Geosyntec was retained by the project owner to provide a geotechnical and structural review for an ethylene plant being constructed in Saudi Arabia. Geosyntec's role included third-party review, direction of a supplemental geotechnical investigation, and subsequent recommendations for site foundations and structural modifications in order to provide more efficient and cost-effective designs.
Geosyntec's Scope of Services
Geosyntec received multiple assignments in support of this project:
- Geosyntec reviewed existing geotechnical investigations and recommendations for site development performed by others. In performing our review, we identified the presence of sabkha materials, which are typically salt-encrusted desert flats with weakly cemented loose sand and some compressible silts/clays below a hard crust that could lead to collapse and uncontrolled settlement during the operational life of the facility. Once these site conditions were identified, we worked with the client and a local geotechnical firm to perform a supplemental site investigation and develop a more complete understanding of variability and the potential implications for foundation designs.
- Geosyntec performed analyses and developed recommendations for a number of structure foundations, including five pipe racks, 58 individually sized shallow footings, eight tall tower column footings, and five large ringer cranes. In almost all cases, foundation recommendations were based on controlling settlements attributed largely to the sabkha layers. Settlement calculations were also performed for the world's second largest ringer crane and recommendations were developed to limit the differential settlement across the base of the crane.
- We performed structural design reviews of a number of critical hybrid steel and concrete structures, including the main pipe racks, cracking heater and miscellaneous equipment support structures, with a view to reducing the required quantities of steel and concrete through more balanced and optimized structural design. Significant quantity reductions were achieved.
As a result of the efforts of the Geosyntec geotechnical/structural team, the project owner reported savings of almost $45 million in concrete and steel material costs compared to the original footing/structure designs and up to $150 million due to schedule compression. Additional benefits included foundations with enhanced reliability, control of potential settlement issues, and a better understanding by the owner of site constraints and associated solutions.