Dmitry M. Zhemchugov-Gitman
postgraduate student. Emperor Alexander I. St.
Petersburg State Transport University (PGUPS). St. Petersburg, Russian Federation
Publications
On the question of setting the level of calculated impact and reliability of high-rise construction
Issue:
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The question of setting the seismic design input
on high rise buildings is considered. The existing approaches to accounting for
increased responsibility of high rise buildings in Russia are described. The
proposal to reduce the probability of an acceptable building failure in
proportion to the number of floors and Guideline proposals to increase the
reliability factor and using maps of general seismic zoning are analyzed. The
main disadvantages of methods described are indicated. It is shown that the current
regulatory documents in the field of earthquake engineering do not provide the
same reliability of designed structures in general and high-rise buildings in
particular. The influence of seismic dangers in according with seismic zoning
maps on the reliability of the designed objects is noted. An approach to
generating the design input based on the permissible probability of its
exceeding is considered using the example of five five-storey buildings and one
25-storey buildings. The probability of the admissible damage value included in
the normative calculations is estimated. An estimate of the allowable failure
probability on the value of acceptable damage (risk) is proposed under the
assumption of a normal distribution of damage caused by earthquake. It is shown
that the allowable failure probability decreases with decreasing acceptable
damage only in the area of small damages. An approach to the assignment of
seismic action based on an assessment of seismic risk has been formulated. The
system of design coefficients used to calculate seismic loads on high-rise
buildings is analyzed. It is noted that along with an increase in the design
level of seismic acceleration, it is necessary to increase the coefficient,
taking into account the low damping of high-rise buildings oscillations. At the
same time, it is possible to significantly reduce the reduction coefficient by
regulating the strains between the building floors.