Optimizing Foundations based on CSM panels using Rapid Load tests-PPT Presentation

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The project involved converting an office site in Breda, the Netherlands, into six residential buildings with underground parking. CSM (cutter soil mixing) barrettes were selected for the deep foundations because the equipment was already on site for constructing the excavation walls. Each column footing was initially designed with one or two panels, each measuring 2.4 × 0.6 m. However, conventional pile-design rules predicted excessive settlement at the required loads, suggesting that three to four panels might be needed.<br /><br />To verify performance and optimize the design, six double-panel barrettes were tested using StatRapid rapid load testing. The method provides a quasi-static assessment, with results corrected for inertia and loading-rate effects. Tests reached loads of approximately 6.6–11.7 MN. At a test load of 9 MN, maximum settlements were below 10 mm (4.8–8.2 mm), and permanent settlements after unloading ranged from 0.6 to 2.5 mm.<br /><br />The test results showed that the two-panel foundations were substantially stiffer than predicted by standard design rules. They had sufficient capacity and acceptable settlement, allowing the design to use one or two panels per column footing rather than the three to four panels indicated by settlement-based calculations.<br /><br />The case demonstrates that rapid load testing can support more efficient foundation design. Integrating pile tests early in future CSM projects may reduce foundation costs, construction time, cement use, and associated emissions. The presenters recommend gathering more test data from different sites to improve design methods and guidance for CSM-panel foundations.

Keywords

Breda

Netherlands

office conversion

residential buildings

underground parking

CSM barrettes

rapid load testing

foundation design

settlement control

deep foundations