The world's first known fully bio-based footbridge has been built by Dutch researchers and students, in an effort to prove that such materials could feasibly replace concrete and metal in future construction projects, as Jim Drury reports.
This isn't any old footbridge.... ....its designers say it's the first fully biocomposite overpass ever made. It combines hemp and flax fibres, stuck to a biological polylactic acid foam core. SOUNDBITE (English) ASSISTANT PROFESSOR RIJK BLOK, OF EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "Actually it's the first bio-based bridge in the world, as far as we know. So it's fully bio-based in the sense that both the resin as the internal foam, which is PLA foam - also bio-based. And the fibres are also bio-based." Built by students and researchers, the bridge crosses a stream at the Eindhoven University of Technology campus. The strain caused by walking or jumping on the 14-metre long construction is measured in real-time by 28 internal sensors. These are contained inside optical fibres embedded in the biocomposite. They were designed by private company, Common Sense. SOUNDBITE (English) GEERT LUCKS, COMMON SENSE CO-FOUNDER AND PROJECT ENGINEER, SAYING: "...We have a scanner which sends in light via the optical fibre and what we get back is light which is reflected on the sensor point. We use that to measure the deformation of bridges....it's that small that we can embed it inside the material, so it's really part of the material, making the material kind of a so-called 'smart structure'...." Biomaterials have been used in construction before, but not in load-bearing structures like this. The biocomposite withstood a 500 kilogram per square metre load in lab stress tests before the bridge was built. SOUNDBITE (English) PROFESSOR PATRICK TEUFFEL, EINDHOVEN UNIVERSITY OF TECHNOLOGY, SAYING: "....This is just the first step and we try to continue in collaboration with our partners here - academic partners but also industry partners - to develop this further and see what other possibilities are there in the build environment." The experiment will last for a year, and the team hopes to show that bio-based technology is coming on in leaps and bounds.