Belfast Transport Hub Track Foundation
State of the art track foundation design was employed to ensure full service-life performance, plus a 5 year zeromaintenance requirement. The trackbed was analysed with PLAXIS FEA software, using the Tensar Stabilised Soil Model plug-in to model the mechanically stabilised layer incorporating Tensar geogrids.
Benefits
- 5 year zero-maintenance design to meet contractor’s obligations
- 15mm maximum settlement target after 5-years incorporated into the design and confirmed by the FEM design approach
- No deep soil stabilisation or removal of weak subgrade needed, reducing overall construction time
The track crosses two zones with distinct subgrade types, a stiff glacial deposit, and soft alluvium with loose made ground. A design based on a target formation modulus (Ev2) would not adequately consider the depth of influence of the rail loading and the associated settlement. In addition to this, the contractor needed a zero-maintenance design to meet a 5-year contractual obligation.
Tensar introduced their elasto-plastic mechanistic empirical design approach for trackbed foundations that can limit subgrade deformations. In addition, the Tensar Stabilised Soil Model plug-in to FEA software enabled design of a mechanically stabilised trackbed to limit settlement. The strain-based design enabled maximum settlements to be assessed with confidence.
