Impact of Adjacent Non-Symmetric Multistory Buildings as a Seismic Response


Abstract eng:
The common situation in towns is existence of so-called "continuous buildings" where buildings are virtually connected, usually on both lateral sides, even though the lateral walls for two buildings are not the same. If the two adjacent buildings were built strictly according to technical building codes, with the appropriate separation gap, their impact would have never happened - they would oscillate during earthquakes independently from each other. However, it is not easy to implement sufficient separation gaps in each case. Hence, in reality, the main aspect of seismic response of two adjacent multistory buildings is their possible impact due to an earthquake. Adjacent buildings, if constructed in accordance with the building codes, in event of an earthquake will oscillate independently. However, if their relevant dynamic characteristics are substantially different and if the separation gap between them is insufficient, the pounding between adjacent floor slabs at the same level is to be expected. The final result of collision between buildings may be a substantial damage, or even worse, their collapse. The paper is analyzing a possible pounding of adjacent multistory buildings with the same story heights due to the same earthquake excitation with a given dominant direction. Buildings are treated as non-symmetric with respect to their stiffness and/or mass characteristics, so the mathematical model is three-dimensional, i.e. each floor slab is undergoing the planar motion in its plane with three DOFs each. Possible impact of buildings is analyzed by combination of a direct numerical integration of the corresponding differential equations of motion and the classical analysis of an impact of two rigid bodies in planar motion. In the case of pounding between adjacent slabs the sudden change in kinematic state immediately before and after the collision is determined by solution of the corresponding collision equations. Formulation of the impact equations is based upon the usual assumptions of the impact theory in classical mechanics, with introduction of the coefficient of impact to account the local dissipation of energy in the zone of collision. Numerical procedure is illustrated by numerical examples. Both cases were considered: the first one when the separation gap is sufficient, so the buildings are oscillating independently and the second one when the separation gap is insufficient, so the pounding between buildings is occurring during the earthquake. The corresponding computer program is developed in order to perform numerical simulations. Besides determination of the time history of adjacent multistory non-symmetric buildings due to earthquake acceleration with a given dominant direction, including the analysis of the possible pounding, the code may also have the practical application to determine the necessary dilatation gap between buildings in order to prevent the pounding for a given earthquake.

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 4254.:
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