Boğazköprü Railway Overpass A2 Abutment Geofoam Approach Embankments

Kocasinan / Kayseri

Site Conditions

  • The local ground profile consisted of highly compressible elastic silt, high-plasticity clay and organic clay layers ranging from very soft to stiff consistency and extending to depths of approximately 40 m.
  • Without ground improvement, a conventional compacted soil embankment could not satisfy the settlement and bearing capacity criteria under the design loads.
  • Conventional ground improvement methods were disadvantageous in terms of overall project cost, constructability and construction duration.
  • A conventional approach embankment reaching heights of up to 10 m behind the bridge abutment would have imposed substantial lateral earth pressures on the abutment.

Designed Solution

  • Construction of the bridge approach embankments using geofoam block technology to satisfy bearing capacity and settlement requirements.

Advantages of the Applied Geotechnology

  • The design criteria for bearing capacity, total settlement and differential settlement of the foundation soils were satisfied.
  • Lateral earth pressure acting on the bridge abutment was effectively eliminated.
  • The project was completed within a substantially shorter construction period compared with conventional construction methods.
  • The geofoam solution provided a more economical alternative in terms of overall project cost compared with conventional ground improvement methods.

Performance Under Service Loads

  • A comprehensive instrumentation and monitoring program using settlement plates and earth pressure cells was implemented.
  • Periodic measurements have been collected since the roadway was opened to traffic on October 19, 2019.