Failure Case Study of Construction at a Solid Waste Site

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Failure Case Study of Construction at a Solid
Waste Site

• K. Madhavan, Ph.D., P.E.,
• Dept. of Civil Env. Engineering
• Christian Brothers University
• Memphis, TN, 38104

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Geotechnical Courses

• Required Courses
• - CE 322 Geotechnical Engineering
• - CE 322L Geotech Lab
• - CE 340 Design of Foundations
• Elective Course
• - CE 418 Advanced Design of Foundations

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Motivation

• Technical Issues Brings together all principles
  applications including from other
  required/elective courses
• Opportunities to discuss professional and ethical
  issues
• Perhaps students understand materials better
  (connecting concepts with applications)

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Project Data

• Site was an old sand gravel dredging area
  around 1900s
• A clay cap was in place
• 23 acre site
• Four buildings (one two storey-140,000 sq. ft.)
  on pile foundations
• Buildings were on monotube piles

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Construction at a Landfill Site

• Geotechnical investigations and report were done
  in 1977-78
• - Not to build at the site and find another site
• - The client chose to build at the site (1979)
• - The cost of construction about 6M
• - After several years of use, buildings
• were not usable and were vacated
• - A remedial work was done for about 10M
• - Litigation between parties and was
• settled out of court

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Construction Details

• A gas collection system was installed in a sand
  layer above the waste
• Numerous obstructions were encountered while
  driving the piles
• Utilities were grade supported
• Monotube piles were filled with concrete

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Structural Details

• All buildings had structural floor slabs
• Floor beams supported by piles and one-way slabs
• Superstructures were of steel frames with
  exterior metal sheathing

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Performance of Buildings, Pavement, and other
construction

• Cracks on floors and walls, floor sloped
• Methane gas inflow in buildings
• Buildings Differential settlements up to 18
  inches
• Parking area settled as much as 3 ft
• Buried utilities were affected
• Large amount of asphalt added to pavement

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Geotechnical Investigations

• About 100 boreholes
• Soil Layers
• Clay cap
• Landfill material 30 to 60 ft (materials
  including car bodies, concrete slabs, etc)
• Beneath landfill loose sand layer (left from
  previous dredging operations)
• Bottom strata (100 ft below) dense sand
  suitable to receive pile foundations

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Remediation

• Use of minipiles to underpin and relevel the
  buildings
• Use of driven piles to support the outside
  structures (lamp posts, access ramps)
• Use of design-build contract
• Use of best value concept in awarding the
  contract

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Analysis of Failure

• Possible reasons
• Pile Foundation System
• - Pile installation monitoring
• - use of proper pile wall thickness
• - depth of piles (obstructions)
• - Negative skin friction (excessive )
• - No provision to minimize it
• - The negative skin friction may have
• added to the load applied at bearing

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Analysis Contd

• Gas Collection System
• - at a landfill site was a poor choice
  Construction of the gas collection system on
  grade
• - water main breaking and washing out part of
  the sand layer gas collection system

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Geotechnical Concepts

• Problems in building at landfill sites
• Total and differential settlements
• Negative skin friction (means of reducing)
• Providing proper gas collection system
• Construction control monitoring
• Design-build concept
• Performance oriented specifications

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References

• ASCEs Journal of Performance of Constructed
  Facilities
• ASCEs Journal of Professional Issues in
  Engineering Education and Practice
• J. Feld K.L. Cooper, Construction Failure,
  Second Edition, 1997, John Wiley Sons.

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Questions?

• Comments?

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Installation of Minipiles

• From the floor surface, holes (7dia) were
  drilled through the beams up to the desired depth
• 4 diameter pipes were inserted
• The smaller pipe was twisted and pulled out for a
  short distance
• and concrete grout was injected

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Installation Contd

• The smaller pipe was withdrawn and high strength
  steel casing was inserted
• For piles at locations other than through the
  existing monotube piles, 12 diameter monotube
  pile was driven and similar minipile was
  constructed

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Installation Contd

• After the pile has reached its design strength,
  the floor was lifted using the pile as a reaction
  pile
• The piles were connected to the beams and the
  original monotube piles were cut off.

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Pile Testing

• Four monotube piles were load tested and the
  ultimate capacity was 150 Tons
• Two other 12 diameter pipe piles were tested and
  the ultimate capacity was 200 Tons.