Critical Infrastructure

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GUEST OBSERVATION
After the tragedy in the Italian city Genoa, where a highway bridge collapsed killing more than 40 people, nations seem to be taking stock of the maintenance levels of their bridges. There are reports thousands of UK bridges are at risk of collapse, and there are hundreds of similarly damaged bridges in France, Germany and Italy itself.
Australia is no different to other developed countries in this regard, where a lot of bridges are old and deteriorating, and we would be foolish to think we are immune. That said, bridges are generally safe structures, with the risk of fatality from a bridge collapse being around one in 100 million per year. This is roughly 100 times less likely than being killed by lightning.
So yes, our bridges are safe, but they need to be kept up-to-date to maintain these low statistics. So how are bridges in Australia managed, and who is responsible?
The age of Australia’s bridges
Bridges are nominally designed to last for some long period of time, such as 100 years. However, such claims are reasonably arbitrary, since much of the technology used in bridge construction hasn’t even existed for 100 years.
Accelerated deterioration testing in laboratories does help make predictions, but it’s not necessarily a good reflection of field performance. This is because of differences between naturally occurring, and artificially impressed, corrosion.
Both age and traffic volume are significant factors in the rate of deterioration of bridge surfaces. Age is likely a proxy for the combination of weather effects and the natural degradation of the material. To combat these effects, inspections and maintenance – or better yet, live monitoring – of bridges, are the best ways we have to ensure public safety.
In Australia, around 800 organisations are responsible for around 53,000 public road bridges. Some (about 23,000) are managed by state road authorities, who manage the high-capacity arterial roads, and local councils who manage the remaining local roads (about 30,000). Of course, the eight state and territory road authorities are the main road bridge owners.
Bridge safety, as with all structural engineering, is a question of whether the imparted load is less than the structure’s strength. Since loads and material strengths are variable, high estimates of loads are used, and low estimates of strengths are used. These extreme (high) loads and (low) strengths are further factored to achieve an acceptably small probability of failure when checking structural adequacy.
Highway traffic loads are known as “normal” when referring to everyday ordinary loading and “abnormal” in the case of special heavy transport. The high estimate of normal traffic loading represents a once in a 1000-year likelihood of a critical event (known as the return period). Abnormal special vehicles might be 300 or 400 tonne loads. During movements of these vehicles, no other traffic will be permitted on the bridge.
Before 1950 Australia’s road bridges were built to design standards set at state level. Around 15% of our bridges on main roads come from this era.
Considering normal traffic use, from 1950 to 1976 short-to-medium span bridges were designed for the MS18 load model. This is roughly a 33 tonne semi-trailer vehicle, or about 20 cars. These now comprise about 50% of the bridge network. From 1976 to 2004 it was the T44 load model, or roughly a 44-tonne vehicle, and these are about 25% of the network. Today, it is the M1600 load model (roughly a 160-tonne vehicle) and these make up about 10% of the network.
These load models have different weight and other aspects, so it isn’t meaningful to rely on the quoted gross weight – it strongly depends on how that load is distributed, and the other factors involved. Still, the loads bridges are designed for have increased together with legal truck weight limits, which themselves have increased by about 10% per decade since the 1950s.
So, how healthy are Australian bridges?
In Australia there are mostly three levels of bridge examination, but NSW has a fourth level. Level 1 inspections are essentially drive-bys to ensure there are no gross deformities present. This takes place roughly twice a year. Level 2 inspections are an “arms-length” visual inspection of all bridge surfaces and components and should take place around every five years at most. The scope of what is included in Level 2 inspections varies across jurisdictions.
Level 3 inspections are detailed engineering inspections, including material sampling and structural modelling. NSW’s level 4 inspections are typically proof load testing. Level 3 (and 4) inspections take place in special circumstances, such as a natural hazard, or change in legal load limits.
Unfortunately, it’s difficult to give a snapshot of the current state of Australia’s bridges. The state road authorities make public very little information about bridge conditions, or inspection and maintenance budgets. In South Australia, bridge inspection results are not available, even under Freedom of Information it seems. Tasmania, the ACT, and NSW offer no data, at least from their websites.
Queensland data is available via email, but has no inspection information. Western Australia offers a GIS interface, but again no inspection data. Victoria seems to be best, offering a GIS website, which includes condition ratings (using Vicroads’ own Bridge Condition Number).
What could we do better?
An open access national bridge inventory, such as exists in the United States, would be of enormous benefit in the study and management of Australia’s bridges. For this to happen, harmonisation of inspection and maintenance routines would be necessary, along with condition rating schemes.
While the present system reflects environmental, practice, and legislative differences between the states and territories, a reasonably general national system with jurisdiction-level tuning is surely feasible.
Risk assessments should move away from subjective qualitative approaches, and adopt an objective quantitative framework. This should help minimise problems associated with loss of corporate knowledge (which contributes to collapses). Such quantitative safety data would enable budgeting for inspection and maintenance to be done on a needs basis, with clear reference to minimum acceptable levels of safety.
There are no simple answers to the complex problems bridge management throws up. The ideal combination of field inspection, expert technical knowledge, management processes, and political decision-making is hard to find. Nevertheless, the case of the Ponte Morandi in Genoa should serve as sufficient warning to be vigilant.

It might be some comfort to the families of the 43 people who died to know their loss has motivated agencies around the world to ensure foreseeable bridge failures are prevented.
Colin Caprani, Senior Lecturer, Structural Engineering, Monash University
This article was originally published on <a href="http://theconversation.com" target="_blank">The Conversation</a>. Read the <a href="https://theconversation.com/are-australian-bridges-safe-and-can-we-do-better-101825" target="_blank">original article</a>.
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j.ballantyne1990-6AQqhLzZaK

Are Australian bridges safe, and can we do better?

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GUEST OBSERVER
Two current global trends are set to make life rather uncomfortable for cities: climate change and the unprecedented rate of urbanisation.
This combination of extreme weather – often involving sudden deluges of water – and high population density will test even the best sewage infrastructure we have today. In the face of such pressures, how adaptable are our sewage systems?
Colonial heritage in our sewage systems
Sewage systems worldwide commonly consist of flush toilets and pipes that rely on a steady supply of water to transport and deposit bodily waste, either to a wastewater treatment plant or, failing that, simply downstream in the nearest river or straight into the ocean.
Many urbanites around the globe are using sewage systems based on a colonial-era template. Initially implemented to cure London’s “Great Stink” of 1858, when a hot summer combined with the excrement-filled River Thames to create an unbearable stench, sewer systems were public health interventions designed to remove pathogens and “miasmatic” offences associated with bodily waste.
They were first transplanted off Britain’s shores in the reconstruction of Paris from 1850–70, and since then have become embedded culture-specific notions of hygiene and sanitation around the globe.
Such colonial infrastructure is now proving increasingly problematic in the face of human-driven global trends (broadly referred to as the Anthropocene).
Using water to flush waste
A paradox of climate change is that there seems to be both more and less water. In South Asia, for example, at least 1.6 billion people struggle to find drinking water despite an abundance of water generally.
<img src="https://images.theconversation.com/files/177976/original/file-20170712-19681-1mjtidi.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" alt="">
A woman siphoning water from a leaky pipe into a bucket on the side of the road during summer. Author provided
For residents of Darjeeling, India, where I am currently conducting my PhD fieldwork, this paradox is very real. Monsoons in Darjeeling last from June through August, sometimes longer, and rain falls frequently throughout the rest of the year. On the face of it, Darjeeling should have plenty of water, but in fact it faces increasingly acute shortages during the summer months from April to June.
The town’s water and waste infrastructure was built by the British in the 1930s, for what was then a population of 10,000. Its population now hovers around the 150,000 mark, and surges to more than 200,000 during peak tourist season from March to May. Despite this, there has been little to no official maintenance or upgrade since Indian independence in 1947.
In town, signs that urbanisation has outpaced infrastructure capacity are everywhere. An impressive number of pipes move water to and from the population. Along with electricity wires, these pipes traverse the city along increasingly bizarre and precarious routes. Ad hoc retrofit attempts to meet rising demand appear to be band-aid solutions and, because the pipes leak, often exacerbate contamination.
<img src="https://images.theconversation.com/files/178026/original/file-20170713-19681-1qpyt4u.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" alt="">
 A typical open sewer in Darjeeling. Note the pipes on either side are water pipes taking drinking water to homes. Author provided
Darjeeling is instructive because it is a landscape struggling with inadequate infrastructure amid a rapidly urbanising population. In such a landscape, fresh water can be contaminated by sewage outflows, largely because the system is completely dependent on water to function.
Such over-reliance underpins another paradox: modern sewerage systems require water to work and yet, if not context-sensitive nor managed appropriately, can dirty vital waterways.
Closer to home
Australia is not immune to such problems. Our changing climate means we too face more severe droughts along with heavier rainfall events. Under these conditions, our sewage systems are under increasing stress.
Earlier this year Melbourne experienced summer flash floods which strained the city’s sewage systems, contaminating three public beaches. In February a heavy downpour in Western Australia caused concern over sewage contamination in the Swan River.
Such experiences are not isolated, and are likely to increase in incidence across the world. They provide important lessons and act as a catalyst for rethinking our relationship to water and waste, particularly amid concerns over water scarcity and extreme weather conditions in southern Australia.
Alternative futures
Many social scientists are now researching alternative forms of infrastructure that are contextually relevant, embedded in community values, and adaptable to current environmental challenges.
These alternative forms include moves to re-examine our relationship with waste in farming, use dry composting toilets, and install public bio-toilets along India’s main railway corridors.
<img src="https://counter.theconversation.com/content/78095/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1">As for my home town of Adelaide, the capital of the driest state on the driest inhabited continent on Earth, should we really continue to use water to flush bodily waste?
Matt Barlow works at University of Adelaide.
This article was originally published on <a href="https://theconversation.com" target="_blank">The Conversation</a>. Read the <a href="https://theconversation.com/finally-facing-our-water-loo-its-time-to-decolonise-sewerage-systems-78095" target="_blank">original article</a>.
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Decolonising our sewerage systems: Matt Barlow

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GUEST OBSERVER
Our cities and regions depend on the critical nodes and arteries that together comprise urban infrastructure systems. This includes energy, food, water, sewerage and communications.
The positioning of critical infrastructure is crucial to our understanding of the world we live in and how we see ourselves. It’s our means of survival as Homo urbanis.
This means key questions around critical infrastructure need to be better considered. How is it critical, when and for whom?
Beyond espionage, sabotage and coercion
Critical infrastructure has received much attention in recent years. The reasons include concerns about exposure to terrorist attack, disruption by disasters, rising awareness of the interdependent nature of urban infrastructure, and changes in ownership and responsibility for infrastructure assets. 
The Australian government defines critical infrastructure as:
… those physical facilities, supply chains, information technologies and communication networks which, if destroyed, degraded or rendered unavailable for an extended period, would significantly impact on the social or economic wellbeing of the nation or affect Australia’s ability to conduct national defence and ensure national security.
This definition expands traditional thinking to include network and information infrastructure. However, the emphasis is on national security and defence issues such as espionage, sabotage and coercion. Infrastructure is defined as critical on the basis of what is at threat should it be destroyed or disabled, and how much that matters.
Yet what is critical about critical infrastructure is not just a matter of national security threats. It is also the key linkages between this infrastructure and human and environmental system vulnerability, integrity and equity. 
Experiences of critical infrastructure are not equal, but highly contingent on political and economic priorities, influence and opportunity.
Critical how and for whom?
When securing urban infrastructure, the focus is on whom or what is being secured – and from what. 
Any issue is capable of securitisation which involves casting the security issue as a threat that calls for emergency measures. But security for whom? From what threats? By what means? And at what cost? 
Critical infrastructure can be government-owned (such as dams), privately owned (like airports), community-owned (like irrigation systems), or involve public-private partnerships (like electricity distribution networks). 
The ownership patterns of infrastructure of all kinds have changed rapidly in recent years. This has left questions of responsibility unresolved. An example is the ownership versus service provision arrangements for the supply and distribution of catchment water resources. 
Alongside the need for improved service quality, cost efficiencies, variety and choice, a growing trend towards highly uneven and inequitable community and environmental outcomes demands our attention. 
How critical infrastructure is defined influences which stakeholders are deemed to have a role or responsibility in protecting it. 
In South Australia, a severe thunderstorm blacked out the state in 2016. The resulting political finger-pointing distracted attention from the real issues of risk and responsibility in delivering electricity to the community. 
Critical when and at what scale?
The scale question leads us to consider assets not normally included as critical infrastructure. An example is the vital role of natural ecosystems in our long-term economic and social welfare. Natural or semi-natural water catchments are in many places the sole source of water for towns and cities. 
However, maintaining the integrity of these water supplies has largely ignored the importance of the catchment itself in providing much-needed filtering and treatment of that water. The contamination of Canberra’s water supply, following the 2003 bushfires in the Cotter River catchment, was unprecedented in redefining what is critical infrastructure.
An alternative to a national security approach to critical infrastructure involves a complementary focus on the local scale. Local access to food, for instance, can be seen as critical. The Australian Food Sovereignty Alliance argues for community-scale urban food policies and practices. 
In 2001, foot and mouth disease broke out in the UK. The crisis exposed individuals’ vulnerability to increasingly integrated, global food supply chains. That underscores the merits of social and environmental policy at local government level. 
Big assets and sudden events are at one level defensible as a prime focus. But this approach is limited by a traditional framing of critical infrastructure and a bias towards certain timeframes.
Decisions on resources, priorities and effort inevitably involve scale-dependent judgements. These judgements should be defined by the nature of the impacts: one-off or cumulative; human or nature-oriented; fast or slow onset. 
For example, local infrastructure – minor roads, flood buffers, bridge culverts and so on – is critical for society to function. Yet it is not well catered for in policy. Local government capacity to provide and manage infrastructure is limited. And varying interpretations of scale and criticality shape the funding debate. 
Our urban arteries
Critical infrastructure networks shape and sustain our cities and regions. But they also expose communities to a range of threats. These include natural disasters, terrorism, peak oil and climate change. 
So how do we decide what is critical and what is not? To arrive at an answer we must consider not only physical or informational assets, but the inclusion/exclusion of communities, places and values. 
How can we better recognise and integrate natural ecosystems as critical to human survival and flourishing? How do we do this amid infrastructure privatisation and securitisation? And where are the points of resistance and pathways for alternative action?
We need to be more imaginative about critical urban infrastructure. A better, more sustainable approach needs to: expand our understanding of what critical infrastructure is to include environmental and local systems; learn from previous security decisions and their outcomes; and include local levels of activity to broaden the narrow national security approach in order to meet contemporary infrastructure challenges.
<a href="https://theconversation.com/profiles/wendy-steele-4698" target="_blank">Wendy Steele</a> is associate professor of Urban Policy and Planning, RMIT University.
<a href="https://theconversation.com/profiles/karen-hussey-48688" target="_blank">Karen Hussey</a> is deputy director, Global Change Institute, The University of Queensland.
<a href="https://theconversation.com/profiles/stephen-dovers-342834" target="_blank">Stephen Dovers</a> is Emeritus Professor, Fenner School of Environment and Society, Australian National University.
All are authors for The Conversation.
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Critical Infrastructure

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