Bridges
- Publication no: AP-G108-25
- ISBN: 978-1-922994-75-2
- Published: 10 June 2025
- Edition: 1.0
- Superseded
- PDF (free) Download
This edition of the Guidelines was superseded by Edition 1.1 in August 2025.
These guidelines provide direction on the standardised design of bridge traffic barriers across Australia and New Zealand. They address inconsistencies in current practice and update the previously available Standardised Bridge Barrier Design (superseded) by incorporating current research, guidance, and standards.
Inconsistencies in the specification and design of traffic barriers for bridges have been identified as a major issue in current practice throughout Australia and New Zealand. The need for standardised solutions has been recognised by road authorities, consultants and contractors. The main areas of concern include determining appropriate barrier performance levels, structural design criteria, the absence of standard barrier design details, retrofitting guidance for existing bridge barriers, bridge transition approach barriers, barrier end treatments and protection for overpass bridge support.
By providing a unified approach, these guidelines aim to support safer, more consistent and cost-effective bridge barrier designs across jurisdictions.
The process to update the guidelines adopted a comprehensive approach, incorporating an extensive literature review of current and previous guidance, as well as stakeholder consultations. To enhance the robustness of the revision, a finite element analysis (FEA) and a MASH-compliant full crash test of a medium performance barrier were also conducted.
The process to update these guidelines has been elaborated in the research report Updating the Standardised Bridge Barrier Design Guidelines (AP-R735-25).
To support the new guidelines, Austroads conducted a world-first full-scale crash test at 90 km/h — exceeding international standards. A 36-tonne truck, SUV and passenger car were tested against a medium performance bridge barrier, delivering insights that directly inform the new guidance.
- Summary
- Acronyms
- 1. Introduction
- 1.1 Purpose
- 1.2 Scope
- 1.3 Safe System considerations
- 1.3.1 Safe System approach
- 1.3.2 Safe System considerations for the design of bridge barriers
- 2. Bridge Barrier Design Process
- 3. Identify Required Performance Level
- 3.1 Bridge barrier performance levels
- 3.2 Bridge support protection barrier performance level
- 3.3 Determine adjusted AADT
- 3.4 Determine barrier performance level
- 4. Barrier Type
- 4.1 Concrete barriers
- 4.1.1 Vertical wall barrier
- 4.1.2 Single slope barrier
- 4.1.3 F-shape barrier
- 4.1.4 New Jersey barrier
- 4.2 Post-and-rail barriers
- 4.3 Combined concrete parapet and metal rails
- 4.4 Acceptance criteria for bridge traffic barrier types
- 4.1 Concrete barriers
- 5. Barrier Design
- 5.1 Barrier performance specifications
- 5.2 Structural design criteria
- 5.2.1 Contact lengths
- 5.2.2 Design forces
- 5.2.3 Minimum effective heights
- 5.3 Concrete parapets
- 5.3.1 Barrier geometry
- 5.3.2 Design process
- 5.3.3 Design of bridge cantilevered deck slab
- 5.4 Post-and-rail barriers
- 5.4.1 Barrier geometry
- 5.4.2 Design process
- 5.4.3 Design of bridge cantilevered deck slab
- 5.5 Concrete parapet and metal rail
- 5.5.1 Barrier geometry
- 5.5.2 Design process
- 5.5.3 Design of bridge cantilevered deck slab
- 5.6 Median barrier
- 6. Bridge Approach Barriers
- 6.1 Introduction
- 6.2 Current design and specification requirements
- 6.2.1 Terminology
- 6.2.2 Current AS 5100 requirements
- 6.2.3 Additional requirements from jurisdictions’ guidelines
- 6.3 Design procedure
- 6.3.1 Determination of length of need
- 6.3.2 Selection of approach barrier performance level
- 6.3.3 Minimum length and performance level
- 6.3.4 Minimum length and performance level of a barrier protecting structures in the median
- 6.4 Transitions between different performance level barriers
- 6.4.1 General
- 6.4.2 Design criteria – physically connected barriers
- 6.4.3 Typical interfaces between barrier types
- 6.5 End treatments
- 6.6 Gore areas
- 6.7 Freeway and highway ramps and side roads
- 6.8 Bridge approach off-structure barrier foundation
- 7. Bridge Support Protection Barrier
- 7.1 Current design and specification requirements
- 7.1.1 Current AS 5100 Requirements
- 7.2 Design Procedure
- 7.3 Determination of Level of Protection
- 7.3.1 Working Width
- 7.3.2 Levels of protection
- 7.3.3 Risk assessment
- 7.3.4 Selection of performance level
- 7.1 Current design and specification requirements
- 8. Retrofit of Barriers
- 8.1 Reasons for retrofitting bridge barriers
- 8.2 Barrier retrofitting design methodology
- 8.2.1 Design procedure
- 8.2.2 Determine appropriate barrier performance level
- 8.2.3 Rationalisation of barrier performance level
- 8.2.4 Design methodology
- 8.3 Determination of appropriate barrier performance level
- 8.3.1 Site-specific risk assessment
- 8.3.2 Benefit-cost analysis
- 8.3.3 Additional considerations
- 8.4 Barrier retrofit design procedure
- 8.4.1 Characteristics of the bridge location
- 8.4.2 Retrofitting the existing structure
- 8.4.3 Design of connections
- 8.4.4 Retrofitting of bridge approach barriers
- 8.5 Bridge barrier upgrade exceptions
- 8.6 Special considerations for historic bridges
- 9. Risk-Based Approach
- 10. MASH Full-Scale Crash Testing
- 10.1 Crash testing standards and guidelines
- 10.2 Compliance testing of the TfNSW medium performance traffic barrier type MAO
- 10.2.1 Test results
- 11. Finite Element Analysis
- 11.1 FEA testing of the TfNSW medium performance traffic barrier type MAO
- 11.1.1 Verification and validation
- 11.1 FEA testing of the TfNSW medium performance traffic barrier type MAO
- References
- Appendix A Barrier Design
- A.1 Design example 1: Concrete parapet – medium performance level
- A.1.1 Step 1: Calculate the concrete capacities of the various components on the parapet
- A.1.2 Step 2: Calculate the critical length of yield line failure pattern, Lc:
- A.1.3 Step 3: Calculate the wall resistance, Rw
- A.1.4 Step 4: Check the structural adequacy of the barrier
- A.2 Design example 2: Post-and-rail barrier – regular performance level
- A.2.1 Step 1: Calculate the ultimate capacities of the post and the rail
- A.2.2 Step 2: Calculate the barrier resistance
- A.2.3 Step 3: Check the structural adequacy of the barrier
- A.3 Design Example 3: Combined concrete parapet and metal rail – medium performance level
- A.3.1 Step 1: Calculate the ultimate capacities of the various components
- A.3.2 Step 2: Calculate the resistance of the combination parapet and rail
- A.1 Design example 1: Concrete parapet – medium performance level
- Appendix B Retrofit of Barrier
- B.1 Evaluation requirements
- B.2 Evaluation methodology
- B.3 Load combinations
- Appendix C Benefit Cost Analysis
- C.1 Available quantitative assessment methods
- C.2 Proposed B/C analysis method
- Appendix D Bridge Support Protection Barrier
- D.1 Additional requirements to AS 5100 from jurisdictions’ guidelines
- D.2 Barrier layout and design
- D.2.1 Typical barrier layout for bridge supports adjacent to undivided roadways
- D.2.2 Typical barrier layout for bridge supports located in median area
- D.2.3 Height considerations
- D.2.4 Foundations for rigid barriers
- D.3 Bridge support protection from railway traffic
- D.4 Typical design drawings
- D.5 Design example 1: Protection barrier for a bridge pier adjacent to an undivided two-way road
- D.5.1 Determine level of protection
- D.5.2 Length of need
- D.6 Design Example 2: Protection Barrier for a Bridge Pier Located in a Median
- D.6.1 Determine level of protection
- D.6.2 Length of need