Manhole jacking and separation
Problem: Deep water and winter freeze cause manhole jacking and separation.
A manhole located in Class ‘A’ wetlands in the city of Anchorage AK., experiences severe frost damage. Adjacent to a creek and subject to high water table and deep winter freezing, over the years frost pulled the manhole apart causing the lid and grade rings to fall off, the cone section to tilt 35° from vertical, and the 4” thick reinforced concrete barrel section broke away from the base, allowing ground and surface water to flow freely into the manhole. End result, soil erosion around the manhole and in the winter months, jacking of the manhole sections and displacement.
Solution: To stop the jacking and the movement EPS Geofoam acts as an insulated concrete form and later as a compressible inclusion virtually eliminating the jacking around, separation and erosion. EPS Geofoam in earthworks applications provides the benefit of reducing both vertical and lateral pressures on below ground structures.
Geofoam installation
Geofoam, insulated concrete form
Geofoam Benefits:
Cost effective
- Reduces associated structural costs
Labor Savings:
- Does not require surcharging, preloading or staged construction
- No secondary compaction required
- Not weather-dependent- can be installed during rain or snow
- Does not require heavy equipment to move
- Ease of installation, ease of cutting
Product Attributes:
- Available in job-specific block sizes
- Engineered per project specifications – can match compressive resistance with job requirements
