In-Situ Evaluation of Bridge MSE Retaining Walls with Excessive Panel Movements

Mechanically stabilized earth (MSE) precast concrete retaining walls have been used extensively in the U.S.A. since the early 1970s. They are reliable, cost-effective, aesthetically pleasing and easily constructible. However, some of these walls have been known to show excessive movements of the precast fascia panels, with some failing walls. There is currently no available comprehensive and in-situ procedure to monitor and evaluate such walls. The current study developed such a procedure involving monthly 3-D robotic laser scanning and backfill soil testing through obtained cores, with application on two recent MSE walls with apparent excessive panel movements in Hurst, Texas. The soil testing involved in-situ resistivity imaging and laboratory soil testing following applicable specifications. Laser scanning results over a 22-month period showed that both walls showed out-of-plane and settlements in the ranges of 4-5 mm and 4-8 mm, respectively, relative to the scan initiation time. The movements varied with seasonal rainfall changes with peaks and valleys, typically lagging by a few months for soil pore pressure build-up. The presence of manholes in the backfill soil can be helpful in reducing this pressure. Soil tests showed that the backfill soil for both walls were not acceptable in regards to fines content, friction angle and optimum dry density. High fine soil content may have retained water for longer time affecting pore pressures. Inadequate backfill soil, faulty drainage in one wall and excessive pore pressures may have led to seasonal wall movements, causing rupture and/or pullout failures of some of the embedded steel straps.

• Record URL:
  https://annualmeeting.mytrb.org/OnlineProgram/Details/15632
• Supplemental Notes:
  • This paper was sponsored by TRB committee AKG50 Standing Committee on Transportation Earthworks.
• Corporate Authors:

  Transportation Research Board

  ,    
• Authors:
  • Momani, Zaid
  • Yazdani, Nur
  • Beneberu, Eyosias
• Conference:
  • Transportation Research Board 100th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2021-1-5 to 2021-1-29
• Date: 2021

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Photos; References; Tables;
• Pagination: 19p

Subject/Index Terms

• TRT Terms: Backfill soils; Electrical resistivity; Evaluation; Lasers; Mechanically stabilized earth; Panels; Pore pressure; Precast concrete; Retaining walls; Settlement (Structures); Soil tests
• Geographic Terms: Texas
• Subject Areas: Bridges and other structures; Geotechnology; Highways;

Filing Info

• Accession Number: 01763428
• Record Type: Publication
• Report/Paper Numbers: TRBAM-21-03320
• Files: TRIS, TRB, ATRI
• Created Date: Feb 4 2021 10:54AM