To effectively solve the problem of communities isolated by damaged or broken bridges resulting from natural disasters such as typhoons, floods, and earthquakes, the National Center for Research on Earthquake Engineering (NCREE), National Applied Research Laboratories (NARLabs) has successfully developed a “light-weight composite transportable bridge for emergency disaster relief” that is lightweight, easy to assemble, and can be used repeatedly. The light-weight composite transportable bridge enables disaster relief materials to be shipped to disasters areas and disaster victims to be evacuated for medical treatment (when necessary) within eight hours, effectively reducing loss of lives and property.

Immediate Access to Isolated Communities Using Composite Material Cable-Stayed Bridges
The light-weight composite transportable bridge measures 20 meters long and 3 meters wide. It can support a live load of up to five tons, which is enough to provide safe access for disaster relief vehicles. The transportable bridge is made from glass fiber reinforced composite, which has the advantages of high strength and low weight. Its asymmetrical cable-stayed design is not affected by rapid floods and allows the main body of the bridge to be extended from one side of a river to the other without the use of piers and foundations – thus quickly allowing access to isolated communities.

The idea behind our light-weight composite transportable bridge is to use steel (at a density of 7.8 g/cm3) for constructing its girders and pylon on one side of the river; then, glass fiber composite (at a density of 1.8 g/cm3 and a weight lighter than steel) is used to build the main body of the bridge in structure module. Lastly, the pylon and main body are connected using cables, which along with the pylon, support the weight of the bridge. Upon its completion, disaster relief units gain quick access to isolated communities.

Enabling Local Residents to Help Themselves Using Quick-Assembly, Reusable and Transportable Bridges
The light-weight composite transportable bridge features three major advantages: quick assembly, DIY applications, and reusability:

• Quick assembly: Currently, “temporary roadways made from concrete pipes” (required time for completion: three to seven days) and “temporary steel bridges” (required time for completion: one to three weeks) are the most common methods for dealing with collapsed bridges. However, because these take a long time to complete, disaster relief is often delayed in the meantime. At approximately half the weight of temporary steel bridges, our light-weight composite transportable bridge is easy to set up – requiring only eight hours – and better able to meet the urgent need of disaster victims in the midst of an emergency.
   
• DIY applications: Traditional bridges must be set up by professional engineers. By contrast, our light-weight composite transportable bridge requires only one professional engineer and a few dozen workers (no experience necessary). The transportable bridge can be set up within eight hours using simple tools and a portable assembly workbench. Composite transportable bridges may be preemptively shipped to areas that are prone to floods and landslides so that in the event of a bridge collapse, only one professional engineer will be needed (who can be sent to the disaster area via a helicopter or cable car) to free trapped residents and reestablish access to the outside world; rather than passively waiting for outside help, local residents can help themselves, which combined with an outside effort, significantly increases the speed of disaster relief.
   
• Reusability: Although glass fiber composite has a number of advantages, it is comparatively twice as expensive as steel. To help our customers save on costs, we have adopted a quick assembly and disassembly design for our light-weight composite transportable bridge, enabling it to be quickly disassembled after use to facilitate repeated usage in the future. Laboratory tests have confirmed that our composite transportable bridge can support a 5-ton truck for over 200,000 crossings.

Effectively Control the Critical Hours of a Rescue
Natural disasters such as typhoons, floods, and earthquakes pose serious threats to human lives and property. For example, Typhoon Morakot, which occurred on Aug. 8, 2009, caused more than 100 bridges to collapse as the result of landslides and isolated numerous mountain communities – hindering the transport of personnel and supplies for disaster relief. Our light-weight composite transportable bridge allows disaster victims to regain access to the outside world in a minimum amount of time for securing disaster aid. Our composite transportable bridge enables people, scooters, and other vehicles to have access in and out of disaster areas and food supplies to be delivered during the critical hours of rescue operations, helping disaster victims at the time when they are most in need.