Settlement Mitigation by Using Cellular Concrete at Nepewassi River Bridge, Ontario: A Case Study

The Ministry of Transportation of Ontario (MTO) trialled the use of cellular concrete to control the ongoing settlements of approach embankments at a bridge located in northern Ontario. The bridge carries Highway 535 over the Nepewassi River, 3.5 km south of Highway 17, in the Township of Dunnet. Historical and recent monitoring data confirmed the approach fill embankments had been settling for over 60 years. Since 2000, the south and north approaches settled 275 and 240 mm respectively. The site is underlain by some 15 to 20 m of soft, compressible clay deposits which overlay more competent soil comprised of compact to dense sands. It was postulated that the continuing settlement of the embankments was due to the primary consolidation of the soft clay deposits. To remediate the grade of the embankment and mitigate the continuing settlement, the existing embankment fill was removed and replaced with a lightweight fill of cellular concrete. This was carried out with the intent of reducing the effective vertical stresses on the soft clay deposits, so that the resulting ground movement would be more tolerable. Cellular concrete is a lightweight fill material that is listed on the MTO’s Designated Sources of Material List and satisfies MTO’s prequalification requirements. Environmental approvals comprised a substantial component of the acceptance of cellular concrete. As part of this trial, extensive instrumentation and monitoring programs were incorporated to assess the geotechnical and environmental performance of the embankment. This paper presents the results of the foundation investigation, the design methodology, the environmental monitoring and post construction settlement monitoring after unloading the approach fills by using cellular concrete.

• Record URL:
  http://tac-atc.ca/sites/tac-atc.ca/files/conf_papers/ahmad.pdf
• 
• Corporate Authors:

  Transportation Association of Canada (TAC)

  401-1111 Prince of Wales Drive
  Ottawa, Ontario  Canada 
• Authors:
  • Ahmad, KSQ
  • Sangiuliano, T
  • Dolton, B
  • Smith, TJ
• Conference:
  • TAC 2016: Efficient Transportation - Managing the Demand - 2016 Conference and Exhibition of the Transportation Association of Canada
• Publication Date: 2016

Language

• English

Media Info

• Media Type: Web
• Pagination: 1 PDF file, 1.6 MB, 20p.
• Monograph Title: TAC 2016: Efficient Transportation - Managing the Demand - 2016 Conference and Exhibition of the Transportation Association of Canada

Subject/Index Terms

• TRT Terms: Access roads; Bridges; Clay; Concrete; Conferences; Embankments; Expanded materials; Ground settlement; Soil stabilization
• Geographic Terms: Canada
• ITRD Terms: 435: Access road; 3455: Bridge; 8018: Canada; 4177: Clay; 4755: Concrete; 8525: Conference; 2801: Embankment; 4502: Expanded material; 5792: Settlement; 3689: Soil stabilization
• Subject Areas: Bridges and other structures; Geotechnology; Highways; I32: Concrete; I42: Soil Mechanics;

Filing Info

• Accession Number: 01616328
• Record Type: Publication
• Source Agency: Transportation Association of Canada (TAC)
• Files: ITRD, TAC
• Created Date: Nov 15 2016 4:51PM