One line on the drawing, two completely different purchases
Vehicle mitigation to the north elevation. That is often the whole of it on the architect's plan, and it stays one line right up until somebody has to price it, at which point it splits into two purchases that share nothing except the alignment they sit on. Precast concrete barrier is a finished product: it is counted in whole units, loaded on a flatbed, and the quantity is fixed the moment the haulier pulls off the precaster's yard. A bollard is not a product at all until it is in the ground. It is an auger hole, a length of pipe, a concrete order and a pour, and none of those are decided by the same person or booked with the same supplier.
The estimating consequence is that the two go wrong in opposite directions. Come up short on precast and you have a gap in the line and a second delivery charge against a unit price that already includes the transport of a two-tonne object. Come up short on ready-mix and you have a part-filled hole, a cold joint at the worst possible elevation, and a truck to chase on a day when the plant is already loaded. The temptation to average the two into a single provisional sum is what produces the variation.
Then there is the temporary version of the same job, which most crews meet more often: a lane closure where portable barrier is deployed and recovered on the same ticket, sequenced under the temporary traffic control provisions of the Manual on Uniform Traffic Control Devices, Part 6. Nothing is poured, the segments go back on the truck, and the only quantity that matters is how many units the run consumes and how many loads that is. The arithmetic below covers both, because the same frontage often gets the temporary line first and the permanent one eighteen months later.
A fixed bollard, from the cover down to the stone
- Cover sleeve — the stainless or thermoplastic shell the client is looking at, which carries no load and is replaced after any strike
- Steel pipe — the structural member, specified by outside diameter and wall rather than by the nominal size everyone says out loud Round Steel Pipe Weight Calculator
- Core fill — concrete inside the pipe, poured in the same visit and quantified separately from the hole around it Concrete Bag Calculator
- Concrete pier — the drilled shaft that turns an impact into bearing against soil, and the item that dominates the concrete order Circular Pier / Cylinder Concrete Calculator
- Compacted base — a bottomed hole rather than a sloughed one, so the pier bears on material and not on its own spoil Gravel Base Layer Tonnage Calculator
Rated against a hostile driver, or against an unlucky one
Two families of test regime meet on this kind of job and they answer different questions. Hostile vehicle mitigation asks what happens when a driver aims: the test vehicle arrives perpendicular, at speed, on purpose, and the rating records the vehicle class, the impact speed and how far the vehicle penetrated past the barrier line. ASTM F2656 Standard Test Method for Crash Testing of Vehicle Security Barriers is the North American method, ISO IWA 14-1 Vehicle Security Barriers: Performance Requirement, Vehicle Impact Test Method and Performance Rating the international one, and PAS 68 Impact Test Specifications for Vehicle Security Barriers the British specification that preceded it and still appears on tenders.
Road safety hardware asks the opposite question. An errant vehicle leaves the carriageway at a shallow angle and the barrier is judged on whether it contains and redirects without hurting the occupants, which is the framework of the AASHTO Manual for Assessing Safety Hardware, of EN 1317 Road Restraint Systems in Europe, and of AS/NZS 3845.1 Road Safety Barrier Systems and Devices. A free-standing precast segment tested under that regime is designed to slide and to let the vehicle down gently. Buy it, set it across a plaza, and call it hostile vehicle mitigation, and you have installed something whose tested behaviour is to move out of the way.
There is a third band that gets forgotten because it is the least dramatic. Storefront strikes are overwhelmingly low-speed pedal misapplications in a car park, and ASTM F3016 Standard Test Method for Surrogate Testing of Vehicle Impact Protective Devices at Low Speeds exists for exactly that population. A device rated under F3016 is honest about being a low-speed device. Presenting it as anti-ram, or refusing to specify it because it is not anti-ram, are both misreadings of what the retail client actually needs.
The rating never belongs to the bollard on its own. What is tested is the whole article, foundation included, and the certificate names the pier diameter, the depth, the concrete strength and the reinforcement it was tested with. Reduce the hole because of a service, thin the pier because the auger bucket on site was smaller, or substitute a different concrete class, and the tested performance no longer applies to what you built. Application guidance is published separately from the test method for this reason: ISO IWA 14-2 Vehicle Security Barriers: Application, PAS 69 Guidance for the Selection, Installation and Use of Vehicle Security Barriers, and for defence and federal sites the Unified Facilities Criteria UFC 4-022-02 Selection and Application of Vehicle Barriers.
| Document | Impact it models | What the rating reports |
|---|---|---|
| ASTM F2656 | Deliberate perpendicular strike at speed | Vehicle class, test speed, and penetration past the barrier line |
| ISO IWA 14-1 | Deliberate strike, international harmonised method | Vehicle type and mass, speed, angle, and penetration |
| PAS 68 | Deliberate strike, British specification | Vehicle, speed and penetration, plus major debris distance |
| ASTM F3016 | Low-speed car park and storefront strike | Test speed and dynamic penetration for a surrogate vehicle |
| AASHTO MASH | Errant vehicle leaving the carriageway | Containment level, occupant risk, and working width |
| EN 1317 | Errant vehicle, European road restraint | Containment class, impact severity, and working width class |
| AS/NZS 3845.1 | Errant vehicle, Australian and New Zealand practice | Test level and acceptance against the same criteria family |
Counting a run that is not a straight line
Measure the barrier along the alignment it is deployed on, not across the gap it closes. A taper into a lane closure, a run curving around a plaza edge, a line stepped out around a tree pit: every one of those makes the deployed length longer than the dimension anyone scaled off the plan, and portable barrier negotiates a curve as a chord-and-angle path rather than a smooth arc, so the tighter the radius the more units the same nominal length swallows.
Then settle the segment length with the precaster before the count means anything. The common unit is nominally 3.05 metres, or ten feet, but the number on the data sheet may be the casting bed length rather than the length the unit occupies once its pin-and-loop or dowel connection is made up, and the two differ in either direction: a loop joint stands proud of the segment end and adds a gap, while a unit cast short of its nominal size takes coverage away. On a 120 metre run at 3.05 metres nominal you are ordering forty units; if each unit in fact covers 2.975 metres of the run, 75 millimetres less than the figure you counted with, the shortfall across forty units is three metres, which is another whole segment and another visit.
What the count deliberately excludes is worth saying out loud on the quotation, because the segment price is per unit and the omissions are not. End treatments, transitions where the temporary line meets permanent barrier or a wall, gate or crossing units, the connection pins and keys themselves, and any pavement anchorage are separate items priced separately, and on a short run they can exceed the cost of the run segments they bracket.
- Walk the alignment with a wheel and record the deployed length, taking curves and tapers on the path the barrier will actually sit on.
- Get the effective segment length in writing from the supplying precaster, over the made-up connection.
- Divide and round up, then add the units consumed by tapers at each end of a lane closure.
- Price end treatments, transitions and crossing units as separate lines, never inside the segment rate.
- Convert the unit count into truck loads on payload, not on deck length, and confirm the delivery window against the closure permit.
Feed it the length you wheeled and the segment length the precaster confirmed, and it gives the whole-unit count for the run itself, before end treatments and transitions are added.
The total length of the barrier run to be protected.
The length of one standard precast barrier segment.
Barrier segments needed
33 segments
They open the calculator with your figures already in it
Concrete Barrier (Jersey Barrier) Segment Count Calculator: 33 segments — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Free-standing precast barrier is designed to MOVE when it is struck, and how far depends on how many segments are pinned together either side of the impact. A short run shoves aside as individual blocks, which is why highway standards set a minimum installed length upstream and downstream of the thing being shielded, and why the clear working width BEHIND the barrier matters as much as the count in front of it. Four segments dropped around an opening is arithmetically correct and functionally nothing.
- The run length entered should be the length of need, not the length of the hazard. How far barrier has to start ahead of an obstruction is set by approach speed, the offset from the travelled way and the flare rate, and that computed length routinely runs well past the obstruction at both ends. A take-off measured across the hole leaves the run short exactly where a vehicle would arrive at it.
- A segment count is not a delivery or a placement plan. A 3.05 m (10 ft) barrier weighs around two tonnes (2.2 tons), so thirty of them is sixty of those arriving on trailers carrying eight to ten units apiece, and every one has to be set in its final position by a machine with the reach and capacity to do it. On a live carriageway that placement rate, not the segment count, is what sizes the lane closure.
The gap a car can use, and the gap a wheelchair needs
Bollard spacing is squeezed between two requirements that pull opposite ways. It has to be tight enough that a vehicle body cannot pass between two units, which is a security number that comes from the certified product's application guidance rather than from a rule of thumb, and it has to be loose enough that the accessible route through the line still works, which is a clear width set by the ADA Standards for Accessible Design in the United States and by the equivalent provisions elsewhere, such as BS 8300-1 Design of an Accessible and Inclusive Built Environment.
Count the units before you fix the spacing, because the spacing you end up with is not the spacing you typed. Bollards sit at both ends of the protected frontage as well as at every interval between, so the count is the number of intervals plus one. Take a 24 metre frontage at a 1.4 metre target: that is eighteen intervals and nineteen bollards, and nineteen bollards across 24 metres puts the true centres at 1.333 metres. Subtract the bollard's own outside diameter, 168 millimetres on a common six-inch pipe, and the clear opening a pedestrian walks through is 1.165 metres. Both numbers have to be checked, and only one of them came out of the division.
Interruptions are where the count stops being arithmetic. A doorway, a fire hydrant, a service cover you cannot pour over, a vehicle crossing that has to stay open: each one breaks the run into a separate stretch with its own end bollards, and the sum of the stretches always needs more units than the frontage measured end to end. Removable and retractable units go on their own line as well, since they cost several times a fixed bollard, need a different foundation detail, and carry their own rating that is rarely equal to the fixed units either side of them.
Run the frontage and your target spacing through it for the unit count, then divide the frontage by the intervals to see the centres you will actually be setting out.
The total length of frontage or opening to be protected by bollards.
The on-center spacing between bollards.
Bollards needed
15 bollards
- Bays between bollards
- 14
- Bollard centres, as installed
- 4.71 ft
They open the calculator with your figures already in it
Security Bollard Spacing Calculator: 15 bollards — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Spacing is handled as an on-centre dimension only, with no bollard diameter anywhere in the division, so the clear opening left between two adjacent units is narrower than the figure you enter by one shaft width, and nothing in the arithmetic tests that remaining gap for pedestrian, pram or wheelchair passage.
- The centres above are the installed ones, not the target you typed: rounding the interval count up before the end unit is added pulls them in tighter, so 20 m (66 ft) at 1.5 m (5 ft) is fourteen bays at about 1.43 m (4.7 ft). Set the line out from that figure rather than from the target, and read it against the clear opening above, which is the tighter of the two.
- The layout assumed is one continuous straight run with a bollard landing on each end, so frontage that turns a corner, follows a curve or butts into an existing wall or pier has to be measured as separate straight segments with the shared end units then deducted from the total.
- No allowance is made for a deliberate break in the line, such as a vehicle entrance, a loading bay or a service crossing fitted with a removable or retractable unit, because every position across the frontage is counted as one fixed bollard.
- Only the bollard count comes back: footing concrete, embedment or sleeve depth, baseplate fixings and the paving reinstatement around each position are quantities these two inputs cannot produce.
What actually goes in the hole, in two quantities
A fixed bollard takes concrete twice and only one of those is the pier. The drilled shaft around the pipe is the volume that dominates the order, and the core fill inside the pipe is the one that gets left off the docket and then delays the crew at the end of the day. Quantify them separately so that neither disappears into the other.
Take fifteen bollards in 450 millimetre holes, 1.2 metres deep. Each hole is a cylinder of 0.191 cubic metres, fifteen of them come to 2.86, and at a five per cent allowance for spillage the order is a shade over 3.0 cubic metres. That is the number the pier calculation gives, and it is the number to start from rather than the number to finish with.
Two corrections then pull in opposite directions and they are the same order of size. The pipe displaces pier concrete over its whole outside diameter, because everything inside it is core fill and is counted separately: a six-inch schedule 40 pipe measures 168.3 millimetres outside to ASME B36.10M Welded and Seamless Wrought Steel Pipe, so 1.2 metres of embedded pipe takes 0.027 cubic metres out of each hole, 0.40 across fifteen. The core fill puts more back than that: the same pipe has a 154 millimetre bore, and filling it over a 2.2 metre run from the bottom of the hole to just under the cap needs 0.041 cubic metres each, 0.61 across fifteen. Net the two off and the pair adds a fifth of a cubic metre to the order rather than taking anything off it, and you have lost the ability to tell the batching plant what you actually want; order the two quantities separately and neither goes missing.
Over-break is the correction that dwarfs both, and it is a site condition rather than a calculation. An auger in stiff clay gives you the hole you asked for. The same auger in made ground, in loose fill behind an old kerb line, or below a water table takes concrete the shape of whatever the sides collapsed into, and on a frontage that has been dug and reinstated three times over a century that is common rather than exceptional. Drill the first hole before the concrete is ordered, look at the spoil, and if it is anything other than what the site investigation described, revisit the quantity and the pier detail together rather than just adding a truck.
The rest of the specification is inherited, not invented. Concrete strength, and the cover the code requires over reinforcement cast against and permanently exposed to earth, come from ACI 318 Building Code Requirements for Structural Concrete and the project specification written under ACI 301 Specifications for Structural Concrete. Delivery is governed by ASTM C94 Standard Specification for Ready-Mixed Concrete, whose limits on elapsed time and drum revolutions before discharge decide whether a fifteen-hole pour can be done off one truck with the crew you have. The pipe itself is usually specified to ASTM A53 Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless, and where it is galvanised, to ASTM A123 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.
Diameter, depth and hole count give the pier volume with a spillage allowance; run it a second time on the pipe bore and the fill height to get the core fill as its own figure.
SettingsSettings for this calculation
Waste is set to 5% by hand. Pick a tier above to replace it, or keep your own figure.
The diameter of the round pier or column.
The height of each pier.
How many identical piers you're pouring.
Extra concrete for spillage.
Concrete volume needed
9.774 yd³
A circular pier is cast in a tube that must be held plumb and restrained against flotation. The volume is straightforward geometry; keeping the form where you put it while the concrete goes in is the part that goes wrong.
- Volume per pier
- 1.16 yd³
- Base volume (no waste)
- 9.31 yd³
They open the calculator with your figures already in it
Circular Pier / Cylinder Concrete Calculator: 9.77 yd³ — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- A CYLINDER, AND A BORED PIER IS NOT ONE. An auger in anything but stiff clay leaves a hole wider than its nominal diameter, and a soft or collapsing stratum can over-break substantially — which is why concrete take on bored piers routinely exceeds the calculated volume and why the overbreak is a ground question rather than a waste percentage.
- No bell, no toe and no casing. A belled pier, a socketed toe into rock, or a permanent liner each change the volume placed, and none of them is an input here.
- Reinforcement is absent. A pier carrying lateral load or uplift has a cage, and the cage's cover requirement can drive the diameter rather than the load does.
- Excludes the bell or spread footing at the base where one is required, which is a separate and often larger volume.
- Does not allow for over-break in an unstable hole, where the excavation exceeds the design diameter and takes more concrete.
- Cardboard forms must be braced and held down. Fresh concrete will float an unrestrained tube, and a pier that lifts during the pour is a demolition job.
When there is nothing to dig into
Podium decks, basement roofs, plaza slabs over car parks and any post-tensioned floor all rule out a drilled pier, and that is the situation shallow-mount and bolt-down products exist for. They are tested as bolt-down products, against a nominated host slab, and the certificate names that slab: thickness, concrete strength, reinforcement, and the edge distance the anchors were tested at. A bolt-down bollard fixed to a slab weaker or thinner than the tested one has no rating at all, however correctly the bolts were torqued.
The anchorage check itself lives in ACI 318 Chapter 17. Basic concrete breakout for a single cast-in anchor is the starting point and nothing more: the design still has to account for edge distance, for anchors acting as a group, for whether the concrete around them is cracked under service load, and for the steel strength of the anchor itself. On a frontage the anchors are almost always close to a slab edge or a construction joint, which is precisely the condition in which the basic value is least representative of the real capacity, so treat the basic number as a sanity check on the order of magnitude and leave the design to the engineer who signs it.
Getting the holes in is its own risk. A post-tensioned slab is scanned before anything is drilled, with ground-penetrating radar or an equivalent method and by somebody who does it for a living, because the tendon layout drawing records intent and not as-built position. Cutting a tendon on a live deck is not a repair, it is an evacuation. Where the scan says no, the answer is a surface-mounted system spread across a wider footprint, or a planter or seating element that achieves the same standoff by mass, not a drill bit and optimism.
Use it on the embedment and concrete strength you have been given to see the basic breakout capacity, and read the answer as the ceiling before edge distance and group effects take pieces out of it.
The effective embedment depth of the anchor into the concrete.
The concrete's specified compressive strength.
Whether the anchor was cast into the wet concrete or drilled and fixed afterwards.
Basic breakout capacity
8.6 kips
This is the BASIC single-anchor breakout strength only (ANc/ANco = 1, no edge-distance, spacing or eccentricity reduction, and no Psi-c,N cracking modifier — ACI 318's basic equation is on a cracked-concrete basis, and an anchor verified to sit in uncracked concrete earns a further increase this figure does not take) — it assumes the anchor is far enough from any edge or other anchor to develop a full breakout cone. Real anchor design requires the complete ACI 318 Chapter 17 procedure, verified by a licensed engineer.
- Equivalent in lbs
- 8,601.4 lb
They open the calculator with your figures already in it
Concrete Anchor Bolt Breakout Capacity Calculator (ACI 318): 8.6 kips — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 8.6 kips — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- This is a nominal strength, not a design capacity. No strength-reduction factor is applied and no factored load is checked against it, so the figure cannot stand as a code compliance check on its own.
- Only concrete breakout in tension is modelled. Anchor steel fracture, pullout at the head, side-face blowout near a free edge, shear breakout and combined tension-plus-shear interaction are not calculated, and any one of them can govern the anchor instead.
- The full unrestricted breakout cone is assumed. Member thickness, group behaviour where several anchors share a cone, and anchor reinforcement designed to carry the load past a breakout failure are all outside this calculation, on top of the edge-distance, spacing and eccentricity factors the result note already flags.
- Normalweight concrete in ordinary service is assumed. There is no lightweight-concrete modification, no cracked-versus-uncracked modification, and no seismic provisions — an anchor in a seismic force-resisting system is subject to extra requirements this page does not touch.
- For post-installed anchors the generic coefficient of 17 stands in for the actual product. It carries nothing about adhesive bond strength, elevated-temperature or sustained-load performance, hole cleaning, drilling method or installation torque, all of which the manufacturer's qualified evaluation report governs.
Delivery day, and the two tonnes that has to land in the right place
Precast barrier is booked on mass, not on volume or on deck length. The precaster publishes a mass per segment and on the common ten-foot units it is measured in tonnes, so a trailer runs out of payload long before it runs out of deck, and the count per load is a division you do against the haulier's plated weight. Get that division wrong and the closure permit expires with a third of the run still at the yard.
Every segment is lifted by the anchors it was cast with, using the inserts and the clutches the manufacturer specifies for them. In the United States the inserts themselves are governed by OSHA 29 CFR 1926.704, in Subpart Q, which requires lifting inserts embedded in precast members to support several times the maximum intended load; the crane lifting them is a separate question, under Subpart CC. Slinging under the toe of a barrier because the inserts are full of grout is how a unit is dropped, and a dropped segment is not repairable in the way people assume: the reinforcement it was tested with is now bent. Check the inserts before the crane arrives, not while it is standing.
Set-out matters more for barrier than for almost any other precast item because the line has to be continuous to work at all. A free-standing run deflects when it is struck, by an amount recorded in the system's own crash test report, and the clear space behind it is part of the design rather than a courtesy. Park a welfare unit, a stack of pallets or a spotter inside that space and you have made the barrier's tested behaviour into a hazard.
Before any drilling starts on the bollard line, the underground services are located. The excavation provisions of OSHA 29 CFR 1926 Subpart P require the utility owners to be contacted and the locations determined before digging begins, and a frontage is the single most congested strip of ground on most sites: water, gas, telecoms, street lighting and the building's own incomers all run parallel to the kerb at roughly the depth the pier wants to occupy. A pier that has to be moved 600 millimetres after the augering has started changes the spacing, which changes the count, which changes the concrete.
- Confirm segment mass against the haulier's plated payload and fix the units per load before the first truck is called off.
- Inspect and clear the cast-in lifting anchors on every unit, and reject any segment whose inserts are damaged or grouted solid.
- Mark the deflection space behind a free-standing run and keep it clear of plant, materials and people.
- Have utilities located and the line marked out before an auger turns, and re-check the bollard count against the marked-out positions.
- Record which certified system went in where, so the as-built matches a certificate rather than a product family.
The ends are where the line stops working
A blunt exposed end of concrete barrier facing traffic is a hazard in its own right, which is why the AASHTO Roadside Design Guide treats end treatments as part of the installation rather than an accessory to it. Crash cushions, tapered end sections and flared terminations each have their own tested configuration and their own footprint, and a run designed right up to the kerb line with nowhere to put the taper is a design that has to change on site.
The same applies at the joins. Where a temporary line meets a permanent barrier, a bridge parapet or a building face, the transition is a designed element, because a stiff object at the end of a flexible run concentrates everything the run was supposed to spread. Gaps left for crossings, service access and emergency egress are legitimate but they are openings in the protected line, and they get closed with a rated gate or a removable unit rather than left as a hole and mentioned in the method statement.
Close the job out on paper as well as on the ground. Photograph every pier before it is backfilled and every bolt-down base before the cover sleeve goes on, record the as-built spacing rather than the design spacing, and file the product certificates against the positions they were installed in. A frontage that is struck two years from now will be assessed against what was actually built, and the difference between an installation that performed and one that did not is usually a documented detail that somebody changed on the day.
Two orders, booked separately
The barrier is a unit count against a payload and the bollards are a volume against a batching plant. Quantify them as two jobs on one alignment, because that is how they are delivered and how they go wrong.
- Barrier segments, by whole units of the deployed length — Wheel the alignment rather than scaling the gap, and use the effective segment length over the made-up connection, not the casting bed length.
- End treatments, transitions and crossing units — Priced individually and never inside the segment rate; on a short run they can outweigh the run they bracket.
- Bollard count, by intervals plus one — Then divide the frontage by the intervals to get the centres you will set out, and check the resulting clear opening against the accessible route.
- Pier concrete, by hole volume plus a spillage allowance — Drill the first hole before ordering; over-break in made ground moves this figure far more than any waste percentage will.
- Core fill, as its own quantity — Bore area times fill height times the number of bollards, kept off the pier docket so that neither number absorbs the other.
- Anchorage, where nothing can be dug — Host slab thickness, strength and edge distance come from the certified product's tested configuration, and a post-tensioned deck is scanned before it is drilled.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.