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Sri Lanka

The road to resilience: sharing technical knowledge on transport across borders

Shanika Hettige's picture
Photo: Sinkdd/Flickr
For many countries, damages and losses related to transport are a significant proportion of the economic impacts of disasters, often more than destruction to housing and agricult+ure in value terms. For example, a fiscal disaster risk assessment in Sri Lanka highlighted that over 1/3 of all damages and losses over the past 15 years were to the transport network. In addition, climate change increases the damages and losses.
 
In the Kyrgyz Republic, where 96% of all cargo travels by road, any disaster-related disruptions to the road network would have severe repercussions on the economy. The Minister of Transport and Roads, Mr. Zhamshitbek Kalilov, is charged with protecting these systems from all kinds of natural hazards, from avalanches to floods.
 
Working to support country officials, like Mr. Kalilov, is why the World Bank Resilient Transport Community of Practice (CoP) and the Disaster Risk Management Hub of the Global Facility for Disaster Reduction and Recovery (GFDRR) organized the Technical Knowledge Exchange on Resilient Transport on May 8-12.

Held in Tokyo, the week-long exchange brought together World Bank clients and teams from 16 countries across all regions to share concepts and practices on resilient transport, including systems planning, engineering and design, asset management, and contingency programming. The exchange drew upon the experience of several countries and international experts who showcased innovative approaches and practical advice on how to address risk at every phase of the infrastructure life-cycle.

The “plastic bridge”: a low-cost, high-impact solution to address climate risk

Oliver Whalley's picture
Also available in: Français
Photo: Anthony Doudt/Flickr
Bridges are critical links in the transport network. In their position across waterways, they are exposed to the full effects of flooding and landslides, and are often the first pieces of infrastructure to be damaged in the event of a disaster. They also typically take weeks or months to repair.  Besides causing expensive damage to the infrastructure itself, disruptions in connectivity also have a much broader impact on economic productivity and people’s ability to access essential services. As many places are expected to witness more intense and frequent rainfall as a result of climate change, the risk to bridges will only worsen: more rainfall will lead to bigger river flows and more damage to bridges, especially those designed to handle smaller storms.

At each end of a bridges is a structure which supports the weight of the deck. These are known as abutments, and they are often the first part of the bridge to fail. Blockage of the main channel by debris can cause water to look for the path of least resistance around the sides of the bridges, thus placing the abutments at risk.

Traditional bridge construction requires the installation of piles for the foundations of abutments—a lengthy and expensive process that involves specialist materials, skills and equipment.

But there is another promising solution: Geosynthetic Reinforced Soil (GRS) abutments. These allow for rapid and resilient construction of bridge abutments using locally available materials, without specialized equipment. With GRS, bridges can be constructed in as little as five days (Von Handorf, 2013) and at a cost 30-50% lower than traditional approaches (Tonkin and Taylor, 2016) .

GRS abutments are based on ‘geogrids,’ a high density mesh made out of polyethylene (plastic). Layers of soil and geogrid are combined to create a solid foundation for the bridge deck. Construction can be completed with basic earthmoving and compaction equipment, and a range of local fill materials can be used with guidance from geotechnical specialists.