Home > PB17B-3R-II Spider Concrete Placing Boom — 17 m

PB17B-3R-II Spider Concrete Placing Boom — 17 m

The PB17B-3R-II is a spider concrete placing boom — a free-standing, easily relocated boom that sits on its own inclined-outrigger base, spreads concrete over a 17 m radius, and is lifted to the next position by the site's tower crane when a pour is done. Unlike a climbing boom, it does not attach to the structure or the formwork; it stands wherever it is set down, legs splayed for a stable, fixed working state, then folds and travels light. At just 6,500 kg, and with a heaviest single piece of only 1,520 kg, it is the most portable boom in the TRUEMAX range — a crane can pick it up and move it around the deck with ease.

That mobility makes the PB17B-3R-II the tool for spreading concrete across slabs and floors where the placing point has to move around the site as the pour progresses. It is fully hydraulic, with a three-arm R-fold boom and 360° slewing driven by a self-locking turbo worm gear that holds the boom steady at any angle. Like every placing boom it is fed by a separate concrete pump rather than pumping itself. It runs on a 380V/50Hz supply with a 5.5 kW motor, and is built and tested at the TRUEMAX factory in Haining to ISO 9001:2015 and CE standards, within a placing-boom line exported to more than 120 countries.

1. Inclined-outrigger spider base — The splayed-leg base sets the boom down firm and fixed on a slab without anchoring into the structure, then lifts clear for relocation — the defining feature of a spider boom.

2. Lightest, most portable in the range — At 6,500 kg total and a maximum single lifting unit of just 1,520 kg, a tower crane can reposition it around the site quickly between pours.

3. Three-arm R-fold hydraulic boom — Three R-fold arms, fully hydraulic, open for a 17 m placing radius and fold compactly for crane handling and transport.

4. Full 360° slewing — The boom rotates a complete circle to cover the area around its set-up point from a single position.

5. Self-locking worm-drive slewing — A turbo worm-gear slewing drive turns smoothly and holds the boom steady at any angle without drifting — well matched to a light, frequently-moved boom.

6. Radio and cable remote control — Two operating modes — wireless radio and cable remote — let one operator place concrete from the clearest vantage on the slab.

7. Compact 17 m reach — Sized to cover a working bay from each set-up, then relocate, rather than carry a longer, heavier boom than the area needs.

8. Quality components — Hydraulic and electrical parts from well-known international brands for stable, reliable operation.

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Technial Parameters

Item	Unit	PB17B-3R-II
Performance
Max. Radius of Placing Boom	m	17
Free-Standing Height (to boom root joint)	m	2.7
Slewing Range	/	360°
Mode of Slewing	/	Turbo Worm Drive
Application Scenario	/	Mobile (Spider)
Circumstance Temperature	℃	-20 ~ 55
Power Supply (customisable)	/	380V / 50Hz
Boom (3-Section R-Fold)
1st Section — Length	m	7.1
1st Section — Articulation	°	0 ~ 86
2nd Section — Length	m	5.5
2nd Section — Articulation	°	0 ~ 180
3rd Section — Length	m	4.5
3rd Section — Articulation	°	0 ~ 180
Delivery Line
Delivery Pipeline Diameter	mm	Φ125 × 4.5
Delivery Hose Diameter	in × mm	5" × 3000
Power & Hydraulics
Motor Power	kW	5.5
Hydraulic Pressure	MPa	25
Hydraulic Oil (5℃–55℃)	/	HM46 anti-wear
Hydraulic Oil (-20℃–5℃)	/	HM32 anti-wear
Weight
Total Weight	kg	6500
Max. Lifting Unit	kg	1520

Dimensions & Working Range

The working-range diagram shows the 17 m radius swept through 360° from the boom's set-up position, plus the vertical fold of the three arms. The 2.7 m free-standing height and the outrigger footprint determine where the boom can be set down on a slab; relocate it by crane to extend coverage across a larger floor. Read the diagram with the outrigger-base dimensions to plan set-up points.

Applications

The PB17B-3R-II suits work where concrete is spread over an area and the placing point moves around the site — the boom is set down, the bay is poured, and the crane shifts it to the next.

Floor slabs and decks

On suspended slabs and decks, the spider boom places concrete across a 17 m bay, then is craned to the next bay — covering a large floor in stages without a fixed installation.

Podiums and transfer slabs

Podium decks and transfer slabs that are poured area by area suit a mobile boom that can be repositioned as each section is cast.

Foundations and rafts

Raft foundations and ground slabs benefit from a light, relocatable boom that spreads concrete evenly without the crew dragging end-hose by hand.

Sites with a tower crane

Because it is moved by crane, the PB17B-3R-II fits projects that already run a tower crane: the crane lifts the 1,520 kg unit to each new position, so no extra handling equipment is needed.

FAQs

What is a spider placing boom?

A spider placing boom is a free-standing, relocatable concrete placing boom on an inclined-outrigger (spider-leg) base. It is not attached to the structure or the formwork; it stands on its legs to place concrete over its radius, then is lifted by crane to the next position. The PB17B-3R-II is the compact 17 m spider in the TRUEMAX range.

How is it moved around the site?

By the site's tower crane. The whole machine weighs 6,500 kg and breaks down so the heaviest single lift is just 1,520 kg, so the crane already on site can pick it up and set it down at the next pour position — no dedicated transport is needed within the site.

How is it different from a climbing placing boom?

A climbing boom (column-climbing or formwork-climbing) attaches to the structure or the formwork and rises with the building; it stays in place and goes up. A spider boom like the PB17B-3R-II stays at one level, spreads concrete across a slab, and is craned sideways to the next area. Spider booms suit floors and slabs; climbing booms suit tall cores and walls.

Is it the same as the wheeled PB17D-3R?

Both reach 17 m, but they move differently. The PB17B-3R-II is a spider boom on outrigger legs, relocated by crane; the PB17D-3R is a mobile boom on a wheeled frame that can be towed or dragged to a new spot. Choose the spider where a crane moves it and a fixed outrigger footing is preferred, and the wheeled boom where it must roll between positions.

Is the placing boom a concrete pump?

No — it places concrete, it does not pump it. A separate stationary or line concrete pump supplies concrete through a pipeline, and the PB17B-3R-II distributes it across the slab. They are used together.

Is it electric, and what does it weigh?

It is electric — a 380V/50Hz supply with a 5.5 kW motor (voltage and frequency customisable), so no on-board engine. Total weight is 6,500 kg, with a maximum single lifting unit of 1,520 kg.

What is supplied, and how is it shipped?

The package is the boom, outrigger base, hydraulic and control system and remote. Delivery line, hose, spares, installation and commissioning are quoted to your project. Tell us your slab layout and crane and we will confirm the configuration and lead time.

Spider booms versus climbing booms

TRUEMAX placing booms fall into two broad families: climbing booms that attach to a structure or formwork and rise with it, and mobile booms that stand free and are moved around. The PB17B-3R-II is a spider boom — the mobile family — built to place concrete on a floor and then be craned to the next position. Where a high-rise core leads the build, a climbing boom is the answer; where concrete is spread across slabs and decks, a relocatable spider boom keeps the placing point exactly where the pour needs it.

How the spider boom works with a pump

Concrete reaches the slab from a batching plant via a truck mixer and a stationary or line pump that runs a pipeline to the boom. The spider boom turns that pipe outlet into reach across a 17 m bay, so one operator places the area by remote rather than the crew hauling heavy end-hose. When the bay is done, the crane lifts the boom — light at 1,520 kg per piece — to the next, and the pipeline is extended to follow.

Choosing within the spider range

TRUEMAX builds the spider boom in two sizes: the 17 m PB17B-3R-II and the larger 21 m PB21B-3R. The PB17B-3R-II is the lighter, more portable choice, with a 1,520 kg lift unit and self-locking worm-drive slewing — easiest to move around frequently. The PB21B-3R reaches further at 21 m with gear slewing, for larger bays. Pick the smaller boom for fast, frequent repositioning, and the larger one where each set-up should cover more ground.