Gaurav led the team of 3 members to design a 3 story office building for an earthquake. The team used ETABS. Gaurav performed Eigen value analysis to find the first three frequency modes. The team used 1940 El- Centro data to perform the linear time history analysis. Gaurav also created the lumped mass model of the building to perform gravity load analysis and analyzed it to see if its possible replacement to normal Eigen value analysis. Then Gaurav performed approximate analysis using Newark's average acceleration method in Excel to create a displacement response from 1940 El-Centro data and performed Eigen value analysis to find the base shear by using first mode data only. Then Gaurav performed the approximate analysis by adding roof mass to see its advantageous or not but increased base shear displays that its not and also the peak displacement of the roof is achieved quite late compared to without roof mass.
ETABS model of the building with seismic mass
Eigen Value Analysis Results displaying time period for all the modes
First Mode shape from Eigen value analysis
1940 El- Centro Data for Linear Time History Analysis
Linear Time History Acceleration Results
Linear Time History Roof displacement graph
Gaurav created lumped mass model and performed gravity analysis and thus Eigen value analysis to get the above mode shapes and got the time period as 0.9454 Hz which is quite close to fundamental frequency.
Gaurav performed approximate analysis using Newark's Average acceleration method in EXCEL and El centro's acceleration data to find this displacement graph and peak base shear as 13% of total building weight as expected.
Then Gaurav added a roof mass like roof garden to the approximate analysis calculation to get the above displacement graph and time of peak displacement is increased as it is shifted on x axis compared to previous graph and peak shear was increased to 18% of total building weight.
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