Bridge Failure

Primary reference(s)

Wardhana, K. and F.C. Hadipriono, 2003. Analysis of recent bridge failures in the United States. Journal of performance of constructed facilities, 17:144-150.

Additional scientific description

Urbanisation leads to a continuous increase in demand for urban infrastructure, including bridges, highways and roads. The service life of infrastructure such as bridges is often shorter than expected due to natural phenomena and lack of sustainable concept in design and construction. Bridge failures are one of the most severe infrastructure problems faced today and pose an imminent threat to life and property. This reinforces the need to conduct sustainability assessments and optimal risk mitigation measures. A key aspect of engineering failures is the relationship between the failure and growth in engineering knowledge, which ensures the sustainable development of society (UNDESA, 2014).

The United States National Bridge Inventory, reports that on average, 188 million trips take place across a structurally deficient bridge per day in the USA. Between 1989 and 2000, a total of 503 bridges failed, resulting in 76 fatalities and 161 injuries. Of the 503 failures, 386 occurred during bridge’s service life rather than during construction (US Department of Transportation, 2020).

In August 2018, a large section of the Genoa Morandi bridge in Genoa Italy, collapsed resulting in 43 fatalities and required over 400 people to evacuate the surrounding area. The collapse led to widespread human displacement and created an economic disaster (Bellini and Calevo, 2019). Lack of maintenance work and/or bridge design have been suggested as the reason(s) for the bridge collapse.

Metrics and numeric limits

Not identified.

Examples of drivers, outcomes and risk management

Lessons identified from past bridge failures should inform the development of new materials, and more efficient forms of substructure and superstructure as well as new technology of construction, are now leading to longer life spans of bridges (Choudhury and Hasnat, 2015). In response to recent bridge failures, research has had a growing focus on three aspects: the general situation and development trend of bridge failures; bridge safety based on structural monitoring and mechanism analysis; and risk assessment and control for sustainability and environmental health (Tan et al., 2020).

Choudhury and Hasnat (2015) classified the more common causes and mechanisms of bridge failures around the world into two groups: natural factors (flood, scour, earthquake, landslide, cyclones etc.) and human factors (poor design and construction method, collision, overloading, fire, corrosion, lack of inspection and maintenance etc.).

However, a bridge designed to current standards and properly maintained can still fail. This is largely due to the gap in research about how exceptional stresses and especially the interaction of different exceptional stresses can compromise bridge integrity. Wardhana and Hadipriono (2003) concluded in the United States, that hydraulics (flooding and flood-related debris strikes), collisions, and overloading failures accounted for 73.4% of bridge failures, with the vast majority caused by external events that subjected the bridges to conditions with which they could not cope. Bridge overload and lateral impact forces from trucks, ships and trains, resulted in 20% of total bridge failures.

To avoid bridge failures in the future, both design countermeasures and management guidelines should be implemented. To improve bridge management, consideration should be given to social, environmental and economic sustainability (Tan et al., 2020). Environmental factors are one of the biggest risk factors engineers must consider in future bridge design. Climate change is a growing concern, with rising sea levels and increased frequency and severity of storms two examples of relevance to bridge design. Adapting to the potential impacts and loads caused by floods, storms and earthquakes are also key considerations for bridge resilience.

The United States National Bridge Inventory, a database of United States bridge failures has been used to estimate the failure rate of bridge collapses. The database shows hazards that have caused bridges to collapse historically throughout the USA and can be used to determine potential failure rates for bridges in other nations (US Department of Transportation, 2020).

Engineering has an important role in the planning, construction and ongoing maintenance of bridges in order to support their function, safety and integrity. Key considerations are ensuring the bridge design: surpasses national standards and guidelines; allows for higher flood levels than experienced historically; and ensures the bridge can withstand significant loads and debris.