CONSISTENT 3D CHARACTERIZATION OF EARTHQUAKE SITE GROUND MOTIONS

• Main Author: Imanuel Maggang, Niakku
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42573
• Institution: Institut Teknologi Bandung

Indonesia needs earthquake resistant structures because they are located in earthquake prone areas. Generating earthquake resistant building structures is very dependent on the type of earthquake used as a dynamic load in its analysis. The use of earthquakes that have destructive characteristics will facilitate the dynamic analysis and produce a reliable structure. Until now there has not been found a single destructive character of the earthquake but destructive character according to the location of the earthquake. The destructive character of the earthquake is obtained by characterizing the earthquake ground motion. There are many methods for characterizing earthquake ground motion. In this study the characterization of earthquake ground motion was carried out on 31 strong earthquakes, namely earthquakes that had a scale of ? MMI 7. All of these earthquakes were reviewed in 3D, which involved three components of ground motion (major, minor, vertical) on a time-consistent at site. This characterization analyzes 18 destructive parameters of earthquake ground motion namely Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), Peak Ground Displacement (PGD), MMI, Arias Intensity (IA), Corner Period (Tc), A0Tc, Elapse, Duration , D05-95, Spectrum Intensity (SI), Seismic Energy Density (SED), Spectra Acceleration (Sa), Spectra Velocity (Sv), Spectra Displacement (Sd), Power Absorbtion per mass unit (Pa/m), Power Excitation per unit of mass (Px/m), Energy Input per unit of mass (Ein/m). Of the 18 parameters analyzed to find a single parameter that eventually became a destructive character of the earthquake. The single parameter chosen is the one that has the most strong correlation with these 18 parameters. A correlation between parameters is considered strong if it has a correlation value > 0,8. The values of the parameters were obtained from 93 earthquake ground motions and from the analysis of the Three DOF Lumped Mass structures with 24 different periods at T = 0,1 s; 0,2 s; 0,3 s; 0,4 s; 0,5 s; 0,6 s; 0,7 s; 0,8 s; 0,9 s; 1 s; 1,2 s; 1,4 s; 1,6 s; 1.8 s; 2 s; 2.2 s; 2,4 s; 2,6 s; 2.8 s; 3 s; 3,5 s; 4 s; 4,5 s; 5 s. The results of the analysis show that the parameter that has the most strong correlation is Sv which represents 31.37% of the earthquake ground motion parameters. With the low percentage value of representation, Sv cannot be a destructive character of an earthquake. To have 100% representation, it requires 10 parameters at once, namely Sv (31,37%), PGV (23.26%), D05-95 (16,67%), MMI (5,56%), IA (5,56%), Tc (5,56%), PGA (5,32%), PGD (4,86%), Ein/m (1,39%), Px/m (0,46%). The multi parameters above can be combined into a single parameter called Composite Parameter (Parameter C) using the Complete Quadratic Combination (CQC) method. The method uses parameter values iv and correlation coefficient values as calculation data. Combination to produce Parameter C can be performed on 18 parameters (Parameter C18), 10 parameters (Parameter C10), and 3 dominant parameters namely Sv, PGV, D05-95 (Parameter C3). The largest C18 parameter value is 65,57; The largest C10 parameter value is 32,59; The largest C3 parameter value is 6,81. The largest value of the three Parameters C was equally generated by the earthquake and in the same structural period, the Kobe earthquake at T = 1,2 s. To compare the three Parameters C above, based on the largest value of the three parameters the Spectrum Destructive Index (IDS) was made from the I-X scale. IDS can be plotted and compared for the three parameters where all three have a similar curve shape. Thus the destructive character of an earthquake can use Parameter C18 or Parameter C10 or Parameter C3. IDS Parameter C18 can be obtained by converting the value of Parameter C18 with an index conversion number of 0,1537. IDS Parameter C10 is obtained by converting the value of Parameter C10 with an index conversion number of 0,3069. IDS Parameter C3 can be obtained by converting the value of Parameter C3 with an index conversion number of 1,4674. Thus everyone can assess the destructive nature of the earthquake against the structure of the building by calculating the IDS of the earthquake through calculating Parameter C.