Sheet pile – Mont Carmel, Switzerland
The project is located in Fribourg, Switzerland, and has been developed for a 6-floor residential building with two basements. The excavation was 6.3m from the natural ground level. Initially, my company won the project tenders by doing the initial shotcrete wall and soil nails solution which designed by a third engineering consultant company, which cost 102.000 CHF.
After we met the investors and carefully investigated the building, soil parameters, and surrounding structures, we proposed a new approach using sheet piles and steel props to give safer and more economical solution.
My roles were:
- Proposed the optimized solutions.
- Conducted geotechnical modelling.
- Created Technical drawings and reports.
The challenges:
- The soils contain very stiff clayey layers (cu ≥ 200 kPa)
- Two big trees are required to protect the root system near the excavation zone. That means no structures interfere within the trunk radius of 9m.
Project details
How?
- Designed a retaining system using sheet piles and steel bracing systems to stabilize the excavation.
- Used GEO5 software to model the sheet pile walls and check excavation stability.
- Calculated the bracing systems using SAP2000 to withstand applied loads and provide adequate support.
- Selected the suitable vibro hammer-MS Muller MS32 HFV for sheet pile driving. This one is strong enough to surpass the very stiff clays.
Results
- The sheet pile driving and prop installation were finished with a high quality within only 5 working days, saving 10 days compared to the initial time schedule.
- The new total budget was only 76.000 CHF, which resulted in a cost saving of 27,000 CHF for the investor.
- The client gave positive feedback and satisfaction in delivering a robust and sustainable design within the project timeline.