Performance of a GRS-IBS Bridge Abutment: Colorado Study

The replacement of the Colorado Department of Transportation (CDOT) Region 1 Twin Bridge over Smith Road and Union Pacific Rail Road (UPRR) on I-70 provided an excellent opportunity for the performance evaluation of GRS (geosynthetically reinforced soils) abutment. The performance of the GRS abutment was measured using SAA (shape accel array) for lateral deformation and vertical settlement measurement, Geokon 4810 for horizontal earth pressure, 4800 for vertical earth pressure, 4420 for separation measurement between abutment and top of sheet pile wall, 4150 for strain of anchor rod, and optic fiber for geosynthetic strain measurement. Phase I covered the West-Bound portion of the Abutment #4 with sheet pile façade. Results of finite element analyses were compared to the measured performance of the SAA and Geokon devices, and excellent agreements were accomplished. Besides the delay in construction and instrument installation and web-site monitoring data presentation, the study program is judged effective. The optic fiber strain gage needs further study for its effectiveness before future use in geosynthetic strain measurement. Conventional strain gages replaced the optic fiber in Phase II East-Bound Abutment #4 study with a drastically scaled-back instrumentation program. Finite element analysis was found to an effective predictor of field abutment performance and was recommended for use prior to construction to better predict potential problems during construction, such as the significant lateral displacement of the sheet-pile wall observed during the excavation for water transport pipeline installation immediate to and along the wall front. The installation of tiebacks and prompt backfilling action prevented the excessive lateral displacement of the sheet pile wall. Subsequent finite element analyses also confirmed the potential problems the excavation caused. It is recommended not to grout the tiebacks with strain gage installation until the measurement was completed to facilitate successful tieback tension measurement. This project provides precious field performance information of GRS-IBS (Geosynthetic Reinforced Soil - Integrated Bridge System) for performance check and finite element program validation. Preconstruction finite element analysis is recommended for performance prediction.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 108p

Subject/Index Terms

Filing Info

  • Accession Number: 01776688
  • Record Type: Publication
  • Report/Paper Numbers: CDOT-2020-07, UCD-CGES-2015-01
  • Contract Numbers: 214.08
  • Created Date: Jul 19 2021 9:40AM