PSI - Issue 64

Maciej Kulpa et al. / Procedia Structural Integrity 64 (2024) 1339–1346 Kulpa / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction The transport infrastructure in the city of Rzeszów, the main city of the subcarpathian Voivodeship in southern Poland, has recently undergone significant changes. Among other things, a network of bicycle paths was expanded connecting parts of the city on opposite sides of the Wisok River. It was not possible to design separate bicycle paths on existing bridges. Therefore, the city authorities decided to create three new bicycle passages near existing road bridges. One of such cases was the Narutowicz Bridge, whose superstructure consists of an arch with hangers arranged in a network system (Fig. 1). Steel arches, located within sidewalks (pedestrian zones), prevented the efficient and safe location of a bicycle path there. Therefore, efforts were made to use the existing, nearby steel structure that carries the heat pipelines, as a supporting structure of the new footbridge.

Fig. 1. The heat pipeline supporting structure before reconstruction next to the Narutowicz Bridge in Rzeszów

2. Adaptation of supporting structure 2.1. Existing supporting structure

The supporting structure of the pipeline, built around 1975, is a continuous beam bridge of three spans with span lengths of 22.75 + 30.03 + 23.43. The existing structure consists of two steel plate girders with the constant depth, braced at the level of the lower flanges with I cross-beams and X-arranged angles. In between the girders, two heat pipes are supported on the cross-beams. Steel grid panels are placed on the crossbeams as well and serve as working and technological platforms for the pipeline service. The steel superstructure is supported on two abutments embedded in the embankments and two piers in the form of round pillars located in the river bed. 2.2. Reconstruction and strengthening The purpose of the reconstruction is to adapt the existing supporting structure as a new footbridge for the newly designed bicycle crossing. For this purpose, it was planned to cover the existing twin girders with a deck slab, thus creating a walkway for pedestrian and bicycle purposes. Various solutions were considered, including a typical steel-