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Full-Text Articles in Engineering
Second-Order Perturbation Analysis Of The St. Venant Equations In Relation To Bed-Load Transport And Equilibrium Scour Hole Development, Frans Joseph Lambrechtsen
Second-Order Perturbation Analysis Of The St. Venant Equations In Relation To Bed-Load Transport And Equilibrium Scour Hole Development, Frans Joseph Lambrechtsen
Theses and Dissertations
This analysis is an expansion of research done by Rollin Hotchkiss during his Ph.D work. The research uses fluid flow, sediment transport, and perturbation theory to predict where scour will occur in a variable-width channel. The resulting equations also determine equilibrium scour depth based upon the stream bed elevation derived from a dimensionless bed slope equation. Hotchkiss perturbed the width of the channel using a second order Taylor Series perturbation but neglected second order terms. The present work follows the same procedures as Hotchkiss but maintains the second order terms. The primary purpose is to examine how the additional terms …
Large-Scale Testing Of Passive Force Behavior For Skewed Abutments With High Width-Height Ratios, Katie Noel Palmer
Large-Scale Testing Of Passive Force Behavior For Skewed Abutments With High Width-Height Ratios, Katie Noel Palmer
Theses and Dissertations
The effects of seismic forces and thermal expansion on bridge performance necessitate an accurate understanding of the relationship between passive force and backwall deflection. In past case studies, skewed bridges exhibited significantly more damage than non-skewed bridges. These findings prompted studies involving numerical modeling, lab-scale tests, and large-scale tests that each showed a dramatic reduction in passive force with increased skew. Using these results, a correlation was developed between peak passive force and backwall skew angle. The majority of these tests had length to height ratios of 2.0; however, for several abutments in the field, the length to height ratio …
Passive Force On Skewed Abutments With Mechanically Stabilized Earth (Mse) Wingwalls Based On Large-Scale Tests, Bryan William Franke
Passive Force On Skewed Abutments With Mechanically Stabilized Earth (Mse) Wingwalls Based On Large-Scale Tests, Bryan William Franke
Theses and Dissertations
Passive force-deflection behavior for densely compacted backfills must be considered in bridge design to ensure adequate resistance to both seismic and thermally induced forces. Current codes and practices do not distinguish between skewed and non-skewed bridge abutment geometries; however, in recent years, numerical models and small-scale, plane-strain laboratory tests have suggested a significant reduction in passive force for skewed bridge abutments. Also, various case studies have suggested higher soil stresses might be experienced on the acute side of the skew angle. For these reasons, three large-scale tests were performed with abutment skew angles of 0, 15 and 30 degrees using …
Evaluation Of Passive Force On Skewed Bridge Abutments With Large-Scale Tests, Aaron Kirt Marsh
Evaluation Of Passive Force On Skewed Bridge Abutments With Large-Scale Tests, Aaron Kirt Marsh
Theses and Dissertations
Accounting for seismic forces and thermal expansion in bridge design requires an accurate passive force versus backwall deflection relationship. Current design codes make no allowances for skew effects on the development of the passive force. However, small-scale experimental results and available numerical models indicate that there is a significant reduction in peak passive force as skew angle increases for plane-strain cases. To further explore this issue large-scale field tests were conducted at skew angles of 0°, 15°, and 30° with unconfined backfill geometry. The abutment backwall was 11 feet (3.35-m) wide by 5.5 feet (1.68-m) high, and backfill material consisted …