The World Economic Forum (2014) reported in February this year that in every corner of the globe, governments are facing an acute need for new or modernised infrastructure. It estimated that the shortfall in global infrastructure investment is at least US$1 trillion a year.
The following month in the UK, HM Treasury (2014) outlined plans for £375 billion of public and private capital in infrastructure projects. This issue of Civil Engineering again places a spotlight on the challenges faced, around the world, by those tasked with delivering the world's much-needed infrastructure projects.
We start in the Swiss Alps, where Simoni (2014) describes how the Gotthard base tunnel will become the longest railway tunnel in the world, at 57 km, when it goes into operation in 2016.
The challenges faced included tunnelling at depths of up to 2500 m, having to deal with blocked tunnel boring machines and cutter heads as well as cooling groundwater coming out of the rocks at 27°C before it can be discharged to watercourses. The overhead cables need to be light to feed passenger trains passing through the tunnel at 250 km/h, but they also need to supply sufficient current to power heavy freight trains.
Tunnelling under the Alps is undergoing a renaissance at present with tunnels planned under the Brenner pass as part of the route between Berlin, Germany and Palermo, Italy. Another tunnel is planned under Mont D'Ambin as part of the Lyon to Turin route. Both of those tunnels will be as long or longer than the Gotthard when completed.
The fuel used to build and operate much of our infrastructure has to be stored and any failings there can have disastrous consequences, as happened at Buncefield in Britain in December 2005. Tarada and Robery (2014) outline the lessons learned as part of the prosecution which resulted in a £9·8 million fine for the site operators and owners.
The fire lasted for 5 days and it was another 15 days before the site was made safe by the fire and rescue services. The environmental consequences included contamination of the local chalk aquifer. Failures in the design of the site layout, drainage and containment bunds were all observed. The lessons learned in detailing liquid-retaining structures are useful for those outside the petroleum industry as well.
Powrie (2014) continues the issue with an exposition of some of the engineering challenges faced by the providers of railway infrastructure faced with ever-increasing demand. There are more passengers on UK railways now than at any time in the last 60 years, despite the railway network being 50% of the size that it was before the Beeching cuts in the 1960s.
Powrie describes how the increased frequency of trains has impact on the ballast used to secure the tracks as well as on the turnouts and crossings. Increased frequency of weather extremes caused by climate change can compromise the stability of railway embankments and cuttings as well as cause scour damage to bridges, as we shall see next.
We conclude in the USA, where Kim et al. (2014) describe the causes and impacts of the floods in Boulder County, Colorado in 2013.
Within 7 days, 429 mm of rain fell, which is 75% of yearly average precipitation totals. Geographical information systems were used to assess damage and prioritise relief efforts, including satellite imagery to compare views before and after the flood event.
The growth of social media means that crowd-sourced mapping has become a source of useful data for relief agencies – in this case, for example, showing where houses were without power. The impact of the storm on highway infrastructure was significant, with about 30% of the 411 bridges in the flooded area needing repairs after the storm.
Once again our thanks go to all those involved with this issue, especially the authors for sharing their experiences with us. I hope you find them useful and that they encourage you and your colleagues to consider sharing your own experiences through this and other ICE Proceedings journals.
