Division / Business Unit: Engineering and Systems

Function: Track & Civil

Document Type: Code of Practice

Structures
Section 9
Applicability

ARTC Network Wide SMS

Publication Requirement

Internal / External

Primary Source

Document Status

Version # Date Reviewed Prepared by Reviewed by Endorsed Approved

4.0 19 Nov 22 National Bridges Stakeholders Manager A/General Manager

and Structures Standards Technical Standards
Engineer 19/11/2022

Amendment Record

Amendment Date Reviewed Clause Description of Amendment

Version #

4.0 19 Nov 22 Various Train collision protection requirements for bridges above
rail tracks carrying double stacked rolling stock,
construction specifications, earthquake detail
categories, fatigue categories for rivets, FFU transom
assembly, removal of ballast mat and minor
clarifications added.

© Australian Rail Track Corporation Limited (ARTC)

Disclaimer
This document has been prepared by ARTC for internal use and may not be relied on by any other party without ARTC’s prior written consent. Use of this document shall be subject
to the terms of the relevant contract with ARTC.
ARTC and its employees shall have no liability to unauthorised users of the information for any loss, damage, cost or expense incurred or arising by reason of an unauthorised user
using or relying upon the information in this document, whether caused by error, negligence, omission or misrepresentation in this document.
This document is uncontrolled when printed.
Authorised users of this document should visit ARTC’s intranet or extranet (www.artc.com.au) to access the latest version of this document.

CONFIDENTIAL Page 1 of 22
 Structures
Section 9

Table of Contents
Table of Contents ............................................................................................................................................. 2
9 Section 9: Structures ............................................................................................................................. 3
9.1 General ........................................................................................................................................... 3
9.1.1 Reference Documents .................................................................................................................... 3

9.1.2 Definitions ....................................................................................................................................... 3

9.2 Design and Load Rating ................................................................................................................. 4

9.2.1 Basis of Design ............................................................................................................................... 4

9.2.2 Matters for Resolution..................................................................................................................... 5

9.2.3 Design Loads.................................................................................................................................. 5

9.2.4 Collision from Rail Traffic ................................................................................................................ 6

9.2.5 Bridge Earthquake Design Category .............................................................................................. 7

9.2.6 Derailment Kerb ............................................................................................................................. 7

9.2.7 Bridge Bearing ................................................................................................................................ 8

9.2.8 Protection Screen ........................................................................................................................... 9

9.2.9 Clearances ..................................................................................................................................... 9

9.2.10 Waterways ...................................................................................................................................... 9

9.2.11 Abutment Slabs ............................................................................................................................ 10

9.2.12 Walkways / Refuges / Handrails ................................................................................................... 10

9.2.13 Road Traffic Barrier ...................................................................................................................... 11

9.2.14 Services ........................................................................................................................................ 11

9.2.15 Survey Control Markers ................................................................................................................ 11

9.2.16 Construction Specification ............................................................................................................ 12

9.2.17 Competency Requirements .......................................................................................................... 12

9.2.18 Certification................................................................................................................................... 12

9.2.19 Acceptance by ARTC ................................................................................................................... 12

9.3 Construction and Maintenance ....................................................................................................12

9.3.1 General ......................................................................................................................................... 12

9.3.2 Maintenance Work ........................................................................................................................ 12

9.3.3 Guard Rails................................................................................................................................... 13

9.3.4 Bridge Transom ............................................................................................................................ 13

9.4 Inspection and Assessment .........................................................................................................19

9.4.1 Inspections ................................................................................................................................... 19

9.4.2 Load Rating .................................................................................................................................. 20

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 Structures
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9 Section 9: Structures

9.1 General

9.1.1 Reference Documents

• ETG-09-01 Structures Inventory

• ETE-09-01 Structures Inspection

• ETE-09-02 Structures Inspection Procedure

• ETE-09-05 Load Rating of Underbridges

• ETN-04-01 Use of Ballast Mat

• EGP-04-01 Engineering Drawings and Documentation

• EGP-03-01 Rail Network Configuration Management

• Track and Civil Code of Practice Section 1: Rail.

9.1.2 Definitions
The following terms and acronyms are used within this document:
Term or acronym Description

ARTC Australian Rail Track Corporation Ltd.

Significant track work Major work changing the alignment of the track, including track
lowering. Does not include alignment changes resulting from routine
track maintenance.

Equivalent Standard A suitable alternative standard approved by the Manger Standards.

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Table 9-1 Asset Class and Structure Type

Asset Class Structure Type

Bridge Underbridge

Overbridge

Footbridge

Culvert Culvert

Tunnel Tunnel

Miscellaneous Structures Access (i.e. stairs, walkways)

Buffer stop

Culvert non-track

Communication Towers

Flood structure

Lighting Gantry

Lighting Tower

Disused Loading Structures (now acting as retaining walls

next to tracks)

Overhead Service crossing

Retaining wall (including old loading banks)

Signal gantry (including cantilever structure)

Sound barrier

Turntable

Water Structures

9.2 Design and Load Rating

The Code of Practice sets out the requirements for the design of new railway, road and
pedestrian bridges, culverts and other significant structures and for the load rating of existing
structures. It defines requirements specifically or by reference to relevant Australian Standards.
“Safety in Design” is mandated by statutory requirements and must be incorporated into the
design.
The safety in design process shall identify potential hazards and the potential risks to persons
during construction, future operation, maintenance and eventual decommissioning of an asset.
During the design phase, risks must be eliminated or minimised so far as is reasonably
practicable. Residual risks shall be documented in accordance with ARTC’s risk management
procedures.

9.2.1 Basis of Design

Bridge design shall be carried out in accordance with the Australian Bridge Design Standard AS
(AS/NZS) 5100, RISSB’s Australian Railway Infrastructure Standard AS 7636 Railway Structures,
RISSB Code of Practice ‘Derailment containment and protection for rail underbridges’ and
RISSB’s guideline ‘Refuges – Bridges and Tunnels’. Where there is a conflict among
aforementioned documents, the requirements of this Code of Practice shall take precedence.

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AS (AS/NZS) 5100 series sets out the requirements for the design, using limit states principles, of
the following:

• Bridges that are required to support road traffic loads.

• Bridges that are required to support rail traffic.

• Bridges that are required to support light rail traffic.

• Pedestrian bridges and walkways, including bicycle and wheelchair access.

• Other structures that are required to support road and rail traffic, e.g. culvert and
structural components related to tunnels, except those covered specifically by other
Standards.

• Structures, other than bridges, that are required to support or resist road or rail traffic
loads, e.g. retaining structures, deflection walls, signal gantries and sign gantries.

• Structures built over and/or adjacent to railways.

Culvert design shall be carried out in accordance with the Precast Reinforced Concrete Box
Culverts Standard AS 1597, Design for Installation of Buried Concrete Pipes Standard AS 3725,
Precast Concrete Pipes Standard AS 4058, Buried Corrugated Metal Structures Standard AS
2041, and Buried Flexible Pipelines – Part 1 Structural Design AS/NZ 2566.1.
Top of drainage pipes under tracks shall not be less than 1.2m below top of rail level unless
otherwise approved by ARTC.
Design of all other structures shall be carried out in accordance with relevant Australian
Standards.
Design of any structures utilising materials not currently covered by any Australian Standards
shall only be undertaken following “Type Approval” by ARTC.

9.2.2 Matters for Resolution

All relevant matters for resolution listed in AS 5100 shall be confirmed as accepted by ARTC prior
to commencement of the design and load rating processes for all internal and 3rd Party projects.
All risk assessment workshops for design, construction, maintenance and disposal of structures
within ARTC corridor shall have in attendance ARTC subject matter experts to ensure all ARTC
concerns are addressed properly unless otherwise waived by ARTC.

9.2.3 Design Loads

All structures shall be designed for the loading effects prescribed in AS (AS/NZS) 5100 and/or AS
7636 unless otherwise loading is specified by ARTC.
For rail traffic load other than 300LA design load, the load shall be taken as the proportion of the
300LA design rail traffic load.
As a minimum, when loading is not specified:

• Rail bridges and culverts shall be designed to 300LA design rail traffic load with
applicable dynamic load allowance.

• Rail bridges and culverts on the NSW Hunter heavy haulage lines shall be designed to
350LA design rail traffic load with applicable dynamic load allowance.

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• Only design rail traffic axle loads, nosing load and derailment loads (AS 5100.2 Clause
11.5.1) shall be proportioned to suit nominated design or load rating loads. All other rail
traffic loads shall be in accordance with AS 5100.2.

• Minimum strength for reinforced concrete or fibre reinforced pipe under track shall be
Class 4 (equivalent to 300LA design rail traffic).

• High Density Polyethylene (HDPE) pipes shall comply with the above design loads and
the requirements of AS 2566. In bush fire prone areas, the pipe suitability shall be risk
assessed.

• All ballast top rail bridges shall be designed for 600mm maximum and 300mm minimum
ballast depth below sleepers. (Plaque(s) shall be clearly displayed on top of ballast
kerb in each span indicating maximum designed low-leg rail height above plaque).

• The height of ballast kerb above concrete deck shall be 600mm minimum unless
otherwise approved by ARTC.

• Road bridges shall be designed to SM1600 wheel design loads with applicable dynamic
load allowance.

• Walkways and Footbridges shall be designed for 5kPa.

9.2.4 Collision from Rail Traffic

9.2.4.1 New bridges
Unless otherwise approved by ARTC, the design of all the new bridges shall comply with all the
minimum requirements of AS 5100 for the protection against rail traffic collision loads in
conjunction with the following additional requirements:
1. As per AS 5100, all new bridges over tracks shall be designed to:
a. Avoid collapse of structures over rail due to impact from derailed trains.
b. Reduce the severity of impacts with structures to reduce the probability of injury to
occupants of derailed trains.
2. A risk assessment acceptable to ARTC shall be carried out to determine the
requirements for protection of bridge piers, abutments and the ends of the through
girder, arch or truss.
The head-on collision loads on a deflection wall can be much higher than minimum
collision loads of 4,000kN parallel to rails and 1,500kN normal to rails specified in AS
5100.2. Designer shall use rational method, taking into consideration train axle
configuration, train mass, train speed, car stiffness (K = 1200kN/m [Note]),track alignment,
etc. for determination of collision loads. These loads shall not be less than minimum
collision loads specified in AS 5100.2.
3. All piers, abutments and the ends of the through girder, arch or truss shall be protected
against head-on collision from derailed trains by deflection walls at both city and country
ends of the tracks.
4. Piers and abutments shall be a continuous concrete wall aligned parallel to the adjacent
tracks and the minimum height of wall shall be subject to site specific risk assessment
but not less than height specified in AS 5100.
5. Deflection wall shall be designed as a continuous wall and the minimum height of wall
shall be subject to site specific risk assessment but not less than height specified in AS
5100.

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Note: Extracted from Texas Transportation Institute report, Analysis and Design of Metrorail -
railroad Barrier System, T.J.Hirsch, May 1989
The vehicle stiffness of 1200kN/m can be taken as a design criterion unless a more
rigorous stiffness analysis is undertaken by the designer.

9.2.4.2 For significant track work below existing bridges for tracks carrying double
stacked rolling stock
1. A risk assessment acceptable to ARTC shall be carried out to determine the
requirements for protection of bridge piers and abutments.
2. Deflection walls shall be provided for the protection of existing piers and abutments and
shall comply with the above requirements in 9.2.4.1 and AS 5100.
3. Deflection walls shall be provided on the track approach side to the existing
substructure.
4. The deflection wall shall be designed for loads specified in 9.2.4.1.The wall shall be
separated from the existing structure and shall not rely on the existing substructure for
support.
5. Barrier protection shall be provided alongside the existing substructure adjacent to the
rail track, unless otherwise approved by ARTC.
6. The barrier shall be designed for loads specified in AS 5100.2 Clause 11.4.4.2
7. The superstructure of existing bridges shall not be assessed to resist a minimum
collision load of 500kN.
9.2.4.3 For new bridges above rail tracks carrying double stacked rolling stock
AS (AS/NZS) 5100 (Part 1 & Part 2) is silent on the requirements for protection of bridge
superstructures above rail tracks carrying double stacked rolling stock.
1. For any part of the structure within 7m vertically of the centreline of the nearest track
carrying double stacked rolling stock shall be designed to resist a minimum collision
load of 500kN. Above 7m and up to 12m vertically above the rail track level, this load
shall vary linearly from 500kN to zero at 12m.
9.2.4.4 Underground rail, air space developments and similar situations
1. The supports for all underground rail and air space developments shall be designed for
the train collision loads specified in AS 5100.2.

9.2.5 Bridge Earthquake Design Category

The bridge earthquake category for new bridges shall be determined as specified in AS 5100.2.
The classification of a new bridge shall be BEDC-4 unless otherwise approved by ARTC based
on a site-specific cost benefit analysis.
The minimum classification for new bridge shall be BEDC-3.

9.2.6 Derailment Kerb

A derailment kerb shall be provided for new bridges. It shall extend 200mm above the top of the
adjacent running rail without infringing maximum kinematic envelope plus 200mm from the
centreline of the nearest track.

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9.2.7 Bridge Bearing

The requirements for rail bridge bearings shall be as follows:

• For new steel spans, the bearings shall be spherical bearings or bearings approved by
ARTC.

• For new concrete spans, the bearings shall be spherical bearings, elastomeric bearings
or bearings approved by ARTC.

• All spherical bearings shall be designed with 100year design life.

• All other bearing types shall be designed with 50year minimum design life.

• All bearings shall be designed for rail traffic loading specified in Clause 9.2.3 Design
Loads.

• All bearings and fixing details shall be arranged to permit removal of the fasteners
without jacking the bridge at all and removal of the bearing by jacking the bridge by no
more than 5mm.

• Bearings shall be tested in accordance with requirements of AS5100.4. The tests shall
be carried out in Australia in a test facility, suitably accredited by NATA. The test
frequency shall be in accordance with Table 9.2;

• For testing purposes, the bearing group is defined as bearings of the same type, with
the same sliding pad and spherical surface geometry and with similar load capacity.
Bearings within a group may have different translational movement ranges.
Table 9.2 Bearing Test Frequency

Type of Test Bearings per group

Up to 10 10 to 25 >25

Vertical Load test 1 per group (2 2 per group 3 per group

min)
Lateral Load Test

Rotational Capacity Test

Geometrical Verification All

Coefficient of Friction Test 1 per stainless steel and sliding material batch
combination

Only Spherical Bearings comprising Ultra High Molecular Weight Polyethylene (UHMPE) as the
sliding material shall be used and shall comply with European Technical Approval ETA-08/115 or
similar and shall demonstrate below minimum performance characteristics

• Maximum Friction Coefficient: 0.0267 (g) ≥ 30 MPa

• Minimum Friction Coefficient: 0

• Minimum Accumulated Sliding Distance (To ensure adequate Abrasion resistance): ≥

75Km

• Minimum Short Term Compressive Strength (To ensure No Damage to Sliding Surfaces
for short term high temperatures and any accidental impacts): 240 MPa @ 48 °C

• Bearing attachment plates shall be detailed and supplied by the bearing manufacturer.

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Where use of pot bearings cannot be avoided, only pot bearings that use Polyoxymethylene
(POM) or Carbon Filled Polytetrafluoroethylene (PTFE) as internal sealing elements complying
with current version of CEN-EN1337-5 Structural Bearings – Part 5: Pot Bearings shall be used.
For all other bridge types, the design of the bearings shall comply with AS (AS/NZ) 5100.
Detailed shop drawings with design loads of all bearings shall be provided for ARTC review prior
to commencement of manufacture of any bearings.
All bearing test reports and final drawings shall be provided with delivery of bearings.

9.2.8 Protection Screen

Protection screens shall be provided to prevent objects falling or being thrown from overhead
bridges.
1. Protection screens shall be provided unless otherwise approved by ARTC.
2. Screen shall have a minimum height of 3m above the roadway, walkway surface or
ledge that people can stand on. Road traffic barrier and barrier railing can act as ledge.
Where height is not taken from ledge but from road surface then ledge shall be
screened off to prevent people from climbing onto it.
3. Preference is for screen to curve inwards facing road as per Figure 16.4 in AS 5100.1.
4. Screen shall not tilt outwards more than 10o from vertical position where it is impractical
to curve it towards road.
5. Screens shall extend across full length of road bridge or full width of railway boundary or
9m minimum as per AS 5100 unless otherwise approved by ARTC.

9.2.9 Clearances
Horizontal and vertical clearances for structures (adjacent to and over the track) shall comply with
ARTC Code of Practice Section 7 ‘Clearance’ unless otherwise approved by ARTC.
All structures over road traffic access with less than the regulated vertical clearance shall have
overhead road clearance signs posted on them.

9.2.10 Waterways
ARTC can set the annual exceedance probability (AEP) for a particular waterway or drainage
system. As a minimum, when the AEP is not specified by the ARTC, the flood openings shall be
designed to accommodate the following:

• Major under track structures (discharge equal to or greater than 50m3/sec): 1% AEP (as
defined in Australian Rainfall & Runoff guideline, previously defined as 100year
precipitation event).

• Minor under track structures (discharge less than 50m3/sec): 2% AEP (previously
defined as 50year precipitation event).

• Structures not under railway track: 2% AEP (previously defined as 50year precipitation
event).
For rail bridges, the flood immunity and serviceability limit state Average Recurrence Interval shall
be 100years as set out in AS (AS/NZ) 5100 unless otherwise specified by ARTC.

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9.2.11 Abutment Slabs

9.2.11.1 Approach Slab
The requirement to use an approach shall be determined by the design. The approach slab
designed as an integral structural component for the stability of the abutment or to square off a
skewed abutment shall not to be used for a transition approach. The approach slab seated on an
abutment shall be adequately piled at the opposite end. The design of slab shall ensure that
there is no uplift on the abutment that could cause track misalignment due to any differential
settlements at the piled end of the slab. Adequate drainage on each side of slab (lateral to track)
shall be provided to ensure there is no entrapment of water on the approach slab or no water
drains off the slab structure onto the formation under the track.
9.2.11.2 Transition Slab
The transition slab shall be provided for all new rail bridges. The slab shall not be seated on the
abutment. The length of slab across the rail track shall suit the width of the bridge approach
embankment and the slab shall be at least 5m wide in direction parallel to running rails or as
approved by ARTC. Where slab is comprised of 2 or more smaller units then these units shall be
mechanically interlocked to form a single rigid transition slab. Adequate drainage on each side of
slab (lateral to track) shall be provided to ensure there is no entrapment of water on the slab or no
water drains off the transition slab onto the formation under the track.

9.2.12 Walkways / Refuges / Handrails

All new walkways / refuges / handrails on rail bridges, culverts or in tunnels or on any other
structures shall comply with the requirements of AS (AS/NZS) 5100 and AS 1657.
The walkways or suitable alternative access shall be provided along both sides of each track
across structures where train crews regularly work on the ground for shunting, train inspections,
etc.
In other cases, a risk assessment shall be performed to assess if walkways, refuges and/or
handrails are required.
“No Safe Place” sign, as per Figure 9-1 below, shall be posted at each end of structure where any
walkway, refuge or wall is within 3m horizontally from nearest running rail. It shall also be
attached at locations along the wall where access is available to the track adjacent to the
structure. Signage shall be attached such that it is clearly visible to authorised staff.
The following requirements shall apply to refuges that could be used in emergency situations:

• For bridges and culverts, refuges shall not infringe the Kinematic Envelope (KE) +
200mm from the centreline of the nearest track.

• For wall structures such as tunnels and retaining walls, refuges shall not infringe the KE
+ 500mm from the centreline of the nearest track.

• Refuges shall not exceed 20m intervals, one side for a single track and staggered for
multiple tracks.

• Refuge is not required for structures less than 20m in length.

• Minimum dimensions of refuge shall be 2m in height, 1.5m wide and 0.7m in depth.

• Handrails on (or at) structures shall not infringe the KE + 200mm from the centreline of
the nearest track.

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Figure 9-1 below illustrates the general configuration of the ‘No Safe Place’ sign.

Figure 9-1 'No Safe Place' sign

The requirements for danger signage are set out in AS 1319.

9.2.13 Road Traffic Barrier

The road traffic barriers for all new road bridges over the ARTC network shall be designed to
minimum standard of Medium Performance Level in accordance with AS (AS/NZS) 5100.
For bridge rehabilitation, the existing road barriers to be upgraded to performance level specified
above or unless otherwise approved by ARTC.

9.2.14 Services
Services, utilities and service ducts shall be designed and fixed to structures so as to allow safe
and unimpeded access to the structure for inspection and maintenance.
No services to be installed under bridges or through culverts or attached to structures without
prior approval of ARTC.
Where service ducts are attached to bridge walkway, refuges or handrails they shall be
positioned so that they do not encroach on the safe working area or create a trip or other safety
hazards.

9.2.15 Survey Control Markers

Survey controls shall be established on all bridges and major culverts as follows:
1. Brass triangle control markers.
2. All markers are intervisible with ease of access and occupiable.
3. All markers are properly coordinated with reduced level.
4. A marker be installed on each abutment and no more than 150m apart on long
bridges/viaducts
5. Permanent control(s) installed within ARTC corridor or on public land such as public
roadway but no more than 150m from structure unless otherwise there is already a
permanent marker nearby.
6. All markers, coordinates and reduced levels are clearly specified on “As Built” drawings.

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9.2.16 Construction Specification

Specifications shall comply with the following requirements:
1. All specifications shall comply with all relevant ARTC Standards and Australian
Standards.
2. All specifications shall be logically, concisely and without any ambiguity presented on
construction drawings.
3. References to include all relevant ARTC Standards, ARTC drawings and/or Australian
Standards, if applicable.

9.2.17 Competency Requirements

The designs, design approvals and verification shall only be carried out by persons holding the
appropriate competency level in accordance with ARTC competency certification, details
available on ARTC web site - EGP0103F-01 Engineering Design & Project Management Matrix
ARTC shall select the designers, design checkers and independent verifiers based on their
demonstrated skills and experience with the construction materials (concrete, steel, timber,
masonry, composites) and structure type (including but not limited to bridges, tunnels,
communication towers).

9.2.18 Certification
All “Issued for Construction Drawings” shall be signed by the Design Engineer, and counter
signed by the Design Check Engineer, Approver and Independent Verifier. Third party
independent verification certificate for all construction drawings shall be provided unless ARTC
waives this requirement. Third party here implies a competent engineer from another engineering
consultancy.
All design changes shall comply with the requirements of Rail Network Configuration
Management Procedure EGP-03-01 Engineering, Design and Project Management Identification
of Competence Procedure

9.2.19 Acceptance by ARTC

All drawings shall be accepted as per EGP-04-01 Engineering Drawings and Documentation.

9.3 Construction and Maintenance

9.3.1 General
All construction and contract maintenance shall be performed in accordance with individual
contracts.

9.3.2 Maintenance Work

All maintenance work on existing structures shall be carried out in accordance with approved
construction drawings or on a like-for-like basis or EGH-09-01 Structures Repair Guideline.
Where the guideline is used the applicable repair methodology shall be subject to approval by
structures representative or competent structures engineer. Any changes to as-designed
structures configuration or structurally critical elements shall be approved by a competent
structures engineer and accompanied by relevant risk assessment, any additional inspections
and signed off by a competent structures representative. All work shall be carried out in

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accordance with EGP-03-01 Rail Network Configuration Management and EGN-03-01

Configuration Management Manual.
All emergency maintenance work shall be adequately maintained and monitored until the
structure is upgraded to safe operating condition.

9.3.3 Guard Rails

Guard rails are not required on rail bridges. Where fitted, existing guard rails shall be safely
maintained by the local ARTC maintenance team in accordance with Code of Practice Section 1:
Rail.

9.3.4 Bridge Transom

9.3.4.1 Transom Material
Transoms are now available in a variety of materials. ARTC still uses hardwood timber transoms
extensively.
Transoms manufactured from fibre composite materials or any other materials shall only be
utilised following “Type Approval” by ARTC.
9.3.4.2 Timber Transom
9.3.4.2.1 Timber Material

Specific requirements for timber transoms are as follows:

• Timber stress grade shall be F22 or higher.

• Structural grade and timber species shall comply with the requirements of
below.

• Timber shall be free of loose knots, unsound knots and knot holes.

• Want, wane and sapwood, individually or in aggregate, shall not exceed one seventh of
the cross-section nor two fifths of the wide face on which it occurs.
All other requirements for transom timber shall comply with the following standards:

• AS 1720.1 – “Timber structures – Design methods”.

• AS 2082 – “Timber Hardwood - Visually Stress - graded for structural purposes”.

• AS 2878 – “Timber classification into strength groups”.

• AS 3818.1 – “Timber – Heavy structural products – Visually graded, Part 1: General

requirements”.

• AS 3818.2 - “Timber – Heavy structural products – Visually graded, Part 2: Railway

track timbers”.

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Table Common Name Visual Stress-grade Botanical Name(s)

9-3 Transom
TimberGroups Structural Structural Grade
Grade No 1 No 2

Group 1 Grey Ironbark F27 F22 E. siderophloia

E. drepanophylla

E. paniculata

Red Ironbark F22 N/A E. fibrosa

E. crebra

E. sideroxylon

Grey Gum F27 F22 E. punctata

E. propinqua

Tallowwood F22 N/A E. microcorys

White Mahogany F22 N/A E. acmenoides

Group 2 Spotted Gum F22 N/A C. maculate

C. citriodora

C. henryi

9.3.4.2.2 Timber transom Size

Open deck rail bridges with steel span lengths greater than 20m have built in camber. The
thickness of transoms shall not be increased at ends of span to remove camber.
Transom dimensions and tolerances shall be as stated in below.
Table 9-4 Transom DIMENSIONS (mm) TOLERANCE (mm)
Dimensions and
Tolerances

Length 2800, 3000, 3200 +50, -0

Width 250 nominal +25, -0

Thickness As per Tables 9.4 and 9.5 below +6, -0

9.3.4.3 Transom Thickness and Holding Down Bolt

Some of the transom top steel span rail bridges in Victoria have 4 girders, compared to 2 girders
in NSW. It is also relevant to note that some transom top bridges in Victoria were originally
designed for Broad Gauge track whereas they are now standardised to Standard Gauge track.
9.3.4.3.1 Transoms for steel spans with 2 girders or timber spans with 3 girders

For transom top steel and timber rail bridges with span main girders at 2m centres maximum, the
transom thickness shall be provided in accordance with below:

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Table 9-5 Minimum Timber Transom thickness and Holding down Bolt for 2 girder spans

AXLE LOAD TRANSOM MAX JOINT HD TRACK MIN.

& SPACING SPACING SPEED STRENGTH BOLT HORIZ. TRANSOM
(mm) (km/h) GROUP3 SIZE ALIGNMENT THICKNESS
(min)4 (mm)5

30t axles 600 115 J1 M30 Straight 190

Curved 2102
as per 80 J1 M30 Straight 185
AS5100.2 -
Curved 2052
300LA
design rail 500 - 550 115 J1 M30 Straight 170
traffic
loading Curved 1851/2002

80 J1 M30 Straight 165

Curved 1801/1902

30t axles 500 - 600 115 J1 M24 Straight 150

at ≥1500 Curved 1651/1702

centres
80 J1 M24 Straight 150
(120t coal
Curved 1601/1652
wagons)

25t axles 500 - 600 115 J2 M22 Straight 150

at ≥1500 Curved 1501/1602

centres
80 J2 M22 Straight 150
(100t
Curved 1502
general
freight
wagons)

9.3.4.3.2 Transoms for steel spans with 4 girders

For transom top steel rail bridges with span main girders at 610, 910 and 610mm centres
maximum, the transom thickness shall be provided in accordance with below:
Table 9-6 - Minimum Timber Transom thickness and Holding down Bolt for 4 girder spans

AXLE LOAD TRANSOM MAX JOINT HD TRACK MIN.

& SPACING SPACING SPEED STRENGTH BOLT HORIZ. TRANSOM
(mm) (km/h) GROUP3 SIZE ALIGNMENT THICKNESS
(min)4 (mm)5

25t axles 400 - 600 115 J1 M22 Straight 110

at ≥1500 or JD2 Curved 1202

centres
80 J1 or M22 Straight 110

or JD2 Curved 1202

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Notes:

1. Maximum superelevation on curved track = 125 mm

2. Max. track offset in relation to span centreline = 30 mm
3. Max. track offset in relation to span centreline = 70mm
4. J groups as specified in Table C1 of AS 3818.1
5. Swage Bolts shall be grade 8.8S bolts with reduced tension to suit timber application. All
other bolts shall be commercial Grade 4.6.
6. Any localised reduction in thickness of a transom shall be achieved by a maximum 1 in 8
bevelling and rounded change of direction away from the reduced section

9.3.4.4 FFU transom

Fibre-reinforced foamed urethane (FFU) transoms are intended for use as underbridge transoms
only. FFU transoms shall not be used for spot re-transoming as they may lead to potential track
problems associated with the effects of differences in elastic modulus between timber and FFU.
Structure representative shall verify design input data provided on FFU TRANSOM DESIGN
CONDITION form and also, design data used by manufacturer to derive transom depth prior to
proceeding with procurement. If necessary, seek engineering advice.
9.3.4.4.1 FFU Material

The FFU components provide an alternative material to hardwood timber for transoms for steel
bridges on the ARTC network. They have equivalent material characteristics to that of timber and
they are specifically designed for individual axle loads and bridge configurations with up to 50year
design life.
9.3.4.4.2 FFU Transom Size

The minimum length of transom shall be the length between holding down bolt holes plus 400mm
and the width shall be 250mm nominal unless otherwise approved by the corridor manager. The
200mm length beyond HD bolt at each end of transom is for a worker to put a foot there whilst
installing transom HD bolts, sleeper plates and/or rails.
9.3.4.4.3 FFU Transom Thickness

FFU transoms are designed and manufactured by Sekisui Chemical Co. Ltd of Japan. FFU
transoms shall be designed and supplied in accordance with ‘JIS E 1203 (JRCEA/JSA) Synthetic
Sleepers– Made from fibre reinforced foamed urethane’ and the manufacturer's requirements.
FFU transoms are designed to mimic the physical and material characteristics of hardwood
timber transoms.
Open deck rail bridges with steel span lengths greater than 20m have built in camber. The
thickness of transoms shall not be increased at ends of span to remove camber.
Project Manager shall provide supplier with fully completed FFU TRANSOM DESIGN
CONDITION form available from supplier. Details required on the form are axle load, train speed,
rail offsets, track alignment, transom length and width, girder spacing, girder flange width, packer
sizes and non-slip surface coating if required and holding down bolt size and locations if they are
required to be pre-drilled by manufacturer.
FFU products are designed to achieve a high level of manufacturing precision that can eliminate
the need for onsite modifications. They can be cut to specified precision, predrilled, pre-cut and
prepacked. To facilitate this, Project Manager shall provide supplier with accurate survey and rail
alignment data.

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Where the gaskets (packers) are necessary, they can be ordered from Sekisui. The order shall
include the correct dimensions (shall be greater than 3mm thick), shape and quantity of gaskets.
Where the gaskets are to be positioned over rivets, the supplier shall be provided with rivet
positions on drawing and required hole or groove sizes over rivets.
Axle load for specific track classification shall comply with the requirements of below.
Table 9-7 – Axle Loads for FFU AXLE LOAD (t) SPEED (kph)
transomsTRACK CLASSIFICATION

Hunter heavy haulage lines (New bridges) 35 >80

Hunter heavy haulage lines (Existing bridges) 30 >80

All other lines 25 >80

Lines requiring specific approval of Corridor Manager 23 >80

9.3.4.4.4 Holding Down Bolt and Screw Spike

The holding down bolt sizes shall be as specified in Table 9- 5

Recommended screw spike and hole dimensions for rail plate installation are given in below:
Table 9-8 – HOLE DIMENSION NOTE
Recommended screw spike
and hole dimensions for rail
plate installation SCREW
SPIKE DIMENSION

22 dia x 150mm long 17 dia x 140mm deep Standard screw spikes with Fe6 washer

24 dia x 150mm long 19 dia x 140mm deep Standard screw spikes with Fe6 washer

24 dia x 165mm long 19 dia x 150mm deep Standard screw spikes with Fe6 washer

9.3.4.4.5 Traceability of FFU Transoms

FFU products are manufactured from non-naturally occurring materials. The manufacturing
process and conformance testing records for each batch of FFU transoms shall be supplied by
the manufacturer and retained by the corridor manager. The corridor manager shall maintain
traceability records of all FFU transoms used in the corridor.

9.3.4.5 Transom Holding Down Assembly

All transoms on steel girder spans shall be seated on rubber pads to reduce impact loading on
steel superstructure and if required packers shall be used to achieve required rail level.
Specific requirements for pads under transoms are as follows:

• Pad shall be SA47 rubber pad or equivalent.

• Nominal pad thickness 5mm.

• Total thickness of pad(s) shall not be greater than 32mm.

• No steel plate or any other packer type to be inserted between layers of rubber pads.
Specific requirements for packers under transoms are as follows:

• Open deck rail bridges with steel span lengths greater than 20m have built in camber. The
thickness of packers shall not be increased at ends of span to remove camber.

• Packer(s) shall be installed below rubber pad unless packer, especially FFU gasket, is glued
to transom.

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• Packers to be steel plates, High Density Polyethylene (HDPE) sheets, FFU gaskets or
equivalent to suit required thicknesses.

• Packer thickness shall not be greater than 50mm in total unless otherwise approved by
ARTC.

• Conical spring is not required for non-shrinking FFU transom.

• Conical spring with flat washers can be installed either under bolt nut or head (spring
expands as timber shrinks).

• No more than 2 flat washers shall be used under bolt head and 1 either side of conical spring
Typical transom holding down assembly is shown in Figure 9-2 below.

• Conical spring with washers can be installed either under collar or head of bolt (spring
expands as timber shrinks).

• No more than 2 flat washers shall be used under bolt head and 1 either side of spring
washer.

Note: For FFU transoms, swage bolt with threaded nut and swage collar is an alternative option
to mild steel bolt provided tension in swage bolt is less than 40kN.

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Figure 9-2 Transom holding down assembly details (typical)

9.4 Inspection and Assessment

9.4.1 Inspections
9.4.1.1 Purpose
The purpose is to identify the requirements for systematic inspections so that:

• All structures are “fit for purpose” to meet operational needs.

• The responsibility and accountability for the structures management, inspection and
maintenance is identified.

• The safety of all operators is ensured.

• The need for unplanned downgrading of service conditions is avoided for all structures.

• The inspections are carried out in accordance with the approved program, in the correct
format and by competent inspectors.

• Data is provided for the development of structures management plans including strategic
maintenance and replacement programs.

• Adequate structural integrity is maintained to an acceptable engineering Standard.

• Routine maintenance works are being effectively implemented.

9.4.1.2 Scope
ARTC shall establish a comprehensive, systematic, condition monitoring and load rating
program for all nominated structures selected from Table 9.1. The program shall comprise the
following inspection types:

• Engineering Inspection.

• Visual Inspection.

• Special Inspection.

• Track Patrol Inspection.

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9.4.1.3 Third Party Structure

Inspection and maintenance of third party structures shall conform to the requirements of Road-
Rail Interface Agreement and/or Infrastructure License Agreement between the parties. Third
party structures here implies structures not owned or managed by ARTC.
9.4.1.4 Redundant Structures
Where possible and reasonable to do so, redundant structures and fittings shall be removed or
isolated from the public and railway workers. Isolation actions can include filling in, entry
barricading, fencing and signage. Some structures may be partially removed, leaving some
residual elements in place. Until total removal or isolation, redundant structures, structural
elements and fittings shall be subject to inspections and the minimum maintenance assessed as
necessary to prevent an increased risk to the public and workers above that considered
necessary SFAIRP during the structure’s service life. Such inspection and maintenance actions
of redundant structures and fittings shall be implemented until the structures are removed or
isolated.
9.4.1.5 Operational Safety
All personnel involved with inspections shall not cause danger, delay, obstruction or stoppage to
railway traffic and not interfere with the general business of the ARTC or its operators.
9.4.1.6 Work, Health and Safety
All inspection personnel shall comply with the ARTC’s Work, Health and Safety procedures.
All inspection personnel shall be appropriately accredited for work on or within rail corridors in
accordance with network operational and safe working requirements.
9.4.1.7 Environment
All inspection procedures shall comply with ARTC’s environmental procedures.

9.4.2 Load Rating

9.4.2.1 Structure Load Rating
All existing bridges (and large culverts, if required) shall be assigned "As New" and “As Is” load
ratings and fatigue assessment in accordance with AS 5100 Part 7 and AS 7636.
For road bridges, the vehicle mass and/or speed shall be reduced to attain a Rating Factor
greater than unity (i.e. RF > 1.0). All deficient road bridges shall be sign posted with R6-17 sign
in accordance with AS 1742.2 and AS 1743.
9.4.2.2 Loads and loading factors
The loads and factors are to be in accordance with AS (AS/NZS) 5100 except as
modified/clarified below.
9.4.2.2.1 Live Loads

In addition to the standard 300LA design rail traffic load and RAS train loads (refer Structures
Inspection Procedure, Train Consists) the load ratings will normally be required in terms of
current trains operating over the structure as nominated by ARTC.
There is a potential risk of rail breaking, failure of deteriorated transoms and ballasted timber
planks or existence of loose transom/plank holding down bolts in bridges. For this particular
reason, their small contribution towards load carrying capacity of span members shall be
disregarded unless otherwise approved by ARTC.

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9.4.2.2.2 Dead Loads

The combined un-factored superimposed dead load such as running rails, any existing guard rails
and transoms of the track together with/without steel walkway(s) can be taken as 5kN/m unless
otherwise more refined analysis is required.
9.4.2.2.3 Load Factors

The value for Live Load factor shall be 1.4 for live load and all loads induced by live load such as
centrifugal, nosing, braking and traction forces for all current and RAS train consists unless
otherwise nominated by ARTC. All other factors shall be as specified in AS 5100.7.
9.4.2.2.4 Dynamic Load Allowance (DLA)

The DLA value for load rating of existing bridges shall be as per AS 5100.2 and shall not be
increased by 50% for existing bridges without any transition slab as required by AS 5100.2 for
new bridges.
9.4.2.2.5 Nosing Load, Wind Load and Centrifugal Force

Nosing load, wind load and centrifugal force induce axial stresses in members bracing the flanges
of stringer, beam and girder spans, axial stresses in the chords of truss spans and in members of
cross frames of such spans, and stresses from lateral bending of flanges of longitudinal members
having no bracing system. The capacity of sway and wind bracing shall undergo detailed
analysis. If this methodology produces the rating factors below permissible values, then Finite
Element Analysis shall be carried out as per AS5100.6. If the aforementioned methodologies
produce unfavourable results, then the effects of lateral bending between braced points of
flanges, axial forces in flanges, vertical forces and forces transmitted to bearings shall be
disregarded as per American Railway Engineering and Maintenance-of-Way Association Manual
for Railway Engineering.
9.4.2.2.6 Braking and Traction Forces

The following characteristics of coal and freight trains shall be used to determine braking and
traction forces when using Rational method in AS (AS/NZ) 5100:

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Table 9-9 Braking and Traction Forces

PARAMATER VALUE

Rail traffic Nominated main line or heavy haulage freight traffic.

Train length 1800m unless otherwise nominated by ARTC

CoG above rail 2.1m for single stack container wagon and 2.65m for double stacked container wagon

Traction acceleration 0.5m/s2

Traction Length 60m (for 3No. 20m long locomotives) unless otherwise nominated by ARTC

Braking deceleration: 1.2m/s2.

Braking length: 1800m (for 3No. 20m long locomotives + 100No. 100t general freight wagons) unless
otherwise nominated by ARTC

Note: Where necessary, track-bridge interaction should be assessed to ensure the rails and
the bridge components are not subjected to any anomalies, guidance provided in UIC
Code – 774-3R.

9.4.2.2.7 Wind load

The Serviceability Wind Speed in AS (AS/NZS) 5100 is 37m/sec. The lower 20m/sec is to be
used on Ultimate Limit State live loads with load factor of 1.0 because of the short-term nature of
the train loading on the structure.
9.4.2.3 Fatigue Rating
Where ARTC requires a fatigue analysis to be undertaken, the minimum theoretical remaining
fatigue life across all structural elements shall be assessed in accordance with AS (AS/NZS)
5100. The Section 13 “Fatigue” in Part 6 of AS (AS/NZ) 5100 (2017) contains numerous
discrepancies. Wherever applicable, the 2004 version of the bridge code should be used for
fatigue assessment until the 2017 version is updated. Detail Categories shall be in accordance
with the 2017 version of the Bridge Code. Detail Category for the assessment of normal stress
for existing riveted bridge members that are in a reasonable condition should be 112 for shop
driven rivets and 90 for field driven rivets, unless otherwise approved by ARTC. Where shop and
field driven rivets cannot be distinguished then detail category should be 90.

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