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Engineering Standard

L1-CHE-STD-040 BRIDGE STANDARD Version: 2

ENGINEERING STANDARD BRIDGE STANDARD

L1-CHE-STD-040 Version: 2 Effective from: 17th July 2018

Approving Manager: Chief Engineer Approval Date: 17/07/2018 Next Review Date: 17/07/2021 PRINTOUT MAY NOT BE UP-TO-DATE; REFER TO METRO INTRANET FOR THE LATEST VERSION of 39

Approval

Amendment Record

Approval Date Version Description

22/12/2017 1 Initial issue under MTM. Supersedes VRIOGS 011.1 (draft), L1-CHE-INS-013, L1-CHE-INS-026, L1-CHE-INS-027, L1-CHE-INS-034, L1-CHE-INS-068. Refer to MOC #24053.

17/07/2018 2 Standard updated to reflect release of L1-CHE-STD-025 Transit Space Clearance Standard. Refer to MOC #44753 for details.




PREFACE

Metro Trains Melbourne (MTM) Standards have been developed to ensure common approaches are employed when designing, constructing or testing any part of the Melbourne Metropolitan Rail Network. It is important to understand that Standards are living documents which take into account learnings to achieve best practice.

All MTM Standards are periodically reviewed and new versions published which incorporate learnings and Technical Notes (TNs). TNs are issued between editions which correct any errors or ambiguities contained in an MTM Standard. Standards may also be withdrawn and replaced. As Standards are uncontrolled once printed, it is imperative to check the currency of the Standard on the MTM Intranet or MTM External Document Portal.

In the event of conflicts or discrepancies between Documents, refer to the order of precedence as defined in ‘Chief Engineer’s Guideline Engineering Standards Listing’ (L1-CHE-GDL-005).

Note: Any clarification described in a TN shall take precedence over the impacted clause or clauses in the associated MTM Standard.

In the event a clause within a Standard is not achievable a waiver must be raised in accordance with ‘Engineering Waiver Procedure’ - L1-CHE-PRO-001.

Note: MTM does not have the authority to grant waivers to any Standards which relate to Government Regulations or Legislation, e.g. Disability Discrimination Act.

Application of this Standard This Standard is applicable from the approval date. It shall be applied to all projects and renewals works on the MTM Infrastructure Lease commencing after the approval date. It shall also be applied to projects and renewals works that are in the delivery phase where there is a requirement for compliance to AS 5100-2017.




Table of Contents 1 Purpose ........................................................................................................................... 6

2 Scope ............................................................................................................................... 6

3 Abbreviations and Acronyms ........................................................................................ 6

4 Definitions ....................................................................................................................... 7

5 References & Legislations ............................................................................................. 9

General ............................................................................................................................. 9 MTM References .............................................................................................................. 9

Industry References ........................................................................................................ 10

Australian References and Legislation ........................................................................... 11

6 Related Documents ...................................................................................................... 11

7 Safety & Environmental ................................................................................................ 11

8 Design of New Bridges, Underpasses and Soil Retaining Structures ...................... 12

General Requirements .................................................................................................... 12

Minimum Clearances ...................................................................................................... 15

8.2.1 General ......................................................................................................... 15 8.2.2 Overbridges .................................................................................................. 16 8.2.3 Underbridges ................................................................................................ 16 8.2.4 Additional provisions for through-girder Underbridges ................................. 16

Drainage ......................................................................................................................... 16

Walkways and Handrails ................................................................................................ 17

Derailment Management on Rail Structures ................................................................... 18

Track Structure ............................................................................................................... 20 Protection Beams............................................................................................................ 20

Soil Retaining Structures Adjacent to Rail ...................................................................... 21

Application of AS 5100-2017 Bridge Design .................................................................. 22

9 Assessment and Load Rating of Underbridges .......................................................... 29


Reporting of Assessment and Load Rating Factors ....................................................... 30

Application of AS 5100-2017 Bridge Design .................................................................. 30

10 Structural Modification of Bridges .............................................................................. 32

Application ...................................................................................................................... 32


Loading ........................................................................................................................... 32

Clearances ...................................................................................................................... 32 Drainage ......................................................................................................................... 32

Walkways and Handrails ................................................................................................ 32

Collision Protection ......................................................................................................... 33




Protective Screens .......................................................................................................... 34

11 Appendix A – Documentation Requirements .............................................................. 35

General Requirements .................................................................................................... 35 11.1.2 All design drawings shall be produced in accordance with the conventions detailed in L1-CHE-POL-001 Engineering Drawings Management Policy (IFC/As Builts), and PTV’s Infrastructure Drafting Standards. ..................................................... 35

Specific Requirements .................................................................................................... 35

12 Appendix B – Indicative Underbridge Arrangements ................................................. 37

13 Appendix C – Load Rating Tables ............................................................................... 38

14 Appendix D – Load Rating Details ............................................................................... 39

List of Tables Table 1 - Derailment Management Systems .............................................................................. 19

Table 2– PTV Asset Integrity Requirements for Elevated Railway Track ................................ 20

Table 3 – Application of AS 5100-2017 Bridge Design for New Bridges ................................. 23

Table 4 – Bridge Specific Design Parameters for the Rational Method .................................. 26

Table 5 – Load Rating Section Loss Categories ....................................................................... 29

Table 6 – Application of AS 5100 for Load Rating and Assessment ....................................... 31

Table 7 – AS 5100.2 Collision Loading Categories ................................................................... 34

List of Figures Figure 1 - Soldier pile and shotcrete soil retaining structure .................................................. 22




1 Purpose The purpose of this document is to provide technical requirements for the:

• Design of Bridges, Underpasses, Soil Retaining Structures, Culverts and associated civil infrastructure within the rail corridor or the MTM Infrastructure Lease;

• Design of structural components related to Tunnels or Underpasses where they are not covered by other MTM standards; and

• Structural assessment and load rating of existing Bridges, Underpasses, Soil Retaining Structures, Culverts and associated civil infrastructure within the rail corridor or the MTM Infrastructure Lease.

2 Scope This Standard shall be read in conjunction with AS 5100-2017.

This standard sets out MTM requirements for the design of Bridges, Underpasses, Soil Retaining Structures, Culverts and associated civil infrastructure in the MTM Infrastructure Lease.

Note: Road and pedestrian Bridges shall comply with the requirements of L1-CHE-STD-025, VicRoads and AS 5100 unless specifically varied by the requirements of this Standard.

This standard sets out the requirements for structural assessment and load rating of Bridges, Underpasses, and Culverts in the MTM Infrastructure Lease.

Note: This standard does not provide requirements for when structural assessment and load rating is undertaken. This is covered by the appropriate Technical Maintenance Plan and project scope where relevant.

This standard is mandatory for all proposed works in the MTM Infrastructure Lease.

This Standard does not include specifications for the construction, deconstruction, installation and placement of Bridges and Bridge materials.

3 Abbreviations and Acronyms DMS Drawing Management System (managed by PTV)

DPN Design Practice Note

KE Kinematic Envelope (refer to STD_R0009)

MTM Metro Trains Melbourne

PTV Public Transport Victoria

RSNL Rail Safety National Law

SFAIRP So Far As Is Reasonably Practicable




4 Definitions As-Is Load Rating Load rating based on the current condition of the Bridge

including all structural modification.

As-New Load Rating Load rating assuming the Bridge, including all structural modification, is in as-new condition.

Bridge An Overbridge, Underbridge, Culvert, suspended station concourse or pedestrian/cyclist Bridge.

Cant The vertical distance that the outer rail is raised above the inner or grade rail of a curve. Also known as superelevation.

Chord Effect The effect resulting from curved track geometry on straight bridge elements

Critical Load Rating Factor

The lowest Component Load Rating Factor which determines the load rating factor for the Bridge.

Culvert An Underbridge having a deck supported on continuous integral walls and (usually) base slabs whose function is to allow water to flow under the track.

Design Life The period adopted for design purposes for which a structure or structural element is required to perform its intended purpose with periodic maintenance but without replacement or major structural repairs.

Generally Accessible Areas

Areas accessible to the general public such as parklands; station platforms, stairways, ramps and concourses; roadways, carparks, pedestrian and cycling paths.

Handrails A system of posts, rails and/or panels that provides protection at the edge of a floor or platform or walkway.

Note: This definition corresponds to the term “guardrailing” in AS1657. The term “handrails” is used in this standard to avoid confusion with guard rails which are a derailment control measure.

Infrastructure Lease The Land and Infrastructure as defined in the Train Infrastructure Module of the MR4 Franchise Agreement.

Kinematic Envelope A two dimensional cross-section of the shape of a rail vehicle that consists of the static outline plus the maximum permitted allowance for vertical and lateral movements. It also includes any Cant and curve effect associated with curved track and dynamic movements in response to track irregularity. Refer drawing STD_R0009.

Load Rating The process of determining a load-rating factor as defined in AS 5100.7.

Overbridge A non-rail Bridge that crosses over track.




Pedestrian and/or Cyclist Path Bridge

A Bridge or station concourse spanning over rail and beyond and intended solely for pedestrian and/or cyclist use; but may include use by maintenance traffic or emergency vehicles. For the purpose of this standard, a pedestrian Bridge includes any associated stair and ramp approaches and landings.

Position of Safety As defined by L1-SQE-PRO-054 Planning Work Site Protection in the Rail Corridor: “a place where people or equipment cannot be struck by rail traffic.”

Protection Barrier Refer to clause 8.5.4.

Rail over Rail Bridge An Underbridge crossing over track.

Note: The requirements for both Underbridges and Overbridges shall apply to Rail over Rail Bridges.

Shall The term shall is used to express a clause that is mandatory to achieve conformance to the standard.

Should Is used as the descriptive word to express a requirement that is recommended in order to achieve compliance. ‘Should’ can also be used if a requirement is a desirable but not a mandatory requirement.

Soil Retaining Structures Structural walls whose primary function is to retain soil whilst in some cases also being required to withstand collision loads from derailed trains.

Soil retaining structures may be of, but are not limited to, the following types:

• Soil nail walls • Diaphragm walls • Secant and contiguous pile walls • Sheet pile walls • Reinforced soil walls • Solder piles with infill walls • Underpass walls • Cantilever walls.

Structural Modification Widening, extending or replacement of Bridges or any other modification that alters their structural capacity and/or function. Structural modification does not include repair, “like for like” replacement or maintenance works

Through-Bridge An Underbridge where the Bridge structure extends above track level (e.g. through-girder, through-arch, through-truss or cable stayed Bridge).

Tunnel An Underpass constructed typically using either boring or mining techniques.

Underbridge A Bridge supporting track. Indicative Underbridge arrangements are given in Appendix B.




Underpass A below ground-level structure for the passage of rail vehicles, road vehicles, maintenance vehicles, and/or pedestrians and cyclists. Constructed typically using eithercut and cover or tunnelling techniques.

5 References & Legislations

General 5.1.1 Bridges, Underpasses and Soil Retaining Structures shall be designed and

constructed in accordance with this standard, other relevant MTM and Australian standards and MTM requirements documents.

5.1.2 Where a conflict arises between documents, or where clarification on the applicability of a standard, specification or a part of either is required, the matter shall be referred to the MTM Chief Engineer or delegate for determination.

MTM References

Document Number Title L0-SQE-PLA-005 Environmental Management Plan

L0-SQE-PRO-031 Enterprise Risk Management Procedure

L0-SQE-PRO-040 Interface Agreements - Procedure

L0-SQE-MAN-002 Safety Management System Manual.

L0-HMR-MAN-001 Business Rules Manual for the Contracting Rail Safety Worker

L1-NAM-PRO-002 Design and Technical Review Procedure.

L1-SQE-PRO-054 Planning Work Site Protection in the Rail Corridor

L1-CHE-GDL-005 Chief Engineer’s Guideline Engineering Standards Listing

L1-CHE-STD-010 Railway Bridges Electrical Protection and Bonding

L1-CHE-STD-025 Transit Space Clearances

L1-CHE-STD-030 Track Drainage Standard

L1-CHE-STD-035 Lighting and Power – Design and Construction Standard

L1-CHE-PRO-001 Engineering Waiver Procedure

L1-CHE-POL-001 Engineering Drawings Management Policy (Issued for Construction/ As Built drawings)

L1-CHE-PRO-031 Engineering Change Procedure

L2-STF-PRO-003 Rail Over Road Bridges – Bridge Strike Impact




Industry References

Document Number Title PTV Infrastructure Drafting Standard

PTV-ED-002:2017 Public Transport Victoria Engineering Directive Track and Structures ‘Asset Integrity Requirements for Elevated Railway Track Infrastructure’

STD_E0001 Standard Drawing for Overhead Conductor Clearance and Protective Requirements at Overline Bridges

STD_R0009 Maximum Rolling Stock Outline Kinematic Diagram – Type 1 Single Deck Cars

UIC 717-2R Laying of track on a reinforced concrete deck

Vicroads Bridge Technical Note BTN004

Bridge joints


FRP for strengthening of bridge structures


Bonded anchors


Noise attenuation walls


Mechanical anchors


RC panels for reinforced soil structures


Integral and semi integral bridges


Approach slabs


Design of large box culverts


Step joints

VicRoads Specification for Roadworks and Bridgeworks – 600 Series - Bridgeworks

VicRoads Road Structures Inspection Manual




Australian References and Legislation

Document Number Title AS 5100 Bridge design

AS 1657 Fixed platforms, walkways, stairways and ladders—Design, construction and installation

AS 1428.1 Design for access and mobility

AS 7633 Railway Infrastructure: Clearances

AS 7636 Railway Structures

RISSB Guideline Refuges – Bridges and Tunnels

SA HB 198 Guide to the specification and testing of slip resistance of pedestrian surfaces

Rail Safety National Law Application Act 2013 (Vic)

Victorian Occupational Health and Safety Act 2004

S.R. No. 22/2017 Victorian OHS Regulations 2017

WorkSafe Victoria Industry Standard “Construction and Erection of Bridge Beams”

6 Related Documents

Document Number Title L1-CHE-STD-039 Track Design and Construction

7 Safety & Environmental The general requirements in relation to safety are included in MTM’s Safety Management

System Manual (L0-SQE-MAN-002).

The design and construction of infrastructure shall comply with the MTM Environmental Management Plan (L0-SQE-PLA-005).

All rail safety workers shall comply with Business Rules Manual for the Contracting Rail Safety Worker (L0-HMR-MAN-001) and have the appropriate competencies to undertake their role.

Under RSNL (s46) MTM is required to:

a. Eliminate risks to safety so far as is reasonably practicable (SFAIRP); and

b. If it is not reasonably practicable to eliminate risks to safety, to minimise those risks so far as is reasonably practicable.

Under RSNL (s47), reasonably practicable means that at a particular time, MTM were able to demonstrate how the risk/s can be reasonably managed to ensure safety, taking into account and weighing up all relevant issues including:

a. The likelihood of the hazard or the risk concerned occurring;

b. The degree of harm that might result from the hazard or the risk;




c. What the person concerned knows, or ought to reasonably know, about:

i. the hazard or risk, and ways of eliminating or minimising the risk;

ii. the availability and suitability of ways to eliminate or minimise the risk; and

d. After assessing the extent of the risk and the available ways of eliminating or minimising the risk, the cost associated with available ways of eliminating or minimising the risk, including whether the cost is grossly disproportionate to the risk.

Under RSNL (s50), rail safety is a shared responsibility of:

a) Rail transport operators; and

b) Rail safety workers; and

c) Other persons who:

i. Design, commission, construct, manufacture, supply, install, erect, maintain, repair, modify or decommission rail infrastructure or rolling stock; or

ii. Supply rail infrastructure operations or rolling stock operations to rail operators; or

iii. In relation to the transport of freight by railway—load or unload freight on or from rolling stock.

Safety and risk assessments shall be undertaken to inform the design. It shall take into account safety considerations for construction and maintenance personnel and any other party, including operations personnel who may be required to use the track. Risk assessments shall be conducted in accordance with the MTM Enterprise Risk Management Procedure L0-SQE-PRO-031.

Where new equipment or systems are proposed to be introduced, the materials and equipment shall be subject to MTM Type Approval processes for use on the metropolitan train network.

For any structures above, below, or within the MTM Infrastructure Lease, but not inspected or maintained by MTM, a Safety Interface Agreement shall be prepared in accordance with L0-SQE-PRO-040.

Where new rail over road bridges are introduced, or existing rail over road bridges are substantially modified, L2-STF-PRO-003 Bridge Strike Impact procedure shall be revised.

8 Design of New Bridges, Underpasses and Soil Retaining Structures

General Requirements 8.1.1 The design of Bridges shall comply with the documentation requirements outlined

in Appendix A – Documentation Requirements.

8.1.2 New Bridges, Underpasses and Soil Retaining Structures shall be designed to meet project specific functional requirements described in the relevant MTM Final Operational Requirements and Final Impact Statement for the project.

8.1.3 Underbridges and Underpasses shall be designed to not preclude any future tracks and/or track realignments specified by PTV.

8.1.4 Earthing and bonding of Bridges shall comply with L1-CHE-STD-010 Railway Bridges Electrical Protection and Bonding.




8.1.5 Designs shall comply with the Vicroads’ requirements referenced Section 5.3 current at the commencement of design.

8.1.6 Bridges shall be designed to minimise disruption to train services and normal railway activities during construction and maintenance. Bridges shall be designed so that they do not diminish the safety of railway operations, or the safety of persons whose duties take them on or near the line, by:

• avoiding potential arcing of traction power equipment, • providing signal sighting for train drivers, • providing sighting for authorised track staff, • providing positions of safety from passing trains for authorised personal and

tresspassers, • providing emergency access, and • providing reasonable inspection and maintenance access to all parts of the

structures, including the interiors of box girders and the like. 8.1.7 The design shall incorporate measures to enable the safe ongoing inspection and

maintenance of Bridges (including individual asset components that are integral or attached to the Bridge) with minimum train service disruption. The design shall mitigate the risk of falls in accordance with Victorian OHS Regulations and Worksafe Victoria Guidelines.

8.1.8 Approved construction materials for main structural elements are steel and concrete. Timber materials shall not be used as permanent structural elements.

8.1.9 Materials shall be selected to avoid colours similar to those used for railway signalling, or that may exhibit reflectivity that may diminish the visibility of train drivers or safety workers.

8.1.10 Buried metal structures, such as steel anchor straps, ties and fitments for reinforced soil retaining structures, steel sheet piles, steel tubular piles and steel H-piles, are considered to be generally unsuitable for use in direct current electrified zones and shall not be used as permanent structural materials unless approved by the MTM Chief Engineer or delegate. Where MTM has approved their use, buried steel structures shall be treated in compliance with Cause 8.1.4 and due allowance made for the loss of steel due to chemical and electrolysis corrosion over their life. Sheet pile walls shall be capped with concrete beams of sufficient strength and stiffness to maintain their line and level. Corrugated metal pipe Culverts and arches shall not be used anywhere in the MTM network.

8.1.11 To allow for use by maintenance vehicles and plant, Underbridges shall be designed for loading from a pair of A160 axles spaced at between 2 metres and 10metres longitudinally apart. This loading shall be applied with the most adverse axle spacing at any location on the Bridge deck accessible by the vehicle. Dynamic load allowances and load factors shall be applied as specified by AS 5100.2.

8.1.12 Bridge designs shall minimise the number of movement joints and bearings as far as is reasonably practicable. Decks shall be continuous and waterproof between movement joints without gaps or openings. Where the beams are not continuous, the deck slab shall be continuous and waterproof. Movement joints and other gaps in ballasted decks shall be protected against ballast loss by cover plates with a minimum Design Life of 50 years.




Movement joints located above Generally Accessible Areas, or above critical operational infrastructure such as track, overhead wiring and signalling or communication equipment shall be designed to be waterproof.

They shall also be able to intercept stormwater overflow resulting from failure of the movement joint waterproofing and discharge it into a suitable drainage system. Bridge deck surfaces shall be graded to drain stormwater away from movement joints and into suitable collection points. Top-down insitu concrete Bridge decks shall be provided with waterproofing membranes and their construction joints suitably treated to ensure their watertightness.

8.1.13 Permanent halving joints shall not be used to support main load carrying elements of an Underbridge.

8.1.14 Hatches shall be provided for access to the interior spaces of Bridges when required for inspection or maintenance and shall comply with AS1657. Opening and locking of hatches shall be capable of being undertaken using one hand only.

8.1.15 Hatches located in the soffits of Bridges shall be located above safe accessible areas away from rail and road traffic. Hatch covers shall be in-swinging only, hinged, lockable from the outside and lockable in the open position from the inside.

8.1.16 Underbridges on curves are not required to have superelevated decks where Cant can be accommodated by the trackform.

8.1.17 Underbridges shall be provided with approach slabs at both ends. Approach slabs shall be a minimum length of 4 metres measured perpendicular to the Bridge abutments. The outer (ground supported) ends of approach slabs shall be perpendicular to the track centre-line. The inner (abutment supported) end of an approach slab shall be connected to the abutment so as to prevent lift-off and to allow the slab to rotate if its outer end settles.

8.1.18 Net uplift forces shall not occur at a bearing of an Underbridge under any serviceability limit state load combination.

8.1.19 The vertical deflection (up or down) at the end of an Underbridge deck (due to the deck extending beyond the line of support) shall not exceed 2mm under any serviceability limit state load combination.

8.1.20 For ballasted Underbridges, ballast mats should be considered for attenuating sound in noise sensitive areas and for reducing ballast degradation where the minimum depth of ballast is less than 300mm.

8.1.21 On ballasted steel Through-Bridges, the trackside faces of the girders shall not act as ballast kerbs. The steel surfaces shall be accessible for inspection and maintenance.

8.1.22 Piers, parapets and any other parts of Bridges vulnerable to graffiti vandalising should have uniform surfaces to facilitate graffiti removal or over-painting.

8.1.23 Bridges shall incorporate features to prevent birds nesting on and in the Bridges. Bird proof screening shall be provided at all openings in box girder Bridges.

8.1.24 Utilities and services supported off Bridges shall be coordinated with the relevant utilities owners to ensure the location, fixing and replacement of services are designed so inspection and maintenance is safe and unimpeded. Services shall be positioned so that they do not encroach on the safe working area or create a trip or other safety hazard.




8.1.25 Feature or security lighting and interior safety lighting of Bridges shall use LED systems in accordance with L1-CHE-STD-035.

8.1.26 All new Bridges, Underpasses and Culverts shall be fitted with a unique Asset ID number engraved on a durable metal plaque and installed in a clearly visible location on each abutment or wall of the structure.

8.1.27 Reinforced Soil Walls shall be designed in accordance with NSW Roads and Maritime Services QA Specification R57.

Minimum Clearances

8.2.1 General

8.2.1.1 The minimum clearance dimensions in section 8.2 apply only to the structural components of a Bridge unless stated otherwise. They do not apply to non-structural Bridge attachments (e.g. overhead wiring and signalling structures, handrails).

8.2.1.2 The minimum clearance dimensions specified shall be increased where required to ensure safe signal sighting for train drivers and sufficient Position of Safety for authorised personnel.

8.2.1.3 The minimum clearance dimensions specified are for tangent track. For track on a horizontal curve of any radius the clearance dimensions shall be increased to allow for curve and Cant effect of a rail vehicle.

8.2.1.4 For track on a horizontal or vertical curve, the horizontal and vertical clearance dimensions shall be increased to allow for the Chord Effect of the structure.

8.2.1.5 The design shall demonstrate that in all cases the required clearances have been achieved.

8.2.1.6 Access between the track and the Position of Safety should avoid requiring more than one single 300mm step, as defined by AS1657. Where it can be demonstrated to the MTM Chief Engineer, or delegate, that this cannot be reasonably achieved, an alternate access arrangement may be accepted following demonstration the risk of a person reaching a Position of Safety is safe SFAIRP.

8.2.1.7 A one metre horizontal clearance should be maintained between adjacent Bridges to allow access for Bridge inspection and maintenance. Where this is not achievable, the designer shall demonstrate that all inspection and maintenance tasks can be safely completed.

8.2.1.8 For the avoidance of doubt the following requirements of L1-CHE-STD-025 shall not apply:

• Section 9.2 Envelope E shall not apply to the structural components of an Underbridge, except where specifically referenced in this standard.

• Section 9.3 Envelope N shall not apply to the structural components of a Bridge or derailment protection and ballast retention structures on the Bridge.




8.2.2 Overbridges

8.2.2.1 Overbridge clearances shall provide a structure gauge envelope defined by the requirements of L1-CHE-STD-025 unless approved by otherwise by the MTM Chief Engineer, or delegate.

8.2.2.2 Where an overbridge spans tracks managed by multiple accredited rail transport operators, approval shall be sought from all the affected accredited rail transport operators for any variance to L1-CHE-STD-025.

8.2.3 Underbridges

8.2.3.1 The minimum horizontal clearance from design track centreline to any part of the structure above top of rail level shall be 2400mm.

8.2.3.2 Elements designed to provide derailment protection or ballast retention and not exceeding a height of 200mm above top of rail may be located within 2400mm of the nearest track centreline providing a minimum clearance of KE +200mm safety margin is provided and access to a Position of Safety complies with clause 8.2.1.6. Any reduction in safety margin will be subject to acceptance by the MTM Chief Engineer or delegate. For elements exceeding 200mm above top of rail refer to clause 8.2.4.2.

8.2.3.3 For ballasted track, a minimum 400mm wide ballast shoulder shall be provided between the end of sleeper and any part of the Bridge structure, derailment protection structure or ballast retention kerb.

8.2.4 Additional provisions for through-girder Underbridges

8.2.4.1 The minimum horizontal clearance from the adjacent track centreline to any part of a through-girder bridge (including protection barriers) shall comply with the requirements of 8.2.3.1.

8.2.4.2 Where it can be demonstrated to the MTM Chief Engineer, or delegate, that compliance with 8.2.3.1 cannot be reasonably achieved, a reduced clearance may be accepted for structural elements exceeding a height of 200mm above top of rail as follows:

• KE +200mm for any structure ≤1080mm above adjacent rail level.

• Provision of 2400mm horizontal clearance on one side of a single track or on the outside of multiple track sections with access to a Position of Safety that complies with clause 8.2.1.6.

Drainage 8.3.1 Underbridge drainage shall be designed in accordance with the drainage principles

specified in L1-CHE-STD-030 Track Drainage Standard.

8.3.2 For other than rail over rail Bridges the drainage from Overbridges and their approaches shall not be discharged into the railway drainage system.

8.3.3 Drainage from the Underbridge approach embankment shall be intercepted so that it does not drain onto the Underbridge deck.

8.3.4 Drainage from the Underbridge deck shall be intercepted so that it does not drain onto the Underbridge approach embankment.




8.3.5 Underbridge decks and underslung pipes shall have a minimum longitudinal grade of 0.3 percent to provide positive drainage. Underbridges carrying one track shall have a transverse grade towards the side of the structure (one-way crossfall or with a central crown).

8.3.6 Underbridges carrying two tracks shall have a transverse grade towards the side of the structure (one-way crossfall or with a central crown), or a transverse grade from each side to the centre of the structure. The transverse slope shall be not less than 1%.

8.3.7 The design of ballast and derailment kerbs shall allow for cross drainage of the deck.

8.3.8 On ballastless Bridges, grated inlets shall be readily accessible for maintenance and inspection, and protected from damage by maintenance activity.

8.3.9 On ballasted Bridges drainage points shall be provided at a maximum spacing of 5m. Ballast shall not be used as a drainage medium for longitudinal flow other than between drainage points. Ballast cages shall be utilised at all grated inlets to allow maintenance access.

8.3.10 The longitudinal drainage system shall be constructed from robust materials capable of supporting the applied construction, operation and maintenance loads. The longitudinal drainage system shall be provided with rodding and flush-out points that are accessible from the Bridge walkway.

8.3.11 On Underbridges secondary drainage outlets shall be installed to allow flow in excess of the 1 in 100 year annual recurrence interval event to discharge from the Bridge.

8.3.12 The minimum pipe size on Bridges shall be 150mm internal diameter. Pipes shall be UV resistant and have the same Design Life as the structure.

8.3.13 The superstructure shall be detailed to prevent water running onto beams or web faces. Drip lines may be provided as a means to achieve this.

8.3.14 Bridge designs should avoid pockets or depressions that may create water ponding.

Walkways and Handrails 8.4.1 On single track Underbridges, a walkway shall be provided on at least one side of

the Underbridge. Where only one walkway is provided, it should be provided on the side of the structure that provides a continuous access path for maintainers without the need to cross the track.

8.4.2 Where there are two or more tracks, a walkway shall be provided on both sides of the Underbridge.

8.4.3 The minimum clear walkway width shall be 1000mm.

8.4.4 Where required, access from walkways to tracks, or to an adjacent section of continuous access path, shall comply with AS1657.

8.4.5 Walkway surface finishes shall be non-slip and shall comply with classification P4 (wet pendulum test) or R11 (oil-wet inclining platform test) as required for external ramps in Table 3B of SA HB 198.

8.4.6 Walkways shall not obstruct or reduce the performance of track drainage systems.




8.4.7 The minimum horizontal clearance from the adjacent track centreline to the inside edge of a maintenance walkway shall be 2400mm. Where this is not possible, a minimum horizontal clearance of 2135mm may be accepted providing:

• A handrail is positioned between the Position of Safety and adjacent track. The handrail shall be compliant with AS1657 with each section no longer than 2m with a gap of 1.2-1.6m between sections to allow access to/from track. It shall be vandal proof; removable by conventional railway hand tools; simple to re-establish if damaged; and arranged to accommodate conventional maintenance activities.

• A continuous painted line at surface level is provided between the position of safety and adjacent track.

• The walkway is positioned to provide access to the position of safety that complies with clause 8.2.1.6.

8.4.8 Walkways shall be continuous between Underbridge abutments and shall be suitably transitioned back to the formation level on the approach embankments for use by maintainers and de-trained passengers.

8.4.9 Handrails shall be provided in the following locations as a minimum:

• On the outside edge of an Underbridge with a fall height greater than 1000mm to provide fall protection for maintenance staff.

• One the outside or inside edge of a walkway with a fall height greater than 1000mm to ground or track level

8.4.10 Handrails shall comply with AS1657.

8.4.11 Handrails on the outside edge of the structure shall have infill welded mesh comprising 3mm diameter galvanised wires at 25 mm x 25mm centres and securely fixed to the posts and rails, or an alternative mesh that provides equivalent screening and rigidity.

8.4.12 Handrails installed within 2400mm from track centreline shall not interfere with maintenance tasks and shall be positioned to provide sufficient clearance for curve and Cant effect of a rail vehicle, Chord Effect of the structure, and a safety margin of KE +200mm.

8.4.13 All handrails shall have toeplates that comply with AS1657 unless the intent is met be alternate means.

Derailment Management on Rail Structures 8.5.1 Unless specified otherwise on a project specific basis, derailment management

systems shall be installed on rail structures in the following situations:

• Underbridges over 20m in length.

• Underbridges over or adjacent to roads, waterways, public spaces or populated areas.

• Underbridges adjacent to high risk infrastructure (e.g. aviation fuel pipelines).

8.5.2 Derailment management systems are not required for the inner tracks of multiple-track Bridges. For example, if an Underbridge has three tracks, the centre track does not require derailment management devices.




8.5.3 Derailment management systems shall, so far as is reasonably practicable, ensure that the proposed derailment management systems would in the event of a derailment:

• keep derailed wheels tracking parallel and in close proximity to their running rails.

• minimise consequential harm to persons and damage to rolling stock and infrastructure.

• greatly increase the likelihood that a derailed rail vehicle would be kept upright and within gauge of the track that it was travelling on.

• prevent derailed rail vehicles from striking critical above-rail structural elements.

8.5.4 Derailment management systems shall comprise one or more of the devices listed in Table 1 that shall be designed to act individually, or in combination where compatible, to meet the functional requirements specified in clause 8.5.3.

Table 1 - Derailment Management Systems

Device Description

Close Containment Devices

Devices designed to retain derailed vehicles in close proximity to the running rails. Examples include guard rails and integrated track systems that replicate the function of guard rails. They may only be used to supplement other containment devices listed below in this table.

Derailment Kerbs Kerbs integrated with the Bridge deck and located in accordance with section 8.2 and AS 5100.2 clause 11.5.4. Their primary function is to retain derailed rail vehicles on the Underbridge deck. Where a conflict exists between derailment kerb height and step height to a Position of Safety, priority should be given to the derailment kerb height.

Protection Barriers

Barriers designed to protect above-deck critical structural members, such as through-girders, through-arch members and through-truss members and cable-stay anchorages, from glancing collisions by derailed rail vehicles within the Bridge.

Deflection Walls • Walls designed to protect piers and abutments that support rail, road or pedestrian Overbridges from the impact of derailed trains.

• Walls designed to protect above-track critical structural members of Through-Bridges and Tunnel or Underpass portals from head-on collisions from derailed trains.

8.5.5 Derailment management systems shall be continuous for the full extent of the Underbridge, including approach slabs, without snag points and without horizontal or vertical deviations greater than 10 degrees.




Track Structure 8.6.1 The track structure above an Underbridge shall comply with the PTV Engineering

Directive PTV-ED-002:2017. An extract of the requirements of this directive relating to track structure are outlined in Table 2. The mandatory requirements of this Directive are network level requirements which MTM cannot grant a waiver against.

Table 2– PTV Asset Integrity Requirements for Elevated Railway Track

1 Length 150-500m

Ballastless track shall be adopted for elevated railway infrastructure including, but not limited to, Bridge, viaduct and station structures between 150metres and 500metres in length. However if, following a risk and economic analysis to the approval of MTM, it can be demonstrated that there would be significant economic benefit with no reduction in the safety, reliability, availability and maintainability by adopting ballasted track, ballasted track may be used for the elevated railway track structure subject to approval by MTM.

2 Length > 500m

Ballastless track shall be adopted for elevated railway track infrastructure greater than 500metres in length.

8.6.2 For ballasted track, the bridge deck and approach slabs shall be designed to allow for a minimum 300mm ballast depth below sleepers and be designed with ballast walls to ensure the lateral retention of the ballast along the length of the structure / slab. Note: approach slabs typically have 210mm deep guard rail sleepers.

8.6.3 Track transitions between ballasted and ballastless trackforms shall demonstrate sufficient management of the track stiffness transition and change in deflection under load, in addition to the transition requirements between the Bridge structure and the abutment / earthworks.

Protection Beams 8.7.1 Where vertical clearance to a railway Underbridge from a road does not meet the

minimum specified in Clause 13.7 “Vertical clearance at structures” of AS 5100.1, protection beams shall be installed to prevent impact of road vehicles with the Bridge superstructure.

8.7.2 The design of protection beams shall provide sufficient structural integrity so that on impact, the structure remains whole and collapse does not occur. Safety chains at each end of the protection beam shall be installed which are capable of supporting its dynamic weight in the event of dislodgment from its supports with a factor of safety of 3.

8.7.3 Infill materials, where used, should not be considered to act compositely for strength purposes. Infill material however may be considered to serve the functions of providing restraint to buckling of webs, the distribution of collision loading and the provision of a measure of internal corrosion protection, where necessary. Drainage shall be incorporated where necessary to prevent water pooling.

8.7.4 The supports of a protection beam shall be integrated with the Bridge substructure.

8.7.5 The soffit of protection beams shall be installed a minimum of 20mm below soffit line of the structure it is to protect. The leading face side of a protection beam shall be positioned to ensure that it takes the initial strike.




8.7.6 Adjustments in the level, along the longitudinal axis of a protection beam, shall also be made to allow for geometric conditions of road and rail.

8.7.7 Protection beams shall be aligned perpendicular to the horizontal alignment of roadway below so far as reasonably practical. All skewed protection beams shall be subject to approval of the MTM Chief Engineer or delegate.

8.7.8 Protection beams shall be placed with a minimum horizontal clearance from the structure of 100mm plus the calculated mid-span horizontal deflection of the protection beam under impact at the ultimate limit state. Access for maintenance of the protection beam and the protected structure shall be considered when determining the clearance value.

8.7.9 Protection beams shall be painted, signed and marked in accordance with the requirements of the relevant road authority. Notices shall be fixed to the Bridge in prominent positions to provide information on the relevant authorities to contact in the event of a Bridge strike.

8.7.10 Protection beams shall be fitted with vehicle collision detection and monitoring equipment as specified by MTM.

Soil Retaining Structures Adjacent to Rail 8.8.1 Soil Retaining Structures shall be designed to comply with AS 5100 with particular

reference to AS 5100.2 clause 11.4 for train collision loads.

8.8.2 Anchoring systems that extend under the track (e.g. soil nails, rock anchors, wall straps, tie backs) should be avoided where they could restrict the installation of future below-ground rail infrastructure such as foundations for overheads and signalling, drainage or cable trenches.

8.8.3 The trackside faces of Soil Retaining Structures in the zone extending from 150mm below finished ground level to a minimum height of 2400mm above the top of the nearest rail:

• Shall be continuous and free of abrupt changes in direction greater than 10 degrees on the approach to a retained abutment.

• Shall be free of catch features greater than 25mm. Catch features exceeding this limit shall be protected by 10 degrees maximum robust approach surfaces which shall be structurally integrated with the parent wall, as illustrated in Figure 1.

• For shotcrete faces, the surface finish face shall comply with VicRoads Specification Section 684.11 Finishing.

• Shall be treated with 20mm minimum render where steel fibre reinforced shotcrete is used adjacent to maintenance or public paths.




Figure 1 - Soldier pile and shotcrete soil retaining structure

Application of AS 5100-2017 Bridge Design 8.9.1 The design of Bridges shall comply with the requirements of AS 5100-2017 Bridge

Design except as specified in Table 3. Where a conflict exists between the requirements of this standard and AS 5100, the requirements of this standard shall take precedence.

TRACK AND STRUCTURES BRIDGE STANDARD



Table 3 – Application of AS 5100-2017 Bridge Design for New Bridges

AS 5100 Clause reference

Requirement

Part 1 Cl 8.1 All Bridges in urban areas and visually important sites in rural areas shall be given appropriate aesthetic design consideration. Supplementary cladding systems shall not be used unless specified otherwise on a project specific basis. Cladding shall not cause impairment to visibility or physical access to structural elements for inspection and maintenance.

Part 1 Cl 8.2 Bridges including rail, road and pedestrian support structures and elevated concourses 100 years Embankments and retaining walls, including reinforced soil structures and soil nail walls 100 years Culverts and major drainage structures including tanked structures 100 years Foundations for Bridges 100 years Protection beams 100 years Architectural cladding 60 years Bridge bearings and movement joints excluding replaceable components such as deck joint seals 50 years Hot dip galvanised systems 50 years Painting systems (to first major recoating) 20 years Products not covered by this Standard Subject to MTM Type

Approval Cast-in, post-fixed components and fasteners, and services that cannot be readily maintained or presents maintenance access restrictions

Same Design Life as the element in/to

which they are fixed. Part 1 Cl 9 Risk assessments shall be conducted in accordance with the MTM Enterprise Risk Management Procedure L0-SQE-

PRO-031. Part 1 Cl 11.1 The afflux limit shall be as specified by the relevant water authority. Part 1 Cl 12 Design shall comply with the relevant requirements of L0-SQE-PLA-005 – MTM Environmental Management Plan. Part 1 Cl 13.11 The minimum distance between handrails of a station pedestrian Bridge shall be 2.4 m.




Part 1 Cl 13.12 Pedestrian only Underpasses under rail shall comply with the maximum grade requirements of the Disability Discrimination Act and, where appropriate, AS 1428.1.

Part 1 Cl 15 A design report on the measures adopted for collision protection shall be submitted with the associated design drawings and documentation.

Part 1 Cl 15.3.5 For abutments located within 10m from the centre-line of the nearest existing or future track, the geometric requirement for walls to have a minimum thickness of 800mm may be varied as follows subject to the approval of the MTM Chief Engineer or delegate: a) For soldier pile walls, the requirement shall be deemed to be satisfied by wall systems comprising reinforced concrete

piles of 900mm minimum diameter at 2.0m maximum spacing with a reinforced concrete infill of minimum thickness 150mm. Wall systems shall be designed for the collision loads specified in either Clause 11.4.2.3 or Clause 11.4.2.4 of AS 5100.2 as applicable, and the reinforced concrete infill shall be designed for the loads specified in Clause 11.4.3 of AS 5100.2.

b) For reinforced soil abutment walls which also act to protect abutment piles from the collision loads, the 800mm minimum thickness may be reduced if the designer can satisfy the MTM Chief Engineer or delegate that the wall systems can withstand the design collision loads whilst still maintaining the structural integrity of the abutment piles.

Part 1 Cl 15.3.6 Deflection walls shall be designed so as to not unnecessarily impede inspection or maintenance operations. The geometric requirement for a deflection wall to have a minimum thickness of 500mm shall be deemed to be satisfied by a soldier pile wall comprising reinforced concrete piles of minimum 750mm diameter at 2.0m maximum spacing with a reinforced concrete infill of minimum thickness 150mm. Deflection walls provided to protect the ends of Through-Bridges may be made integrated with their abutments provided that they do not impose unacceptable forces or movements on primary Through-Bridge members when subjected to the ULS collision loads. Similar provisions would apply to deflection walls protecting the portals of Underpasses and Tunnels.

Part 1 Cl 16.3 Electrification protection screens shall be provided where required by, and shall comply with, Standard drawing STD_E0001A “Overhead Conductor Clearance and Protective Barrier Requirements at Overline Bridges”. Electrification protection screens within the conductor fault zone as identified in L1-CHE-STD-010 Railway Bridges Electrical Protection and Bonding shall be electrically isolated from the support structure to remove the requirement to bond screens to rail. If electrical isolation is not achievable, the screen shall be bonded in accordance with L1-CHE-STD-010.




Part 1 Cl 16.4 Protection screens for objects falling or being thrown shall be fitted along the outer edges of publicly-accessible areas above and adjacent to tracks. Along the edge of Overbridges carrying road vehicles, pedestrians or cyclists, screens shall have a minimum height of 2.4 m above the roadway, walkway surface, or ledge that people can stand on, and in other respects shall be as shown in illustrations (a) and (b) of AS 5100.1 Figure 16.4. On ramps, staircases and station concourses, and along the top of retaining walls, wing walls and significant embankments located adjacent to and overlooking the tracks, the extent and height of protection screens shall be specified on a project specific basis. The minimum height should be 1.8 m above the roadway, walkway surface, or ledge that people can stand on. The protection screens shall be detailed to prevent climbing on the pedestrian side. In order to prevent access to the rail corridor side of the screen, consideration shall be given to the use of return screens or screen extensions. The design of screens shall be modular, so that individual panels can be easily removed and replaced if damaged without requiring access to the rail corridor. Panels shall be securely fixed to the frames. Where screw fixings are used they shall be tamper-proof. Wire mesh panels shall be constructed with welded mesh. Protection screens within the conductor fault zone as identified in L1-CHE-STD-010 ‘Railway Bridges Electrical Protection and Bonding’ shall be electrically isolated from the support structure to remove the requirement to bond screens to rail. If electrical isolation is not achievable, the screen shall be bonded in accordance with L1-CHE-STD-010.

Part 2 Cl 6.1 The density used in the calculation of all precast concrete elements shall be given on the drawings, and for the purpose of cranage, transportation and erection shall not be less than 2,700 kg/m3 in accordance with the WorkSafe Victoria Industry Standard “Construction and Erection of Bridge Beams”.

Part 2 Cl 6.3 ‘Special cases’ load factors shall not be used for permanent and removable superimposed dead load on Underbridges. Part 2 Cl 6.5 The minimum superimposed dead load of sleepers and rail shall be 6 kN/m per track. Where more than 2 rails are used per

track (dual gauge track or guard rails), the weight of the additional rails shall be added. The superimposed dead load of ballast shall be calculated using a ballast density of 19 kN/m3 as listed in AS 5100.2 Table 6.1(A) with no reduction based on the density of the proposed ballast material (this allows the use of heavier ballast materials during the Design Life). The top of ballast shall be assumed level with the top of sleeper at sleeper end. The ballast profile shall be assumed to extend horizontally. The ballast volume shall not be reduced by the volume occupied by sleepers. Paragraph 2 of AS 5100.2 Clause 6.5 shall not apply.

Part 2 Cl 8.1 A minimum design load of 5kPa shall be used with no reduction for loaded area. Part 2 Cl 8.2 Service walkways shall be designed for a concentrated loading applied through a 150mm × 150mm pad of not less than

2.2kN, in addition to the loading of 5kPa.




Part 2 Cl 9.1 The design rail traffic load shall be 245LA. 245LA load shall be derived by multiplying the 300LA rail traffic loads specified in AS 5100.2 Clause 9.2 by a factor of (245÷300). The fatigue design load (Cl 9.8) and the collision loads (Cl 11) shall be based on 300LA loading.

Part 2 Cl 9.7.2.3 Table 4 – Bridge Specific Design Parameters for the Rational Method Vehicle Length Traction

acceleration Traction length1

Braking deceleration

Braking length

Minimum clear distance between trains2

m m/s2 m m/s2 m m

Freight train 1200 0.5 60+604 1.5 1200 1200

Passenger train 230 1.5 230 1.5 230 300

Work train3 300 0.5 25 0.75 300 300

1 Traction length is the length of the rail vehicle over which the traction forces are to be applied so as to produce the most adverse effect. These lengths are based on 50% maximum adhesion between the wheels and the rail. Braking forces can be assumed to be applied uniformly over the full length of the vehicle. 2 The specified minimum clear distances between trains are intended to be used only for the purpose of determining the positioning of longitudinal rail traffic forces for structural design purposes. 3 The parameters for the work train were derived for a ballast hopper wagon. 4 The 120m traction length is to be split equally between front and rear of a push-pull operation.

Part 2 Cl 9.8.4 For tracks subject to freight the base number of load cycles (CT) shall be determined on a first principles basis by the designer and is subject to approval by the MTM Chief Engineer or delegate.

Part 2 Cl 9.10 The note in this clause shall be a mandatory requirement. Bridges shall be designed so that their hog does not exceed 1/300 of the span and they do not sag under permanent loads.

Part 2 Cl 11.3 Refer to clause 8.7.1.




Part 2 Cl 11.4.4.2

Protection barriers (refer Clause 8.5.4 of this Standard) shall be designed to resist a minimum collision load of 500 kN where an Underbridge carries passenger trains only and 750 kN where an Underbridge also carries freight trains. The collision load shall be applied in any direction and at any height, directed towards the component from the adjacent track centre-line, except downwards. Above 5 m and up to 10m vertically above the rail track level, this collision load shall vary linearly from the above values as applicable at 5 m to zero at 10m. When applied vertically upwards, the force shall be distributed over an area of one square metre, to allow for roof crushing of the rail vehicle. Protection barriers need not be designed for the collision loads specified in Clause 11.4.2.3 or Clause 11.4.2.4 of AS 5100.2. There shall be a smooth transition from deflection walls (on the Bridge approaches) to the protection barriers (within the Bridge). Protection barriers shall not unnecessarily impede inspection or maintenance operations of Underbridges or track infrastructure.

Part 2 Cl 11.4.4.3

Deflection walls provided at the approach to a Through-Bridge, rail Underpass or rail Tunnel as protection from a head-on derailed train collision shall be designed to resist the collision loads defined in AS 5100.

Part 2 Cl 11.5.4 Derailment kerbs shall not unnecessarily impede inspection or maintenance operations of Underbridges or track infrastructure. Trackside faces of derailment kerbs shall be vertical. Derailment kerbs shall extend for a minimum distance off the Bridge of 4.0 metres from the back of the abutment wall or for the extent of the approach slab, whichever is the greater. When a derailment kerb is provided on ballasted Bridges it shall act as both a derailment kerb and a ballast kerb and shall comply with all the requirements for both.

Part 2 Cl 15.1 The displacement based earthquake design method of Appendix B shall not be used, unless approved otherwise by the Chief Engineer or delegate.

Part 2 Cl 15.4.1 Bridges shall be designed for earthquake category BEDC-3 unless specified otherwise on a project specific basis. Part 2 Cl 25.4.1 A protection screen shall be designed to withstand a ULS load of 2 kN applied over an area of 50mm x 50mm on the screen,

at any point, which produces the most adverse effect. Part 3 Cl 4.1 All foundations shall be protected from stray current corrosion in accordance with L1-CHE-STD-010 ‘Railway Bridges

Electrical Protection and Bonding’. Part 4 Cl 12.6.3 For Underbridges, the deflections due to train braking and traction forces shall be considered in determination of εsh.

Deflections due to earthquake need not be considered.




Part 5 Cl 2.2.2 A capacity reduction factor of 0.67 shall be applied to the maximum stress range given in equation 2.2.2. This leads to the requirement that during a fatigue load cycle (i.e. a cycle of any load combination that includes the fatigue design loading) the compressive stress at the extreme fibre under consideration shall not exceed the lesser of:

• 0.615f’c, and • 0.3f’c + 0.7σmin, where σmin shall be the lesser of the minimum compressive stress during the load cycle at the extreme

fibre under consideration (taken as zero if tensile), and 0.45f’c. Part 5 Cl 4.14 The concrete covers specified in this clause shall be increased by 5 mm for concrete surfaces that are directly in contact

with track ballast. This abrasion allowance may be waived where ballast mats are installed against these surfaces.

Part 5 Cl 8.1.9.1 The minimum clear distance between parallel bars, tendons, ducts, bundled bars and the like shall be not less than: • 1.5 times the maximum nominal size of the aggregate; • 1.5 times the diameter of the bar; • 40mm; or • 30mm for pre-tensioned tendons in precast concrete, except for grouped tendons where the provisions of AS 5100.5

Clause 8.1.9.2 are applicable.

Where positive or negative reinforcement is placed in two or more horizontal layers the bars in the upper layers shall be placed directly above those in the bottom layers with a clear distance between layers not less than:

• 1.5 times the maximum nominal size of the aggregate; or • 1.5 times the diameter of the bars in layers.

Part 6 Cl 6.2.4 Further to Clause 6.2.4 of AS 5100.6, non-participating steel permanent formwork shall not be used above electrified track or above track that may be electrified during the Design Life of the Bridge, nor shall it be used above Generally Accessible Areas or above critical operational infrastructure such as track, overhead wiring, signalling or communication equipment, unless it is satisfactorily clad or factory coated to provide a Design Life of 50 years.




9 Assessment and Load Rating of Underbridges

General Requirements 9.1.1 The naming of structural components shall be in accordance with the VicRoads

‘Road Structures Inspection Manual’.

9.1.2 All load carrying structural components (including but not limited to members, connections and bearings) shall be load rated unless specified otherwise on a project specific basis.

9.1.3 The load rating shall be undertaken, and the results shall be presented separately, for every nominated load rating vehicle.

9.1.4 The load rating shall be undertaken for the following cases unless specified otherwise on a project specific basis

• as-new condition with full dynamic load allowance

• as-new condition with dynamic load allowance of zero

• as-is condition with full dynamic load allowance

• as-is condition with dynamic load allowance of zero

• where the Critical Load Rating Factor for as-is condition with full dynamic load allowance is less than 1.0 and the Critical Load Rating Factor for as-is condition with dynamic load allowance of zero is greater than 1.0, the reduced speed (and corresponding dynamic load allowance) required to give a Critical Load Rating Factor of 1.0 shall be calculated in accordance with AS 5100.7 Cl 11.4.3.

• where wind or sway bracing under the combined action of wind and traffic loads governs the critical Bridge load rating factor, a Critical Load Rating Factor ignoring that bracing load rating shall also be provided

9.1.5 For As-Is Load Ratings of steel Bridges the adoption of reduced strength arising from structural steel section loss shall be clearly stated and justified in the load rating report. Where as-is ratings are based on qualitative defect descriptions from inspection reports, the following losses shall be used.

Table 5 – Load Rating Section Loss Categories

Loss level Losses as percentage of plate thickness Minor Not more than 10% loss Moderate Not more than 20% loss Heavy Not more than 30% loss

9.1.6 Current fatigue damage shall be calculated using an assessment of the historical loads and related number of stress cycles, and expressed as a Miner’s Rule summation. The remaining fatigue life shall be calculated using the fatigue design traffic load, the fatigue design stress range (f*), and the number of equivalent stress cycles per train (nT) in accordance with AS 5100.2 Clause 9.8. The number of train cycles (C) to cause the cumulative fatigue damage to sum to unity shall be calculated. The remaining fatigue life shall be calculated as (C÷CT) x 100 years, where CT is the base number of load cycles for the track category in accordance with AS 5100.2 Clause 9.8.




9.1.7 For the purpose of fatigue calculations plates in riveted plate girders shall be treated as Detail Category 71 as per Table 13.10.1(C) of AS 5100.6 and the fatigue stress shall be based upon the net area.

Reporting of Assessment and Load Rating Factors 9.2.1 An assessment report shall be prepared describing all inputs and outputs for the

nine steps in Bridge assessment and load rating set out in AS 5100.7 Clause 9.

9.2.2 The load rating vehicle shall always be reported with any load rating factor.

9.2.3 The report should include details outlined in Appendix A – Documentation Requirements.

Application of AS 5100-2017 Bridge Design 9.3.1 The assessment and load rating of an Underbridge shall comply with the

requirements of AS 5100 ‘Bridge Design’, and in particular AS 5100.7 ‘Bridge Assessment’, except as specified in Table 6.

9.3.2 Where a conflict exists between the requirements of this standard and AS 5100 the requirements of this standard shall take precedence.




Table 6 – Application of AS 5100 for Load Rating and Assessment

AS 5100 Clause reference

Requirement

Part 2 Cl 15.4.1 Bridges shall be load rated for earthquake category BEDC-3 unless specified otherwise on a project specific basis. Part 7 Cl 3.7 Level 2 inspections shall be in accordance with the VicRoads ‘Road Structures Inspection Manual’ Part 7 Cl 3.8 Level 3 inspections shall be in accordance with the VicRoads ‘Road Structures Inspection Manual’ and shall include a

measurement of the position of the tracks relative to the structure. Part 7 Cl 10.8 The assessment report shall comply with the requirements of Clause 9.2 of this standard. Part 7 Cl 11.4.1 (a) Unless otherwise required on a project-specific basis, the rating vehicle shall be 245LA in lieu of 300LA. 245LA load

shall be derived by multiplying the 300LA rail traffic loads specified in AS 5100.2 Clause 9.2 by a factor of (245÷300). The fatigue design load (Cl 9.8) and the collision loads (Cl 11) shall be based on 300LA loading.

Part 7 Cl 11.6.1 Wind load on rail traffic shall be included in both ULS and SLS load combinations and shall be considered to act with the design rail traffic load in accordance with AS 5100.2 Cl 17.6.

Part 7 Cl 12.1 Where superimposed dead load effects are not directly measured (hence AS 5100.2 Cl 6.3 applies and AS 5100.7 Table 12.1 does not apply) ‘special cases’ load factors shall not be used for permanent and removable superimposed dead load on Underbridges.




10 Structural Modification of Bridges

Application 10.1.1 The requirements of Section 10 apply only to the part of the Bridge that is

modified, except as noted in clauses 10.1.2 and 10.7.

10.1.2 Where modifications of existing Bridges are proposed, an assessment of the total estimated cost of the modification work compared to the change in risk profile and alternative cost of upgrading the existing Bridge to comply with Section 8 shall be completed to determine if risks are being managed safe SFAIRP.

General Requirements 10.2.1 The design for structural modification of Overbridges shall comply with

Section 8 of this standard, except where varied by the requirements of Section 10.

10.2.2 Modification of a Bridge may affect the stability, capacity and serviceability of an existing structure and the design shall take into account the effects of the modification on the existing structure.

10.2.3 When undertaking structural modification of an Underbridge superstructure only, the structural capacity of the substructure shall be assessed for the same design loading as the superstructure modification.

Loading 10.3.1 Design loads for the structural modification of Underbridges shall be in

accordance with Section 8 of this standard unless specified otherwise on a project specific basis.

Clearances 10.4.1 When undertaking structural modification of a Bridge, clearances should

comply with Section 8 of this standard. Where compliance with this requirement is not practicable, reduced clearance may be considered in accordance with L1-CHE-STD-025 Section 9.4.

Drainage 10.5.1 When undertaking structural modification of a Bridge, drainage should comply

with Section 8.3.

Walkways and Handrails 10.6.1 When undertaking structural modification of a Bridge, walkways, handrails

and barriers should comply with Section 8.4. Where this has been deemed not practicable by the MTM Chief Engineer or delegate, clause 10.6.2 and 10.6.3 shall apply.




10.6.2 A design shall be produced for all proposed works where walkways, handrails or barriers are retrofitted to existing structures. The design shall ensure that walkways and handrails are installed as far as practically possible from the track centreline.

10.6.3 The absolute minimum clearance for handrails shall comply with L1-CHE-STD-025 Envelope K. Additional allowances for curve and Cant effect of rail vehicles shall be applied where necessary.

Collision Protection 10.7.1 When undertaking structural modification of a Bridge, collision protection

should comply with AS 5100 as modified by Section 8.9 of this standard. Piers and abutments that do not satisfy these requirements shall have deflection walls, complying with the requirements of AS 5100, provided to protect the existing pier or abutment. Independent deflection walls shall be provided where space permits, otherwise deflection walls may be integral with the pier or abutment.

10.7.2 Existing abutments located within 10m from the centre-line of the nearest existing or future track are not required to comply with the AS 5100 requirement for a minimum thickness of 800mm, unless specified otherwise on a project specific basis.

10.7.3 In exceptional circumstances, AS 5100.2 collision load requirements may be relaxed subject to the approval of the MTM Chief Engineer. A derailment risk assessment shall be undertaken considering, as a minimum, the following criteria:

• site condition, cutting, embankment etc. • derailment history • type of structure, particularly the robustness and potential for collapse • location of the structure relative to the track • track geometry • track speed • location of points or crossovers relative to the structure • type of rolling stock • future usage and growth in patronage • any other relevant site specific criteria.

10.7.4 The results of the risk analysis may determine a relaxation of the collision loading in AS 5100.2 as tabulated below.




Table 7 – AS 5100.2 Collision Loading Categories

Risk Matrix Ranking

Relaxation to AS 5100.2 collision loading

8 or more No relaxation of AS 5100.2 requirements

4 to 7 The collision loads of Clause 11.4.2.3 (when applicable) may be replaced by the collision loads of Clause 11.4.2.4.

3 or less The collision loads of Clause 11.4.2.3 or 11.4.2.4 (as applicable) may be replaced by the collision loads of Clause 11.4.3.

Protective Screens 10.8.1 When undertaking structural modification of a Bridge, electrical protection

screens and protection screens for objects falling or being thrown shall be fitted in accordance with AS 5100 as modified by Section 8.9 of this standard.

10.8.2 A relaxation of this requirement may be approved by the MTM Chief Engineer or delegate subject to the outcome of a risk assessment in accordance with MTM Enterprise Risk Management Procedure L0-SQE-PRO-031.




11 Appendix A – Documentation Requirements

General Requirements 11.1.1 Design documentation will be prepared in accordance with the MTM Design

and Technical Review Procedure L1-NAM-PRO-002.

11.1.2 All design drawings shall be produced in accordance with the conventions detailed in L1-CHE-POL-001 Engineering Drawings Management Policy (IFC/As Builts), and PTV’s Infrastructure Drafting Standards.

Specific Requirements 11.2.1 Design documentation should be provided to include the following:

a. Design report

b. PTV DMS compliant drawings. The drawings shall clearly articulate:

construction/ deconstruction sequences, notes and/or constraints where they are relevant to the structural integrity of the Bridge.

methodologies for safe ongoing inspection and maintenance access, including to abutments and bearings. This must include provision of fall protection in accordance with Worksafe Victoria guidelines.

jacking points, jacking assembly (including minimum jack or spreader plate size and any requirements for synchronised jacking), and jacking loads and displacements to enable bearing maintenance and replacement

drainage provisions for the abutment sill beam and for the subsurface drainage behind the abutment, including flushing details and the connection point into the project drainage network

treatments to ensure the stability and maintainability of batters adjacent to abutment wing walls and fender walls

fixtures, fittings, handrails and access provisions to enable safe inspection and maintenance

fixtures, fittings, bracing or temporary works required to ensure safe transport and erection of structural components

railway centrelines

a clearance diagram

distances to track and overhead line equipment

railway chainage at the intersection of railway and road (or waterway etc.) centrelines

details of all existing railway infrastructure, including maintenance and emergency access, under and in the vicinity of the Bridge

all critical design loads and criteria.




11.2.2 When completing assessment and load rating of Bridges, design reports shall be provided and should include the following:

a. Executive summary including load rating executive summary table (sample layout provided in Appendix C of this standard)

b. Description of the Bridge, including details of the original design load where known. As-built general arrangement layout drawing of the Bridge showing the arrangement of the main structural components and the span layout should be included in an appendix.

c. Description of the methodology for data collection referencing all data sources (drawings, inspection reports, field measurements, materials testing etc.). Copies of data documents that are not available by reference should be included in an appendix.

d. Description of the Bridge condition. Copies of condition documents that are not available by reference should be included in an appendix.

e. Description of findings from field geometry measurements (or justification if field geometry was not measured). Copies of field geometry information that is not available by reference should be included in an appendix.

f. Discussion of the methodology for capacity assessment including the basis for all material strengths and section capacities assumed in the load rating calculations, and the standards and other reference documents used

g. Discussion of the methodology for fatigue assessment including loading input and the criteria for fatigue failure

h. Discussion of the methodology for calculation of the load rating factor including key assumptions and details of software used:

listing and justification for all load factors and capacity reduction factors

traffic loading including dynamic load allowance

justification for the use of higher tier analysis where utilised

appendix – selected input and output from structural analysis as required to illustrate the process

i. Discussion of the Critical Load Rating Factor for the Bridge for each of the nominated rating vehicles and load cases, including, for each of the cases listed in the results, explanation of the element and design action responsible for the Critical Load Rating Factor.

j. Detailed results of the Bridge condition assessment and load rating process, for each load rated structural component, for each rating vehicle, for each loading case. The presentation of assessment and load rating factors should conform to the sample layouts provided in Appendix C of this standard. Results of the fatigue assessment should be presented as both current fatigue damage (as a Miner’s Rule summation) and remaining fatigue life (in years).




12 Appendix B – Indicative Underbridge Arrangements These diagrams are for information only.

A Refer to clause 8.2.1.2 and 8.4.3. B Refer to clause 8.2.3 and 8.4.7. C Refer to clause 8.2.1.6, 8.2.3.2 and 8.4.7. D 300mm minimum E Refer to clause 8.1.20, 8.6.1 and 8.6.2. F 4000mm typical (refer to L1-CHE-STD-025 for requirements)




13 Appendix C – Load Rating Tables Load rating executive summary - sample format

Bridge and type

Location

Route and tracks

km

Load capacity as per design

Critical components for nominated load rating vehicles

245LA (e.g.) Comeng

As-new As-is As-new As-is

Component Design action

As-is section loss (%) and element

Rating factor and train rating full DLA

Rating factor and train rating DLA=0



Reduced speed for RF=1 (km/hr) (if applicable)





Reduced speed for RF=1 (km/hr) (if applicable)

Main girder moment 10% bottom flange

1.25 306LA

1.67 408LA

1.20 294LA

1.61 394LA

N/A

Main girder shear 20% web thickness

1.0 245LA

1.23 301LA

0.91 223LA

1.12 274LA

42




14 Appendix D – Load Rating Details Load rating details - sample format

Bridge and type XXX

Location XXX

Route and tracks XXX

km XXX

Load capacity as per design XXX

Nominated rating vehicle 245LA

Com

pone

nt

Des

ign

actio

n

Mem

ber l

engt

h

As-

is s

ectio

n lo

ss (%

) and

ele

men

t

Cap

acity

redu

ctio

n fa

ctor

(φ)

As

new

des

ign

capa

city

(φR

u)

As

is d

esig

n ca

paci

ty (φ

Ru)

Dea

d lo

ad fa

ctor

(γg)

Sup

erim

pose

d de

ad lo

ad fa

ctor

(γgs

)

Rai

l bal

last

and

trac

k lo

ad fa

ctor

(γb)

Fact

ored

per

man

ent l

oad

effe

cts

PE

As-

new

ava

ilabl

e ca

paci

ty fo

r liv

e lo

ad e

ffect

s [φ

Ru-

PE]

As-

is a

vaila

ble

capa

city

for l

ive

load

ef

fect

s [φ

Ru-

PE]

Live

load

fact

or (γ

Q)

Dyn

amic

load

allo

wan

ce (α

)

Mul

tiple

trac

k fa

ctor

(W)

Fact

ored

live

load

effe

cts

[γQ

S*Q

W

(1+α

)]

As-new As-is





Reduced speed for RF=1 (if applicable)

Main girder

Bending moment

20m

10% bottom flange

0.9 3960 kNm

3600 kNm

1.1 2.0 1.7 600 kNm

3360 kNm

3000 kNm

1.6 0.34 1.00 2500 kNm

1.25 306LA

1.67 408LA

1.20 294LA

1.61 394LA

N/A

etc.