The effect of a seismic wave on a two-span beam on rigid supports interacting with the ground

The transverse vibrations of a two-span beam bridge, the shore supports of which interact with the surrounding soil during seismic action, are considered. The condition is accepted that the deformations of structures do not go beyond the limits of elasticity and vibrations are linear in nature. The bridge supports are assumed to be submerged in the ground and interacting with a rigid body under the action of non-stationary dynamic influences. The case is considered when the left, middle and right supports have equal masses and interact with the surrounding soil in the same way. The symmetry condition is applied, and it is sufficient to consider the equation of the right half of the beam. The problems are solved by the analytical Fourier method under the given boundary conditions. The results obtained are presented in the form of stress distribution over time and length of bridge structures, and their analysis is also presented

Underground polymeric l-shaped pipeline vibrations under seismic effect

The simultaneous equations of longitudinal and transverse vibrations of an underground polymeric L-shaped pipeline under the arbitrary direction of seismic load were derived in the paper. A computational scheme of the problem was constructed using central finite-difference relations. The analysis of the results obtained on the simultaneous longitudinal and transverse vibrations of underground polymeric L-shaped pipelines under seismic loading was conducted. The stress-strain state of the L-shaped polymeric pipeline subjected to seismic effect was determined, and the axial forces and bending moments arising in curved pipelines during an earthquake were determined

Study of the seismodynamics of spatially located underground pipelines with a nodal connection of non-orthogonal configuration

The article deals with the seismodynamics of underground pipelines of various configurations under spatial seismic influences. The stress-strain state of spatially located underground pipelines of complex orthogonal configuration at different angles of seismic load incidence was determined. Several problems were solved by analyzing numerical results of the seismodynamics of underground pipelines of complex orthogonal and non-orthogonal configurations

Assessment of possible damages of residential buildings in the Fergana Valley of Uzbekistan

The Fergana Valley is the most densely populated cross-border region of Central Asia; it is located in three states - Uzbekistan, Tajikistan, and Kyrgyzstan. The seismicity of this region suggests possible earthquakes up to 9-intensity degrees by the MSK macroseismic intensity scale (further “Scale”). About 10 million people live in the Uzbek part of the valley. A significant part of the population lives in residential dwellings built in the traditional style. Legislative measures nowadays do not include an obligation of individual developers to comply with the aseismic norms. It has an advisory character only. So, assessment of possible damages after different intensity seismic events is vital for measures developed by local authority and other responsible institutions. Based on data on the design features of individually built housing, predictive estimates of damage in the event of strong earthquakes are provided in this issue

Underground polymeric l-shaped pipeline vibrations under seismic effect

The simultaneous equations of longitudinal and transverse vibrations of an underground polymeric L-shaped pipeline under the arbitrary direction of seismic load were derived in the paper. A computational scheme of the problem was constructed using central finite-difference relations. The analysis of the results obtained on the simultaneous longitudinal and transverse vibrations of underground polymeric L-shaped pipelines under seismic loading was conducted. The stress-strain state of the L-shaped polymeric pipeline subjected to seismic effect was determined, and the axial forces and bending moments arising in curved pipelines during an earthquake were determined

Long-term monitoring of earth dam of the Charvak hydroelectric power plant (HPP) considering the water level of the reservoir

A numerical method for determining the settlement and stress-strain state (SSS) of high earth dam of the Charvak hydroelectric power plant is developed based on the finite element method (FEM). The results were compared with the available data from long-term field observations and with records of continuous geodetic monitoring of the dam behavior based on processed space radar images obtained from the Sentinel-1 satellite. To conduct calculations, OJSC Gidroproekt of the Republic of Uzbekistan provided the structural and piecewise non-homogeneous physical and mechanical characteristics of soil of the structure body. The results of calculations of vertical displacements, normal stresses, and pore pressure were compared with field observation data for the section in which the corresponding control and measuring equipment was installed. A cause-and-effect relationship was identified between the water level in the reservoir and the deformation of the dam. The difference between the theoretical results obtained and field observations was up to 10%. A comparison of the results obtained using the finite element analysis calculations (taking into account the level of water filling in the reservoir) with the actually measured deformations of the dam during the filling of the reservoir, and with processed space monitoring data depending on the time of year, showed a good agreement between the measured and calculated displacements

Study of the seismodynamics of spatially located underground pipelines with a nodal connection of non-orthogonal configuration

The article deals with the seismodynamics of underground pipelines of various configurations under spatial seismic influences. The stress-strain state of spatially located underground pipelines of complex orthogonal configuration at different angles of seismic load incidence was determined. Several problems were solved by analyzing numerical results of the seismodynamics of underground pipelines of complex orthogonal and non-orthogonal configurations

Seismic stress state of a high earth dam using the spectroscopic method

The reliable and safe operation of earth dams located in seismic regions of the Republic of Uzbekistan requires engineers and researchers to constantly improve the design normative methods for their calculation in order to identify safety margins and stability under various types of loads. A method is proposed for calculating the seismic stress state of an earth dam (on the example of the Pskem HPP being designed), based on the spectral method, in accordance with the current standards for the design of hydro-technical structures in seismic areas. Structural and piecewise non-homogeneous physical and mechanical characteristics of soils of the structure body were provided by Hydroproject JSC of the Republic of Uzbekistan. The results of the calculations show that under a horizontal seismic impact, the dam performs transverse oscillations. It was determined that the maximum vertical stresses are observed in the lower part of the upper slope, where the maximum hydrostatic pressure is reached. The maximum shear stresses appear at the base of the dam and on the surface of the downstream slope, where the risk of loss of strength under shear is greater.