Five augered cast-in-place piles bearing in a stiff Coastal Plain formation of South Carolina wer... more Five augered cast-in-place piles bearing in a stiff Coastal Plain formation of South Carolina were load tested using the conventional top-loaded setup. Four of the five test piles failed well below the predicted ultimate compressive capacity. Interpretation of the load test results suggested that the test piles were damaged during testing, and this conclusion was supported by the results of pile integrity testing. Numerical analysis indicates that even small eccentricities developing within the pile section could lead to damage at higher axial compressive loads. The lessons learned are: (1) augered cast-in-place piles can exhibit eccentricity that is inherent to the construction process; (2) high axial compressive loads applied during load testing can intensify eccentricity effects; (3) unreinforced augered cast-in-place piles can be vulnerable to damage from shear and moment forces, and; (4) successful design should consider the potential for eccentric loads during load testing and...
This article describes a study to determine the effectiveness of three ground-modification method... more This article describes a study to determine the effectiveness of three ground-modification methods for densifying granular material and thus reducing the possibility of settlement or liquefaction. The three methods tested were: vibro-compaction, used when dealing with relatively clean cohesionless sands with silt contents less than 12-15% and clay contents less than 3%; vibro-replacement, generally used in marginal soils; and deep dynamic compaction (DDC), which is also used in relatively clean granular materials. The study compares the tip resistance of pre- and post-construction cone penetrometer test soundings at several study sites. The effectiveness of the individual procedures can be determined by comparing these resistance measurements and determining the improvement index. A previously developed improvement index was used, but the authors in the current study tried to account explicitly for the effects of fines content on the degree of improvement. Findings show that densification achieved through vibro-compaction and vibro-replacement is a function of the initial density and fines content of the material. As the fines content increases, the densification improvement generally decreases. Densification performance also appears to be affected by the type of fines. Findings show that the DDC process is not influenced by the fines content of the material to the same degree as the other 2 methods. These results indicate that the success of ground improvement technologies should be measured based on verification testing rather than an improvement index alone.
The combustion of subbituminous coals in electrical generating units produces a fly ash that has ... more The combustion of subbituminous coals in electrical generating units produces a fly ash that has proven benefits for the construction industry. Fly ash consists of the inorganic material within the coal that has been fused during combustion, solidified while suspended in the ...
Five augered cast-in-place piles bearing in a stiff Coastal Plain formation of South Carolina wer... more Five augered cast-in-place piles bearing in a stiff Coastal Plain formation of South Carolina were load tested using the conventional top-loaded setup. Four of the five test piles failed well below the predicted ultimate compressive capacity. Interpretation of the load test results suggested that the test piles were damaged during testing, and this conclusion was supported by the results of pile integrity testing. Numerical analysis indicates that even small eccentricities developing within the pile section could lead to damage at higher axial compressive loads. The lessons learned are: (1) augered cast-in-place piles can exhibit eccentricity that is inherent to the construction process; (2) high axial compressive loads applied during load testing can intensify eccentricity effects; (3) unreinforced augered cast-in-place piles can be vulnerable to damage from shear and moment forces, and; (4) successful design should consider the potential for eccentric loads during load testing and...
This article describes a study to determine the effectiveness of three ground-modification method... more This article describes a study to determine the effectiveness of three ground-modification methods for densifying granular material and thus reducing the possibility of settlement or liquefaction. The three methods tested were: vibro-compaction, used when dealing with relatively clean cohesionless sands with silt contents less than 12-15% and clay contents less than 3%; vibro-replacement, generally used in marginal soils; and deep dynamic compaction (DDC), which is also used in relatively clean granular materials. The study compares the tip resistance of pre- and post-construction cone penetrometer test soundings at several study sites. The effectiveness of the individual procedures can be determined by comparing these resistance measurements and determining the improvement index. A previously developed improvement index was used, but the authors in the current study tried to account explicitly for the effects of fines content on the degree of improvement. Findings show that densification achieved through vibro-compaction and vibro-replacement is a function of the initial density and fines content of the material. As the fines content increases, the densification improvement generally decreases. Densification performance also appears to be affected by the type of fines. Findings show that the DDC process is not influenced by the fines content of the material to the same degree as the other 2 methods. These results indicate that the success of ground improvement technologies should be measured based on verification testing rather than an improvement index alone.
The combustion of subbituminous coals in electrical generating units produces a fly ash that has ... more The combustion of subbituminous coals in electrical generating units produces a fly ash that has proven benefits for the construction industry. Fly ash consists of the inorganic material within the coal that has been fused during combustion, solidified while suspended in the ...
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