on marked paths, without forming a closed barrier that prevents all crossing. Lighted bollards can line and illuminate a pedestrian pathway at night. Solar-powered lighting is becoming the most frequently used form of lighting bollard since each unit functions on its own with very little maintenance.
3. Construction Bollards
On roadway construction zones, temporary bollards can be placed to define and protect the work area from traffic. These bollards are usually made of flexible brightly color plastic ringed in reflective tape, and sit on removable rubber bases. They are usually spaced closely, to provide a continual visual edge to the oncoming traffic.
4. Security Bollards
Security bollards are also visual guides to pedestrians and traffic but are additionally built to resist vehicle impact. Many security bollards are made of steel and filled with concrete but can be decorated with the aesthetics of an area in mind with either paint or for a wider range of styles, with bollard covers.
5. Ram-Raid Bollards
Ram-raiding is a version of “smash-and-grab” burglary in which a heavy vehicle is driven through the windows or doors of a closed shop so that the perpetrators can loot many high-value items in a short period of time. Security bollards are an affordable way for these locations to prevent the possibility of ram-raiding.
6. Bicycle Parking Bollards
Bicycle parking-bollards take a cue from the mooring function of marine bollards, providing a hitching post for safe short-term bike lock-up. They often have a post-and-arm shape, where two bike-locking-arms circle the central post. Modern designs sometimes feature channels that go right through the post, specified to allow u-locks or chains.
Materials Used in the Construction of Bollards
1. Cast Iron Bollards
Cast iron is the most common material from which traditionally-styled bollards are constructed. It is durable and is a well-loved traditional material for ornamentation and enhancement to architecture, which makes it a top choice for many applications. Cast iron bollards are heavy enough to be used in standalone applications or can be used as covers for steel-and-concrete security posts.
2. Steel Bollards
Steel is an iron alloy that is lighter and more impact resistant than cast or ductile iron. Structural grade steel is often used in security bollards, filled with concrete, but standard steel is also commonly used to create decorative bollards for standalone applications, or bollard covers in security bollard installations.
3. Stainless Steel Bollards
Stainless steel bollards have a sleek, functional, contemporary look. They have a high level of weather resistance and can be used in an application where the weather is a concern. The metal can be left exposed in its distinguished silver-grey or can be powder-coated with color to fit in with the surrounding aesthetic.
4. Concrete Bollards
Concrete can be used in conjunction with steel pipe bollards or embedded rebar to create impact-resistant security-bollards or can be formed on its own to create attractive bollards appropriate to certain architectural styles. Whether or not a concrete bollard is installed to be impact protective, concrete’s imposing profile and inherent weight make it a clear guide to traffic.
5. Aluminum Bollards
Aluminum is lightweight and malleable, making it a good choice in the design of removable, decorative bollards. If dented or scratched, the oxidization of aluminum usually leads to speckling in a similar shade, which is less noticeable than the high-contrast red rust that can develop on iron or standard steel.
6. Polyurethane Bollards
Polyurethane is a polymer composite that makes a flexible bollard that is durable, UV resistant, and maintains integrity even in variable weather conditions. Poly bollards are usually installed when function and cost take priority over architectural style.
Polyurethane is often seen in parking lots, along medians, and can be used for delimiting lanes. Polyurethane is shatterproof and comes in eye-catching colors, as well as dark shade for architectural applications. It is often accented with reflective tape for maximum visibility in all conditions.
7. Plastic Bollards
Stand-alone polyethylene bollards are usually found in construction and parking applications as a low-cost and low-maintenance option. Bollard covers are where plastic’s merits really shine. Unlike polyurethane, plastic is inflexible and can shatter on impact. Plastic is UV resistant and durable.
8. Wood Bollards
Wood bollards are less common than the other bollard forms, providing very little impact resistance and being more susceptible to weathering. However, pressure-treated wood bollards are sometimes selected in wooded or park areas, where the wood echoes the natural surroundings. Carved wood is sometimes used decoratively in artistic bollard installations.
Installation of Bollards
- Layout the desired location for the bollard placement and mark the ground at the approximate center point.
- Dig a hole using a post hole digger. The diameter of the hole should be the diameter of the bollard plus 6 inches and it should be 18 to 24 inches deep.
- Mix the concrete following the manufacturer's printed directions on the bag label. Add an extra 1/2-gallon of water to make the mix slightly wetter. This will help the concrete flow to fully pack the post hole.
- Insert the bollard into the hole and use a level to hold it plumb.
- Shovel the concrete mix into the hole opening around the perimeter of the bollard. Gently tap the bollard's side with a rubber mallet or hammer while inserting the concrete mix to help pack the mix and fill the mix up to the ground level.
- Allow the concrete mix to cure for a minimum of 48 hours to complete the bollard installation.
Application of Bollards
Bollards have become a ubiquitous part of the modern landscape. Planners and architects use them to manage both pedestrian and vehicle traffic enhances landscape and architecture, light pedestrian pathways, secure and protect buildings and people, and provide bike parking. Bollards are also now being used indoors, in warehouses, for asset protection.