This is not a substitute for your organisation’s safety procedures, a risk assessment, or a competent person on site. It is an account of the hazards that are specific to this work, written because they are consistent across sites and because the pressure that causes people to accept them is also consistent.
The hazard nobody writes on the assessment
Pressure to keep working past the point of good judgement.
An emergency has an asset at risk, an audience, and a clock. Crews work long shifts, in poor light, in bad weather, on ground they do not know, being asked when it will be open. Every one of those degrades decision-making, and together they produce the conditions in which someone accepts a risk they would refuse on a Tuesday.
The countermeasure is organisational rather than technical: someone with the authority to stop, who is not the person under pressure to finish, and a shared understanding that stopping is a legitimate outcome.
Ground that is failing
The most under-appreciated hazard on this work.
The bank or embankment being repaired is failing. It has lost material, it may have voids, it is saturated, and the failure surface may extend well behind the visible damage.
That is the ground the plant is standing on.
What matters:
- Tension cracks behind the crest mark the back of the failure. Plant should not be inside that line
- Voids beneath pavement or fill are invisible from above. Probe or sound before positioning
- Saturated fill has lower strength than the same material dry
- The failure can progress during the work, so a position that was safe at 8am may not be at 2pm
- Vibration from plant can trigger movement
Reassess the standing position through the shift rather than once at the start.
Moving water
- Fast water is stronger than it looks. People are swept off their feet in surprisingly shallow flow
- Cold water causes rapid incapacitation regardless of swimming ability
- Undercut banks may have nothing beneath the edge you are standing on
- Debris in the flow is a strike hazard
- Levels change, including from upstream releases and further rainfall, and can change fast
- Contamination. Floodwater commonly carries sewage, fuel, and agricultural runoff
Standard controls: rescue provision appropriate to the conditions, buoyancy where the risk warrants it, a person watching who is not doing the task, a defined evacuation route, and upstream level monitoring where releases or further rain are possible.
Lifting
Placement is a lifting operation, and the emergency context makes it harder:
- Suspended loads over water, where a dropped load cannot be seen
- Placement into water where the landing point is not visible, so the load is being positioned blind
- Plant on soft or unstable ground, affecting stability
- Reach at the limit of the machine’s capacity, which is where things go wrong
- Rigging under adverse conditions — wet, cold, muddy, in poor light
- Fatigue across long shifts
The exclusion zone under and around a suspended load is the control that matters most, and it is the one most eroded by people trying to see what is happening.
The answer bank covers lifting and placement generally, and the rigging arrangement for these units specifically — note that the correct description is a single attached ring, not four corners.
Working under a structure
At an abutment or a pier:
- Restricted headroom limits boom position and escape
- The structure itself may be compromised, and it is above the crew
- Debris and material can fall from the deck or the structure
- Confined access limits egress if conditions change
If the structure’s integrity is in question, that question is answered before anyone works under it.
Fatigue and darkness
Emergency response runs long. Both of these are real hazards rather than inconveniences:
- Shift limits, enforced rather than aspirational
- Handover between crews, so incoming personnel know the ground conditions and what has changed
- Lighting adequate for the task, including the load path
- A decision, made in advance, about night working, rather than one made at dusk by a tired crew
Environmental hazards
- Electrical services in embankments and near structures
- Buried utilities, whose position may have changed if ground has moved
- Weather, including lightning near cranes and open water
- Wildlife, which floods displace
- Contaminated material in floodwater and sediment
The checks worth making at each shift start
- Has the ground moved since the last shift?
- Has the water level or velocity changed, and what is forecast?
- Is the plant standing position still sound?
- Is the structure’s condition unchanged?
- Is the rescue provision in place and manned?
- Does everyone know the evacuation route and the stop signal?
- Is anyone too tired to be here?
The one that matters
No armor placement is worth an injury. An asset that fails is expensive and replaceable. A crew member who is hurt is neither.
If the conditions are wrong, the correct action is to stop and let the event pass. A structure that is already closed and an event that is receding does not need a crew in the water at night. See placing armor at flood stage for the judgement about when to intervene at all.