T HR CI 12060 ST Retaining Walls - Transport for NSW · 2019-06-22 · T HR CI 12060 ST Retaining Walls Version 2.0 Issue date: 21 June 2019 . Important message This document is one

Retaining Walls

T HR CI 12060 ST

Standard

Version 2.0

Issue date: 21 June 2019

© State of NSW through Transport for NSW 2019

T HR CI 12060 ST Retaining Walls

Version 2.0 Issue date: 21 June 2019

Important message This document is one of a set of standards developed solely and specifically for use on

Transport Assets (as defined in the Asset Standards Authority Charter). It is not suitable for any

other purpose.

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property of the State of New South Wales (Transport for NSW).

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© State of NSW through Transport for NSW 2019



Standard governance

Owner: Lead Civil Engineer, Asset Standards Authority

Authoriser: Chief Engineer, Asset Standards Authority

Approver: Executive Director, Asset Standards Authority on behalf of the ASA Configuration Control Board

Document history

Version Summary of changes

1.0 First issued, 17 March 2016

2.0 Second issue

© State of NSW through Transport for NSW 2019 Page 3 of 24



Preface The Asset Standards Authority (ASA) is a key strategic branch of Transport for NSW (TfNSW).

As the network design and standards authority for NSW Transport Assets, as specified in the

ASA Charter, the ASA identifies, selects, develops, publishes, maintains and controls a suite of

requirements documents on behalf of TfNSW, the asset owner.

The ASA deploys TfNSW requirements for asset and safety assurance by creating and

managing TfNSW's governance models, documents and processes. To achieve this, the ASA

focuses on four primary tasks:

• publishing and managing TfNSW's process and requirements documents including TfNSW

plans, standards, manuals and guides

• deploying TfNSW's Authorised Engineering Organisation (AEO) framework

• continuously improving TfNSW’s Asset Management Framework

• collaborating with the Transport cluster and industry through open engagement

The AEO framework authorises engineering organisations to supply and provide asset related

products and services to TfNSW. It works to assure the safety, quality and fitness for purpose of

those products and services over the asset's whole-of-life. AEOs are expected to demonstrate

how they have applied the requirements of ASA documents, including TfNSW plans, standards

and guides, when delivering assets and related services for TfNSW.

Compliance with ASA requirements by itself is not sufficient to ensure satisfactory outcomes for

NSW Transport Assets. The ASA expects that professional judgement be used by competent

personnel when using ASA requirements to produce those outcomes.

About this document

This standard details the life cycle requirements for retaining walls on the TfNSW Metropolitan

Heavy Rail Network.

This standard is a second issue.

The changes from the previous version include the following:

• updates to referenced documents

• removal of safety refuges and handhold devices and, no safe place sign, which is now

covered in T HR CI 12073 ST Safe places

• addition of durability requirements

• addition of refurbishment and upgrade requirements

• addition of requirement for piled walls

• updates to anchoring systems




• updates to environmental and sustainability requirements

• updates to electrical requirements

• updates to decommissioning and disposal requirements

• rearrangement of the order of requirements




Table of contents 1. Introduction .............................................................................................................................................. 8

2. Purpose .................................................................................................................................................... 82.1. Scope ..................................................................................................................................................... 8 2.2. Application ............................................................................................................................................. 8

3. Reference documents ............................................................................................................................. 9

4. Terms and definitions ........................................................................................................................... 10

5. Safety requirements .............................................................................................................................. 115.1. Provision of safe areas ........................................................................................................................ 11

6. Approved materials ............................................................................................................................... 11

7. Environmental and sustainability ........................................................................................................ 127.1. Green infrastructure ............................................................................................................................. 12 7.2. Sustainability assurance ...................................................................................................................... 12 7.3. Ambient environmental conditions ....................................................................................................... 12 7.4. Aesthetics ............................................................................................................................................ 12 7.5. Heritage ............................................................................................................................................... 13

8. Durability requirements ........................................................................................................................ 14

9. Clearances .............................................................................................................................................. 14

10. Drainage ................................................................................................................................................. 15

11. Design requirements ............................................................................................................................. 1511.1. Design standards ............................................................................................................................. 15 11.2. Structure classification ..................................................................................................................... 15 11.3. Retaining walls supporting road traffic ............................................................................................. 16 11.4. Retaining walls supporting rail traffic ............................................................................................... 16 11.5. Geotechnical considerations............................................................................................................ 16

12. Gabion retaining walls .......................................................................................................................... 17

13. Post and panel walls ............................................................................................................................. 17

14. Cantilevered piled walls ........................................................................................................................ 18

15. Reinforced soil walls ............................................................................................................................. 18

16. Crib walls ................................................................................................................................................ 18

17. Anchoring systems ............................................................................................................................... 1917.1. Earthing and bonding ....................................................................................................................... 19 17.2. Ground anchors ............................................................................................................................... 19 17.3. Soil nails........................................................................................................................................... 19 17.4. Passive resistance anchors ............................................................................................................. 20 17.5. Fatigue ............................................................................................................................................. 20 17.6. Temporary anchors .......................................................................................................................... 20

18. Existing structures ................................................................................................................................ 2018.1. Refurbishment ................................................................................................................................. 20




19. Provision for services ........................................................................................................................... 21

20. Advertising signs................................................................................................................................... 21

21. Electrical requirements ......................................................................................................................... 22

22. Drawing standards ................................................................................................................................ 22

23. Construction .......................................................................................................................................... 2223.1. Joints ................................................................................................................................................ 22 23.2. Earthworks ....................................................................................................................................... 23

24. Maintenance ........................................................................................................................................... 23

25. Decommissioning and disposal ........................................................................................................... 23




1. IntroductionRetaining walls are constructed in areas to retain earth where it is not possible to provide

natural ground batters.

Retaining walls are structures designed to:

• provide right of way for rail tracks in cuttings or on embankments

• protect the railway track from subsidence or land slips

2. PurposeThis standard specifies the design, construction, maintenance, refurbishment and

decommissioning and disposal requirements for retaining walls on the Transport for NSW

(TfNSW) Metropolitan Heavy Rail Network (formerly known as the RailCorp network).

2.1. Scope This standard covers the requirements for the life cycle, from design through to

decommissioning, of retaining walls on the TfNSW Metropolitan Heavy Rail Network associated

with rail infrastructure. Refer to TS TOC 1 Train Operating Conditions (TOC) Manual – General

Instructions which defines the areas associated with the network.

Retaining walls covered by this standard are associated with the following:

• retention of embankments supporting rail tracks

• retention of cutting faces adjacent to rail tracks

• retention of access roads used for the maintenance of rail infrastructure

Retaining walls not covered by this standard include:

• retaining walls associated with station platform walls; refer to T HR CI 12065 ST Station

Platforms

• retaining walls associated with building works and civil works, for example, car parks

2.2. Application This standard applies to the design of new retaining walls and the refurbishment of existing

retaining walls on the TfNSW Metropolitan Heavy Rail Network.

In addition to the requirements of this standard, asset decisions take into account the life cycle

cost considerations specified in T MU AM 01001 ST Life Cycle Costing.

If when using this standard it is considered that the intent of stated requirements is not clear, a

clarification should be sought from the ASA.




3. Reference documentsThe following documents are cited in the text. For dated references, only the cited edition

applies. For undated references, the latest edition of the referenced document applies.

Australian standards

AS 4678–2002 Earth-retaining structures

AS 5100 Bridge design

Transport for NSW standards

ESC 215 Transit Space

ESC 302 Structures Defect Limits

SPC 301 Structures Construction

T HR CI 12002 ST Durability Requirements for Civil Infrastructure

T HR CI 12020 ST Underbridges

T HR CI 12065 ST Station Platforms

T HR CI 12073 ST Safe Places

T HR CI 12105 ST Vegetation Hazard Management in the Rail Corridor

T HR CI 12110 ST Earthworks and Formation

T HR CI 12130 MA Track Drainage (manual)

T HR CI 12130 ST Track Drainage (standard)

T HR CI 12190 ST Service Installations within the Rail Corridor

T HR CI 12200 ST Access Roads

T MU AM 01001 ST Life Cycle Costing

T MU AM 01003 ST Development of Technical Maintenance Plans

T MU EN 00005 ST Ambient Environmental Conditions

T MU EN 00007 GU Integrating Green Infrastructure

T MU EN 00008 ST Sustainability Assurance Requirements

T MU MD 00006 ST Engineering Drawings and CAD Requirements

T MU MD 20001 ST System Safety Standard for New or Altered Assets

T MU MD 20002 ST Risk Criteria for Use by Organisations Providing Engineering Services

TMC 302 Structures Repair

TN 016: 2015 Overbridges and footbridges – Earthing and bonding requirements




TS TOC 1 Train Operating Conditions (TOC) Manual – General Instructions

Transport for NSW standard drawings

CV 0212048 Post & Panel Type Retaining Walls – Example of Typical General Arrangement

CV 0212049 Post & Panel Type Retaining Walls – Posts

CV 0212050 Post & Panel Type Retaining Walls – Panels

CV 0212051 Post & Panel Type Retaining Walls – Miscellaneous Details

Legislation

Heritage Act 1977 (NSW)

Work Health Safety Act 2011 (NSW)

Other reference documents

APAS specification 1441/1 Permanent exterior clear graffiti barrier

MN A 00100 Civil and Track Technical Maintenance

NSW State Heritage Register

Office of Environment and Heritage January 2005, State Agency Heritage Guide – Management

of Heritage Assets by NSW Government Agencies

RailCorp Section 170 Heritage and Conservation Register

Roads and Maritime Services, QA Specification B114 Ground Anchors (Lump Sum)

Roads and Maritime Services, QA Specification R55 Rock Filled Gabions and Mattresses

Roads and Maritime Services, QA Specification R57 Design of Reinforced Soil Walls

Roads and Maritime Services, QA Specification R64 Soil Nailing

SafeWork NSW, Safe design of structures Code of Practice

VicRoads, Standard specification for roadworks and bridgeworks, Section 683 - Soil Nails

4. Terms and definitionsThe following terms and definitions apply in this document:

AEO Authorised Engineering Organisation

APAS Australian Paint Approval Scheme

ASA Asset Standards Authority

GRP/FRP glass fibre reinforced polymer or glass fibre reinforced plastic




RIM rail infrastructure manager; in relation to rail infrastructure of a railway, means the person

who has effective control and management of the rail infrastructure, whether or not the

person—

(a) owns the rail infrastructure; or

(b) has a statutory or contractual right to use the rail infrastructure or to control, or provide,

access to it (Rail Safety National Law 2012, NSW)

TfNSW Transport for New South Wales

TMP technical maintenance plan

5. Safety requirementsSafe design is mandated in the Work Health Safety Act 2011 (NSW) and shall be incorporated

into the design. Guidance on the safe design of structures can be found in the SafeWork NSW

publication Safe design of structures code of practice.

The design of retaining walls, including the refurbishment of existing retaining walls, shall take

into account the safety considerations for construction, operational, maintenance and

decommissioning workers, and the potential users of the structure.

The Authorised Engineering Organisation (AEO) shall establish and implement a design

process system that manages safety across the full life cycle of the structure. The design

process system shall be developed in accordance with T MU MD 20001 ST System Safety

Standard for New or Altered Assets.

5.1. Provision of safe areas The design of retaining walls shall provide for safe places in accordance with T HR CI 12073 ST

Safe Places.

Where the height of the retaining wall above ground level is two metres or more, a safety

handrail on top of a retaining wall shall be provided.

For retaining walls up to two metres, the rail infrastructure manager (RIM) shall determine

whether or not handrails are required.

6. Approved materialsApproved construction materials for main structural elements are steel and concrete.

Timber materials may not be used as structural elements for retaining walls.

Brick and stone masonry are approved for the refurbishment of existing structures and for

cladding of new structures where required. For example, the use of masonry for cladding of new

structures may be appropriate for locations where heritage considerations are important.




If any products specified in the design documentation that can reasonably be deemed to be new

or infrequently used, shall be identified by the AEO and referred to the Lead Civil Engineer, ASA

for approval. The AEO shall ensure that the manufacturer, constructor or maintainer of the

product understands any special requirements or practices relating to the product prior to

release of the design documentation. The special requirements shall be included in the

documentation.

Glass fibre reinforced plastic (GRP) anchors shall not be used for permanent applications in the

TfNSW Metropolitan Heavy Rail Network. However, they may be used for temporary

applications in accordance with Section 17.6 of this standard.

7. Environmental and sustainabilitySection 7.1 to Section 7.3 set out environmental and sustainability requirements for retaining

walls during investigation, design, construction and operational activities.

7.1. Green infrastructure The design of retaining walls shall identify opportunities to integrate green infrastructure. For

further guidance refer to T MU EN 00007 GU Integrating Green Infrastructure.

Plant species used in landscaping the precinct around the retaining wall shall be carefully

selected to ensure that they do not accelerate the deterioration, or prevent the examination, of a

retaining wall.

Only low maintenance species with non-invasive root systems shall be planted on areas

retained adjacent to rail infrastructure.

7.2. Sustainability assurance The design of retaining walls shall incorporate solutions to TfNSW key sustainability areas as

outlined in T MU EN 00008 ST Sustainability Assurance Requirements.

7.3. Ambient environmental conditions Retaining walls shall be designed to operate under the current and projected environmental

conditions as defined in T MU EN 00005 ST Ambient Environmental Conditions.

7.4. Aesthetics An important part of the process of designing new retaining wall structures or changes to

existing retaining walls is the careful consideration of how the structure will look once

construction is complete.

Designers shall strive to develop assets that will be visually coherent and have refined detailing.




Careful thought shall be given from the outset to the basic aesthetic principles of scale, form,

proportion, order, rhythm and harmony to produce designs for structures that are appropriate for

their context and that have an attractive character.

Designs shall reflect an aim to create visually appealing structures that will relate well to their

surroundings.

Life cycle considerations require designers to consider the likely appearance of retaining walls

across the short, medium and long terms. Structures should be designed to weather and age

gracefully so that the potential unsightly effects of staining, discoloration, vegetation growth and

so on can be controlled.

7.4.1. Graffiti

Anti-graffiti coating shall be used on retaining walls in all areas accessible by the public and in

areas within the corridor where the RIM determines that there is a high risk of graffiti.

Anti-graffiti coatings shall comply with APAS Specification 1441/1 Permanent exterior clear

graffiti barrier.

7.5. Heritage Transport agencies are responsible for maintaining and appropriately managing heritage items

under their stewardship and control. The Heritage Act 1977 (NSW) is designed to protect,

maintain and manage environmental heritage in NSW, including items of archaeological

significance.

When changes are proposed to items that have heritage significance, the following applies:

• for items listed on the State Heritage Register, the provisions of the Heritage Act shall be

met

• for items listed on a state agency RailCorp Section 170 Heritage and Conservation

Register, the principles and relevant guidelines contained within the State Agency Heritage

Guide – Management of Heritage Assets by NSW Government Agencies shall be followed

Identifying the significant features, values and characteristics of a heritage item or precinct is an

essential step in developing appropriate designs for new elements within heritage-listed

precincts. The identified significance of a particular item or precinct and its contributory

elements and values shall not be unduly compromised by any new works. Advice from a

professional heritage practitioner shall be obtained early in a project's scoping and design stage

to assess any potential heritage impacts and to guide the nature and extent of all proposed

works.




For works to retaining structures that comprise heritage fabric, or retaining walls which are an

integral part of a heritage listed precinct, the following shall apply:

• retaining walls that contribute to the aesthetic appearance and heritage significance of a

transport precinct, particularly where highly visible to customers, shall be sensitively

conserved in order to extend their useful life as part of a regular maintenance program

under the care and direction of professional heritage practitioner or experienced

tradespeople as applicable

• maintenance programs shall undertake active vegetation management to ensure that

structural integrity is maintained

• for major projects, protection of heritage significance shall be sensitively incorporated from

the scoping stage under the direction of a professional heritage practitioner

• where a retaining structure is notable for its rarity or representativeness of technological

development, its significance shall be further considered within the context of the heavy rail

network

Where new retaining walls are proposed within heritage listed precincts or within the visual

catchment of heritage listed items, the heritage significance of the precincts or items shall be

established and a design approach developed to provide material solutions that respect the

heritage significance of a precinct, in conjunction with a professional heritage practitioner.

8. Durability requirementsThe durability requirements, including design life, of retaining walls, rock and soil anchors, and

soil nails shall be in accordance with T HR CI 12002 ST Durability Requirements for Civil

Infrastructure.

9. ClearancesHorizontal and vertical clearances for retaining walls shall comply with ESC 215 Transit Space.

For retaining walls within five metres of the centreline of an existing or proposed track, the top of

the footings shall be located no less than one metre below rail level, in order to facilitate cess

drainage and maintenance activities such as ballast cleaning and track reconditioning.

Retaining walls located beyond five metres shall have the top of the footing located no less than

half a metre below finished ground level, or as advised by the RIM.




10. DrainageRetaining walls shall be designed with appropriate drainage systems in accordance with

AS 4678-2002 Earth-retaining structures. Where the wall is adjacent to a rail line, the discharge

of water shall be integrated into the track drainage system in accordance with T HR CI 12130

ST Track Drainage standard and T HR CI 12130 MA Track Drainage manual.

11. Design requirementsThe design of a retaining wall shall take into account the associated factors such as service

routes, overhead wiring and signalling infrastructure, earthing and bonding, drainage, traffic

barriers, architectural treatments, construction and maintenance constraints and any other site-

specific requirements.

Retaining walls facing the track shall be finished smooth where possible without projections,

except as permitted in this standard or where required to fit around an existing structure, to

ensure that they do not create a snagging risk to authorised personnel, maintenance activities

and in the event of train derailment. The smooth face shall extend from 150 mm below finished

ground level to a minimum height of 2400 mm above the nearest rail.

11.1. Design standards Retaining walls that support road or rail traffic shall be designed in accordance with AS 5100

Bridge design. Other retaining walls shall be designed in accordance with AS 4678, and other

relevant Australian standards and the requirements as specified in this standard.

Where a conflict exists between standards, the requirements of this standard shall take

precedence.

The design of soil supporting structures for bridges shall comply with AS 5100.

The design of all retaining walls shall take the construction load surcharge into account.

11.2. Structure classification Retaining walls, where located to provide for main lines, branch lines and sidings, shall be

Classification C in accordance with Table 1.1 of AS 4678–2002. Other walls shall be classified

in accordance with Table 1.1 of AS 4678–2002, as approved by the RIM.




11.3. Retaining walls supporting road traffic Retaining wall adjacent to public roads shall be designed for surcharge loads in accordance

with AS 5100.

Traffic surcharge for a retaining wall supporting an access road shall be determined in

accordance with the requirements in T HR CI 12200 ST Access Roads, or as specified by the

RIM.

The AEO shall undertake a risk assessment to assess the risk against a vehicle falling into the

rail corridor. The risk criteria defined in T MU MD 20002 ST Risk Criteria for Use by

Organisations Providing Engineering Services shall be used. The risk assessment shall be site-

specific.

Retaining walls that meet any of the following criteria shall be constructed with a road traffic

barrier at the top of the wall:

• the retaining wall supports vehicular traffic associated with roads, industrial areas, car

parks and bus stops

• the retaining wall is located within 10 m of the centreline of the track

• where required by the RIM

The barrier performance level shall not be less than medium.

11.4. Retaining walls supporting rail traffic Retaining walls supporting a railway embankment shall be designed for surcharge load

surcharge from rail traffic where it is applicable. The provision of future tracks shall be taken into

account.

The rail traffic surcharge shall be determined in accordance with the requirements set out in

AS 5100 for the design rail traffic load specified in T HR CI 12020 ST Underbridges.

The AEO shall undertake a risk assessment against the risk criteria defined in

T MU MD 20002 ST to determine the likelihood of a derailed train coming to rest near the edge

of a retaining wall, or whether a containment kerb is required to prevent a derailed train from

falling off the retaining wall.

11.5. Geotechnical considerations Footings for retaining walls supporting railway embankments, where not founded on sound rock,

shall be founded at a minimum depth of 500 mm below the finished ground level directly in front

of the retaining wall.




Footings for retaining walls supporting railway cuttings, where not founded in sound rock, shall

be founded at a minimum depth of 500 mm below finished ground level (for example, top of

capping level) or 1300 mm below the adjacent design rail level, whichever is deeper.

Where footings are founded in sound rock, the depth to foundation level may be reduced by

200 mm. Sound rock shall be rock with unconfined compressive strength, UCS ≥ 3.0 MPa.

The depth to foundation level shall be increased as required to take adjacent drainage or

service installations into account.

The depth to foundation level shall be increased appropriately where the ground slopes away

from the face of the wall.

11.5.1. Passive resistance in front of walls

The effect of passive resistance shall be ignored to a minimum depth of 500 mm below finished

ground level.

For cantilevered piled walls, the effect of the passive fill in front of the wall to a depth of 1.5

times the pile diameter shall be ignored.

12. Gabion retaining wallsGabion walls shall only be used to support railway embankments or railway cuttings where the

height of the wall is one metre or less measured from the founding level and the distance from

the trackside face of the wall to the centreline of the track exceeds five metres.

Gabion walls shall also be in accordance with the requirements of Roads and Maritime Services

QA Specification R55 Rock Filled Gabions and Mattresses.

13. Post and panel wallsSite conditions and limitations on construction time can preclude the construction of traditional

retaining structures. While it is not a preferred method of construction, post and panel retaining

walls may be used where these constraints are encountered.

Post and panel retaining walls comprise steel UC section posts extending above ground level

that constructed in reinforced concrete piled footings, with precast concrete panels installed

between the posts.

TfNSW has standard drawings for post and panel type retaining walls. Post and panel walls

shall be designed in accordance with the details of the following standard drawings:

• CV 0212048 Post & Panel Type Retaining Walls – Example of Typical General

Arrangement

• CV 0212049 Post & Panel Type Retaining Walls – Posts




• CV 0212050 Post & Panel Type Retaining Walls – Panels

• CV 0212051 Post & Panel Type Retaining Walls – Miscellaneous Details

The use of standard designs is not mandatory unless required in this or other TfNSW standard

or by the RIM.

Where the designer proposes to adopt a standard design or detail for a specific location, the

designer shall assess the currency and suitability of the standard design for use and where

necessary, shall specify modified or alternative designs. Modified or alternative designs shall

comply with all relevant TfNSW and Australian standards, as applicable.

Standard precast panels with ribbed surface finish are deemed to be acceptable.

14. Cantilevered piled wallsPiled walls include the following configurations:

• contiguous piles

• secant piles

• spaced piles with sprayed concrete infill between the piles

• all piled walls (as listed) with permanent anchors or props

The requirements for piled walls are as follows:

• The wall shall have a capping beam of sufficient strength and stiffness to maintain their line

and level.

• Steel fibre reinforced sprayed concrete, where used adjacent to public spaces, shall have

cement mortar render of not less than 20 mm thickness.

15. Reinforced soil wallsReinforced soil walls (also termed mechanically stabilised earth) shall comply with the

requirements in AS 4678 and Roads and Maritime Services QA Specification R57 Design of

Reinforced Soil Walls. The deformation limits in QA Specification R57 are not necessarily

appropriate for rail embankments. The requirements for deformation limits for walls subject to

rail loading shall be assessed by the AEO and the limits in QA Specification R57 modified

appropriately.

16. Crib wallsCrib walls shall not be used to support railway embankments, railway cuttings or at any location

where failure of the wall could affect the rail operations.




17. Anchoring systemsAnchoring systems covered by this standard include the following:

• rock and ground anchors

• soil nails

• straps for mechanically stabilised earth

• passive resistance anchors such as deadman and tie-backs

Anchoring systems that extend under the track should be avoided where they could restrict the

installation of future below-ground rail infrastructure such as foundations for overhead wiring

structures and drainage or signalling cable trenches. Anchors that extend under the track shall

be submitted for approval by the RIM.

Anchors shall not extend outside the rail corridor or under private property without the approval

of the affected property owner.

17.1. Earthing and bonding The design of anchoring systems shall include the mitigation of the effects of stray currents.

Electrical requirements shall be obtained from the Lead Electrical Engineer, ASA.

17.2. Ground anchors Ground anchors shall comply with the requirements in AS 4678 and Roads and Maritime

Services QA Specification B114 Ground Anchors.

The AEO shall specify the number of anchors to be tested and the requirements for testing on

the drawing and in the technical specification in accordance with B114.

The AEO shall specify requirements for long term performance monitoring, where required, and

a technical maintenance plan (TMP) shall be prepared.

The anchor heads shall be protected to ensure that they do not cause an obstruction. The

anchor heads shall be recessed or protected against damage by a derailed train or by

maintenance activities.

17.3. Soil nails The design of soil nails shall comply with the requirements in AS 4678 and Roads and Maritime

Services QA Specification R64 Soil Nailing.




17.4. Passive resistance anchors Passive resistance anchors such as deadman and proprietary systems shall be designed using

recognised methods. The design life shall not be less than that of the retaining wall and shall be

submitted for approval by the RIM.

17.5. Fatigue Permanent anchor systems that are subject to cyclic loading due to transient traffic load shall be

designed for fatigue.

Fatigue traffic load shall be in accordance with AS 5100 or as nominated in T HR CI 12020 ST

Underbridges.

17.6. Temporary anchors Temporary anchors are permitted in the rail corridor, subject to the following requirements:

• Temporary anchors shall not remain in service for more than five years.

• Design life shall not be less than 10 years.

• GRP/FRP anchors are permitted as temporary soil nails.

• GRP/FRP anchors shall comply with VicRoads Standard Specification for roadworks and

bridgeworks, Section 683 – Soil Nail Walls.

• Temporary anchors shall be designed to be removed where possible.

18. Existing structuresExisting retaining structures may require repair or strengthening at some stage in the asset life

cycle.

Timber and masonry may be used in the like-for-like repair and replacement of components in

an existing retaining wall.

18.1. Refurbishment For the purpose of this standard, refurbishment means like-for-like replacement, rehabilitation or

repair of retaining wall elements to provide the minimum equivalent load capacity, functionality

and performance as the original component.

Repair methods and procedures documented in TMC 302 Structures Repair may be specified

by the AEO in refurbishment design works. Where repair methods are not adequately detailed

in TMC 302, the AEO shall document appropriate repair methods and materials.




18.1.1. Design life The AEO shall determine the design life of refurbishment works based on the consideration of

whole-of-life costs. The proposed design life shall be submitted for approval by the RIM.

The design life for the refurbishment works shall not be less than the expected remaining life of

the retaining wall and not less than 20 years.

18.1.2. Design loads Where practical, the design for repair or strengthening of existing retaining walls should be in

accordance with the loads specified in Section 11.

Where it is not practical to comply with these requirements, the AEO designer shall prepare

appropriate design criteria and submit for approval by the RIM.

19. Provision for servicesThe design of retaining walls shall accommodate services owned by TfNSW and third parties.

Services owned by TfNSW can include signalling and communications, and high voltage and

low voltage systems. Utilities owned by other organisations can include telephone, water

supply, sewer lines, power and gas.

The AEO shall consult the relevant authorities and shall provide ducts for current services and,

where appropriate, future services. The provision of services shall be submitted for approval by

the RIM.

The location and fixing of such service ducts shall facilitate access to services for maintenance

activities without the interruption of rail operations. The location and fixing of service ducts shall

not obstruct access to the main structure for inspection and maintenance activities.

Requirements for services in the rail corridor are set out in T HR CI 12190 ST Service

Installations within the Rail Corridor.

20. Advertising signsAdvertising signs that are attached to the retaining walls shall not create an obstruction that

causes water to pond or debris to accumulate anywhere on the retaining wall. Signs shall not be

a factor in the deterioration of a retaining wall.

Signs and fixings shall not obstruct access to the main structure for inspection and maintenance

activities.




21. Electrical requirementsIn electrified areas, the design of retaining walls shall provide for earthing and bonding of

metallic components of the retaining wall (for example steel reinforcement) in order to mitigate

touch potential hazards and corrosion of steel.

Retaining walls shall be electrically isolated and have adequate clearances in accordance with

the design strategy specified in TN 016: 2015 Overbridges and footbridges – Earthing and

bonding requirements, and other requirements of the Lead Electrical Engineer, ASA.

22. Drawing standardsConstruction drawings shall comply with T MU MD 00006 ST Engineering Drawings and CAD

Requirements. The construction drawings shall detail the design loadings, horizontal clearances

and vertical clearances. The construction drawings shall include any other information that is

relevant to ensure that the new structure is constructed and maintained in accordance with the

design. The relevant safety in design aspects shall be documented on the construction

drawings.

23. ConstructionThe design documentation shall identify standards for construction, including construction

methods, processes and materials.

Retaining walls shall be constructed in accordance with SPC 301 Structures Construction.

The design documentation shall reflect this requirement and shall include any project specific

requirements necessary for completeness of the technical specifications.

The design of retaining walls, including the refurbishment of existing structures, shall take into

account the construction constraints, particularly under live rail operating conditions and track

possession constraints.

23.1. Joints Joints shall be provided in concrete and masonry retaining walls to allow for, but not be limited

to, the following:

• movements due to thermal expansion and contraction of the wall

• settlement and consolidation of the foundation and backfill material

Joints shall be fitted with stainless steel dowel bars to maintain line and level of the exposed

wall surfaces.




23.2. Earthworks Compaction and drainage of earthworks associated with the construction of retaining walls shall

be in accordance with AS 4678, or if supporting rail traffic, shall be in accordance with

T HR CI 12110 ST Earthworks and Formation.

The stability of excavations shall be maintained at all times.

24. MaintenanceThe design of retaining walls including the refurbishment of existing structures shall provide

ease of access to components for inspection and maintenance activities.

The AEO shall carefully select components, materials and finishes that will minimise

maintenance during the life of the structure. See Section 8 for durability requirements.

Maintenance programs shall include active vegetation management to ensure that structural

integrity is maintained. Vegetation management shall be in accordance with the requirements in

T HR CI 12105 ST Vegetation Hazard Management in the Rail Corridor.

Maintenance requirements shall be specified, in the form of a TMP, in the design documentation

of the structure. The requirements shall include examination tasks and frequencies, damage

limits and repair standards. In most cases, the requirements in MN A 00100 Civil and Track

Technical Maintenance and ESC 302 Structures Defect Limits apply. However, it may be

necessary to document site-specific maintenance requirements.

The requirements and high-level processes for the development of TMPs are detailed in

T MU AM 01003 ST Development of Technical Maintenance Plans.

25. Decommissioning and disposalDecommissioning is the final process of withdrawing an asset from operational service on the

network.

Disposal is the process of physically removing an asset from the network; for example,

demolition of a retaining wall followed by removal and recycling.

The decommissioning and disposal of an asset is the final stage of the asset life cycle. Proper

planning for this phase of the life cycle is an integral part of the strategic life cycle process.

The process for the disposal of a retaining wall, usually undertaken in conjunction with a

replacement, shall include the following:

• justification (safety, financial, and so on) for disposal of the asset




• confirmation of stakeholder engagement regarding the proposed action; such engagement

shall include all relevant authorities, but not be limited to heritage, local, state and federal

government, the RIM and environmental body consultation

• agreement from all stakeholders to the decommissioning or disposal of the existing

underbridge

After decommissioning and disposal, the asset database shall be updated by the RIM to reflect

network changes.

Ninety-five per cent of construction and demolition waste by weight of the decommissioned

asset shall be diverted from landfill.


Documents

T HR CI 12060 ST Retaining Walls - Transport for NSW · 2019-06-22 · T HR CI 12060 ST Retaining Walls Version 2.0 Issue date: 21 June 2019 . Important message This document is one