B61a Overhead bridge family with free-formwork
The design of the bridge family for the B 61a Pullendorfer Strasse near the Austro-Hungarian state boundary follows a spatially free-shaped geometry (free-formwork). No bridge can be described by classical cuts and axes. In the plan view, the deflector front edges are oblique as seen in the elevation and arcuate, corresponding to an obliquely intersecting tunnel. The abutment wing has an oval hole, which is perceived distorted by the oblique abutment in the plan view as well as the arch shape in the elevation when passing through. The diagonally arranged triangular poles have a strongly curved or flared formwork contour and pass continuously into the support plate. Consequently, the structure can not be classified into classic bridge categories.
Building Information Modeling
The free form of the bridges could only be implemented through the use of Building Information Modeling (BIM). Instead of working with static drawings, it was developed, planned and designed for the first time using a 3D printer on a three-dimensional model. At the same time, solutions were required for the selection of a suitable static calculation model, the detection of the forces that occur due to temperature and earth pressure or stress transitions due to non-linear effects such as creep, shrinkage or crack formation.
Photos © DI Martin Schwartz