GRUBENMANN, HANS ULRICH; AND GRUBENMANN, JOHANNES

born March 23, 1709, Teufen, Switz. died Jan. 24, 1783, Teufen born 1707, Teufen?, Switz. died 1771, Teufen? Swiss carpenters and bridge builders whose bridge (1758) over the Limmat River at the town of Wettingen, near Zrich, is believed to be the first timber bridge to employ a true arch in its design. The brothers' ingenious combination of the arch and truss principles made it possible to construct longer and better timber bridges than ever before. More is known about Hans Ulrich than about Johannes; both were village carpenters in the hamlet of Teufen, and they constructed churches as well as bridges. The first of three bridges for which the brothers are known was built by Hans Ulrich at Schaffhausen over the Rhine, in 1755, in two spans of 171 feet (52 m) and 193 feet (59 m) that met at an angle in midstream, resting on a central stone pier. Johannes later built a bridge at Reichenau, a single span 240 feet (73 m) long. In 1758 the brothers began work on the 200-foot (60-metre) Wettingen bridge, the design of which was an arch-truss combination, the arch of heavy oak beams joined by iron straps and rising 25 feet (7.5 m). Though these three bridges were later destroyed, the fame of the Grubenmanns influenced designers throughout Europe.