What is a working platform and why is it required?

At Dawson Foundation Engineering, we are often asked to design working platforms for piling rigs. But what is a working platform, why is it needed and what must be considered before piling begins?

A piling working platform is a temporary, engineered surface designed to provide safe and stable support for piling rigs, cranes and associated construction equipment.

It is particularly important where the existing ground is soft, weak, variable or affected by water. However, even a site that appears firm at the surface must be assessed against the weight, dimensions and operating pressures of the specific piling equipment being used.

A working platform is not simply a layer of stone placed across the site. Its design, construction, use and maintenance must be appropriate for the ground conditions and the plant operating on it.

Why Is a Piling Working Platform Required?

Piling rigs are large items of construction equipment that can impose substantial loads on the ground beneath their tracks or supports.

If the surface cannot safely support those loads, excessive settlement or local failure could cause the rig to tilt, become unstable or overturn.

A correctly designed and maintained platform helps provide a suitable working area for piling operations.

Does Every Piling Project Need a Working Platform?

Every piling project requires a safe and suitable working area, but this does not always mean that a new stone platform must be constructed.

The solution will depend on:

• The piling rig and associated equipment
• The loads and bearing pressures imposed by the plant
• The existing ground conditions
• The site layout and access route
• The pile positions and installation sequence
• Groundwater and drainage conditions
• Nearby excavations, slopes, services and structures

An existing concrete slab, tarmac surface or established hardstanding may provide a suitable platform, but only where it has been assessed for the specific equipment and ground conditions.

Smaller piling systems may require a different working-area solution from a large CFA or commercial piling rig. Suitability must therefore be assessed on a project-by-project basis.

What Information Is Needed to Design a Working Platform?

A working platform must be designed around both the site and the equipment that will operate on it.

Useful information can include:

• The make, model and operating weight of the piling rig
• Track dimensions and maximum bearing pressures
• Details of cranes, concrete pumps, excavators and support plant
• Ground investigation information
• Existing surface construction and ground levels
• Groundwater and drainage conditions
• The platform footprint and access route
• The position of excavations, retaining structures and slopes
• The location of underground and overhead services
• The proposed construction and piling sequence

Without reliable information about the ground and the equipment, it may not be possible to confirm an appropriate platform design.

Read more about why site investigation is important for pile design.

How Do Ground Conditions Affect the Design?

The existing ground beneath the platform has a major influence on the required construction.

The assessment may need to consider:

• Soil type, strength and consistency
• Weak, soft or compressible layers
• Made ground or variable fill
• Previously disturbed ground
• The depth of the groundwater table
• Drainage and surface-water conditions
• Buried foundations, voids or obstructions
• Changes in ground level across the site

A thicker or reinforced platform may be required where the underlying ground is weak or inconsistent. Stronger existing ground may allow a different solution, subject to engineering assessment.

Sites containing fill or disturbed material can require particular care because the strength and composition of the ground may vary across the working area. Our guide to piling in made ground explains how these conditions can affect foundation and piling operations.

What Materials Are Used to Construct a Working Platform?

The materials and construction details will depend on the platform design and the conditions beneath it.

Working platforms are commonly formed using suitable compacted granular material, which may include:

• Well-graded crushed stone
• Suitable crushed concrete
• Other approved granular fill
• Geotextile or geogrid reinforcement where required by the design

The material must be placed and compacted in accordance with the platform specification. Simply tipping loose stone across the site does not confirm that the platform is suitable for piling equipment.

The finished platform should also provide a practical and reasonably level surface for the rig to travel, position and operate.

Why Is Drainage Important?

Water can weaken both the platform material and the ground supporting it.

Poor drainage may lead to:

• Softening of the formation beneath the platform
• Standing water within the working area
• Rutting and displacement of platform material
• Reduced support beneath the piling rig
• Damage caused by repeated plant movements

The platform design and site preparation should therefore consider how surface water will be managed throughout the piling works.

Drainage arrangements must not create soft areas, unsupported edges or channels that could affect the movement and positioning of the rig.

What Is a Working Platform Certificate?

A Working Platform Certificate provides formal confirmation that responsibilities for the platform have been considered before piling operations begin.

It records important information concerning the platform, including its design, construction, maintenance and any restrictions affecting its use.

The certificate does not remove the need to monitor the platform throughout the works. The platform must continue to provide safe access and support for the piling rig and associated equipment for as long as it is required.

If the plant, platform layout, site conditions or working sequence changes, the design may need to be reviewed.

Working Platform Maintenance and Inspection

A working platform can deteriorate after construction, particularly where it is exposed to heavy plant movements, excavation, prolonged use or adverse weather.

The platform should be monitored and maintained throughout the piling works. Particular attention may be required:

• Before the piling rig begins operating
• After heavy or prolonged rainfall
• Where rutting or pumping of the surface develops
• After platform material has been disturbed or excavated
• Where trenches or services have been installed through the platform
• Where the piling rig or support equipment changes
• Before moving plant into a new area of the site

Damaged, contaminated, displaced or heavily rutted areas should be repaired before piling equipment continues to operate over them.

Maintenance should continue until piling, testing and any associated activities requiring access have been completed.

Can Existing Concrete or Tarmac Be Used?

An existing concrete slab, tarmac surface or established hardstanding may sometimes be used as the working platform.

However, the visible surface alone does not confirm its suitability. The assessment may need to consider:

• The thickness and condition of the existing surface
• The construction and strength of the underlying layers
• Voids, cracking or previous repairs
• The ground beneath the hardstanding
• The loads imposed by the selected rig
• Edges, basements, cellars or buried structures

If sufficient information is not available, investigation or additional strengthening may be required before the existing surface can be relied upon.

Can Bog Mats or Track Mats Be Used?

Bog mats, track mats or similar temporary systems may provide part of a suitable working-area solution on some projects.

They should not automatically be treated as a substitute for an engineered platform. Their suitability will depend on:

• The condition and capacity of the ground beneath them
• The size, arrangement and condition of the mats
• The piling rig and bearing pressures
• The method used to connect or restrain the mats
• The proposed travel and operating positions

The complete support system must be assessed for the equipment and operations proposed.

Can a Piling Rig Operate from Scaffolding?

In specialist circumstances, piling equipment may operate from a purpose-designed temporary structure or scaffold-supported platform.

This is not a standard scaffold arrangement. The structure must be specifically designed by a competent engineer for the piling equipment, imposed loads, movements and installation activities.

The design would also need to consider:

• The weight and bearing arrangement of the rig
• Dynamic and operational loads
• Bracing and overall stability
• Access for personnel and materials
• Edge protection and fall risks
• The supporting structure and foundations
• The piling sequence and changing load positions

General-purpose scaffolding should not be assumed to have the capacity to support piling equipment.

Who Is Responsible for the Working Platform?

Working-platform responsibilities should be agreed before the piling contractor arrives on site.

Depending on the project arrangements, responsibilities may include:

• Providing ground and site information
• Supplying details of the piling equipment
• Completing the platform design
• Constructing the platform to the specified requirements
• Inspecting and maintaining it throughout the works
• Controlling excavations or alterations within the platform area
• Confirming any restrictions affecting its use

Clear communication between the client, principal contractor, platform designer and piling contractor is essential.

Working Platforms for Different Piling Methods

The platform requirements will depend on the selected piling method and equipment.

CFA and Larger Commercial Piling Rigs

Larger rigs may impose substantial track pressures and require sufficient space for manoeuvring, concrete deliveries, reinforcement and support equipment.

Visit our Continuous Flight Auger Piling and Commercial Piling pages for more information.

Mini Piling and Restricted Access Equipment

Compact rigs may require a smaller working area, but the ground must still safely support the equipment throughout installation.

Restricted access, work inside buildings or operations close to excavations can create additional platform and temporary-works considerations.

Learn more about our mini piling and restricted access piling capabilities.

Screw Piling Equipment

Screw piles may be installed using handheld, compact machine-mounted or excavator-mounted equipment.

A formal stone platform may not be necessary for every small screw-piling project, but a stable and suitable working area is still required for the chosen equipment and installation torque.

Visit our Screw Piles page for further information.

Common Working Platform Problems

Problems can arise where the working platform is not properly planned, constructed or maintained.

Common issues include:

• Insufficient platform thickness
• Poorly compacted or unsuitable material
• Weak areas beneath the surface
• Uncontrolled water and poor drainage
• Rutting caused by repeated plant movements
• Excavations extending into the platform area
• Unrecorded trenches or services
• Unsupported platform edges
• Changing the piling rig without reviewing the design
• Failing to repair damage during the works

Identifying platform requirements early can help avoid delays, additional mobilisation and unsafe working conditions once piling begins.

Discuss Your Working Platform Requirements

Dawson Foundation Engineering can assess and design working platforms for piling rigs as part of a wider foundation package.

The design will need to consider the proposed piling equipment, ground conditions, platform layout and associated construction activities.

Where available, please provide ground investigation information, site drawings, proposed piling-rig details and any existing hardstanding information.

To discuss your project, call 0333 224 5196 or contact our team to arrange a free site visit and no-obligation quotation.