The innovative construction concept for a new Light Rail System, for which architectural studio ZJA, Woosung D&C, C&SC, GS E&C, SIDstudio and Iv-infra joined forces, commissioned by the South Korean Railroad Research Institute (KRRI), has passed its first tests with flying colours. In South Korea a full-scale, forty-metre-long sample was tested under load, and scale models were tested for resistance to wind load and to earthquakes.

Clever structure with a positive spatial impact

Lighter than a metro, faster than a bus, less environmentally polluting and with a greater capacity – the Light Rail System is a popular means of transport in cities. The problem, however, is that the raised horizontal structures, which have previously always stood on closely spaced columns, have a negative visual and spatial impact in already jam-packed cities. For that reason the choice if often made to build more expensive underground transport solutions.

Rob Torsing (architect/partner at ZJA) describes the system as ‘Economically viable, elegant, sustainable and innovative. Our task was to come up with an above-ground solution for an Elevated Light Rail System in a city environment that would have less spatial and visual impact than the traditional design. Our proposed network looks like a tendril, winding at a great height through the metropolis, leaving room for walkers and green space below.’

Maximum span, extremely strong and dimensionally stable

The structural solution was found in a slim design with a limited construction height, based on the principle of the I-beam profile.

Rob Torsing explains. ‘By using a central beam between the tracks with “flanges” cantilevered outwards, it becomes possible to increase the distance between the columns considerably and to optimize the play of forces. Even at places where the structure is around fifteen metres high, the distance between the columns could be extended to 200 metres without the need for extra stays or cables. Strong, able to retain its shape and – unlike a tubular structure with cut-aways – giving passengers a completely open view on one side.’

First tests passed with flying colours

To test its strength and stability, the structure was recently subjected to a stress test at its most fragile part. It proved able to bear a load of 430 tons without collapsing. Furthermore, tests on scale models showed that the structure could withstand wind speeds of up to 80 metres a second and earthquakes of up to 6.5 on the Richter scale.


Watch the Korean news with pictures of the tests.

Read more here about the research project.