Project: Civil subdivision with mixed service trenching
Location: Brisbane, QLD
Sector: Civil Construction / Subdivision Infrastructure
Services Provided: Concept Design, Temporary Works Engineering, Equipment Supply, Site Coordination
Equipment Used: Legend VertiShores, Steel Shoring Boxes, Aluminium Shoring Boxes, Handrail Systems, Davit Arms
Project Overview
A Brisbane civil contractor reached out to Legend Hire mid-project with a shoring challenge that wasn’t going to be solved with a single product line. Their subdivision works required service trenching at depths varying from 2m to 6m across the site, with mixed soil conditions, differing excavator sizes between work fronts, and tight access in some areas.
Legend Hire’s engineers developed a concept design that combined three different shoring systems, VertiShores, steel shoring boxes, and aluminum shoring boxes , calibrated to the depth, soil and access conditions at each work front. The package was matched to the customer’s available plant so each excavator on site could lift and place its assigned shoring system without bringing in additional machinery. Temporary works design was issued next day, and the equipment was on site the following day, allowing the contractor to keep their crews productive without disrupting the programme.
The Challenge
The site presented three challenges in one. First, depth, the trenching programme ran from shallow service runs at around 2m, through to mid-depth runs at 3m, and into deeper sections at 6m where trench stability and confined-space access both became governing factors.
A single shoring system would either be oversized, and unliftable by the smaller excavators on site, or undersized and unsafe at the deeper sections.
Second, plant compatibility, the contractor’s fleet on site varied in lift capacity and reach. Any shoring solution had to be light enough for the smaller excavators where appropriate, and rated for the deeper, heavier work where it was needed, without forcing the customer to bring additional machinery onsite.
Third, access and ground conditions. Some trench sections sat in tighter areas where placement angles were restricted, and soil conditions varied work zone. The temporary works needed to suit both, and safe access in and out of the deeper trenches needed to be designed in from the start and not left to bolt on afterwards.
The contractor needed answers fast. Crews were on site, the programme was live, and downtime would have cost them across multiple trades.
The Solution
Legend Hire designed and supplied a mixed shoring package, VertiShores, steel shoring boxes and aluminium shoring boxes, to safely trench at 2m, 3m and 6m depths. Three shoring systems working together across the one project, with each system specified to the section it would be used in.
VertiShores were specified for the shallower service trenches where speed of installation and a low equipment weight mattered more than absolute depth capacity. Their hydraulic, drop-in nature meant the contractor’s smaller excavators could install them without needing operators in the trench.
Steel shoring boxes were specified for the deeper 6m sections where panel strength and rated load capacity were the governing factors. The 4000 x 2010mm steel panels (755kg) gave the contractor the wall capacity to safely work at depth across the mixed soil conditions on site.
Aluminium shoring boxes filled the mid-depth and access-constrained sections, where their lighter lift weight let the contractor place them with the excavators already on those work fronts, avoiding the cost of mobilising a larger machine just for shoring.
Handrail systems and davit arms were specified across the shoring package to provide compliant fall protection at trench edges and safe vertical access in and out of the deeper boxes, including rescue provision for the 6m sections.
Temporary works design was turned around next day, and the full equipment package was delivered to site the day after. The contractor was able to keep their crews productive rather than stand down work fronts while waiting on shoring.
Engineering Considerations
The engineering brief was to match the right system to each work front rather than over, or under-specifying a single product across the whole site.
Depth and panel rating: Each work front was assessed against its design depth, soil class and surcharge conditions. Steel panels were nominated where the depth and ground conditions demanded the heavier rated wall; aluminium boxes were selected where the depth allowed and where reducing the lift weight unlocked the customer’s existing excavator fleet.
Lift compatibility with available plant: Rather than asking the contractor to mobilise additional heavy plant, the design was calibrated against the lift charts of the excavators already on site. This kept plant utilisation high and avoided a hidden cost the contractor would have absorbed under a one-size-fits-all shoring spec.
Safe access at depth: At 6m, vertical access becomes an engineered item in its own right. Davit arms were specified to provide rated anchor points for safe entry, egress and rescue, paired with handrail systems at the surface to manage the trench-edge fall risk.
The mixed-system approach was the engineering decision that unlocked the project, it gave the customer wall capacity where they needed it, lift compatibility where they needed it, and rated access at every depth.
Equipment Used
- Legend VertiShores: hydraulic drop-in shoring for shallow service trenches; allows installation without operators entering the trench.
- Steel Shoring Boxes (4000 x 2010mm panels, 755kg): heavier rated wall capacity for the 6m deep sections and tougher soil conditions.
- Aluminium Shoring Boxes: lighter lift weight for mid-depth work fronts and access-constrained sections, matched to the customer’s existing excavator fleet.
- Handrail Systems: compliant fall protection at trench edges across all work fronts.
- Davit Arms: cated vertical access and rescue provision for the deeper 6m trench sections.
The Outcome
The mixed-system shoring package allowed the contractor to keep all work fronts active across the subdivision without mobilising additional plant or standing down crews while waiting on engineered temporary works.
Trenching at 2m, 3m and 6m depths proceeded under compliant, engineered conditions, with rated access provided where it was needed.
Three outcomes the customer flagged directly:
- Project stayed on programme. Next-day temporary works design and next-day equipment delivery meant the live works didn’t lose a day to shoring procurement.
- One package, three systems, one engineering hand. The contractor didn’t have to brief three suppliers or reconcile three different temporary works packs; Legend Hire engineered the full mix as a single coordinated solution.
- Plant fleet stayed efficient. Matching the shoring spec to the customer’s existing excavators avoided the cost and lead time of mobilising additional machinery just to handle a one-size-fits-all shoring product.
The customer in Brisbane is now working with Legend Hire as their shoring partner across follow-on subdivision works.
Frequently Asked Questions
Whenever depth, soil conditions or plant access vary materially between work fronts. Specifying a single shoring product across a mixed site usually means oversizing for some areas, which strands lift capacity, or undersizing for others, which creates a safety exposure. A mixed-system design lets each work front run with the right wall capacity and the right lift weight.
A VertiShore is a hydraulic shoring system that is dropped into a trench from the surface and pressurised to brace the trench walls. They’re typically used on shallower service trenches where speed of installation matters and where keeping operators out of the trench is a priority.
Each shoring panel and box has a known lift weight and footprint. Legend Hire’s engineers assess the customer’s excavator fleet and the access conditions at each work front, then specify the system whose lift weight and reach matches the available plant. This avoids the cost of bringing in additional machinery purely to handle shoring.
At depth, vertical access and rescue need to be engineered, not improvised. Legend Hire specifies davit arms, rated anchor points at the trench surface, paired with handrail systems at the edge. Together they provide compliant entry, egress and rescue provision throughout the work.
In many cases temporary works design can be issued the next day, and the full equipment package delivered the day after. Lead time will vary with depth, scope and stock availability, but Legend Hire’s in-house engineering and local depot network are set up to move quickly on live works.