High-Rise Foundation Design in St Marys

Overview

In 2023, our firm was engaged by a developer to design the foundation system for a multi-story commercial tower in St Marys, a rapidly developing precinct in Sydney. The project involved constructing on a site characterised by soft, compressible alluvial soils. The location’s proximity to adjacent structures added complexity, as vibrations from construction activities needed to be minimised to avoid structural damage to adjacent properties.

The Challenge

• Soft Soil Conditions: The site had soft, compressible alluvial soils, requiring a carefully engineered foundation system.
• Proximity to Structures: Minimising construction vibrations to protect adjacent buildings.
• Data Limitations: Initial investigations provided limited soil data, leading to uncertainty in foundation design.

Our Approach

BHM Geotechnical employed a structured, multi-phased strategy to address these challenges:

1. Geotechnical Investigation

Conducted Standard Penetration Testing (SPT) and laboratory analysis to map soil stratigraphy and assess bearing capacity.

2. Advanced Footing Analysis

Used commercial software for in-depth analysis to calculate settlement and reduce footing depth.

3. Vibration Monitoring

Implemented real-time vibration monitoring systems to comply with Penrith City Council’s noise and vibration standards.

The Solution

The team redesigned the foundation using improved soil analysis, cutting down on footing depth and saving costs.

1. Foundation Redesign

Re-evaluated and redesigned the foundation system based on additional geotechnical analysis, reducing the depth of footings and lowering project costs.

2. Collaborative Execution

Ensured seamless coordination between geotechnical engineers, contractors, and environmental consultants.

3. Monitoring Compliance

Deployed vibration monitoring during piling and confirmed settlement levels through post-construction monitoring.

Results and Impact

The project turned a polluted site into a safe, useful space for homes and businesses. It helped protect the environment and brought new opportunities to the local community.

• Cost Savings: The revised foundation design resulted in a 15% budget reduction.
• Structural Integrity: Achieved less than 10 mm of vertical displacement, well within AS 2159 standards.
• Urban Sensitivity: Minimized construction impact on adjacent structures through precise vibration monitoring.
• Client Satisfaction: Delivered a cost-effective, timely solution praised for its innovative application of geotechnical expertise.

Conclusion

This project exemplifies our commitment to delivering innovative, cost-effective, and environmentally sensitive geotechnical solutions. By leveraging detailed analysis and real-time monitoring, we ensured the success of the high-rise foundation in St Marys, contributing to the region’s sustainable urban development.