New Modular Construction Method for the Erection of Multi-span Concrete Bridges

Abstract

Recently a new construction method for thin-walled post-tensioned bridges was developed at the Institute of Structural Engineering (TU Wien). Innovative precast elements for the longitudinal girders and the deck slab were designed to keep up with the latest trend in resource- and time-efficient building. The semi-finished precast deck slab elements consist of thin plates stiffened by one to two cross-beams. In addition, upstands are arranged, which act as a formwork for the cast-in-place concrete. The precast deck slab elements can be placed on the completed longitudinal girders and span in the transverse direction. These girders are composed of several precast thin-walled hollow box segments, which are clamped together with post-tensioning cables at the construction site and span in the longitudinal direction. For the placement of the precast elements, either a launching gantry or cranes, when the topography allows, can be used. The combination of thin-walled hollow box segments, precast deck slab elements, cast-in-place concrete, and post-tensioning cables allows for the fast construction of multi-span concrete bridges. In the span range from 30 m to 60 m, this method will make the erection of one span per week possible, thus achieving the same construction speed as segmental bridge construction. Compared with segmental box girder bridges, the new construction method permits a reduction of construction materials and avoids transverse joints extending over the entire height of the cross-section. The first application of the new construction method took place in Austria in September 2022. The pilot project represents a railway bridge for the Austrian railway company “ÖBB-Infrastruktur AG”.