A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Numerical Analysis of Dense Narrow Backfills for Increased Passive Resistance
Previously, full-scale lateral load tests conducted on pile caps with different aspect ratios showed that placement of a narrow, dense backfill zone against the cap could substantially increase the passive resistance. The objective of this study is to develop design equations to predict the increased passive resistance for these limited width backfills for both 2D and 3D conditions. For this purpose, the finite element program, PLAXIS 2D was used to investigate the 2D or plane strain passive resistance. To validate the procedure, numerical results were calibrated against analytical results obtained from PYCAP and ABUTMENT. The analytical models were additionally validated by comparison with measured ultimate passive resistances. The calibrated model was then used to simulate the passive behavior of limited width gravel backfills. Parametric studies were also executed to evaluate the influence of a range of selected design parameters, related to the pile cap geometry and backfill soil type, on the passive resistance of limited width backfills. Numerical results indicated that significant increases in passive resistance could be expected for long abutment walls where end effects are less pronounced and the geometry is closer to a plane strain condition. Based on results obtained from the parametric studies, a design method was developed for predicting the ultimate passive resistance of limited width backfills, for both plane strain and 3D geometries. Comparisons between measured and numerical results indicated that using the Brinch- Hansen 3D correction factor, R3D, as a multiplier to the plane strain resistances, will provide a conservative estimate of the actual 3D passive response of a pile cap with a limited width backfill.
Numerical Analysis of Dense Narrow Backfills for Increased Passive Resistance
Previously, full-scale lateral load tests conducted on pile caps with different aspect ratios showed that placement of a narrow, dense backfill zone against the cap could substantially increase the passive resistance. The objective of this study is to develop design equations to predict the increased passive resistance for these limited width backfills for both 2D and 3D conditions. For this purpose, the finite element program, PLAXIS 2D was used to investigate the 2D or plane strain passive resistance. To validate the procedure, numerical results were calibrated against analytical results obtained from PYCAP and ABUTMENT. The analytical models were additionally validated by comparison with measured ultimate passive resistances. The calibrated model was then used to simulate the passive behavior of limited width gravel backfills. Parametric studies were also executed to evaluate the influence of a range of selected design parameters, related to the pile cap geometry and backfill soil type, on the passive resistance of limited width backfills. Numerical results indicated that significant increases in passive resistance could be expected for long abutment walls where end effects are less pronounced and the geometry is closer to a plane strain condition. Based on results obtained from the parametric studies, a design method was developed for predicting the ultimate passive resistance of limited width backfills, for both plane strain and 3D geometries. Comparisons between measured and numerical results indicated that using the Brinch- Hansen 3D correction factor, R3D, as a multiplier to the plane strain resistances, will provide a conservative estimate of the actual 3D passive response of a pile cap with a limited width backfill.
Numerical Analysis of Dense Narrow Backfills for Increased Passive Resistance
K. M. Rollins (author) / M. Nasr (author) / T. M. Gerber (author)
2010
210 pages
Report
No indication
English
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