midas expert engineer webinar series analysis for assessment...
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MIDAS Expert Engineer Webinar Series
Analysis for Assessment of
Iconic Steel Structure
Connel Bridge, Scotland
Javier Lancho
Senior Principal Bridge Engineer
Jacobs UK 02/10/2018
About myself
Javier Lancho CEng MICE
→ Senior Principal Engineer.
→ Bridges Team, Jacobs UK.
→ 15+ years of experience.
→ Bridge design/assessment.
→ Foundation design/assessment.
MIDAS Expert Engineer Webinar Series
About myself
MIDAS Expert Engineer Webinar Series
M8 White Cart Viaduct
A9 450 River Tay Bridge Spans: 67.5m-87.0m-67.5m
Assessment
Assessment check
A828 10 Connel Bridge
About myself
MIDAS Expert Engineer Webinar Series
M8 White Cart Viaduct
M8 White Cart Viaduct
23 no. spans
Central span: 76.2m
Assessment check of steel piles
About myself
MIDAS Expert Engineer Webinar Series
Assessment in jacking position
Specifications for jacking and lifting
Bridge lifted and weighed to obtain CoG
A82 1190 Laggan Swing Bridge
About Jacobs
→ Founded in 1947 by Joseph J. Jacobs.
→ Headquartered in Dallas, Texas (USA).
→ 77,000+ employees.
→ 400+ locations around the world.
→ One of the largest and most diverse providers of technical,
professional and construction services across multiple markets
and geographies.
→ Architecture, engineering and construction, operations and
maintenance, scientific and specialty consulting.
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About Jacobs
MIDAS Expert Engineer Webinar Series
Montana Department of Transportation
Two Medicine River Bridge
PRKil Wroclaw SA
Improvement of Existing Line
New Link
NJDOT
New Jersey 36 Highlands Bridge
Caltrans
Benicia-Martinez Bridge
2. Application project
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General information
Commission
Complexity
General information
A828 10 Connel Bridge
Scotland, UK
→ Originally named Connel Ferry Bridge.
→ Located between Connel and North Connel, 5 miles north east of
Oban, Argyll.
→ Constructed in 1903 to carry the railway line to Fort William over
Loch Etive.
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General information
A828 10 Connel Bridge
Scotland, UK
→ Owner: Transport Scotland.
→ Designer: John Wolfe Barry.
→ General Contractor: Arrol’s Bridge and Roof Company.
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General information
A828 10 Connel Bridge
Scotland, UK
→ Riveted steel structure 224m long.
→ 77m cantilever sections supporting a 70m suspended span.
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Pier
Anchor Tie
embedded in
abutment
Cantilever
Section
Suspended
SpanCantilever
Section
Anchor Tie
embedded in
abutment
Pier
General information
A828 10 Connel Bridge
Scotland, UK
→ It currently carries the road A828 over Loch Etive.
→ Composite steel and concrete deck installed in 1957 and 1967.
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19571903 WestEast
General information
A828 10 Connel Bridge
Scotland, UK
→ It currently carries the road A828 over Loch Etive.
→ Composite steel and concrete deck installed in 1957 and 1967.
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1967 1957
CarriagewayFootway Verge
Service bay
East West
Commission
Assessment of Structural
Capacity to British Standards
→ Record information were made available by the client.
→ Inspection for assessment carried out by the client.
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Complexity – Complex modelling
Geometry of original
steel structure
→ Large number of structural members.
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East
truss
West
trussTop
bracing
Cross girders
Complexity – Complex modelling
Geometry of original
steel structure
→ Large number of structural members.
MIDAS Expert Engineer Webinar Series
Complexity – Complex modelling
Cross sections → The cross sections are not regular sections that can be found in
Midas Civil library.
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Complexity – Complex modelling
Loads out of the plane of the
trusses
→ The connections between the trusses and the loaded cross
girders are located out of the plane of the truss.
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Plane of trussCross
girder
Connection
Complexity – Complex modelling
Connections between
Suspended Span and
Cantilever Sections
→ 8 no. spherical rocker bearings.
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Spherical rocker bearings
Cantilever
Section
Suspended
Span
Complexity – Complex modelling
Connections between
Suspended Span and
Cantilever Sections
→ 3 no. spring plates at top.
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Elevation looking towards Suspended Span
1
Suspended Span Cantilever Section
2
3
1
2
3
Longitudinal
Cross
Section
Complexity – Complex modelling
Connections between
Suspended Span and
Cantilever Sections
→ 3 no. spring plates and 8 no. bars with volute springs at bottom.
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Sectional Plan below deck
Suspended SpanCantilever Section
2
1
3
Longitudinal
Cross
Section
1 to 3
Bars and
volute springs
Complexity – Complex modelling
Deck articulation arrangement → Simply supported deck units.
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Simply supported
deck units
Complexity – Complex modelling
Deck articulation arrangement → Some base plates resting on cross girders with no further
connection. ‘Rattle fit’ of deck to be modelled.
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Cross girder Base plates
3. Assessment process
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Knowledge of available record information
Inspection for assessment
Modelling
Analysis
Results
Structural capacity check
Knowledge of available record information
Aim → Know available and required information.
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Inspection for assessment
Reference
Aim
Analysis
Resistance
→ BD 21/01 and BD 56/10.
→ Actual form, dimensions and condition of the structure.
→ Actual form, dimensions, stiffnesses and loading are to be
considered.
→ Actual resistance is to be considered, from actual dimensions
and condition.
→ The condition of the structure is considered by applying an
overall condition factor, which is additional to the material safety
factor.
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Modelling
Type of elements → All structural members of original steel structure modelled by
one line of beam elements. Therefore, lacing excluded.
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Lacing
Analysis model
Original steel structure
Modelling
Type of elements → Steel and concrete deck modelled by beam elements, using
grillage analysis method. Rigid vertical elements to connect the
grillage to the original steel structure.
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Grillage
Rigid vertical elements
Modelling
Type of elements → Beam elements.
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Analysis model
Original steel structure and deck
Modelling
Type of elements → Beam elements.
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Analysis model - Plan
Analysis model - Elevation
Modelling
Cross Sections → Sectional Property Calculator.
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Analysis model – Render view
Modelling
Loads out of the plane of the
trusses
→ Rigid beam elements
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Transverse element
representing a
cross girder
Longitudinal element
representing a
bottom boom
Rigid element
Modelling
Connections between
Suspended Span and
Cantilever Sections
→ Beam End Release
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Moment release to model
spherical rocker bearings
Suspended Span
Modelling
Connections between
Suspended Span and
Cantilever Sections
→ Rigid beam elements (very high Izz only)
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Rigid (Izz)
Cantilever Section Suspended SpanCantilever SectionSuspended Span
Modelling
Connections between
Suspended Span and
Cantilever Sections
→ Rigid beam elements (very high Izz only)
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Plan on top
Cantilever SectionSuspended Span Cantilever Section Suspended Span
Longitudinal Cross Section
Rigid (Izz)
Modelling
Connections between
Suspended Span and
Cantilever Sections
→ Rigid beam elements (very high Izz only)
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Rigid (Izz)
Cantilever Section Suspended SpanCantilever Section Suspended Span
Modelling
Connections between
Suspended Span and
Cantilever Sections
→ Rigid beam elements (very high Izz only)
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Cantilever
Section
Suspended
Span
Sectional Plan below deck
Cantilever
Section
Suspended
Span
Rigid (Izz)
Rigid (all properties)
Rigid (Izz)
Rigid (all properties)
Modelling
Deck articulation arrangement → Beam End Release
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Shear release to model ‘rattle fit’ of deck
Moment release to model
simply supported
deck units
Rigid vertical element
Longitudinal element
representing a steel and
concrete composite
girder
Modelling
Deck articulation arrangement → Beam End Release
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Shear release at base of rigid vertical elements
to model ‘rattle fit’ of deck
Modelling
Boundary conditions → Supports.
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Supports at
pier locations
Supports at
anchor tie embedment
Modelling
Material properties → Original steel and rivets (1903):
NR/GN/CIV/025 Issue 3 June 2006.
For assessment of rail bridges.
Tables A2 includes strength of early steels (pre-1906).
→ Steel and concrete composite deck (1957 and 1967):
BD 21/01.
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Modelling
Loading → BD 21/01 Assessment of Highway Bridges and Structures.
Assessment for the ULS only. The need for assessment for the
SLS shall be agreed by the Technical Approval Authority.
Limited to dead, superimposed dead and vertical live loads.
Assessment live loadings:
- 40t - full range of vehicles under Authorised Weight
Regulations.
- 26t, 18t, 7.5t, FE and 3t - restricted traffic.
When loading or combination of loads other than those
specified above are considered necessary for assessment:
- BD 37/01 Loads for Highway Bridges.
- BD 86/11 The Assessment of Highway Bridges and
Structures for the Effects of Special Types General Order
(STGO) and Special Order (SO) Vehicles.
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Results
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Compression – blue colour
Internal forces and stresses
Compression – blue colour
Tension – green colour
Tension – green colour
Structural capacity check
Strength of members → Steel - BD 56/10.
→ Concrete and reinforcement – BD 44/15.
→ The above are assessment standards which are based on pre-
Eurocode BS 5400 (for design) and include specific criteria for
assessment.
→ In-house spreadsheets.
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4. Main Midas Civil features used
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Import AutoCAD DXF File and Mirror
Sectional Property Calculator
Beam End Release
Moving Loads according to British assessment standards
Concurrent forces in beam elements
Moving Tracer
Midas Civil Text Command Shell
Import AutoCAD DXF file and Mirror
Import AutoCAD DXF
Mirror
→ Very convenient for complex geometry.
→ A new structure group created per AutoCAD layer.
→ Material and section properties, boundary conditions and loads
may be copied into the 2nd half of the model.
→ The 2nd half of the model will not be part of any structure group.
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Sectional Property Calculator
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Example
Sectional Property Calculator Midas Civil
Beam End Release
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Example
Bending moments under UDL
→ Simply supported deck units.
Moving loads to British assessment standards
BD 21/01 UDL and KEL
BD 21/01 pedestrian load
BD 21/01 single axle load, wheel
load, individual vehicles for
transverse members, accidental
vehicle loads and accidental
wheel loads
BD 86/11 special vehicles
→ Standard vehicle HA in Midas Civil.
→ Standard pedestrian load in Midas Civil.
→ User defined vehicle Permit Truck in Midas Civil.
→ Standard vehicles SV80, SV100, SV150, SV-Train, SVTT,
SOV250, SOV350, SOV450 and SV600 in Midas Civil.
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Concurrent forces in beam elements
Example
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→ Minimum axial load (maximum compressive load) and
concurrent forces in Element 6445 node J under the effects of UDL
and KEL for 40t Assessment Live Loading.
Element 6445
Node J
Concurrent forces in beam elements
Example
MIDAS Expert Engineer Webinar Series
→ Minimum axial load (maximum compressive load) and
concurrent forces in Element 6445 node J under the effects of UDL
and KEL for 40t Assessment Live Loading.
Element 6445
Node J
Moving Tracer
Example
MIDAS Expert Engineer Webinar Series
→ Minimum axial load (maximum compressive load) and
concurrent forces in Element 6445 node J under the effects of UDL
and KEL for 40t Assessment Live Loading.
Element 6445
Node J
Midas Civil Text Command Shell
Example
MIDAS Expert Engineer Webinar Series
→ Minimum axial load (maximum compressive load) in Element
6445 node J and concurrent forces in several elements under the
effects of UDL and KEL for 40t Assessment Live Loading.
Element 6445
Node J