Numerical simulation of seismically isolated buildings with friction pendulum bearings

Introduction. At present, in Tajikistan, buildings and structures are designed and constructed on the basis of passive methods of ensuring seismic resistance, which ultimately leads to an increase in stiffness and weight of structures and, accordingly, in seismic load. The present paper analyses seismic isolation of buildings provided by friction pendulum bearings. The dynamic model of the object under study is represented as a system consisting of a superstructure, substructure and seismic isolation.

Aim. To contribute to the development of methods for analysis and evaluation of seismic isolation and earthquake protection of buildings and structures in order to justify the conditions for their effective application in earthquake-resistant construction on the territory of the Republic of Tajikistan.

Materials and methods. The authors used methods of structural mechanics, structural dynamics, and numerical simulation. The research methodology involves mathematical modeling of the systems under consideration, numerical analysis, comparison of the obtained results with the available data. Experimental investigation was carried out on a building fragment model and a vibration platform.

Results. The authors developed a mathematical model for investigating the stress-strain state of a building with friction pendulum bearings subjected to various external influences, including seismic ones. The differential equation system using successive approximations is transformed into a system of algebraic equations, which is solved at each time step. On the basis of the created algorithm, the authors developed a computer program in Fortran and obtained the numerical results of the dynamic calculation for a multistory building with friction pendulum bearings. The results from the action of an instantaneous impulse are obtained on the example of a 10-story frame building.

Conclusions. The results show that the application of seismic isolation in the form of friction pendulum bearings leads to a significant reduction of internal forces in the support part, as well as to a reduction of velocity and acceleration in the upper part of the building compared to the model without seismic isolation bearings. At the same time, the deflections of both the lower and upper parts of the investigated object slightly increase.

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