TECHNICAL CONDITION ANALYSIS OF PREFABRICATED REINFORCED CONCRETE BRIDGES ON ROADS OF LOCAL SIGNIFICANCE

Abstract

When constructing bridges over regulated rivers, mistakes were made and the then-existing construction norms were violated due to imperfections in the production of precast reinforced concrete structures, lack of construction experience, inadequate technological equipment and machinery, and insufficient quality control during construction. Over time, the condition of the precast concrete bridges deteriorates, reducing their reliability and safety. They may fail to meet project requirements and essential requirements stipulated in construction law, the most important of which are mechanical resistance and stability. The article examines the condition of precast reinforced concrete hydraulic bridges located on local significance roads in the Kaunas district. After analyzing 15 hydraulic bridges on local significance roads, the main bridge defects and defects were identified, and deformation sizes were measured. The article analyzes surface defects of precast reinforced concrete bridges such as construction defects - construction corners, edges, exposed reinforcement, concrete spalling, longitudinal cracks in decking slabs, and more. It was found that poor condition of precast hydraulic bridges is due to poor bridge deck waterproofing, open porosity, high water absorption, use of low frost-resistant concrete, inadequate thickness of concrete cover protecting reinforcement, concrete carbonation and reinforcement corrosion, deformation of slope fixation plates, increased loads due to heavy agricultural machinery use resulting in sagging of decking slabs and tilting of column supports due to pressure from the soil behind them. It was also found that bridge maintenance is very poorly performed, as the slope fixation plates are overgrown with grass and spontaneous vegetation. The article presents the results of selected concrete specimen density and water absorption tests.

Research methods used: desktop studies, visual - instrumental method for evaluating bridge condition, photographic documentation, determination of concrete strength by non-destructive method, laboratory tests.