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Dogging and rigging activities
Demolition rigging
Find out the requirements you should follow when using cranes to do demolition work.
Refer to Demolition Code of Practice for:
- risk management process
- planning the demolition work
- demolition methods
- demolition of special structures.
Definition of demolition work
Demolition work means to demolish or dismantle (take apart) a structure or part of a structure in a planned and controlled way. This includes any parts that are load-bearing or related to the physical integrity of the structure.
Demolition work on a structure or load-bearing part of a structure includes:
- altering
- maintaining
- remodelling
- repairing.
Demolition work does not include:
- the dismantling of formwork, falsework or scaffolding
- the dismantling of other structures used to provide support, access or containment during construction work
- the removal of poles used for power, light or telecommunication.
A person planning to do any of the following types of demolition work needs to give written notice to the regulator at least 5 days before starting:
- demolition of a structure (or a part of it that is load-bearing or related to the physical integrity of the structure) that is at least 6m in height
- demolition work with load shifting machinery on a suspended floor
- demolition work involving explosives.
Demolition licence
A demolition licence is required for a number of conditions. These conditions relate to the way demolition work is carried out.
For example, WorkCover Queensland requires a demolition licence to demolish or dismantle a structure that involves use of load shifting equipment (like a crane).
Refer to individual State Authority requirements on:
- notification of demolition work, and
- demolition licence requirements.
Are you in doubt about whether work is demolition or not? If so, contact State WorkSafe authorities to clarify before you start the work.
The use of cranes in demolition work
Cranes are used in demolition work for a number of purposes, including:
- lifting and lowering plant and/or materials
- lifting and lowering personnel work boxes
- holding suspended loads.
Requirements for deration of cranes used for demolition work
For different crane applications in demolition work, crane lifting capacity should follow the deration rules specified in this section.
A Safe Work Method Statement (SWMS) needs to be prepared before cranes are used for demolition work.
The crane manufacturer should be consulted for special use of the crane. This is because demolition work is a special duty.
The correct type of high risk work licence is required according to the capacity and type of crane.
Traffic management arrangements should be put in place to prevent collision with pedestrians or other mobile plant.
Lifting and lowering plant and materials
Lifting demolition products may be hazardous. It can be dangerous if the loads are greater than assessed, or if they put too much dynamic loads on the crane. Extra crane rated capacity may be based on the Design Factor applied.
Types of lifts
Non-engineered lifts
When the weight of the load to be lifted is unknown, the mass needs to be calculated using material density calculations.
For example:
- concrete 2.5t/m3
- steel 7.8t/m3
This should be assessed through consultation by the rigger and crane operator.
Where there is no extra consulting engineering, a Design Factor of 2x load should be used as a minimum. For example:
- a 4t estimated load should have a crane capacity of at least 8t, plus hook block and rigging.
Plan the lift so that you perform the first lift of an estimated weight with the crane at the minimum setup radius. This is to confirm the mass where the crane has the highest rated capacity.
Engineered lifts
When a consulting engineer is engaged for lifts on a demolition/deconstruction site, they are normally involved with the following steps:
- methods
- section sizes
- lift plans
- consultation with crane company and crew.
These steps take place before the lift is carried out.
A minimum Design Factor of 1.5x load should be adopted. For example, a 4t load requires a crane capacity of 6t plus hook block and rigging.
Returnable lifts
You should think about making loads returnable. This means considering extra support to put the load back to its original location. Loads may need to be returned if:
- weather conditions turn bad
- load is more than estimated weights
- outrigger pressures are exceeded
- crane rated capacity is exceeded.
There are many ways to achieve a returnable load, including:
- installing seating cleats, brackets or propping
- Vee cutting of steel structures to allow load to sit and be reattached.
Precast concrete
Never rely on existing installed lifting points. The condition of the lifting clutch retention bar(s) in the concrete is impossible to determine.
Core holes through panels at least 500mm below panel edge. This makes sure cores are below the external ring reinforcing in the panel.
Use chain slings to sling loads. Include dunnage under the load to prevent damage when removing the chains.
Trees
Trees are very difficult to assess. There are many variables to consider in determining mass and centre of gravity (CoG). For example, density, moisture and tapering bows.
Shock loading or static overloading of the crane can occur if the CoG or mass are miscalculated. The rated capacity of the crane should be capable of 2x the calculated load to allow for miscalculation.
Lifting and lowering personnel work box
Refer to AS2550.1, for requirements for suspension of persons by crane.
Swinging-ball demolition (Not recommended)
The use of cranes with a swinging ball for demolition is not recommended. There are many hazards and risks associated with this type of operation.
The Demolition Work Code of Practice does not have this application under cranes. This type of application has been replaced with excavators that have specialist demolition attachments.