The role of the drivers has increased drastically during the last decade due to the great security concerns. They are a simple, practical and profitable way to build an anti-ram perimetral defense without creating the vision of a fortified bunker. The balls are widely used for the direction and control of traffic and in purely decorative applications. However, pilots can perform many functions beyond security. They can be used for purely aesthetic purposes, working as landscaping elements. Billiards can create visible limits of a property or areas separated within sites. They can control traffic and are often organized to allow pedestrian access while preventing the entry of vehicles.
Removable and retractable barges can allow different levels of access restriction for various circumstances. They tell us frequently where we can and can not drive, park, bike or walk, protect ourselves from crime, shield vehicles and accident goods and add aesthetic characteristics to the outside and around our building. Boletos can incorporate other functions such as lighting, security cameras, bicycle parking or even seats. The decorative pilots are manufactured in different patterns to harmonize with a wide range of architectural styles. The prevalence of the most common form of security bollard, the steel tube full of concrete, has encouraged the manufacture of decorative balls designed to adapt to roofs on the standard sizes of steel pipes, adding a nice way to the required function.
What is a bollard?
A bollard is a short vertical post. The first bays were designed to tie large ships to the dock, and are still in use today. A typical marine bollard occurs in cast iron or steel and has a shape similar to a mushroom; the enlarged upper part is designed to prevent the mooring ropes from dropping.
Today, the word ballot also describes several structures used in the streets, around buildings and in landscaping. According to the legend, the first bollards of the street were actually cannons (sometimes it is said to have been captured enemy weapons) planted on the ground as border posts and markers of the city. When the supply of old guns was used, iron castings were made in a similar way to fulfill the same functions. Since then, bolards have evolved into many varieties that are widely used on roads, especially in urban areas, as well as outside supermarkets, restaurants, hotels, shops, government buildings and stadiums.
The most common type of ticket is fixed. The simplest is a non-aesthetic steel pole, about 914 to 1219 mm (36 to 48 inches) higher than the degree. The specially manufactured balls include not only simple sticks, but also a large variety of decorative designs. Some have square or rectangular sections, but most are cylindrical, sometimes with a dome lid, inclined or flat. They have a variety of finishes in metallic, painted and durable powder.
They use removable tablets when the need to limit access or direct traffic changes occasionally. Both retractable and folding styles are used when the selective input is frequently used and designed so that the bollard can easily collapse at ground level and re-assemble it quickly. The two retractable units can be handled or automated manually with hydraulic movements. Mobile balls are heavy and heavy objects, often made of stone or concrete, which are based on their weight rather than on a structural anchorage to stay in place. They are designed to be shifted few times, and only with heavy machinery, such as a fork lift.
Bollards usually include three types of applications:
- Decorative balls – decorative bricks for architectural and / or landscape elements;
- Traffic and security tickets – barges that provide patrimonial and pedestrian security, as well as traffic management; i
- Security bills and mail covers – Decorative improvements, resistant to impacts
Some piles are intended solely to be an ornament. As autonomous architectural or landscape architectural features, they can border, divide or define a space. They can also be accents, watchdogs or supporting players to a bigger and more dramatic architectural gesture.
The decorative trinkets are manufactured to harmonize with traditional and contemporary architectural styles. The latter incline towards visual simplicity, often straight places with one or more revelations close to the top. The styles made to combine various historical periods tend to have shapes and more elaborate surface details. These include flutes, bands, scrolls and other ornaments. The post-top is a distinctive feature; The traditional design of beads usually includes decorative purposes elaborated, whereas the contemporary versions frequently present a cleared or inclined upper part simple to dissuade the passersby to leave the sweepings or to use them for improvised seats. On the other hand, sometimes plans and widths are made specifically to animate the seats. The usual decorative materials are iron, aluminum, stainless steel and concrete.
Ornamental designs with elaborate details are often made of cast iron or aluminum. Aluminum beads are desirable for applications that produce a weight, such as a removable balloon. Aluminum units are usually slightly more expensive than iron. For applications in which a decorative mushroom may be subject to a destructive impact, the ductile iron is a safer option than the more brittle metals, since the force will deform the metal instead of breaking it and transforming it into possible projectiles dangerous flying
The iron and aluminum mushrooms are manufactured frequently by sand casting, a traditional casting technique that is economical and adapts well to objects of this size. However, sandy objects often have superficial irregularities that usually leave the finished product less attractive to the eye. If you want a high-end consistency, look for a manufacturer that is 100% of the surface after casting to produce units with a uniform surface to obtain a maximum visual appeal.
The finish is an important consideration in a decorative pylon, both from a functional and aesthetic point of view. The pilots are, by nature, prone to scratching or stinging by pedestrians and vehicles. Those located close to the roads are exposed to a rather aggressive environment; The petrochemical waste and the splashing of salts by dilution of diluted roads may compromise some painted finishes. The coating applied to the factory, available in iron, aluminum and steel, is a particularly durable finish of painted. The application process generates a coating with a very consistent coverage. During the coating, any naked metal tends to attract the powder, eliminating the holes of the cover. The baking process that completes the finish gives you additional resistance and resistance to abuse.
In applications where more physical abuse can be expected, aluminum decorative balls can be a better option than iron. If the finishing layer is damaged, aluminum is oxidized to a generally more acceptable color than the red rust produced by iron. Aluminum and stainless steel are also available in various finishes of naked metal. The functionality can be added to the decorative bollard otherwise. For example, the common option is the eye of the chain: linking two or more balls to the string, creating a simple traffic orientation system. A large loop or metallic arm next to the pole allows parking and blocking bicycles, an increasingly popular option, as more people seek alternative green transportation. The balls may also contain lighting units or safety devices, such as sensors or cameras.
Traffic and security tickets
The most common bollard applications are the direction and control of traffic, together with security and safety. The first function is achieved by the visual presence of the pilots and, to a certain extent, by the impact resistance, although in these applications, the primary function is visual dissuasion. Security and security applications depend on higher levels of impact resistance. The main difference between the two is that security designs are related to the detention of accidental violations of a defined space, while security is to stop the intentional timbre.
The lines of very spaced balls can form a filter of traffic, that separates the motor vehicles of the pedestrians and the bicycles. Placing the posts with 1m free distance between them, for example, allows an easy step for humans and vehicles with a human motor (such as wheelchairs or shopping carts), but prevents the cars from moving. These facilities are often seen in front of the entrance of the car park to a store and at the mouth of the converted streets into open-air shopping centers or strollways. In the design of pitch facilities for a place, you should be careful not to locate them wherever they will become a danger of navigation for authorized vehicles or cyclists.
Some traffic targeting applications depend on the cooperation of drivers and pedestrians and do not require impact resistance. A line of bundles linked by a chain presents a visual indicator to avoid crossing the limit, although it may be easy enough for a pedestrian to pass or underneath the chain if he decides. Balls designed to steer traffic are sometimes done to fold, deflect, or break the impact.
Adding more resistance to collisions allows a ticketholder to apply traffic restrictions instead of just suggesting them. Plane pipes are commonly found in the corners of buildings or flanking lights, public telephones, fire hydrants, gas pipes and other facilities that must be protected against accidental contacts. A bollard on the edge of the road prevents cars from overpassing and hurt pedestrians. Bell-shaped bricks can drive a vehicle to the road when their wheels hit the sloping side sides.
They are used when the U turns and the adjusted radius turns are frequent. This type of use is particularly frequent in the corners where often the drivers of the vehicle turn erroneously and the pedestrians are especially close to the road they hope to cross. In some cities, they install impact resistant bolts with automatic retraction to regulate the flow of traffic at an intersection. Internet videos of & # 39; ball runners & # 39; demonstrate graphically the efficiency of a low pair when stopping the cars.
Security bills and mail covers
The consequences of the 1995 bombings in Oklahoma City and the Sept. 11 attacks in 2001 suffered a sharp increase in the installation of pilots for security purposes. Anti-ram installations do not only include sticks, but other objects designed to withstand impacts without presenting the appearance of a protection barrier, such as large planters or banks that conceal pellets. Once the threat of design has been determined, the necessary resistance can be calculated to stop it. (See "Security design concepts" below). The specification of the anti-ram perimeter takes into account both the mass and the speed of an attack vehicle that is approaching, considering that this is the most significant.
According to the director of Weidlinger Associates, Peter DiMaggio, an expert in security design, requires a careful evaluation of the site that surrounds him. "The architecture of streets and places will determine the maximum approximation speed possible," he said. "If there are no approaches to the building with a long duration, an attack vehicle can not accumulate a great speed and the resistance of the anti-ram barriers can be adjusted."
The anti-ram strength is usually measured by a standard developed by the State Department, called K-rating. K-4, K-8 and K-12 refer to the ability to stop a truck with specific weight and speed and prevent penetration of the payload more than 1 m (3 feet) beyond of the anti-ram barrier. Resistance does not depend solely on the size and resistance of the bolard itself, but also on the anchorage and on its substrate.
There are block testing videos on various manufacturers websites. The truck impacts two or three high speed balls and the front of the vehicle often cuts, wrapping completely into the most central pole. A part of the cab can fly from the truck, the front or rear end could raise several feet to the air and the front or rear axles could be released. The riders and their feet are sometimes raised several feet upwards. In all tests successfully, the payload of the rear of the truck does not penetrate more than one meter beyond the line of balls, thus satisfying the standard.
The easiest bolus of security is a pipe piece of carbon steel structure of 203 mm (8 in.), 254 mm (10 in.) Or 305 mm. A certain resistance to the impact is achieved even with a 102 mm (4 in.) Tube, depending on the engineering of its foundation. It is often filled with concrete to increase the rigidity, although the pipe without filling with plates hardeners inside it can produce a better resistance to the tube of the same diameter. Without internal hardening, the thickness of the wall must be significantly larger. For fixed-type security pilots, simple pipe bundles can be functionally enough, if mounted correctly. Special types of piping auction are also manufactured.
The biggest disadvantage of a flat pipe is aesthetics. A piece of painted pipe does not really blend, much less, in most architectural patterns. However, this can be overcome with a decorative ball cover. Many autonomous pilots that do not have impact resistance are designed with an alternative mounting capacity to slide over the standard sizes of the pipes, forming an attractive and architecturally appropriate impact resistance system. These decorative covers can also be available to improve specially designed (but not decorative) pipes.
Concepts of security design
Much of the modern security design focuses on the threat of bomb attacks. The most significant factor to protect against explosions is the distance between the detonation and the target. The shock wave strength explodes, depending on the square of the distance. The more distance you can place between the detonation and the protected structure, which is called the wall distance, the greater the resistance to the threat or, conversely, the less blurriness is needed to incorporate to the structure. Therefore, the creation of a safe perimeter is the first step in the global design of the resistance to explosions.
The whereabouts are valuable architecturally because it allows to protect a building without having to look like a bunker. It also has an economic impact, because it is often less expensive to create a stop than to test bombs of the structure itself. Security pilots and similar anti-ram installations are designed and positioned to create a frustrating challenge to deliver explosives near the goal of a vehicle.
Any security design depends on an estimate of the size of the threat to be resisted – the threat of design. & # 39; The force of the explosion that can be expected is directly related to the transport capacities of weight and volume of the delivery vehicle. The explosives are measured in relation to tons of trinitrotoluene (TNT). The most powerful molecular explosives, such as composition 4 (that is, C-4), are about a third more powerful than TNT, while a fuel and fertilizer pump (as used in Oklahoma City) is considerably less Powerful than TNT. Reasonable approximations can be made about the amount of explosive power that a person carrying a backpack, a passenger vehicle, a truck, a flat lorry, etc. can provide, depending on their capacity to load weight and volume.
There are three basic types of mallet assemblies: fixed, removable and operable (retractable or folding). Fixed bolts can be mounted in existing concrete, or installed in new bases. Manufactured drivers are usually designed with their own mounting systems. The independent assemblies can be as non-invasive as existing concrete drilling and anchoring with epoxy or concrete plates. These surface-mounted bicycles can be used for purely aesthetic installations and a significant visual deterrent and direction, but only provide a minimal impact resistance.
Balls designed to protect against impacts are often incrusted in concrete at several feet deep, if the conditions of the site allow it. Mounting engineering depends on the threat of design, soil conditions and other site-specific factors. The strip bases that mount several pilots provide a better resistance, distributing the load of impact for a wider area. For places where deep digging is not desirable or possible (for example, an urban location with a basement or a subway under the pavement), balls are available made with low-power installation systems both for individual masts and for pilot groups. In general, the lower the assembly, the wider it must be resistant to the load of the impacts.
A removable pile usually has a support or sleeve installed permanently below the degree, while the upper part of the sleeve is colored head with the floor. The mating ballot can be lifted manually from the mount to allow access. This system is intended for locations where occasionally the change of access is necessary. It may include a blocking mechanism, either exposed or concealed, to prevent unauthorized removal. Both tickets and decorations are available for this type of application. Most removable balls are not designed for high impact resistance and are not used in anti-ram applications.
Retractable armchair telescope below floor level, and can work manually or automatically. Manual systems sometimes have lift support mechanisms to facilitate and accelerate the deployment. Automatic systems can be electric or hydraulic, and sometimes they include a dedicated backup power installation, so that the balloon remains functional during emergencies. Shrink systems are usually disassembled.
Billiards are as ubiquitous as they are overlooked. They talk about the need to define space, one of the basic tasks of the built environment. The tickets and the decorative covers offer a versatile solution to provide a pleasant way to various functions. The range of available options is broad in terms of visual style and performance properties. For security applications, a design team with security experience must be included in the planning team.
Look for the revision of the original version of this bullard reference article completed with images and references.