The article analyzes the natural conditions of the Northern latitudes of Russia, where the main reserves of fossil hydrocarbons and metals are concentrated. It is shown that mining requires the development of the road network and artificial structures on the roads. It is noted that the most difficult stage in the construction of bridge structures is the construction of foundations. The types used in the Northern latitudes of foundations are considered, and their positive and negative qualities, such as weight, method of construction and volume of earthworks, are noted. The paper emphasizes the relevance of the problem of maintaining the stability of permafrost soils in seasonal thawing and loss of their bearing capacity. Methods of maintaining the soil in a solid state can be natural and artificial. The methods of thermal stabilization of soils, as well as machinery and equipment used in these conditions.
Keywords: permafrost, road network, bridge, polystyrene, superstructure, pile support, Foundation, thermal insulation screen, heat stabilizer
This article is dedicated to one of the symbols of Volgograd city, which is the Astrakhanskiy Bridge. We described the history of creation and the technical specifications of the bridge over the Tsaritsa river. After conducting an investigation, some defects in the bridge construction were uncovered. The framework arcs have longitudinal cracks, the protective layer of concrete is destroyed; the longitudinal main reinforcement is exposed and corroded. The protective layer of concrete was removed and the longitudinal main reinforcement was corroded on the longitudinal beams. During operation of the bridge, the defects that decrease load capacity and durability appeared: destruction of the protective layer of concrete on a plate of about 2 square meters. This led to the beginning of corrosion of the lower reinforcement net. Steel brackets, holding the walkway slabs, are heavily corroded; the protective paint coating on them is destroyed over significant lengths. The analysis of detected damage allowed to evaluate their impact on the durability and load capacity of the construction and determine those, who are responsible for its occurrence. It is noted that postponing of repair operations has a negative impact on the state of the bridge.
Keywords: bridge, city symbol, superstructure, roadway plate, defects, arch, bridge system, bearing structures, durability, load capacity