Bagged armor ships empty and becomes armor on site. That is the economic advantage — the heavy component never travels far — and it is also the reason the site needs room for a production operation rather than just a delivery.
What needs space
The bank covers how much staging space is needed for empty bags, aggregate, filling, and lifting. Four things:
Empty units. Compact, but they need to be somewhere dry, off the ground, and out of sunlight if they will sit for any length of time. UV is the fastest degradation mechanism and it starts before installation. See EN 12224 and weathering.
Aggregate stockpile. The largest footprint by volume. The bank covers how close the stockpile should be to the filling area, and the trade is cycle time against room to work.
The filling operation. Frame or hopper, the machine feeding it, and room to manoeuvre a unit onto and off the frame.
Lifting and placement. The machine, its standing position, and its swing.
On a generous site these can be laid out sensibly. On a constrained one they compete.
Working a constrained site
Options, roughly in order of preference:
Fill off site or at a remote staging area and transport filled units in. Removes the production footprint from the work area entirely. The cost is transporting filled units, which is the heavy version, so it only makes sense over a short distance.
Sequence rather than parallel. Fill a batch, clear the area, place the batch, repeat. Slower, and it fits where a continuous operation would not.
Use the carriageway or a temporary closure. On road and rail work, a lane or a possession can be the staging area. It also means the staging is on the critical path of a traffic management arrangement.
Barge staging. Where land access is the constraint and water access is not. See barge and vessel-based placement.
Build a working platform. Where none of the above works. See temporary working platforms.
Access routes
Two different routes, and both need checking:
Delivery access, for trucks bringing empty units and aggregate. Weight limits, width, overhead clearance, turning, and offloading capability at the destination.
Working access, from the staging area to the placement position, for the machine and for filled units.
The bank covers which access details should be provided before freight and equipment deliveries are scheduled. Getting this wrong produces a truck that cannot reach the site, which is a wasted delivery and a day lost.
Access at the condition that matters
Worth stating separately because it recurs across this site.
An access route checked on a dry day is not the same route in the condition the work will happen in. On flood response, on a saturated bank, or after an event that damaged the approach, the question is whether plant can reach the work then. See before the storm vs. after.
The same applies to tidal sites, where the workable window each day may be a few hours and the access route may be under water outside it.
Ground bearing
Beneath the filling operation and beneath the lifting machine, checked rather than assumed. The bank addresses this directly.
On an eroding bank the ground the plant stands on may be inside the failure. Tension cracks behind the crest mark the back of a failure, and plant should not be inside that line. See how to read a failing bank and safety during emergency placement.
Environmental constraints on staging
Staging is disturbance, and it counts:
- Stockpiles away from the water, and stabilised
- Access tracks are disturbed area for the purposes of construction stormwater permitting, and they can push a site over a threshold on their own. See construction stormwater permitting
- Fuel and plant handling away from the water
- Reinstatement of the staging area afterwards
A permit application that describes the works and omits a substantial temporary access track is describing less than the project.
The checklist before delivery
- Delivery route, weight limits, width, overhead clearance
- Offloading capability and hours at the destination
- Staging footprint available, and where each of the four elements goes
- Stockpile position relative to the filling area
- Working route from staging to placement
- Standing positions and ground bearing
- Access condition at the time the work will actually happen
- Environmental controls on the staging area
- Site contact and access arrangements
Where to go next
- Equipment selection
- Site assessment before you order
- Temporary working platforms
- Barge and vessel-based placement
- The rock bag FAQ for the full equipment and access section
- The installation hub for the rest