PSI - Issue 70

Maheshwar Bose et al. / Procedia Structural Integrity 70 (2025) 137–144

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4.7 Time History Analysis It is an important method for seismic performance of the structure. It is also known as non-linear dynamic analysis. It is considered as the most accurate method of all the analysis methods. The model of L-shape building is subjected to the actual ground motions which represents the spectral accelerations. Here the ground motion data used is the Bhuj Earthquake data, 2001. The THA method is the step-by-step analysis of the dynamic response of the structure to a specified loading that may vary with time. The Fig. 4(b) represents the Plastic Hinge formation in Beams, Columns and Braces with the hinge location of hinges in Braces having relative to clear length of 0 and 1 on Beams, columns and Braces. Table 6: Description of Three earthquake ground motion data Ground Motions Station Year P.G.A Magnitude Whittier Narrows (FF) Canyon-County 1987 0.0929g 5.9 Imperial Valley El Centro 1979 0.258g 6.53 Bhuj Ahmedabad 2001 0.1099g 7.7

Fig.4. (a) Bhuj EQ ground motion data of acceleration, velocity and displacement (b) Plastic hinge formation of the Beams, Columns and Braces

5. Conclusion In this study, L-shaped six-story reinforced concrete (RC) buildings have been analysed with and without the steel bracings. A total of five structural models were developed in which first 3 models are L1, L2, L3 and rest Models are nothing but L3 but replaced with Eccentric bracing and V-Bracing formation. These models (L1, L3 and last two models are further processed under three approaches: Modal Analysis, RSA, and THA. The primary objective of this research is to evaluate the influence of bracing type and placement on the seismic performance of irregularly shaped RC buildings. The modelling and analysis were performed using ETABS software, focusing on key seismic response parameters which were shown in result case. The comparative analysis of RSA and THA results reveals several significant findings: • Among various bracing configurations, the L2 arrangement exhibits optimal performance characteristics in terms of enhanced story stiffness and reduced inter-story drift and drift ratios. • The introduction of steel bracing substantially increases the V B capacity of the structure. Eccentric bracings result in a 79% increase in base shear, V-bracings yield a 90% increase, and X-bracings show the highest improvement at 98%. The reason being X- Bracing forms good diagonal system and provides redundancy and these intersecting diagonal act like a truss.