Concentrated load
A load applied over a small contact area, such as a tower crane leg or outrigger foot, rather than spread evenly across a large foundation footprint.
Tower Crane Base Mats: Load-Spread Principles and ALIMATS Configurations
How ALIMATS aluminium mat configurations spread concentrated tower crane base and outrigger loads, why stiffness matters more than compressive strength, and where the system is already proven on major UK infrastructure projects.
Tower crane base and outrigger loads are highly concentrated, so the mat beneath them needs stiffness, not just compressive strength, to spread that load across the ground rather than letting it punch straight through.
ALIMATS® patented aluminium mat configurations, from 1.346m² up to 8.073m² with safe working loads to 80 tonnes, are built exactly for this, independently verified with a Fellow of the Institution of Structural Engineers and already proven on projects including HS2, Heathrow, and Manchester's Co-op Live Arena.
At a Glance
- Configuration range
- 1.346m² to 8.073m² in the core ALIMATS range
- Module weight range
- 13kg (Mini) to 48kg (Long / Extra Long)
- Safe working load
- Up to 80 tonnes, depending on configuration
- Suits cranes up to
- 150 tonnes, varying by configuration
- Aluminium modulus of elasticity
- 69,000 MPa vs 1,350 MPa for UHMWPE plastic
- Deflection under 3.5 tonne load
- ALIMATS 8mm vs double-layer plastic mat 161mm
- Delivery
- 24/7 nationwide via BIL's own FORS Bronze fleet
The Load Problem Under a Tower Crane Base
A tower crane does not spread its load the way a building foundation does. Almost the entire weight of the crane, the load it is lifting, and the moment generated as the jib slews comes down through a small base or a handful of outrigger legs, concentrating enormous pressure into a tiny contact area. It falls to the temporary works engineer to confirm the ground beneath that footprint can actually take it.
The same problem sits behind mobile crane outrigger loads, and the same principles apply to a tower crane base: ground bearing capacity has to be checked against the load, and where the ground cannot take the concentrated pressure on its own, that pressure needs to be spread across a wider area before it reaches the soil.
Brilliant Ideas draws a clear line between the two product categories used to do this. BIL only recommends certified Nylanite Nylacast Big Foot pads, rather than standard HDPE, for smaller outrigger loads, while ALIMATS crane mats handle the larger base and outrigger loads above that threshold, often with a Nylacast pad paired alongside to protect the mat surface and optimise load transfer.
Quick Definitions
Ground bearing capacity
The pressure the ground beneath a crane base can safely support before settlement or failure, verified by a temporary works engineer against site investigation data.
Crane pad
A single round or square load-spreading unit suited to smaller outrigger loads up to around 1.0 square metre.
Crane mat
A larger, typically modular load-spreading platform used for outrigger or base loads exceeding around 1.0 square metre.
Why Stiffness Matters More Than Compressive Strength
It's tempting to judge a mat purely on compressive strength, the figure most manufacturers lead with. But that only tells you how much a material resists crushing under direct pressure, not how well it spreads load sideways across the full plan area of the mat before it reaches the ground.
That second property is stiffness, measured as modulus of elasticity, and it's the one that actually matters for load spread. A mat with high compressive strength but low stiffness will bend and let load triangulate straight down through the middle rather than distributing it evenly, which can produce misleadingly favourable results on a rigid test rig rather than real, variable ground. This distinction is set out in the industry design guide Construction Ground Condition for Plant, published October 2014.
Proof: BIL's Own Bending Test
BIL's own bending test rig makes the difference concrete. Using a three-point load through a 500mm by 500mm steel plate to simulate a mobile crane outrigger, a 38kg ALIMATS module deflected just 2mm under a 1 tonne load and 3mm under 2.25 tonnes, against 102mm and 328mm respectively for a comparable UHMW-PE plastic mat.
Under a 3.5 tonne load, a single 60mm-deep ALIMATS module deflected 8mm, compared with 161mm for a double-layer 100mm plastic mat, roughly 20 times more movement.
The material numbers explain why. Ranked purely on stiffness, the order runs steel, aluminium, timber, nylon, then polyethylene, which is why aluminium sits close behind steel as the material of choice for spreading a concentrated crane load.
| Property | ALIMATS Aluminium (6005A) | Ekki/Azobe Timber (D70) | Oak Timber (D40) | Plastic (UHMWPE) |
|---|---|---|---|---|
Compressive Strength (MPa) | 280 | 34 | 26 | 21 |
Tensile Strength (MPa) | 270 | 42 | 24 | 28 |
Modulus of Elasticity (MPa) | 69000 | 20000 | 13000 | 1350 |
Property:
Compressive Strength (MPa)
ALIMATS Aluminium (6005A):
280
Ekki/Azobe Timber (D70):
34
Oak Timber (D40):
26
Plastic (UHMWPE):
21
Property:
Tensile Strength (MPa)
ALIMATS Aluminium (6005A):
270
Ekki/Azobe Timber (D70):
42
Oak Timber (D40):
24
Plastic (UHMWPE):
28
Property:
Modulus of Elasticity (MPa)
ALIMATS Aluminium (6005A):
69000
Ekki/Azobe Timber (D70):
20000
Oak Timber (D40):
13000
Plastic (UHMWPE):
1350
ALIMATS Configurations for Base and Outrigger Support
ALIMATS is a patented, modular aluminium mat system built from certified recycled extruded aluminium, using a unique interlocking design that locks individual modules together into a single rigid plan area rather than behaving as loose, independent boards. Modules run from the 13kg Mini (0.58m x 0.58m) through Short, Standard and Long sizes up to the 48kg Extra Long module (3.480m x 0.290m), used in the larger 6 to 8 square metre configurations.
Configuration Highlights
1.346m² to 8.073m²
Eight core configuration sizes give a temporary works engineer a genuine range to match against a specific leg load and ground bearing capacity, rather than a single one-size solution.
SWL up to 80 tonnes
Safe working loads across the range run up to 80 tonnes, with configurations suited to cranes up to 150 tonnes, varying by configuration.
13kg to 48kg modules
From the 13kg Mini through Short, Standard and Long, up to the 48kg Extra Long module used in the larger configurations.
The Half Loader for Extra-High Loads
Where outrigger or base loads are especially high, BIL's Half Loader module moves part of the load away from the mat centre and spreads it across two locations instead of one, reducing pressure on the supporting ground and, in some cases, removing the need for a separate crane pad altogether. It's designed to work alongside standard ALIMATS configurations rather than replace them.
Verified Loads, Full Inspection, Hire or Purchase
Every ALIMATS safe working load figure is independently verified with a Fellow of the Institution of Structural Engineers, so the numbers a temporary works engineer works from have been checked outside BIL's own design team. Every mat is also fully inspected, cleaned, and quality-checked between hires, so a configuration arriving on your site has been through the same verification process regardless of how many previous jobs it has done.
Hire, Purchase and 24/7 Delivery
ALIMATS is available on single day, weekly, or long-term hire, or for outright purchase, and mats can be painted in corporate colours on request. Delivery runs 24 hours a day, seven days a week, through BIL's own FORS Bronze fleet, driven by CSCS card holding staff, most of them CPCS certified, with fully automated proof of delivery.
One verified example saw a mat configuration ordered at 2.50pm arrive on site in Grangemouth by 8.02am the following morning, all within 18 hours.
Proven on Major UK Sites
ALIMATS has already been used on Manchester's Co-op Live Arena, HS2, Hinkley Point C, Heathrow and Gatwick airports, Google's King's Cross headquarters, Euston Station, Grangemouth Refinery, London Bridge, a number of major Scottish wind farm developments, and a residential build featured on a well-known national homebuilding television series. Brilliant Ideas is trusted by more than 80 percent of the UK's top twenty Tier 1 contractors.
Ainscough Crane Hire
“
When we needed a quick turnaround on mats, the Brilliant Ideas team delivered. The 7.06m² mat configurations we hired were ordered at 2.50pm and arrived on site in Grangemouth at 8.02am – all within 18 hours. The mats are handleable and easier and quicker to set-up than steel mats, which are heavy.
Frequently Asked Questions
What is a tower crane base mat?
A tower crane base mat is a load-spreading platform placed under a tower crane's base or outrigger legs so the concentrated point load is distributed across a wider area of ground, timber grillage, or piled mat foundation. ALIMATS modules interlock into configurations sized to match the leg load and the ground bearing capacity confirmed by a temporary works engineer.
Why not just use timber or plastic mats under a tower crane base?
Timber and plastic mats have useful compressive strength but relatively low stiffness, which lets load triangulate down through the mat rather than spreading sideways across the full plan area. ALIMATS aluminium has a modulus of elasticity many times higher than timber or UHMWPE plastic, so it deflects less and spreads the same load over more ground.
What size ALIMATS configuration do I need under a tower crane leg?
ALIMATS configurations in the core range span 1.346 square metres up to 8.073 square metres, built from Mini, Short, Standard, Long, and Extra Long modules weighing between 13kg and 48kg each. The right configuration depends on the leg load, the number of legs, and the verified ground bearing capacity, so it is best confirmed with our team against your specific site.
Are ALIMATS crane mats or crane pads?
Crane pads are single round or square units suited to smaller outrigger loads up to around 1.0 square metre, and Brilliant Ideas only recommends certified Nylanite Nylacast Big Foot pads in that category. ALIMATS are crane mats, built for larger outrigger and base loads above roughly 1.0 square metre, and a Nylacast pad is often used alongside an ALIMATS configuration to protect the mat surface and optimise load transfer.
How quickly can ALIMATS be delivered to a tower crane site?
Brilliant Ideas runs its own FORS Bronze delivery fleet with CSCS card holding, largely CPCS certified drivers, operating 24 hours a day, seven days a week. One verified example saw a mat configuration ordered at 2.50pm arrive on site in Grangemouth by 8.02am the next morning, all within 18 hours.
Can I hire ALIMATS for a single lift rather than buying?
Yes. ALIMATS are available on single day, weekly, or long-term hire as well as outright purchase, and every mat is fully inspected, cleaned, and quality-checked before it goes back out on hire.
Get a Price on Tower Crane Base Mats
Give our team your tower crane leg loads and ground conditions and we will help you select the right configuration, whether you need it for a single lift or a long programme of works. Configure a hire or purchase quote in minutes using the live ALIMATS configurator.
Aluminium Crane Mats
A specifier's guide to aluminium crane mats, covering material properties, the patented modular interlock, module weights and independent safe working load verification, using ALIMATS® as the engineered example.
Concrete Pump Outrigger Pads
ALIMATS aluminium mats spread concentrated concrete pump outrigger loads through stiffness, not just compressive strength, and are available from 1.346m2 to 8.073m2 for hire or purchase on 24/7 nationwide delivery.
Crane Mats for Hire
ALIMATS® aluminium crane mats are available for single day, weekly or long-term hire with 24/7 UK delivery, guest quoting, and every mat inspected and cleaned before it goes back out.
Heavy-Lift Crane Mats
ALIMATS® aluminium crane mats, including the Half Loader module for the highest outrigger loads, give heavy lifts a safe working load of up to 80 tonnes under cranes up to 150 tonnes, backed by independent verification and bending test data against plastic and timber mats.
MEWP Outrigger Pads
A guide to choosing the right MEWP outrigger pad or mat, when to use a Nylacast Big Foot pad against an ALIMATS® crane mat configuration, and how the Powered Access Solution protects ground under scissor lifts and spider cranes.
Mobile Crane Outrigger Mats
ALIMATS aluminium mats spread mobile crane outrigger loads through stiffness rather than compressive strength alone, backed by purpose designed bending test data and a proven 18 hour nationwide turnaround.
Piling Rig Mats
A plain-spoken look at how engineered aluminium mats spread high point loads from tracked and outrigger-mounted plant, and why stiffness, not just strength, is what actually protects the ground under a piling rig.
Spider Crane Mats
ALIMATS Powered Access Solution is a modular aluminium mat configuration built specifically for spider cranes, mini cranes and MEWPs, so ground protection keeps working while the machine is tracking, not just standing on outriggers.