COMPARISON OF THE EFFICIENCY OF RECONSTRUCTION METHODS OF STEEL-CONCRET SINGLE-SPAN BRIDGES

Abstract

The paper contains developed the method of strengthening steel-reinforced concrete single-span bridge structures that have undergone wear and tear due to long-term operation and require expansion. Have been described the structural solution and the principle of operation under load of the existing typical steel-reinforced concrete single-span bridges. As an example have been considered real emergency bridge structure in the village of Dashiv of the Haysyn district of the Vinnytsia region, in need of urgent reconstruction. Have been described in detail its main structural elements and technical condition. Have been shown possible rational ways of expanding and strengthening the structure in two variants. Variant 1 – reinforcement of existing steel and reinforced concrete structures with partial blocking of road traffic. Variant 2 – replacement of the span structure with a complete shutdown of the bridge for the duration of the construction and installation works. Have been developed basic constructive schemes for the reconstruction of the structure for the first and second variants. Have been described the technological sequence of strengthening the bridge structure according to both mentioned methods, have been analyzed the advantages and disadvantages and have been estimated the cost indicators of the reconstruction of each of the proposed variants. Have been proven that the strengthening method (variant 1) is more appropriate if it is necessary to partially operate the structure during construction and installation works. This method makes it possible to restore the design load-bearing capacity of the bridge structure with the provision of modern dimensional requirements and traffic safety requirements for less cost. The method of complete replacement of the span structure (variant 2), despite the higher cost, should be preferred in all other cases according to dynamics of constant growth of traffic flow in our country. With variant 2, it is possible to achieve not only the required dimensions, but also higher load-bearing characteristics of the bridge structure in a shorter period of time. The reliability and efficiency of each of the methods is confirmed by the corresponding strength calculations.