Problems of Engineering Seismology: article

Аnnotation: The paper notes that the increase of peak acceleration of about 1.4 times proposed by seismologists in the project of seismic intensity scale reflects the undoubtedly experience of past earthquakes. However, using the suggested values of accelerations in the design codes requires modification of the codes themselves, and a differentiated approach to defining the design level of peak ground accelerations. Engineers should consider the dependence of the design peak accelerations on the oscillation period of the structure, and seismologists should differentiat the value of peak ground accelerations depending on the prevailing period of seismic input. It is noted that for the design and maximum design earthquakes the transition to a new seismic scale leads to completely different consequences. The seismic intensity of the design earthquake for mass construction objects does not exceed 7 degrees on the MSK scale, and in this area the new seismic scale differs little from the existing one. For maximum design earthquakes, peak accelerations increase substantially, but the criterion of seismic resistance is not the acceleration of the structure, but the work of plastic deformation forces. The possibility of structure destruction depends not so much on peak accelerations as on the energy characteristics of seismic input, such as Arias intensity, absolute cumulative velocity, seismic energy density. With a correct approach to calculation for performance based designing, the transition to a new scale of points will not lead to a rise in the cost of most buildings and structures. Moreover, without the use of a new scale, a transition to modern methods of performance based designing is impossible.