Estimation of Rheological Effects in Cantilever Concrete Bridges on the Basis of a Span's Deflection Line

Abstract

A characteristic feature of bridges as large span objects made using cantilever concreting technology are their excessive deflections, which are a result of rheological processes in concrete and pre-stressing steel. These deflections can be caused by the destruction of the material, e.g., concrete cracking, as well as the changing of the static scheme of the bridge structure, such as the subsidence of supports. The purpose of the work is to determine internal forces based on the deformation of a span. An algorithm for the correction of the deflection function, which is determined from geodetic measurements with a low accuracy, was proposed. It is characterized by a marked improvement in the results of calculations and, to a small extent, leads to the smoothing of the original measurement results. The algorithm is adapted to the analysis of a selected fragment of the structure, e.g., spans with the largest length and can be useful for monitoring bridge structures.

Sensory monitoring system of the post‐tensioned concrete bridge over the Odra River in Poland

“…The bridge consists of five spans with lengths of: 53.82 m + 75.00 m + 140.00 m + 75.00 m + 53.82 m. The spans of the bridge were constructed by means of cantilever method. At the time of opening for traffic in 2010, the bridge had the longest span in Poland (140 m) built using this method [11], [12]. The shape and basic dimensions of the structure are shown in Fig.…”

“…Due to the skew location of the bearings (Fig. 3), the construction of spans using the cantilever concreting method required the use of a specific support scheme for starting segments located above the current supports [11], [12]. The skew system of bearings and the applied technology of their construction results in the presence of significant torsional moments in the span structure.…”

“…Changes in the geometry of the bridge spans are mainly determined by rheological phenomena occurring in the concrete of the span structure (e.g. [12]), but also -to a lesser extent -by progressive damage to the concrete.…”

“…Example of the last situation described above is presented in this paper [11], [12]. The article presents implementation of a pilot monitoring system of the prestressed concrete bridge requiring deepened, continuous diagnostics due to poor technical condition (significant cracks and growing deformations of the superstructure).…”