The Sunniberg Bridge was built in 1998 and won the Outstanding Structure Award in 2001 for its aesthetically pleasing appearance and innovative design.
Since completion has been a major landmark in the Landquart River Valley near Klosters in Switzerland.
Bizarrely, the bridge was opened seven years after completion, in 2005, by Prince Charles.
The Sunniberg Bridge ,with a length of 526 m ,12m wide, with a longest span of 140m, and pylons up to 77m above ground level ,ranks as one of the largest bridges in the Swiss Alps. In the largely rural valley, the Sunniberg Bridge is the only major engineering structure. It stands out from far away and is a landmark on the approach to the holiday resort of Klosters. Although the bridge crosses the valley at a remarkable height, it has been designed not to dominate the entire landscape. To show consideration for the local population, it has been designed to fit into this rather rural area unobtrusively, but with a certain elegance. For visitors arriving by road or rail, the bridge should appeal as a modern technical achievement and provide a memorable bridge experience.
The bridge was designed without any expansion joints, which means that under temperature variations, the deck “breathes” in plan i.e. sways sideways. The piers are designed with relatively slender bases to be flexible enough to withstand this movement, and along with the need to maintain highway headrooms, this leads to their distinctive and elegant Y-shape. Everything about the piers and pylons is well thought out – their gentle curves, echoing the tall trees nearby; the way the bridge deck nestles between their arms; their continuity (many cable-stayed bridge have very different pylon forms above and below deck); the clever way the massive steel cable anchorages are hidden within them; and their delicate but robust proportioning.
This five-bay cable-stayed bridge is supported by unusually low pylons on top of piers up to 60 m high. The slender deck consists of a continuous slab with slightly thickened edges. Together with the pylons and piers, it forms a structurally closed system. The parallel cables are fixed in steel sleeves in the recessed pylons, and the bridge was calculated in such a way that a single cable can be removed at a time for maintenance purposes without interrupting traffic. The curvature on plan allows changes in length to be absorbed by horizontal changes in the radius. The bridge is rigidly fixed at both ends without expansion joints. As a result, the piers are held almost immovably in position at the level of the carriageway.
The bridge is part of a road scheme that will enable vehicles to bypass Klosters and is a indubitable proof of human innovation spirit and word class engineering .