Acrow Props Safe Work Method Statement

Australian Standard AS 2601 The Demolition of Structures explicitly requires structural engineering input for any demolition work affecting structural stability. Section 4.2.2 states that demolition must be planned and carried out under the supervision of a competent person, defined as someone with appropriate qualifications and experience including structural engineering knowledge when structural stability is involved. For acrow prop installations supporting structures during demolition, this means a qualified structural engineer must assess the loads, specify prop capacities and positions, design adequate foundations, and specify installation and removal sequences. Experienced demolition workers may have excellent practical knowledge, but they are not qualified to perform the load calculations, structural analysis, and stability assessments required for temporary works design. Field decisions about prop locations, sizes, or quantities can result in catastrophic structural collapse because structural load paths and force distributions are often not visually obvious. Work health and safety regulators consistently prosecute cases where demolition contractors relied on experience rather than engineering design for temporary support, with penalties reaching hundreds of thousands of dollars and potential criminal charges if workers are killed. Professional indemnity insurance typically requires structural engineering certification for temporary works, and insurance claims may be denied if prop installations were not properly engineered. The relatively modest cost of structural engineering input—typically a few thousand dollars—is insignificant compared to the consequences of collapse including deaths, serious injuries, project delays, regulatory prosecution, and business closure. Always engage a qualified structural engineer to design acrow prop installations for demolition work.

Foundation adequacy beneath acrow props requires specific assessment combining structural engineering calculations with site conditions evaluation. The structural engineer designing the temporary works must calculate the concentrated load at each prop position based on the structural elements being supported. For suspended concrete floors, compare this calculated prop load to the floor's design capacity remembering that concentrated loads are more critical than distributed loads—a floor adequate for general construction loads may fail under concentrated prop loads. Request the original building structural drawings to identify floor design capacity, or engage a structural engineer to assess floor capacity if drawings are unavailable. For props bearing on ground, conduct bearing capacity assessment through geotechnical testing or conservative estimation based on soil type—typical bearing pressures range from 50 kPa for soft clay to 300 kPa for dense sand or gravel. Visible signs of inadequate foundation support include floor deflection or sagging around prop positions, cracking in concrete floors radiating from prop base plates, props settling into ground leaving visible depressions, props tilting as one side of base plate settles more than the other, and creaking or movement when loads are applied. Prevent foundation failures by installing steel spreader plates beneath props on suspended floors increasing bearing area and distributing loads, casting reinforced concrete pads for props on ground providing known bearing capacity and preventing settlement, using structural timber bearers spanning multiple floor joists when props must be installed on timber floors, and conducting daily inspections measuring prop settlement from fixed reference points detecting any movement. If any doubt exists about foundation adequacy, provide conservatively oversized foundation support—the cost is minimal compared to the catastrophic consequences of foundation failure causing complete collapse of the propping system and the structure above.

Any settlement or movement of installed acrow props is a critical safety issue requiring immediate action. If you observe or measure prop settlement exceeding 5mm from original position, prop tilting or leaning from original vertical alignment, foundation cracking or distress around prop base plates, or prop displacement from original marked positions, implement the following emergency response procedure immediately: stop all demolition work in the affected area immediately and evacuate workers from beneath or adjacent to structures supported by the affected props, establish exclusion zones preventing re-entry until the situation is assessed and rectified, notify the site supervisor and structural engineer immediately providing details of observed conditions, photograph the affected prop showing settlement measurements, tilting, or foundation conditions, assess whether adjacent props are also affected by the same foundation or load conditions, and prohibit any further demolition work until additional support is installed or existing props are adjusted and re-certified. The structural engineer must attend site to reassess temporary support adequacy, determine the cause of settlement or movement—common causes include inadequate foundation preparation, unexpected load increases from demolition sequence, foundation deterioration from vibration or moisture, or props being undersized for actual loads, specify immediate remedial measures which typically include installing additional packing to restore prop height and bearing, installing supplementary props adjacent to affected props, or providing foundation strengthening beneath affected props. All remedial work must be completed and verified by the structural engineer before demolition activities recommence. Settlement or movement of props indicates the temporary support system is not performing as designed—continuing demolition work without rectification is extremely dangerous and likely to result in progressive failure and catastrophic collapse. Work health and safety regulations require immediate notification to regulators if a serious incident occurs, and prop failure creating imminent collapse risk would meet this threshold. Document all remedial actions taken and the engineering assessment confirming adequate support is restored, providing evidence of appropriate incident response if regulatory questions arise.

You must follow the structural engineer's prop removal sequence exactly as specified in the temporary works drawings—never remove props based on visual assessment or assumptions about structural stability. This requirement exists because structural load paths in partially demolished buildings are complex and often not visually apparent. A structure may appear completely stable while actually relying on specific props for critical support, and removing these props will cause immediate collapse despite the structure's stable appearance. Structural engineers design removal sequences based on detailed analysis of load paths, structural capacity of remaining elements, and understanding of how forces redistribute as props are progressively removed. The removal sequence typically mirrors the reverse of construction or demolition sequence, removing props only after permanent support structures are in place or after demolition has progressed to stages where specific props are no longer required. Premature prop removal is the single most common cause of structural collapse during demolition work. Australian coronial inquests into demolition fatalities consistently identify cases where workers removed props earlier than structural engineering specifications permitted, often based on the rationale that 'the structure looked stable' or 'we've done similar work before without problems.' These decisions invariably result in catastrophic collapse killing or seriously injuring workers. If you believe props are no longer necessary or if you want to remove props earlier than specified to facilitate other work activities, you must contact the structural engineer to reassess the temporary support requirements based on current site conditions—never make this decision yourself in the field. The structural engineer may approve early removal after reassessment, or may confirm that props must remain in place despite the structure's apparently stable condition. Work health and safety regulations place clear duty of care on workers to follow documented safe work procedures including structural engineering specifications for temporary works. Deliberately removing props earlier than engineering specifications permit constitutes willful breach of safety procedures and eliminates any defence against prosecution if collapse occurs. Always err on the side of caution—if any doubt exists about whether a prop can be safely removed, assume it must remain in place until the structural engineer explicitly confirms removal is safe.

While no specific license is required solely for installing acrow props in Australia, workers must meet competency requirements under the Work Health and Safety Act 2011 to safely perform this high-risk work. Appropriate competency includes understanding of basic structural principles including how loads transfer through structures, how temporary support systems work, and consequences of inadequate support; ability to read and interpret structural engineering drawings including floor plans, sections, and temporary works specifications; training in manual handling techniques for heavy components and use of mechanical handling equipment; understanding of foundation requirements and how to assess bearing capacity adequacy; practical experience installing and adjusting acrow props under supervision of experienced personnel; and knowledge of inspection and monitoring procedures to detect settlement, overload, or failure indicators. For demolition work generally, many states require workers to hold a Demolition Work High Risk Work License issued by the relevant WorkSafe authority, and this license typically includes coverage of temporary support requirements. However, the High Risk Work License focuses on general demolition competency rather than specific temporary works expertise. Most importantly, workers installing acrow props must work under direct supervision of a competent person as defined in AS 2601—typically a supervisor with extensive structural demolition experience and thorough understanding of temporary works principles. Site-specific training should be provided before each project covering the particular temporary works design for that project, the specific prop positions and installation sequence, foundation requirements at each location, inspection and monitoring procedures, and emergency response if props fail or settlement occurs. This site-specific training should reference the actual structural engineering drawings and explain the logic behind the temporary support design—workers who understand why props are positioned in specific locations and why sequence matters are more likely to implement the system correctly than workers simply following instructions without understanding. Documentation of all training should be maintained including attendance records, training content, and competency assessments. If workers demonstrate inadequate competency during initial prop installation activities, provide additional supervision and training or reassign to other activities where their skills are adequate. Never compromise on competency requirements for this critical safety-critical work regardless of project schedule pressures.