Guideline for the Assessment of Existing Bridges and Other Structures for Fatigue
Tender ID: 602377
Tender Details
Tender Description
Purpose
The purpose of this project is to provide guidance around the assessment of existing bridges and other structures for fatigue.
Scope:
This project will assist Austroads members agencies to identify and refine maintenance programs for bridges and other structure types that are at a higher risk of developing fatigue related issues. Fatigue constitutes significant risk to the asset owner. Liability risk will be reduced if the collapse risk from fatigue can be calculated more accurately. With Standards Australia unable to provide resolution or guidance on this topic due to divestment of interest, Austroads can provide much needed leadership and guidance in this space.
The scope of this project to produce a guideline for best practice for fatigue assessment in the two following areas:
- Topic 1 – Fatigue assessment options for existing bridges with focus on bridges with overloading and where historical data on vehicle loads are unavailable.
- Topic 2 – Fatigue assessment options for gantries with particular focus on Square/Rectangular hollow sections. Fatigue assessment for other infrastructure assets prone to fatigue such as high mast lighting and noise walls.
The scope of the project includes the following:
- Undertake a literature review to establish what work has already been done on this subject both in Australia and internationally.
- Identify case studies that highlight the issue and produce worked examples, guidance and commentary on how to apply current provisions in the Australian Standards (notionally 4 bridges consisting of steel, prestressed concrete, reinforced concrete, timber, 3 gantries and 1 noise wall examples).
- For Bridges, the worked examples will provide detailed guidance on the assessment of bridges where overstressing/beyond serviceability has occurred. Where the loading history is insufficient to ascertain assessment in strict adherence to AS5100, a sensitivity assessment with detailed description of parameters (such as the different outcomes between normal traffic loading, all terrain cranes at high frequency and High Performance Freight Vehicles [HPFVs]) will be documented and completed.
- For gantries and other structures, provide worked examples on fatigue assessment. The worked example should include application of the new requirements from AS1170.2:2021 as well as undertake a comparison between AS1170.2, AASHTO and DoT Bridge Technical Note 14 outcomes to provide any risks and conditions of use to be considered when applying the three different methods, especially in the Australian environment. The comparison should include galloping, vortex shedding and truck induced loads to compare in what scenario it may govern. The guideline is also to provide comparison of the use and non-use of levelling nuts at the bottom of the base plate and the effects on fatigue reactions and risks.
- Identify any field trials and results available to compare outputs to theoretical.
- For both bridges and gantries, provide a fatigue assessment workflow guide to illustrate steps and stages for the stakeholder or designer to decide which approach to use. For example, for bridges: provide new process/workflow chart for assessments based on set overstress and assumed repetitions and look at stress analysis based on stress levels above infinite cycles. Also consider the process for backward calculation from allowable overstress versus stress limits and cycles.
- Make recommendations on how to address the problem, including timing/staging of new requirements (e.g. load or speed limitation on bridges, mandatory strain gauging for gantries).
- Identify potential improvements to existing Austroads specifications and Australian Standards.
- Explore what constitutes a representative cyclic loading regime that could be constructed with assumed parameters.
Austroads Publication Design and Construction Guidelines for the Delivery of Large Cantilever and Gantry Structures (AP-G95-21) already provides commentary and recommendations for gantry fatigue assessment and the contents should not be repeated. This best practice guideline is to provide clarity on the method recommended for use for square and rectangular sections.
Deliverables:
This project will produce the following final deliverables:
- Guideline with recommendations and appendices
- Webinar
- Project data with populated metadata spreadsheet.
Location
New South Wales : Central West : Far North Coast : Far West : Hunter : Illawarra : Mid North Coast : Murray : New England : Orana : Riverina : Southern Highlands : Sydney
Queensland : Cairns & Far North Queensland : Gladstone : Mackay Whitsunday Region : Mount Isa & North West Region : Rockhampton : South East Queensland : South West & Darling Downs : The Central West : Townsville : Wide Bay Burnett
Victoria : Barwon South West : Gippsland : Grampians : Hume : Loddon Mallee : Melbourne
South Australia : Adelaide : Eyre & Western : Far North : Fleurieu & Kangaroo Island : Limestone Coast : Murray & Mallee : York & Mid North
Northern Territory : Barkly : Big Rivers : Central Australia : East Arnhem : Greater Darwin : Top End
Australian Capital Territory
Tasmania