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Failure Case Study of Construction at a Solid Waste Site

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. Geotechnical Courses. Required Courses - CE 322 Geotechnical Engineering - CE 322L Geotech Lab

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Failure Case Study of Construction at a Solid Waste Site

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  1. 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

  2. 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

  3. 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)

  4. Project Data • Site was an old sand & gravel dredging area around 1900’s • 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. Analysis Cont’d • 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

  13. 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

  14. References • ASCE’s Journal of Performance of Constructed Facilities • ASCE’s Journal of Professional Issues in Engineering Education and Practice • J. Feld & K.L. Cooper, “Construction Failure,” Second Edition, 1997, John Wiley & Sons.

  15. Questions? Comments?

  16. Installation of Minipiles • From the floor surface, holes (7”dia) 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

  17. Installation Cont’d • 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

  18. Installation Cont’d • 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.

  19. 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.

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