If you have structural assets located in a marine environment it’s important to adopt good coastal asset management to minimise corrosion. Once these structures start to show signs of wear and tear safety is compromised and repairs can become costly.
Industrial port cities, such as Newcastle on the Eastern seaboard of Australia, are continuously subject to severe coastal weather. Assets located in these areas are constantly under attack from the conditions imposed by this harsh environment, so ongoing coastal asset management is essential.
Steelwork structures in particular are susceptible to the rigours of this coastal environment. Long-term exposure has resulted in the breakdown of the original corrosion protection leaving steelwork with significantly reduced corrosion protection.
It is important to regularly undertake inspections and assessments of steelwork assets which have sustained corrosion. Where damage has occurred the assessment should also include the development of a repair strategy.
Damage to steelwork structures resulting from corrosion may consist of loss of section to members, connection components, bolts, welds and anchor bolts.
Here is a guide to making sure your coastal assets remain safe and in good working order at all times.
Use A Coastal Asset Management Expert
Employing a coastal asset management professional to regularly assess your structures is vital. They have the skills and knowledge to identify how safe your structures are and highlight any damage they may have sustained.
Identifying the condition, understanding the risk and component criticality, and developing a planned approach to remediation of the asset are the stages to be followed.
Your coastal asset management expert will assess the priority of the damage, when the repairs are likely to be required, and what type of repairs are involved. For example if they require replacement, partial repair or a combination of both.
Conduct Regular Structural Assessments and Inspections
Your structural assessment should include a visual inspection of the asset, undertaken from walkways and platforms within normal working areas. However, depending on the size of the structure and its elevated arrangement it may require the use of access equipment such as an Elevated Work Platform.
You should ensure these inspections are regularly conducted and documented by your coastal asset management specialist. It is essential they include the location of the structural defects on a drawing or sketch, a condition assessment, a proposed action, a preliminary risk assessment and a photographic record of the defect.
Measurements should be taken and recorded for loss of section of members or components. The degree of loss of section allows the damage to be quantified and prioritised.
An assessment normally consists of the modelling and analysis of assets to determine the level of loading structures and their components are subject to.
Once the analysis is complete a comparison of the level of loading and the degree of damage of a member or component can be made. Based on this a priority can be placed on the damage.
As part of this process a risk assessment may be undertaken.
Assess Risk and Implement A Management Strategy
A risk assessment considering the likelihood of failure and the consequences of that failure based on injury, operational and business impact, is developed using a consistent risk assessment system. The type of action and priorities can then be placed on each defect. Actions may be to repair, replace, monitor or remove the asset.
If you are a long-term resident of a coastal area, you may own assets which were designed in the mid to late twentieth century. These assets were designed to previous, now superseded, design codes which do not reflect the current code requirements.
A risk assessment of loading conditions may be undertaken to accurately reflect the actual use of the asset. The risk assessment is developed based on the likelihood and the consequences of failure and considers the remaining design life, changed loading conditions and stricter controls over imposed loads. These can be adopted as the minimum design criteria for any repairs.
Controls may be as follows, but not limited to, asset modifications, operational controls, work permit controls, electronically interlinked safeguards or signage controlled barriers.
Implement a Suitable Repair Strategy
Repairs may consist of full replacement of members that are inadequate, supplementing members with additional members, overplating members or connections and replacement of connection bolts.
When making the repairs, controls must be put in place to ensure the structure is not overloaded by personnel, equipment and scaffolding. This can be achieved by limiting repairs to a local area of the structure and then progressively moving the work front along the structure.
The staging can be analysed and planned to ensure the structure can cope with the load from the progressive work fronts during the repair work.
The Non Destructive Testing of all welds undertaken during the repairs is important, this helps to confirm quality. Following that, the reinstatement of the corrosion protection on the structure should be added to ensure a durable structure for its remaining design life.
To summarise, the course of action outlined above considers the safety of the structure and personnel during the repairs and addresses the damage to the asset in a practical and economic way. The result being you will achieve a structure that will be operational and serviceable for its remaining design life.
Are You Looking for a Coastal Asset Management Specialist?
Principal Structural Engineer, Engenium Pty Ltd