Combigrid® – Stabilisation and Reinforcement for Crane Working Platform, Canada

Project snapshot – flood resilience at Fry’s Corner

Surrey in south-west British Columbia has a wet climate. At the junction known as Fry’s Corner, land lies 1–2m above sea level close to the Serpentine River. This low-lying location has long been prone to flooding. As part of British Columbia’s Flood Strategy, works on the east bank of the Upper Serpentine River were launched to safeguard the drainage-pump station and dike.

The challenge – heavy crane on soft ground

To construct a fish-friendly screw pump, spillway and diversion structure, the contractor planned to operate a 70-tonne crawler crane. Its working radius extended across the river and partially over a public highway, demanding a highly stable working platform. Ground investigations revealed silty clay over medium-plastic clayey silt with moisture content up to 70%, creating high risk of punching shear and settlement. Because the platform would be removed after construction, a cost-effective solution using fewer resources was essential.

Digital path to the solution – Naue Portal & Platform module

Tetris GEO approached Naue for technical support. The project team turned to the Naue Portal and used the Naue Platform software module to design and compare geogrid-reinforced options. Site and crane parameters were entered into the online interface, which assessed Ultimate and Serviceability Limit States for stability and differential settlement. Working within the Naue Portal allowed rapid iteration, optimisation of aggregate thickness and direct comparison with an unreinforced design – giving confidence in safety, constructability and cost-efficiency. Three design variants were generated:

1. Unreinforced solution with over-excavation and engineered granular fill.

2. Reinforced solution using a single layer of Combigrid® 40/40 Q1 GRK 4 C.

3. Dual-layer reinforced solution combining Combigrid® 30/30 Q1 GRK 4 C and Secugrid® 30/30 Q1.

The final design – lean, strong, buildable

To achieve the required strength and drainage performance within the construction timeline, Tetris GEO selected a two-layer Combigrid® 30/30 Q1 GRK 4 C system. Naue’s local distributor, White Cap Supply Canada, supplied the installer, Drake Excavating.

On the 100m² platform footprint, Naue Platform calculations enabled a reduction of approximately 600mm in aggregate thickness, cutting aggregate demand by around 60m³ – equivalent to roughly 120 tonnes. This significantly reduced material procurement, transport emissions, construction time and labour requirements, while eliminating the need to remove corresponding volumes of native soil.

Value delivered – safer, faster, lower-carbon

The combination of Combigrid® reinforcement and Naue Portal/Platform design produced a safe and cost-effective working platform on challenging, water-saturated soils. By decreasing aggregate usage and simplifying installation, the solution supported faster construction, lower carbon emissions and improved economic viability. For temporary working platforms where safety and sustainability are key, the Naue Portal and Naue geogrids provide a proven, optimised solution.

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