In the inter-war period, the robust growth of today's Southern Suburb stopped at the deep valley of the Radbuza River, which at that time could be crossed only via roads leading to Klatovy and Radobyčice or Štěnovice. It was here on the county road to Štěnovice that a new bridge was to be designed to replace the older steel structure and bypass the 200-meter-wide river valley.
Engineer František Faltus, Head of the Counselling Centre for Welded Structures at the Škoda Works, was entrusted with this task. Just two years earlier, he had designed an innovative welded steel truss bridge for the central Škoda premises. To overcome the Radbuza, he chose an arch type construction, which he believed would be more in harmony with the landscape. It was the first arch bridge in Czechoslovakia to apply electric welding. Until then, steel elements had usually been joined by rivets or screws. In comparison with this conservative technology, the welded structure offered considerable reductions in material – in the case of Tyršův Bridge, František Faltus anticipated reduction in the weight of the steel portion of the bridge by 22%.
The experienced Pilsen engineer planned to overcome the wide flood plains on the left bank of the river with an embankment, at the foot of which he placed the left concrete abutment separating the arches from the reinforced concrete bridge approach (the use of concrete was due to the economic crisis; due to a sales recession, a balanced ratio of steel and concrete was carefully observed in state supplies at the time). Two "I"- profile arches with a span of 50.6 meters and a height of 10.4 meters above the water surface were produced in the bridge-building division of the Škoda factory. They were then transported to the site in ten pieces, assembled, temporarily bolted, and then welded together on a solid wooden scaffold. The deck pressure was transferred to the arches by welded steel columns. Faltus dealt with the right bank rising from the water in a similar manner; however, he only used the embankment here to correct the uneven height of both banks.
For its pioneering technical design, Tyršův Bridge was declared an immovable cultural monument in 1994. Almost immediately, however, it underwent a rather insensitive general reconstruction, during which the concrete bridge approach was removed and the nine-metre deck was widened. Only the arc of the original bridge was preserved.
OM
Investor
Czechoslovak State