Bridgestone Warehouse - Port of Brisbane

The Bridgestone Warehouse project at the Port of Brisbane required significant ground improvement to achieve the necessary bearing capacity for footings. The site presented complex conditions, including fill overlying Holocene clays and dense sand, with a specific 'hot spot' area prone to excessive settlement that had been missed during previous preloading.

DGSA implemented a targeted Mass Soil Mixing (MSM) strategy. To optimise performance, we engineered individual MSM blocks beneath footings rather than a single massive block. For the 'hot spot' area, we utilised a hybrid system of MSM blocks underlaid by a load transfer platform to ensure uniform load distribution.

Methodology: We utilised approximately 1,600 m³ of ready-mix grout. Precision was maintained by integrating GPS technology with our mixing rigs, which were pre-loaded with site design drawings. The water-cement ratio was managed via a ground-based "marination" process, ensuring the grout was perfectly incorporated into the soil matrix.

Verification: Comprehensive CPT testing was conducted to verify the homogeneity of the MSM blocks and ensure the structural strength met all engineering specifications.

A primary challenge was maintaining the specific rheology of the readymix grout in transit. We resolved this by performing final water-cement ratio adjustments on-site during the "marination" process. The use of GPS-guided rigs eliminated manual positioning errors, ensuring each block was constructed precisely according to the structural design.

The MSM solution provided a high-performance alternative to traditional piling, which would have required an extensive and costly working platform. For the 'hot spot' zone, MSM proved superior to a 'dig and replace' strategy, avoiding the need for complex shoring and large-scale soil disposal, ultimately saving the client time and project costs.