Gilbert, Smith, Melbourne

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An experimental study of soil-arch interaction in
masonry arch bridges
intro
Matthew Gilbert Colin Smith (University of
Sheffield, UK)Clive Melbourne Jinyan Wang
(University of Salford, UK)sponsored by
Gilbert, Smith, Melbourne Wang Universities of
Sheffield Salford
IABMAS conference Porto, July 2006
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contents

• why is soil important?
• limitations of existing analysis methods
• the experimental study

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why is soil important?
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why is soil important? 2

• however
• limited range of fill types have been tested
• spandrel walls obscure our view of soil response
• the rigid abutments used in the lab. may be
  unrepresentative

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soil in real arch bridges
as taken from trial pits
or taken through core holes from below
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soil in real arch bridges
mixed
granular
clay
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how is soil modelled at present?

• i.e. common to use rather crude indirect models

Dispersion of applied load e.g. 21 or
Boussinesq
Passive fill pressures e.g. borrowed from
retaining wall theory
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example passive restraint modelled using bar
elements

• RING 1.5 / 2.0 - http//ring.shef.ac.uk
• existing analysis programs calibrated using a
  limited dataset (e.g. granular fill rigid
  abutments)
• urgently need high quality experimental data so
  that better soil models can be developed

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new test facility Salford University

• key features
• very stiff tank
• transparent, low-friction sides

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backfilling
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instrumentation

• displacement transducers
• soil pressure cells
• acoustic gauges

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(No Transcript)
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applied load
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bridge 1 limestone fill free abutments
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bridge 1 limestone fill free abutments
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bridge 2 clay fill free abutments
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bridge 2 clay fill free abutments
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bridge 2 clay fill free abutments
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Load deflection response
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Perth Penetrometer results
field data
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enhanced soil model example

• currently trialling the use rigid-plastic finite
  elements
• simple robust problem formulation
• parameters just c and ?
• other approaches also being investigated
• (being developed as part of EPSRC funded project
  at Sheffield)

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compare with experimental
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conclusions

• soil can significantly increase the ultimate
  capacity of an arch bridge
• however, soil-arch interaction is poorly
  understood
• especially when clay fill and free abutments
• a new test rig has been designed to enable
  collection of high quality data
• the acquired data is being used to help develop
  improved analysis models