Практичні методи ремонту мостів з використанням полегшеної монолітної плити

Abstract. Problem. Over 60% of bridges on Ukraine's public road network do not meet modern technical standards due to deterioration, outdated structural solutions, and lack of proper maintenance. During major repairs or reconstruction, current regulations require the installation of a monolithic reinforced concrete overlay slab. However, this leads to overloading of the superstructures and supports due to the significant increase in weight—especially when the roadway width must be increased or the road surface elevation raised. The search for effective solutions to reduce the weight of the structure while ensuring its strength and durability represents a pressing engineering challenge. The goal is to develop and implement a practical bridge reconstruction solution by designing an optimized lightweight monolithic reinforced concrete overlay slab that meets modern dimensional standards, accommodates increased roadway elevations, and minimizes structural weight. Methodology. An analysis of the existing bridge's technical condition was carried out. A design for a lightweight overlay slab was developed, incorporating a system of transverse and longitudinal ribs, void-formers made from extruded polystyrene foam, and plastic pipes embedded in the sidewalks. The economic feasibility of the proposed lightweight monolithic slab design was assessed by comparing the material volumes and weights of the lightweight and non-lightweight alternatives. Results. The implemented technical solution reduced the total weight of the overlay slab and sidewalks by 150,3 tonnes (38,8%) while simultaneously increasing the roadway width and structural height. Preliminary calculations indicate a 10–20% increase in the load-bearing capacity of the voided superstructure, enabling successful integration into the updated design configuration. Originality. An improved design for a lightweight monolithic overlay slab was proposed, utilizing void-formers to reduce the structural weight while increasing the slab's height and reinforcing it for enhanced performance. Practical value. The proposed lightweight slab technology ensures significant material savings, reduces the load on bridge supports and beams, and allows for the adaptation of aging bridges to modern operating conditions without the need for full demolition of the existing structures.