CALCULATION OF THE DYNAMIC EFFECTS OF A MONOLITHIC OVERPASS TAKING INTO ACCOUNT THE POST-TENSIONING OF THE SPAN ROPE ON THE BASIS OF REAL EARTHQUAKE RECORDS

In order to improve the transport infrastructure of the Republic of Uzbekistan started to use monolithic structure of bridges and overpasses. The paper presents the calculation of a monolithic overpass 120 metres long, located in the area of 8 point seismicity according to MSK-64 in Jizzak over the high-speed railway line Tashkent-Samarkand (Republic of Uzbekistan). Numerical solution of the problem of earthquake resistance of the overpass determines the change of its stress-strain state in time. The results of calculation of monolithic bridge from dynamic loading on records of real accelerograms of Gazli (Uzbekistan) earthquake with intensity more than 9 points on MSK-64 scale are presented.  The results of calculations of normal stress variation in the upper and lower parts of the span along the length of the bridge have been analysed. The calculations show that the bridge span and supports have a safety margin for a 9-point earthquake. In order to ensure guaranteed seismic safety of bridge structures, it is necessary to carry out design calculations using sets of records of earthquakes that are close in dominant frequencies to the characteristics of the construction site.