Bollard Types and Ideal Applications

This post will be part of a five part article which describes traffic bollards types and their typical uses.  In this post, I’ll discuss bollard types and introduce the four main uses for traffic bollards.

Traffic bollards come in four main types:

1. Embedded Bollards
2. Surface Mounted Bollards
3. Rebounding Bollards
4. Retractable / Removable Bollards

Each type is specifically designed for its purpose and has its own benefits and limitations.  Within those groups, there are sub-groups which I will discuss as well.  Also, bollards that fit in those categories can also fall into other sub-categories less dependent on function and more on aesthetics.  Architectural Bollards might be any of the above, but are also designed to also include pleasant or unique shapes.  A Lighted Bollard is simply a bollard with a light source built in either to add conspicuity to the bollard or to light the surrounding area.

Embedded Bollards

 

Embedded Bollards are simply bollards which are embedded deep into the ground.  This is usually for added

strength and security.  Embedded bollards can be made out of any common bollard material, be it steel, concrete or even wood, however the bollard will only be as strong as the foundation in which it is buried.

A steel post filled with concrete and buried very deep within a reinforced concrete foundation will be strong indeed.  On the contrary, a wooden post buried in soft sand or dirt will not provide as much protection.

Costs for this type of bollard can be significant when coring out existing concrete or asphalt surfaces.   It also potentially weakens the foundation, and therefore may not even be appropriate in an application such as a structural concrete parking deck.  On the other hand, when placing a bollard in an unpaved area, this is perhaps the least expensive and simplest approach.

Surface Mounted Bollards

This type of bollard uses some sort of anchor system, usually mechanical, to mount the bollard to the surface.  Although this is an inexpensive method of installation, it also is not a very secure method.  Upon impact, the anchors are often the weakest link and quickly give way, leaving a tilted bollard and damaged foundation.  However, when the purpose of the bollard is more to provide a mere presence or psychological barrier, this type of installation is most cost effective.  It also may be necessary to use shear bolts in a post-tensioned concrete structure in order to prevent impact to the bollard to potentially compromise the building.

The next type of bollard, the rebounding bollard, is often surface mounted, but overcomes the strength and damage issues associated with standard surface mounted bollards.

Rebounding Bollards

A relative newcomer to the bollard field, rebounding bollards use energy absorption technology to provide

the strength of some embedded bollards, with the low installation costs and flexibility of surface mounted bollards.  When a rebounding bollard is impacted, it is allowed to tilt as some mechanism, be it an elastomer or spring system, more slowly absorbs and dissipates the energy of the vehicle.  The bollard then ideally returns to its original position undamaged and fully functional.  Some barriers use advanced polymers which do not yield like metal or concrete might under extreme load.

A further advantage of this type of system is that damage to vehicles, passengers and loads is reduced due to the more gradual absorption of impact energy.  Imagine crashing a vehicle into a large concrete bollard.  Since there is almost no give, it is much like hitting the proverbial brick wall; all energy is immediately felt by the vehicle and its passengers.  With a flexible bollard system, that energy might be dispersed over several hundred milliseconds.  While that doesn't sound like much, it makes a great deal of difference to the peak forces felt.

Some bollards in this type are actually not intended to provide traffic denial capabilities at all.  As such, they are used mainly as sign markers and psychological barriers.  These are extremely prevalent in the United Kingdom.

Retractable / Removable Bollards

Not all applications for bollards are intended to be permanent or always prevent access.  As such, retractable and removable bollards have been designed to allow the owner or a potential traveler access the area normally denied by the bollard.

From Wikipedia.org

This is typically done in one of several ways.  The lowest technology is the pipe-in-a-tube method where a socket is created in the ground.  The bollard can then be removed from the socket when access is to be granted.  This is inexpensive, but requires manual intervention to access the area.

A second way is through the use of pivoting bollards.  A locking pin is used to hold the bollard upright under normal circumstances, and removed to allow the bollard to lay flat when a vehicle is to pass over it.   These bollards are generally flat in shape to allow for vehicle clearance.  Often, the pin is locked in place with a padlock to prevent unauthorized access.

Finally, the most expensive method is the automatic retractable bollard.  Usually hydraulic powered, the bollard actually retracts straight down into the ground and becomes flush with the surface during access.  Actuation of a hydraulic bollard can be by any number of methods, from security guard push button to remote controls and toll booth pay systems.

Uses of Bollards

In the next four parts of this article, I’ll discuss ideal uses for bollards for each of the following areas of concern:

1. Traffic Denial
2. Parking Lot Protection
3. Drive-Thru Lanes
4. Factories and Warehouses

Certain types of bollards I discussed today are more or less appropriate for each application, depending on the required function.  I’ll discuss that in detail for each type.

The Importance of Bollard Signs

Bollard signs have become increasingly prominent sights in both public and private spaces over the past several years.  As cities become more densely packed and the planet grows increasingly urbanized, they will play ever greater roles in public welfare.  This is true for the following reasons:

1. The signage can be prominently displayed, especially when the sign is mounted on top of an existing bollard, such as those found in front of parking spaces.  Such bollards typically rise approximately one meter high, providing a handy perch to mount signs on.  Traffic studies have shown that the addition of less than a meter in signage height makes a significant difference in how quickly motorists perceive public notices.
2. With a removable signage arrangement, signs can be changed at will to meet evolving needs.  This is a simple matter of installing a standard sized metal sleeve in the top of the bollard, as well as a locking mechanism to prevent removal or tampering.
3. Attaching signage to existing pedestrian or traffic bollards protects them from damage by motor vehicles, due to the bollards’ exceptionally sturdy structure.  Low-speed collisions with signs are common in parking areas, due to careless or inattentive drivers.  However, bollards both discourage such accidents (due to their high degree of prominence) and mitigate their effects on important notices when they do occur.
4. Bollards also enhance signage prominence by the fact that they are traditionally painted high-profile colors, such as bright orange and yellow.  This is especially significant in today’s urban environment, where drivers are subjected to ever-increasing competition for their attention from both public and private notices.

Urban planners and safety engineers will face ever-greater challenges in the years to come, as the world’s growing population increasingly flocks to large cities in pursuit of economic opportunities.  Bollard signs have an important role to play in ensuring public safety in these tightly packed environments, and their use should be greatly encouraged.

Find out more about our bollards at www.slowstop.com.

Gaining Peace of Mind with Traffic Bollards

Traffic bollards are the most common bollards found today.  They’re used both to guide traffic and to help ensure public safety.  They accomplish the first objective by their visual presence, which alerts motorists to the need to follow a marked route or to avoid a prohibited area.  They fulfill the second purpose by forming physical barriers, strong enough to stop an errant motorist or out-of-control vehicle from striking passersby.

Traffic bollards are often painted bright yellow or orange to make them more prominent when viewed against the surrounding landscape. To aid nighttime visibility, traffic bollards often have reflective tape affixed to them.

Benefits of Traffic Bollards

1. Increased safety of city foot traffic – Bollards are used in many large urban areas to surround pedestrian islands.  There, they act as physical barriers against misguided and out-of-control vehicles.
2. Traffic calming – Several studies have shown that bollards cause motorists to drive slower and to pay more attention to their surrounding environment.  This leads to fewer vehicular accidents of all types.
3. Improved building access – Traffic bollards are also used to prevent vehicles from blocking entrances to buildings, by making it impossible for drivers to park too close to the entrance or for vehicles to park too closely together.
4. Psychological assurance – The vast majority of vehicle-related accidents are caused by a small minority of drivers, who fail to operate their automobiles in a responsible fashion.  However, traffic bollards act as a physical barrier between them and those who would otherwise be victims of their carelessness.  This allows both pedestrians and conscientious motorists to breathe a little easier as they go about their daily activities.  This enhanced level of mental comfort is far from the least of the many ways in which bollards benefit the public.

Conclusion

Traffic bollards play a vital role in today’s transportation systems.  Their use benefits drivers, pedestrians, and bike riders in innumerable ways.  For these reasons and more, urban planners should use them as integral components for helping to assure the public’s safety, comfort, and peace of mind.

When to Utilize the Safety Bollard

While all bollards are designed to promote public well-being to some extent, a safety bollard is intended specifically for this purpose.  Because of this, its construction is likely to be both permanent in nature and highly resistant to efforts to dislodge it.

While this can be beneficial in many ways, it increases the likelihood of damage to motor vehicles, cyclists, and even pedestrians that strike them.  It can also impede the entrance of emergency responders, such as fire and police units.  Given these facts, safety bollards should only be used when the circumstances warrant.  Such situations include the following:

1. When access to a particular area is likely to be especially hazardous.  A prime example is the typical construction site, where heavy equipment, falling objects, and scattered debris all pose significant dangers to unauthorized persons.  Scenes of recent motor vehicles collisions, places where sinkholes have opened, and areas where industrial accidents have occurred also fall into this category.
2. When ensuring the proper flow of traffic is vital to human safety.  For example, hospital entrances include dedicated lanes that are only meant to be accessed by ambulances.  However, on frequent occasions, misguided motorists drive their vehicles into these areas, preventing emergency vehicles from arriving.  In such locations, the prospect of damage to privately owned vehicles is outweighed by the potential harm caused to the sick and injured.  Hence, using safety bollards is thoroughly justified.
3. When a site is a likely target of terrorists or other criminals.  Nuclear facilities, for example, use safety bollards as well as other impediments to traffic.  This is because tight control of the location’s perimeter is of paramount importance to public safety.  Other locations at high risk of attack include police stations in high-crime areas, military installations, and hydroelectric plants. 

In summary, while a safety bollard is far from an ideal solution in many instances, it can serve a vital role in protecting sensitive areas from unauthorized access.  Use in accordance with sound judgment should be continued.

Find out more about our bollards at www.slowstop.com.

Can the Safety Bollard be Too Sturdy?

Human society can only exist when the need for security is balanced against the importance of allowing free access to facilities and resources.  Lean too far in either direction, and the results can include a police state on one extreme or chaos on the other.  This principle underlies all aspects of civic planning, including the use of the safety bollard.

Safety bollards must protect public safety above all.  However, this task should always be balanced against other considerations, such as allowing access to those with legitimate reasons to be on site.  Additionally, of course, aesthetics play a role in these matters as well.

The tension between security and public appeal in using safety bollards has led to impassioned debates in urban areas such as New York City.  Barriers put in place since the World Trade Center attacks have been criticized for being too utilitarian and foreboding in appearance.

1. Given the delicate balance that civic planners must maintain between these considerations, how sturdy should safety bollards be?  While there are no easy answers to this question, there are some general guidelines to use for specific instances.  These include:
2. Safety bollards should be sufficient to deal with any likely threat.  A 10-meter high stone fence, for instance, would be thoroughly inappropriate at a shopping mall where parking control is the main concern.  On the other hand, a removable “no trespassing” sign mounted atop a flexible bollard would be similarly inadequate at a nuclear power plant.
3. Safety bollards must allow ready access to a location, unless such access poses a credible risk to public well-being.  To illustrate: it’s sensible to erect sturdy bollards to prevent unauthorized entrance to construction sites.  However, such locations must not be so secure as to not allow rapid entrance by fire, medical, or police units in case of emergency.
4. When possible, safety bollards should be erected in such a way as to add to a site’s visual appeal.  For example, bollards can take the form of substantially-sized planters or works of art.  In these forms, they enhance safety and beautify the surrounding area at the same time.

To conclude, so long as the need to weigh security against mobility exists, the issue of safety bollard construction will remain a point of contention.  However, by following common sense principles like those outlined above, these controversies can be minimized.

Find out more about our bollards at www.slowstop.com.

Traffic Bollards Aren’t What They Used to Be

Traffic bollards are used in urban areas to guide traffic and protect human life.  However, despite their benefits, some city governments still resist using them on large scales.  Historically this has been the case in New York City, although this has changed somewhat over the last decade.  Some of the reasons for this reluctance to use bollards include:

• The belief that they may impede those with visual and mobility limitations.
• Concerns over them interfering with snow plowing.
• Worries about damage to vehicles that strike them.

To address these issues, modern traffic bollards are mounted in a number of ways, including:

1. Fixed – where they are intended as permanent fixtures.  In such cases, they are installed in one of two different ways: by drilling bolt holes into the surrounding concrete and securing the bollard to the surface by using inserts fed through the openings or by excavating several feet deep, inserting a bollard of considerable length, then pouring concrete around it to ground level.  The first method is used in areas where access isn’t tightly controlled.  The second is employed at locations where the danger of sabotage or terrorist activities is significant, such as around nuclear power facilities and military installations.
2. Removable – This setup incorporates an underground sleeve or other type of mounting that is set permanently in place.  There is a gap at the top that allows the easy installation and removal of bollards for temporary purposes.  Sometimes a locking mechanism is employed as well.  These bollards are used at spots where access control needs vary at different times.
3. Retractable – Sometimes bollards are needed on a regular basis at a location, but only at specific times of the day, week, or month.  In such cases, retractable models are installed.  The mechanism that raises and lowers these bollards may either be hydraulic or electrically driven; often a backup power source is included onsite so that the unit remains operable even if the area is suffering an electricity blackout.

The trend away from seeing traffic bollards only as permanent, immovable objects allows them to be used in new ways, all of which enhance public safety.  So, it’s true that bollards aren’t what they used to be.  In fact, they’re better than ever before.

Find out more about our bollards at www.slowstop.com.

How Pedestrian Bollards Protect Drivers and Pedestrians: Examples from New York City

Pedestrian Bollards are closely related to traffic safety bollards in design and purpose, with the chief difference being that they direct foot, as opposed to motorized, traffic.  Nonetheless, they perform an important function in promoting public safety, by maintaining a buffer zone between pedestrians and motorized vehicles.

A powerful example of the role that pedestrian bollards can play is found in New York City.  While it’s a great metropolis, NYC has traditionally been hesitant to use bollards to protect its millions of walkers.  This is largely responsible for the high incidents of pedestrian-vehicle accidents that occur within the city annually.  A recent report by New York City’s Department of Transportation (NYCDOT) mentions 7,000 injuries and fatalities caused by such collisions.

In response, the NYCDOT launched an initiative in 2008 to make the city safer for those on foot.  Many of the measures involve the use of bollards.  Here are some of the many examples.

1. Development of bicycle paths connecting all five boroughs, to encourage the use of bikes as an alternative means of transportation.  Bollards have been installed on many of these paths, to provide a physical barrier against drivers intruding on the cycle routes.  This measure has had tangible results.
2. The redesign of public spaces to create designated zones for foot, horse, and bicycle traffic.  One splendid example of this measure’s success is the revamping of Park Circle in Brooklyn, as seen in this report.  It includes several images of how bollards have been used successfully, along with concrete curbs and lane markings, to create safe zones for non-vehicular traffic.
3. A special emphasis on the Broadway areas of Times and Herald squares, including the use of bollards to establish pedestrian plazas and “refuge spaces,” seen clearly in this video.  The resulting improvements to public safety have been dramatic.

The successes enjoyed by the NYCDOT in using pedestrian bollards are clear evidence of their effectiveness.  As the world becomes ever more urbanized, the role of bollards in guarding public safety will only increase.

Find out more about our bollards at www.slowstop.com.

How Bollard Signs Help Your Patrons

The world is changing rapidly around us.  Studies show that societies around the globe are becoming increasingly urbanized.  The mass exodus from rural locations is having significant economic and social effects, which are of importance to owners and managers of private properties as well as public spaces.  In this new environment, bollard signs can be especially helpful to your business patrons.  This is so for the following reasons:

1. Bollard signs are more conspicuous than other common forms of signage.  This is due to the visual prominence of bollards themselves, as well as the enhanced height they give to notices mounted on top of them.  This fact alone will help patrons identify a particular location, especially when visiting it for the first time. 
2. Bollards are usually sturdy structures, designed to resist impacts from misguided motor vehicles.  This fact helps to ensure that patrons will always be able to see any notices placed on them. 
3. Bollard signs can be easily switched to match changing needs.  For example, if a location undergoes exterior renovations to adopt a particular theme, the exterior signage can be changed to match the new motif.  This benefits both business owners and patrons by giving locations a more unified, aesthetically pleasing appearance.
4. When strategically placed, bollard signs not only inform the public but also play an important role in ensuring patrons’ access to dedicated facilities.  This is especially true in parking areas, where they can serve as physical barriers to motorists who would otherwise park their vehicles too close together to allow entrance for customers. In the case of residential properties, using bollard signs in this way can guarantee availability to all residents, while ensuring that owners remain in compliance with accessibility statutes.

For these reasons and more, those in charge of private businesses should consider the advantages of bollard signs for their patrons.

Find out more about our bollards at www.slowstop.com.

The Importance of Properly Spacing Pedestrian Bollards

An important consideration when installing pedestrian bollards is the amount of spacing that should be allowed between each unit.  Improving public safety while not impeding legitimate use of the enclosed area is always the underlying factor.  While regulatory standards may not exist, the following are guidelines use to determine spacing and location:

1. Availability should  not be restricted for those with legitimate access to the property, including those with physical handicaps.  This is spelled out in US law in the Americans with Disabilities Act.
2. The spacing scheme used should, on balance, contribute to public safety, not detract from it.  This guideline has applicability to bollard placement along combination pedestrian/bicycle paths, where in the past a staggered configuration was used.  This often led to cyclists either having to tightly maneuver their way through the bollards or collide with them, causing a number of injuries and a few fatalities.
3. Bollard spacing should not impede the ability of emergency responders to reach victims of a crime or accident.  For this reason, a spacing of approximately eight feet (2.4 meters) is common in many parts of the United States, such as public parks located in low-crime areas.
4. Tighter spacing of pedestrian bollards is indicated when access control to sensitive locations is of primary important.  For example, counter-terrorism experts in New York City recommend placing bollards four feet (2.1 meters) apart as a general rule of thumb.  In reality, however, the gap is often much narrower, sometimes as little as three feet (approximately one meter).
5. In the event of an automobile crash or other accident, poor spacing of bollards can leave both private and public property owners open to lawsuits.  For this reason, potential exposure to civil liabilities must be considered in determining bollard layout.

In conclusion, while standardized spacing measures may be used as general guides, they should not override good judgment in determining the needs of each particular location.  As with so many things in life, the question of pedestrian bollard placement defies a simple answer.

Find out more about our bollards at www.slowstop.com.

Flexible Delineators or Safety Bollards: When to Use Each

Flexible delineators are often mistaken for bollards due to their similar appearance.  The intended functions of both devices are distinct from each other, however.  This article will clarify the ways in which the two differ.

The Purpose of Bollards
Bollards convey a simple message: “don’t go here!”  They are intended to provide obstructions to either foot or vehicular travel.  In some cases, they take the form of massive structures made of steel or concrete.  In other cases, they are made of highly flexible materials and are meant to “bend rather than break” if struck by motor vehicles.  Regardless of their construction, however, their purpose is to discourage or prevent unauthorized or undesired access to certain areas.

The Purpose of Delineators
Delineators are used not so much to obstruct traffic as to guide it.  The non-verbal message they’re intended to convey is: “please go this way.”  Like bollards, they’re often highly reflective and easily visible at night.  They also alert motorists to changing road conditions due to the presence of structures such as guardrails.  A common use for them is to alert a motorist of a guardrail in place alongside a curving road.  Delineators are often installed atop the rail to make it more visible to passing autos.

Flexible delineators rise vertically from the road surface.  This affords them a higher degree of visibility compared to traditional channelizers, which are typically level with the road.  They’re especially useful in areas where side-swipe types of accidents are likely to occur, such as when traffic is merging from one road onto another.  They guide vehicles from moving leftward too quickly as they enter the stream of traffic.  Their flexibility keeps them from becoming or causing damage even if they’re struck.

Both bollards and delineators serve similarly important functions.  Knowing when each should be used is important for maintaining public safety, both on the streets and off.

Reducing Damage from Vehicle-Bollard Impacts

Reposted from www.slowstop.com.

ABSTRACT

Bollards are short vertical posts, usually made of steel, typically used to prevent access and to protect pedestrians and assets from vehicle collision damage.  In so doing, vehicles (and their passengers) that impact bollards face damage (and injury) due to the collision, as well as damage to the bollard structure itself.  A new bollard system, known as SoftStop® in Europe and SlowStop® in the United States, solves this problem by allowing the bollard to give slightly upon collision, greatly reducing the maximum impact forces felt by both the colliding vehicle and the bollard system itself.

BOLLARD APPLICATIONS

Bollards are used in a myriad of applications, for one of several purposes:

• Equipment Protection
• Utility Protection
• Building Protection
• Access Restriction
• Pedestrian Safety

 One needs only to keep a sharp eye to see bollards around us every day.  In parking lots, driveways, and drive-thru lanes, bollards are used to protect buildings, teller machines, utilities such as gas meters, electrical equipment and fire hydrants, handicap parking signs, gate entry keypads, and to restrict access to undesired areas.  In factories and warehouses, bollards are important for protecting pedestrians as well as guarding storage racks and capital equipment from fork truck collisions.

Other industries which find a heavy use of bollards include automated car wash facilities, self-storage facilities, gas stations and convenience stores, propane dispensing, and parking garages, among others.

THE PROBLEM

Foundation mounted bollards are typically installed in one of two ways.  The first, least expensive way, is with a plate mounted bollard.  These bollards are steel pipes welded to a flat steel plate that can be anchored to a hard surface using concrete anchors.  This method of installation is quick and inexpensive, requiring the installer to drill four to eight holes in the concrete and bolt down the bollard with expansion or screw anchors.

The downside to this installation method, when used with a rigid bollard, is that the anchors are generally not strong enough to withstand anything more than a minor collision.  The plate anchors often are pulled up and possibly the plate bends, leaving a post which leans and is no longer able to properly serve its purpose.  Plate mounted bollards often require constant maintenance and replacement.

The second method for installing bollards involves using a longer steel pipe and burying a portion of it deep in the ground.  This method gives the bollard far more strength than surface mounted, however it can be very expensive to install if the surface is concrete and already poured.  Installation in this case requires coring a hole in the surface using an expensive diamond bladed coring saw.  These machines and their blades are expensive and require water cooling, creating a mess during installation.  Once the concrete is cored and the bollard is in place, the hole must be backfilled with concrete to secure the bollard.  For added strength, these bollards are often filled with concrete, as well.  Though the bollard pipe itself is relatively inexpensive, this installation method is costly and time consuming.

 

Although very strong, there are significant disadvantages to core installations.  Most importantly, there is no give to this system upon impact.  Though desired in high security applications, any vehicle impacting such a bollard will be significantly damaged and its passengers at risk of injury.  Loads carried by fork trucks can also be thrown given the jarring impact likely to occur.  Further, the bollard or its foundation can be damaged by such an impact, again leaving a tilted and less effective barrier requiring costly maintenance to correct.  Often the steel bollard itself is beyond repair and must be replaced with an entirely new bollard.

 

Another disadvantage of this type of installation is that it is a permanent installation with little flexibility for movement.  In factory applications, equipment is often moved and rearranged.  Bollards used to protect equipment or storage racks which are core-installed are not easily moved.  The concrete surrounding the bollard must be broken out and the large remaining hole filled, leaving a factory floor full of unsightly patches.  If the bollard itself is reusable after removal, the entire expensive installation process is started over at the new location.

Some designs have been created to attempt to solve these problems through the use of plastic or spring loaded bollards, however these designs suffer from a lack of strength.  If the plastic is of insufficient stiffness, the entire function of access denial is lost.  On the other hand, very stiff plastic designs have had difficulty with long term durability.  Minor collisions tend to wear away at such devices, and in outdoor applications UV degradation becomes a concern.

REVOLUTIONARY NEW DESIGN

 

Designed and patented by Belgian inventor Gerard Wolters as SoftStop® in Europe, the SlowStop® Bollard system is a unique design which solves many of the problems associated with traditional foundation mounted bollards.  Simply put, the SlowStop® system uses a compressed rubber base to act as an energy absorbing mass.  This elastomer allows the bollard to tilt slightly when impacted, in the range of 20° from vertical, then return upright while still stopping the colliding vehicle.

The SlowStop® design consists of four major pieces:

• Elastomer
•   Base
• Adapter
•  Post

This system is anchored to concrete using concrete anchor screws.  These anchors affix the base component over the adapter, which pre-compresses the elastomer against the ground.  The base and adapter pieces are made of a special ductile cast iron, which makes the pieces less brittle than typical cast iron, and also has a very low (-40°) brittleness temperature.  The steel pipe which serves as the bollard post is a typical steel pipe inserted into the adapter.  In the US, standard ANSI schedule 40 pipe is used to give the end user the flexibility to weld fencing using standard components if necessary.  Concrete fill is not required inside the bollard pipe, though is permitted.  In fact, sign posts can be inserted into the post and concrete filled in place.

Upon collision, the pipe and adapter are allowed to tilt within the base, forcing the adapter to further compress the elastomer in the direction of the impact.  The elastomer absorbs much of the energy of the impact and lengthens the deceleration time of the vehicle.  The elastomer is of sufficient strength to then rebound, usually pushing the vehicle away from the bollard and returning to an upright position.  The tilt of the pipe is limited to approximately 20° at which point the bollard will become rigid.

 

SlowStop Bollards® are designed in a variety of sizes, each of which is appropriate for various expected collision speeds and masses.  Further, they are available with modular connectors which can be used to create fencing and guards out of multiple base units.  By using multiple base units, the ultimate strength of the rebounding bollard unit can be increased.

PERFORMANCE ADVANTAGES

SlowStop® Bollards utilize the much simpler method of surface installation, greatly reducing installation costs, while maintaining the flexibility to move bollards as conditions warrant.  This is accomplished without the normal disadvantage of lack of strength, as the elastomer within the bollard system greatly reduces the maximum impact forces applied to the base anchors.  This is because deceleration of an impacting vehicle is much less severe than during an impact with a rigid bollard.  Energy is transferred to the elastomer instead of directly to a rigid post.  The chart show below demonstrates the difference in impact forces felt by impacting vehicles between a rigid bollard and the SlowStop® Bollard system.

This leads directly to the most important advantages of the SlowStop® Bollard system and that is the reduction of damage to both offending vehicles and to the bollard system itself.  Direct damage to vehicles is reduced due to the reduction of peak impact force seen by the vehicle.  Not only will this avoid damage to the vehicle, but also the chance of injury to a passenger is likewise reduced.  In the case of a fork lift in a factory or warehouse, the chance of a thrown load is also reduced, avoiding the potential for bystander injury and stock loss.

 

Finally, damage to the bollard and its foundation is reduced.  Because the post is constructed of Schedule 40 steel pipe, it maintains its strength, but because of its forgiving nature, much less force is transferred to the foundation.  This simplifies and eliminates maintenance while preserving an aesthetically pleasing facility.

LIMITATIONS

SlowStop® Bollards must be installed on concrete, as an asphalt surface is not of adequate strength to anchor the bollard system.  Considering the replacement costs of damaged bollards, however, it may be cost effective to pour a concrete pad and eliminate years of costly maintenance and asphalt repair.  As previously mentioned, each bollard is sized for expected loads in terms of mass and speed.  Should that limitation be exceeded, it is possible to break a component of the SlowStop® system.  Most likely that involves the post, adapter, or base.  Fortunately, the SlowStop® system is modular and easily repaired.  Posts can be replaced by loosening several set-screws, removing and replacing, and re-tightening the set screws.  Adapter and Base components can be replaced by carefully removing the concrete screw anchors and replacing the component.

CONCLUSION

The SlowStop® Bollard system is a revolutionary new product which solves many of the problems involved with bollard collisions as well as installation and maintenance issues.  Damage to vehicles, passengers, vehicle loads, and the bollards themselves is greatly reduced due to the absorption of impact energy by an elastomer hidden within the base of the bollard.  This elastomer allows the bollard to tilt when impacted and return upright afterward.  SlowStop® Bollards are quick and inexpensive to install, flexible as they are easily moved, and simple to maintain should there be the need.  Safety fencing and barriers are easily created using modular connectors, avoiding the need to weld pipe together.

Further information can be found at www.slowstop.com or by calling Impact Recovery Systems at 1-800-736-5256 (210-736-4477).