Evaluation of Bridge-Scour Research: Abutment and Contraction Scour Processes and Prediction (2011) / Chapter Skim
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2 ABUTMENT FORM AND CONSTRUCTION
2 ABUTMENT FORM AND CONSTRUCTION
Pages 15-24
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From page 16... ...
, coffer-dams, and construction caissons. The nature of an abutment inevitably requires that the layout of an abutment be tailored to fit the local topography of a bridge site.
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From page 17... ...
Pile supports are more common than are footing supports, unless the abutment is founded directly on rock. Spillthrough abutments are formed around a "standard-stub abutment," which comprises a concrete stub supported by a pile cap on two rows of circular piles.
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From page 18... ...
The geometry and dimensions of a wing-wall abutment - compacted earthfill embankment extends back from the abutment structure (prototype scale indicated) ; design provided by the Iowa DOT (Ettema et al.
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From page 19... ...
The foregoing descriptions of common abutment forms and construction arrangements are not reflected in the leading design guides and bridge-monitoring guides addressing scour at bridge abutments. For example, FHWA's (2009)
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From page 20... ...
Direct, dynamic simulation of the strength behavior of an earthfill embankment or a floodplain soil poses a practical difficulty for laboratory experiments on scour at bridge abutments. The difficulty is to replicate, at a reduced scale, the shear strength of a representative earthfill embankment.
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From page 21... ...
To varying extents, all flow boundaries are erodible. As this figure indicates, the major flow features of a short contraction prevail at a bridge waterway comprising a two-lane road.
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From page 22... ...
This flow field is characterized by a local contraction of flow and by generation of large-scale turbulence. For a severely contracted bridge waterway, flow contraction dominates the flow field and a substantial backwater occurs upstream of the bridge.
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From page 23... ...
For spill-through abutments comprising erodible embankments flow contraction dominates the abutment flow field. Once scour begins, the geometry of the bridge waterway (as a short contraction)
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From page 24... ...
Figure 2-11. For a spill-through abutment well set back on a flood-plain, deepest scour usually occurs where flow is most contracted through the bridge waterway.
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