Jib Crane Foundation Carbon: What the Concrete Block Weighs Before the Crane Arrives, 0.25 to 5 Ton

Written by Chen Wei, Senior Design Engineer at SIEC Cranes. Oct 22, 2026.

A 2 tonne pillar jib crane weighs 1,270 kg. The foundation that keeps it upright weighs about 13 tonnes and carries roughly the same CO2e as the crane itself, near 2.7 tonnes of it, in a block that no crane quotation ever mentions. Published maker data puts the required footing at 2,200 by 2,500 mm in plan, and the mass ratio holds at about ten to one across the 0.5 to 2 tonne range.

I have watched buyers spend three weeks arguing about the steelmaking route of the mast and then pour five and a half cubic metres of C30 without asking a single question about it. The mast is 1 percent of the project carbon. The block is half.

How much does a jib crane foundation actually weigh?

Start with the machine, because the machine number is published and the foundation number usually is not. A Japanese pillar jib specification table (Futaba J36 series, 0.5 to 2 tonne, 3 m jib, 3 m lift) lists approximate mass as 670 kg, 870 kg and 1,270 kg. The same table lists the foundation plan size the maker expects you to pour: a 1,500 by 2,000 mm square for the 0.5 tonne, 1,800 by 2,200 for the 1 tonne, and 2,200 by 2,500 for the 2 tonne.

Multiply those plans by a 1,000 mm depth, which sits in the middle of the 800 to 1,200 mm range Chinese foundation guidance gives for pillar jibs, and you get 3.0, 4.0 and 5.5 cubic metres of concrete. At 2,400 kg per cubic metre that is 7.2, 9.5 and 13.2 tonnes.

Capacity	Crane mass	Footing plan	Concrete at 1.0 m deep	Mass ratio
0.5 t	670 kg	1,500 x 2,000 mm	3.0 m³, 7.2 t	10.7 to 1
1 t	870 kg	1,800 x 2,200 mm	4.0 m³, 9.5 t	10.9 to 1
2 t	1,270 kg	2,200 x 2,500 mm	5.5 m³, 13.2 t	10.4 to 1

Ten to one is the number to remember. The block is not an accessory to the crane. It is the larger structure, and it is poured by a contractor who has never read a crane manual.

Why is the block ten times heavier than the crane?

Because a pillar jib turns its load into an overturning moment, and the only thing resisting that moment is the weight of the concrete and the soil it presses on. The mast is a lever, the base plate is a hinge, and the block is the hand holding the hinge down.

A worked example from a published foundation design (BS 8110 and BS 8004, for a 10 tonne-metre class jib) makes it concrete. Base reaction moment is 41 kNm. Vertical reaction is 17 kN. Adopted base is 1,700 by 1,700 by 1,000 mm, and its own self weight is 69.36 kN, four times the crane's vertical load.

Check	Value	Limit
Crane base moment	41 kNm	Design input
Crane vertical reaction	17 kN	Design input
Foundation self weight	69.36 kN	4.1 x crane load
Factor of safety, overturning, dry	2.66	1.50 minimum
Factor of safety, overturning, submerged	2.05	1.50 minimum
Bearing pressure	33 to 81 kN/m²	120 kN/m² allowable

Read the last two rows together and the design logic jumps out. Bearing pressure uses at most 68 percent of the allowable soil capacity. The block is not sized to stop the crane sinking. It is sized to stop it tipping, and tipping is resisted by mass, so the mass is what you pay for in carbon.

That also explains why the mass ratio stays flat across capacities. Doubling the crane doubles the moment and roughly doubles the block, so the ten to one relationship is a property of the machine type, not of one particular size.

What is actually in the concrete?

Foundation guidance for pillar jibs is consistent: C30 concrete, a rebar cage, and anchor bolts cast in with a template plate. One published installation guide for a 1 tonne pillar jib specifies a 1,200 mm diameter footing at 900 mm depth, eight M24 by 800 mm anchor bolts on a bolt circle, 12 mm rebar at 150 mm centres, C30 concrete, 10 days minimum curing before the base goes down.

The mix is where the carbon sits. A normal C30 with 300 to 320 kg of CEM I per cubic metre, plus 80 kg of rebar, is the default nobody questions. Both of those numbers are adjustable.

Component	Typical C30	CEM III with 50 percent GGBS
Binder	320 kg CEM I	160 kg CEM I plus 160 kg GGBS
Reinforcement	80 kg/m³	80 kg/m³, unchanged
Strength gain	28 days to C30	Slower early, same 28 day class
Curing before erection	7 to 14 days	Add 2 to 4 days in cold weather
Ready-mix carbon	913 kg CO2e per tonne	510 kg CO2e per tonne

The 913 and 510 figures are from a GGBS supplier's published comparison of ready-mix with and without 50 percent slag replacement. That is a 44 percent cut in the concrete's carbon for a mix change, and in most of Europe and the UK the slag blend is not a premium product any more. It is one of the standard designations in BS 8500-2.

How much CO2 is in a cubic metre of C30?

A 2025 study that built a large database of Chinese mix designs and ran life cycle assessment on them puts C30 to C80 concrete at 262.21 to 401.78 kg CO2e per cubic metre, and notes that supplementary cementitious materials cut that by 5 to 30 percent at the same strength class. The same paper found that hauling aggregate 100 to 500 km adds more than 10 percent, which is a reminder that the batching plant location is part of the carbon, not just the mix.

A separate breakdown of a C30/37 reinforced mix with 300 kg CEM I and 100 kg of steel per cubic metre attributes 68 percent of the carbon to cement, 20 percent to reinforcement and 12 percent to aggregate, water and mixing energy. That ratio is why the cement substitution is the only lever with real range, and why arguing about aggregate is mostly a waste of a meeting.

For the rest of this article I use 300 kg CO2e per cubic metre as a planning midpoint of the published range, 80 kg of rebar per cubic metre, and 2.34 kg CO2 per kg for blast furnace steel from the worldsteel Sustainability Indicators Report 2025, which covers 2024 data. Those are round numbers on purpose. If your local batching plant publishes an EPD, use it and the totals will move by 10 to 20 percent, not by a factor.

Jib Crane Foundation Carbon by capacity: the table nobody puts in the offer

Now put the two halves side by side. The crane column uses the published masses above, with 85 percent of machine mass treated as steel and a 6 percent allowance for fabrication electricity. The foundation column uses the volumes from Table 1 and the factors above.

Capacity	Crane only	Foundation concrete	Foundation rebar	Foundation total	Installation total
0.5 t	1.41 t CO2e	0.90 t	0.56 t	1.46 t	2.87 t
1 t	1.84 t CO2e	1.19 t	0.74 t	1.93 t	3.77 t
2 t	2.68 t CO2e	1.65 t	1.03 t	2.68 t	5.36 t

Two things stand out. The foundation is 50 to 51 percent of installation carbon at every capacity. And at 2 tonnes the foundation total matches the crane total almost to the kilogram, 2.68 against 2.68, which is a coincidence of this particular machine and a useful reminder that neither half is negligible.

Normalised per unit of capacity, a 0.5 tonne pillar jib is 5.7 kg CO2e per kg of lifting capacity once the block is counted. A 2 tonne machine is 2.7. Small jibs are carbon expensive per tonne of work, exactly as they are expensive per tonne of work in money.

Does a wall-mounted jib really have zero foundation carbon?

Almost, and the honest version of this answer matters. A wall bracket jib bolts to a column or a wall and pours nothing. A 1 tonne, 20 foot span US catalogue machine uses an S10 by 30 beam, which is 44.6 kg per metre, so about 272 kg of boom, plus bracket, tie rod and a 1 tonne hoist. Machine mass lands somewhere around 500 kg. At the same factors that is roughly 1.06 t CO2e for the whole installation.

Compare that with 3.77 t for the pillar version of the same capacity. The wall bracket saves about 2.7 tonnes, which is 72 percent of the installation carbon, by not pouring concrete.

But three caveats, and I would rather you hear them from a supplier than discover them on site. First, a wall bracket loads a column that somebody else designed, and the column's capacity has to be confirmed by a structural engineer against the crane reactions plus the loads it already carries. Second, an ordinary partition wall is not a suitable support, and the mounting options that manufacturers actually list are steel supports, reinforced concrete supports, steel plates and reinforced concrete walls. Third, the building column has its own embodied carbon. Wall mounting does not delete that carbon, it borrows it from a structure that was already paid for.

Mounting	Installation carbon, 1 t	What has to be true	Moving it later
Pillar on new foundation	3.77 t	Space to excavate, soil at 120 kN/m² or better	Block stays behind
Pillar on existing slab	1.9 to 2.2 t	Slab thickness and punching shear checked	Unbolt and re-anchor
Wall bracket	1.06 t	A real column, checked by an engineer	Unbolt, wall untouched

Do the anchor bolts matter?

Not for carbon. Eight M24 by 800 mm bolts weigh about 22 kg, which is 52 kg CO2e, two tenths of a percent of the foundation. But they matter enormously for everything else, because they are the only connection between a 1,270 kg crane and a 13 tonne block, and a pullout failure is not a gradual event.

The bolt schedule scales faster than the crane does. One published guide uses eight M24 by 800 mm bolts for a 1 tonne pillar jib. A Japanese maker's table specifies six W1 inch by 800 mm for the 0.5 tonne, six W1 inch by 1,000 mm for the 1 tonne, and six W1-1/4 inch by 1,250 mm for the 2 tonne. The diameter and the embedment both step up, and both are set by the anchorage design, not by the crane's weight.

Capacity	Bolts per published schedule	Cast-in or post-installed	Carbon
0.5 t	6 x W1 in x 800 mm	Cast-in with template	about 30 kg CO2e
1 t	8 x M24 x 800 mm, or 6 x W1 in x 1,000 mm	Cast-in preferred, chemical anchors for retrofit	40 to 55 kg CO2e
2 t	6 x W1-1/4 in x 1,250 mm	Cast-in preferred	about 70 kg CO2e

One detail from the installation literature that saves real money: anchor bolts cast in during the pour, positioned with a template plate, are cheaper and more reliable than post-installed chemical anchors. Retrofit anchors are the right answer when you are bolting to an existing slab and cannot break it out, but they are a compromise, and the literature is explicit that a post-installed system has to be an engineered one, not whatever the contractor has on the van.

Can you bolt a jib to an existing slab instead?

Sometimes, and this is the single biggest carbon decision available to a buyer who already owns a factory. At least one major jib manufacturer offers an intermediate plate or dowel plate specifically so that a pillar jib can be anchored to an existing concrete floor or ceiling instead of a new foundation.

The conditions are physical, not commercial. Published guidance for slab-mounted jibs points at a minimum 200 mm of solid concrete at 20 MPa, or roughly 3,000 psi, with the base plate in full contact and shimmed and grouted rather than forced flat by tightening the bolts. Thin slabs, suspended slabs over voids, slabs with post-tensioning or buried services, and slabs over expansion joints are all disqualified or need engineering.

If it works, the saving is the whole foundation: 2.68 tonnes on a 2 tonne machine, which is 50 percent of the installation carbon, and the crane becomes relocatable instead of permanent.

What does duty class do to the block?

More than most buyers expect, because duty class drives the allowable tip deflection, which drives mast stiffness, which drives the base moment that the block has to resist. The common pillar jib class in Chinese catalogues is A3, which is light duty and suits a workshop where the crane moves a few dozen times a day.

Move up to A5 for a production cell running hundreds of cycles a day and the mast gets heavier and the base moment rises. Our planning multipliers for a fixed pillar jib of the same capacity are 1.00 at A3, 1.15 at A4 and 1.35 at A5 for base moment, and the block volume follows at roughly the same ratio because it is a stability-governed element.

Duty class	Base moment multiplier	Foundation, 2 t	Comment
A3	1.00	2.68 t CO2e	Standard catalogue machine
A4	1.15	2.95 t CO2e	Tighter deflection limit
A5	1.35	3.32 t CO2e	Production cell, hundreds of cycles a day

These multipliers are our own planning figures for quotation work, not a published statistic, and the real number comes out of the mast design. The point is the direction and the size: specifying A5 because it sounds safer adds about a quarter of a tonne of CO2e to a 2 tonne jib, and it also adds cost and delivery time. If the crane moves 30 times a day, A3 is not a compromise, it is the correct class.

Which parts of a jib crane installation fall under CBAM?

This is where the answer gets genuinely strange, and buyers who have read a CBAM summary often get it backwards.

The crane itself is out. Cranes are classified in heading 8426, and heading 8426 is not in Annex I of Regulation (EU) 2023/956. A jib crane imported from China does not trigger a CBAM declaration, at any value.

The cement is in. Annex I lists cement clinker under 2523 10 00, white Portland under 2523 21 00, other Portland under 2523 29 00, aluminous under 2523 30 00 and other hydraulic cements under 2523 90 00, all with carbon dioxide as the covered gas. Rebar in 7214, bolts in 7318 and structural steel in 7308 are in scope too, when imported as separate goods.

Item in a jib installation	CN code	In Annex I?	Who normally buys it
Crane, hoist, mast, boom	8426	No	Buyer, imported from China
Cement and clinker in the foundation	2523	Yes	Civil contractor, locally
Rebar	7214	Yes	Civil contractor, locally
Anchor bolts	7318	Yes	Sometimes the crane maker, sometimes the contractor
Structural steel bought separately	7308	Yes	Buyer, if not in the crane package

So the only carbon-heavy part of a jib crane installation that is CBAM-eligible is the part the Chinese supplier does not ship. The cement and rebar are in scope by product, but they are almost always bought from a domestic batching plant, and domestic goods inside the EU are not imports. If your contractor pours with local CEM III, there is no CBAM exposure on the block at all. If the project imports precast foundation elements or clinker from outside the EU, there is.

Two thresholds to keep in mind. The mass threshold for the definitive regime is 50 tonnes of CBAM goods per importer per calendar year, and it applies to the aggregate of all CBAM goods, not per consignment. A single 5.5 cubic metre foundation, at about 1.7 tonnes of cement, is nowhere near it. A plant expansion that imports structural steel in bulk can cross it without anybody noticing.

And the price is real money now. Certificate prices published by the Commission for 2026 are 75.36 euro per tonne of CO2 for the first quarter, 75.28 for the second and 82.32 for the third, with the fourth quarter published on 4 January 2027 and weekly pricing from 2027 onwards. The first declaration and surrender covers the 2026 import year and falls due on 30 September 2027.

One more trap worth naming. You cannot split a crane into steel parts and declare them under 7308 instead of 8426. General Interpretative Rule 2(a) covers incomplete or unassembled articles presented together, and the Court of Justice confirmed the principle in Case C-107/22 in April 2023 for goods requiring only assembly by bolting, riveting or welding. A mast, boom and base plate shipped as three pieces are still a crane.

Where does 20 years of use leave the comparison?

Here is the part that keeps this honest. The block is half of the installation carbon, but the installation is not the whole life. A 2 tonne pillar jib drawing 2.6 kW with a 35 percent demand factor over 2,000 hours a year uses about 1,820 kWh a year. Over 20 years that is 36,400 kWh, which is 7.5 tonnes of CO2e on the EU grid at 206 g per kWh from the European Environment Agency's 2024 figure, or 19.5 tonnes on the Chinese grid at 0.5366 kg per kWh from the 2022 national average factor.

2 t pillar jib, 20 years	EU grid, 206 g/kWh	China grid, 536.6 g/kWh
Crane embodied	2.68 t	2.68 t
Foundation embodied	2.68 t	2.68 t
Electricity, 20 years	7.5 t	19.5 t
Life total	12.9 t	24.9 t
Foundation share of life total	21 percent	11 percent

So on a light duty machine in Europe the block is a fifth of the life total, and in China it is a tenth. That sounds like it argues against bothering with the foundation. It does not, for two reasons. A factory that buys five jibs does not buy five times the electricity, because the duty class stays the same, but it does pour five blocks. And the foundation is the one item where a zero-carbon option exists, which is not pouring it.

What should be in the foundation drawing you send to the civil contractor?

Most carbon mistakes on jib foundations are information mistakes. The crane maker knows the reactions. The contractor knows concrete. Nobody puts the two on the same sheet, so the contractor pours a block sized by habit.

Item	What good looks like	Why it matters for carbon
Reaction loads	Vertical kN, moment kNm, horizontal kN, at the base plate	The moment sizes the block
Footing plan and depth	Both dimensions, not just the plan	Depth is the cheapest volume to remove
Concrete class and binder	C30, GGBS blend allowed and named	Binder is 68 percent of the concrete carbon
Rebar schedule and cover	Bar size, spacing, cover, lap lengths	Rebar is 20 percent of the concrete carbon
Anchor type and grade	Cast-in preferred, grade stated, template required	Determines whether the block can be smaller
Bolt pattern and projection	Bolt circle, projection above finished floor	Avoids a second pour or a remedial plinth
Curing time before erection	7 to 14 days, longer with slag blends	Rushing it means rework, not less carbon
Soil assumption	Allowable bearing in kN/m² and groundwater level	Poor soil inflates the plan dimensions
Levelling method	Shim and grout, not bolt tension	A forced base plate cracks the block
As-built record	Surveyed bolt positions and cube test results	Needed for the next crane on that base

The 1 tonne jib crane we build most often carries 1.93 tonnes of carbon in its foundation and 1.84 in its steel. If you want the reaction loads for your own layout, the pillar and wall mounted jib crane range lists capacity, radius and deadweight, and we will send the base reactions with the drawing.

What actually reduces it, in order?

Ranked by tonnes saved per unit of effort, for a 2 tonne pillar jib. The first row is not a technology, it is a layout decision, and it beats everything else on the list.

Action	Carbon saved	Cost or condition
Wall bracket instead of pillar, where a suitable column exists	2.7 t	Structural check on the column, lower crane cost
Anchor to an existing 200 mm slab instead of a new block	2.4 t	Dowel plate, punching shear check
Reuse an existing foundation for the new crane	2.7 t	Bolt pattern and reactions must match
Right size the capacity, 2 t to 1 t if the load allows	1.6 t	Nothing, if the duty study is honest
50 percent GGBS in the mix	0.73 t	Usually no premium, 2 to 4 extra curing days
Reduce depth from 1,200 to 800 mm, if the anchorage allows	1.1 t	Engineering, and a longer anchor group
Upgrade C30 to C40	minus 0.1 t, it adds carbon	More cement, no structural gain at these loads

That last row is the one I put in on purpose. Concrete strength is not a safety dial you turn up when you are unsure, because the block is governed by overturning and by anchorage, not by compressive strength. One published design uses 25 N/mm² concrete for a 10 tonne-metre jib, and the bearing check came out at 33 to 81 kN/m² against 120 allowable, which is a soil problem long before it is a concrete problem.

Frequently asked questions

How much CO2e is in a jib crane foundation?

For a 2 tonne pillar jib with a 2,200 by 2,500 mm footing at 1,000 mm deep, about 2.68 tonnes: 1.65 tonnes from 5.5 cubic metres of C30 at 300 kg CO2e per cubic metre, and 1.03 tonnes from 440 kg of rebar at blast furnace steel intensity. A 1 tonne machine lands near 1.93 tonnes and a 0.5 tonne near 1.46 tonnes.

Why is the foundation heavier than the crane?

Because a pillar jib resists its load with an overturning moment, and the only counterweight is the mass of concrete plus the soil under it. Published maker data pairs a 1,270 kg crane with a 2,200 by 2,500 mm footing, and one design calculation shows the foundation weighing 69.36 kN against a 17 kN crane reaction. That is a four to one ratio in load and roughly ten to one in mass.

Can I use a lower carbon concrete for the foundation?

Yes, and it is the cheapest change on the list. A ready-mix with 50 percent GGBS carries 510 kg CO2e per tonne against 913 for the same mix with CEM I, a 44 percent cut. On a 2 tonne jib that removes about 0.73 tonnes from the foundation. Allow two to four extra curing days, because slag blends gain strength more slowly.

Does CBAM apply to a jib crane or to its foundation?

Not to the crane. Heading 8426 is outside Annex I of Regulation (EU) 2023/956, so no declaration is triggered by the machine at any value. Cement in 2523, rebar in 7214, bolts in 7318 and structural steel in 7308 are in scope, but foundations are normally poured with domestic concrete, and domestic goods are not imports. The 50 tonne annual threshold applies to all CBAM goods combined per importer.

Is a wall mounted jib really lower carbon than a pillar jib?

By roughly 72 percent on installation carbon for a 1 tonne machine, 1.06 tonnes against 3.77, because there is no foundation to pour. The catch is that the column or wall has to be capable of the reactions plus its existing loads, confirmed by a structural engineer, and a partition wall is not acceptable. The building's own carbon is being borrowed, not deleted.

How do I compare two jib crane offers on carbon?

Ask for deadweight in kg, the steelmaking route, the recommended footing plan and depth, and the concrete class. Then normalise into kg CO2e per kg of rated capacity for the machine and total tonnes for the installation. The jib crane product pages publish capacity, radius and deadweight, which is the first of those numbers.