FINDING THE RIGHT BOND

Professors and students from a Swiss university built a dual-span glass fiber reinforced polymer (FRP) bridge to gain a better understanding of how composite materials behave and how best to connect them. Each of the two spans uses a different connection technique: one span is held together with bolts, the other uses epoxy adhesives. The designers discovered that the bolts did not correlate well with the properties of glass FRP materials and that span does not act to its full capability. The epoxy-connected span has a more even distribution of forces, allowing the FRP elements to act to their full strength. The pedestrian bridge is used during the winter months to cross a creek near the town of Pontresina. Each spring, it is dismantled, studied and fine-tuned in university laboratories.