CYCLIC LOAD CAPACITY AND ENDURANCE LIMIT OF MULTI-RING MASONRY ARCHES Clive Melbourne, Adrienn Tomor Jinyan Wang School of Computing, Science and Engineering, University of Salford

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CYCLIC LOAD CAPACITY AND ENDURANCE LIMIT OF
MULTI-RING MASONRY ARCHESClive Melbourne,
Adrienn Tomor Jinyan WangSchool of Computing,
Science and Engineering, University of Salford
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Background and context

• 40 of all European bridges is masonry

• 60 of masonry bridges are over 100 years old

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Background and context

• Due to the increasing traffic loading the life
  expectancy, capacity and fatigue performance of
  arch bridges needs to be better understood.
• Most experimental work so far has been carried
  out under static loading.
• Ring separation failure under cyclic loading is
  one of the main sources of concerns as it can
  significantly reduce the capacity of multi-ring
  brickwork arches.

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Test series
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A series of 3m span arches (2 rings)
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and a series of 5m span arches (3 rings)
under static and cyclic loading.
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Loading
Dead load
Live load
Cyclic loading
Static loading
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TEST RESULTSStatic loading
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STATIC LOADING3M SPAN

• Four hinge mechanism

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STATIC LOADING5M SPAN

• Ring separation

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TEST RESULTSCyclic loading
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CYCLIC LOADING3M SPAN
Ring separation
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CYCLIC LOADING3M SPAN
Collapse
Hinging
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CYCLIC LOADING5M SPAN
Ring separation
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CYCLIC LOADING5M SPAN
Collapse
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• Small increase in the load level can cause rapid
  failure.
• Failure occurred within a relatively few number
  of cycles (400,000) once endurance limit was
  reached.
• Endurance limit was reached around 37-57 of the
  static load capacity of fully bonded arches.
• Typical failure mode was ring separation.

57 37
Endurance limit (5m arch)
Endurance limit (3m arch)
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57 37
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Load ( of static load)
Endurance limit (5m arch)
Endurance limit (3m arch)
Endurance limit
Number of cycles
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Interactive S-N curve
An Interactive S-N (ISN) curve can be developed
for each mode of failure for every arch.
Endurance limit (E) can be expressed for each
mode of failure from the Interactive S-N curve as
a function of the load range (R), slope (m) and
intersection (H) E 10H Rm

• As a practical tool an Interactive S-N (ISN)
  curve can be developed for each mode of failure
  for every arch.

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Shear testing

• Shear capacity of the mortar-brick bond was also
  investigated

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Triplet tests

• Mortar bond in arches is rarely perfect (100).
• Shear capacity with various extent of mortar bond
  was tested
• under static and cyclic loading.

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Shear testing summary
Shear testing summary

• Exponential relationship between shear strength
  and the extent of mortar bond was indicated under
  static loading.
• Significant reduction in the static shear
  capacity was observed for lt90 bonded surface
  area.
• Large-scale arch sections show significantly
  greater shear capacity compared to triplets.
• Cyclic shear capacity seems to be significantly
  smaller than the static load capacity.

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Conclusions

• Cyclic load capacity of arches is significantly
  lower (by up to 60) than static load capacity.
• Under cyclic loading multi-ring arches failed by
  ring separation at significantly lower loads than
  that associated with a four-hinge mechanism.
• A model for an Interactive S-N curve for the
  various modes of failures was proposed for
  assessment of residual life and fatigue
  performance.
• Shear capacity of the mortar bond showed strong
  relationship to the extent of mortar bond.