MIDAS Expert Engineer Webinar Series Analysis for Assessment …uk.midasuser.com/web/upload/sample/MIDAS_UK_Expert... · 2018-12-20 · → Bridge design/assessment. → Foundation

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

1 About

2 Application project

3 Assessment process

4 Main Midas Civil features used

CONTENTS

1. About


About myself

About Jacobs

About myself

Javier Lancho CEng MICE

→ Senior Principal Engineer.

→ Bridges Team, Jacobs UK.

→ 15+ years of experience.

→ Bridge design/assessment.

→ Foundation design/assessment.


About myself


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




23 no. spans

Central span: 76.2m

Assessment check of steel piles

About myself


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.


About Jacobs


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


General information

Commission

Complexity

General information


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.


General information


Scotland, UK

→ Owner: Transport Scotland.

→ Designer: John Wolfe Barry.

→ General Contractor: Arrol’s Bridge and Roof Company.


General information


Scotland, UK

→ Riveted steel structure 224m long.

→ 77m cantilever sections supporting a 70m suspended span.


Pier

Anchor Tie

embedded in

abutment

Cantilever

Section

Suspended

SpanCantilever

Section

Anchor Tie

embedded in

abutment

Pier

General information


Scotland, UK

→ It currently carries the road A828 over Loch Etive.

→ Composite steel and concrete deck installed in 1957 and 1967.


19571903 WestEast

General information


Scotland, UK

→ It currently carries the road A828 over Loch Etive.

→ Composite steel and concrete deck installed in 1957 and 1967.


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.


Complexity – Complex modelling

Geometry of original

steel structure

→ Large number of structural members.


East

truss

West

trussTop

bracing

Cross girders


Geometry of original

steel structure

→ Large number of structural members.



Cross sections → The cross sections are not regular sections that can be found in

Midas Civil library.



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.


Plane of trussCross

girder

Connection


Connections between

Suspended Span and

Cantilever Sections

→ 8 no. spherical rocker bearings.


Spherical rocker bearings

Cantilever

Section

Suspended

Span


Connections between

Suspended Span and

Cantilever Sections

→ 3 no. spring plates at top.


Elevation looking towards Suspended Span

1

Suspended Span Cantilever Section

2

3

1

2

3

Longitudinal

Cross

Section


Connections between

Suspended Span and

Cantilever Sections

→ 3 no. spring plates and 8 no. bars with volute springs at bottom.


Sectional Plan below deck

Suspended SpanCantilever Section

2

1

3

Longitudinal

Cross

Section

1 to 3

Bars and

volute springs


Deck articulation arrangement → Simply supported deck units.


Simply supported

deck units


Deck articulation arrangement → Some base plates resting on cross girders with no further

connection. ‘Rattle fit’ of deck to be modelled.


Cross girder Base plates

3. Assessment process


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.


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.


Modelling

Type of elements → All structural members of original steel structure modelled by

one line of beam elements. Therefore, lacing excluded.


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.


Grillage

Rigid vertical elements

Modelling

Type of elements → Beam elements.


Analysis model

Original steel structure and deck

Modelling

Type of elements → Beam elements.


Analysis model - Plan

Analysis model - Elevation

Modelling

Cross Sections → Sectional Property Calculator.


Modelling

Cross Sections → Sectional Property Calculator.


Analysis model – Render view

Modelling

Loads out of the plane of the

trusses

→ Rigid beam elements


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


Moment release to model

spherical rocker bearings

Suspended Span

Modelling

Connections between

Suspended Span and

Cantilever Sections

→ Rigid beam elements (very high Izz only)


Rigid (Izz)

Cantilever Section Suspended SpanCantilever SectionSuspended Span

Modelling

Connections between

Suspended Span and

Cantilever Sections



Plan on top

Cantilever SectionSuspended Span Cantilever Section Suspended Span

Longitudinal Cross Section

Rigid (Izz)

Modelling

Connections between

Suspended Span and

Cantilever Sections



Rigid (Izz)

Cantilever Section Suspended SpanCantilever Section Suspended Span

Modelling

Connections between

Suspended Span and

Cantilever Sections



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


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


Shear release at base of rigid vertical elements

to model ‘rattle fit’ of deck

Modelling

Boundary conditions → Supports.


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.


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.


Analysis

Linear static analysis


Results


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.


4. Main Midas Civil features used


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.


Sectional Property Calculator


Example

Sectional Property Calculator Midas Civil

Beam End Release


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.



Example


→ 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


Example





Element 6445

Node J

Moving Tracer

Example





Element 6445

Node J

Midas Civil Text Command Shell

Example


→ 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

Thank you

Questions to [email protected]

Documents

MIDAS Expert Engineer Webinar Series Analysis for Assessment …uk.midasuser.com/web/upload/sample/MIDAS_UK_Expert... · 2018-12-20 · → Bridge design/assessment. → Foundation