Ground Conditions For Mobile Cranes

Vehicle track

When it comes to lifting operations using a mobile crane, there is a complex interface between the appointed person (AP) for lifting and the customer or temporary works coordinator.

Common problems

  • Ground Conditions
  • Weather conditions
  • Incorrect Planning


  • PBT/CBR tests (ACS?)
  • Daily checks and updates for weather
  • Dimensioned and detailed lift plans

Generally above ground elements, such as the mobile crane and lifting accessories are the responsibility of the AP while below ground elements from outrigger mats downwards fall under the responsibility of the temporary works coordinator.

As such, the role of the temporary works coordinator in managing this interface is critical to safe lifting.

The guidance published to support the Lifting Operations and Lifting Equipment Regulations (LOLER) states it is the employers’ responsibility for lifts to be “properly planned by a competent person”. Placing the risk for the lifting operation with the AP is important so the operation can be planned competently.

This can present challenges if the AP lacks the adequate information regarding the ground conditions. As mentioned, generally the ground conditions are to be controlled by the customer.

The AP is reliant on the customer to ascertain the ground bearing capabilities. With this information the AP can clearly calculate the loadings applied by the crane and specify the correct size rigger mats to transfer the load safely but ultimately, they must satisfy themselves that the entire

Too often, responsibility is off set on to the customer, purely by ‘signing off’ the ground as capable of supporting the loadings applied. This not only places responsibility on a person potentially unqualified but also does not provide the information to the AP to enable them to ensure the stability of the crane. This creates an unsafe practice for the lifting operation.

The ground on which the mobile crane is positioned should be appropriately checked by a plate bearing test which can produce maximum permissible loading in that location. A safety factor should be applied to allow for any adverse weather that could affect the stability of the ground.

If the AP does not have complete understanding of the ground or if it is not correctly communicated, this is a dangerous gap in responsibility and the lifting operation should not go ahead. Cultural change is required in the lifting industry to tackle the issue and is too often overlooked due to costs and programme.

It is important to apply the guidance that does exist. There is sufficient legislation and guidance included in LOLER, PUWER and BS7121 but is not always properly managed. In the precast industry the Precast Flooring Federation ACOP includes substantial advice of the safe use of cranes and the responsibilities of each stakeholder.

Ultimately, there is responsibility on principal contractors and their supply chains to provide a safe place of work under CDM (Construction Design and Management) Regulations and under the Health & Safety at Work Act. Failure to do any of the things is a failure of responsibility and can be resolved by simply exercising that authority.

Although, increased collaboration is key. Training must be formalised for the temporary works coordinator, appointed person and crane supervisor. Getting the professionals together and having a constructive conversation to provide complete management of the lifting project.

At PSS we engage with our clients at the very beginning about the responsibilities involved. We require that a plate bearing test is carried out in each crane position and will provide accurate lift plans and dimensions to allow for precise testing.

All planning and management will be carried out by our CPCS competent Appointed person for crane lifting operations who will utilize the information to collate a comprehensive lift plan.

The operation itself will be controlled by a CPCS crane supervisor, and CPCS Slinger/Signaller to consistently ensure a safe operation. The crane and operators are hired from a reputable crane company under Construction Plant Association (CPA) hire conditions.

Weather will be monitored daily leading up to the operation and any delays due to safety concerns will be communicated to the customer at the earliest opportunity. The crane will be fitted with an anemometer to notify the crane operator of high winds on the day and the operations will be amended or cease under the guidance of the crane supervisor.