engleski

DYNAMIC ANALYSIS OF A MULTISTOREY STRUCTURE USING MULTIPLE DYNAMIC METHODS

After the March 2020 Zagreb and December 2020 Petrinja earthquakes, seismic engineering in Croatia was pushed into the spotlight. Even though earthquakes are well-known and documented in these parts, there are still a plethora of old buildings that don’t meet the required safety standards set after past earthquakes, and until March 2020, seismic action was an afterthought in the general public’s minds. Now, in this time of restoring, rebuilding, and looking into the future, it is important to review and possibly learn new ways of considering earthquakes – in order to accurately calculate them and model existing and new structures according to their possible influence. To this end, this paper aims to compare and review the four most known and most used methods of performing seismic calculations. Multiple static and dynamic calculations of a fictitious, but representative building model will be done, with special attention being brought to the dynamic calculations. The imaginary building is a steel frame 12 (13) storey structure with reinforced concrete plates and a reinforced concrete inner core. One steel frame will be taken from this building and calculated upon – this will be a centrally located frame with the largest loads applied to it. The frame will have some usual loads applied to it, so it represents a realistic structure. This structure is placed in Zagreb, Croatia. A modal analysis will be done to start, then a spectral seismic analysis, then the equivalent lateral force method analysis. After these, two non-linear analyses will be done - the pushover analysis and a non-linear time-history analysis. Every one of these will be preceded by a short introduction, and the main parameters observed will be the internal forces on the ground floor columns and the displacements of the upper-most stories. In the end, a comparison of the internal forces, maximum displacements, and sizing (unity checks) according to Eurocode standards for each analysis will be done. The following calculations are based on the conditions, rules and data obtained from the relevant Eurocode standards, complimented by US standards and guidelines.

Building dynamics, earthquake engineering, modal analysis, spectral analysis, equivalent lateral forces, pushover analysis, time-history analysis, sizing

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