COMPARATIVE STUDY OF PERFORMANCE BASED BEHAVIOUR OF MOMENT RESISTING FRAMES WITH STRUCTURAL SHEAR WALLS, CONCENTRIC BRACED FRAMES & BUCKLE RESISTING BRACED FRAMES

© 2020 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 123 COMPARATIVE STUDY OF PERFORMANCE BASED BEHAVIOUR OF MOMENT RESISTING FRAMES WITH STRUCTURAL SHEAR WALLS, CONCENTRIC BRACED FRAMES & BUCKLE RESISTING BRACED FRAMES


INTRODUCTION
A static non-linear analysis i.e. pushover analysis, is performed in the analytical investigation. The investigation is performed by developing three different models in ETABS-2017 software. First model consists of building with ductile reinforced concrete structural walls. Second model consist of building with special braced frames having concentric braces, these concentric braces are modeled as X-braces. Third model consist of buckle resisting braced frames, these braces are modeled as single inclined braces. Since the Indian Standard Codes do not address the BRBF system and also the performance-based analysis of the structure, we will be proceeding with the procedure prescribed in ASCE 41-13. Evaluation of the performance needs to be described in terms of reliability of the structural system against various limit states over a given period of time. In view of the large uncertainties in both demand and capacity, the performance of the structural systems can be described meaningfully only when these uncertainties are taken into consideration explicitly.

METODOLOGY
• Modeling the separate models for SSW, CBF and BRBF of a concrete building with their respective analytical system. • Introducing a static nonlinear case to investigate a performance-based behavior in the above defined system. • Analyzing the models and evaluating the study.

MODELLING AND ANALYSIS
The structure consists of G+10+T floors, the usage of the structure is for the residential use with 48meters height. In the first model structural shear walls are modelled, in the second model steel box section is used for the bracing and in the third model star seismic buckle resisting braced frames properties were imported in the model and these were assigned to the bracing members for the analysis of concrete structure. Although all the three models are similar in its properties and parameters in model but they differ by using the SSW, CBF & BRBF system.

RESULT AND CONCLUSION
The evaluation of the analysis based on the parameters such as target displacement, inter-story drift, pushover curve and life expectancy level are as follows with a comparison of the results and discussion.

TARGET DISPLACEMENT
The target displacement is evaluated from different analysis carried out on moment resisting frame with SSW, CBF & BRBF. The peak target displacement at top level is enlisted in table no. 5.1.1. From figure no. 5.1.1, it is evaluated that moment resisting frame with SSW have maximum target displacement between CBF & BRBF and target displacement between CBF & BRBF analysis has come out to be same.

STORY DRIFT
The story drift is evaluated from different analysis carried out on moment resisting frame with SSW, CBF & BRBF. The results are evaluated story wise which are enlisted in in table 5.2.1. From figure 5.2.1, it is evaluated that moment resisting frame with SSW have maximum story drift as compared with CBF & BRBF and from ground floor level to 6 floor level story drift exist more in CBF than BRBF system and above it goes inverse.

HINGES FORMED IN THE LIFE EXPECTANCY LEVEL
A plot is drawn to know about the hinges formed in the life expectancy level in various steps defined in the analysis. From figure 5.3.1 to 5.3.6, it is evaluated that maximum number of hinges lies in the immediate occupancy level in all the three systems. As number of steps increased in the analysis states of hinges starts changing to the higher states. Moment resisting frame with SSW have maximum number of hinges in life safety level than CBF & BRBF system. Maximum number of hinges beyond the collapse prevention level is formed in the BRBF system and least number of hinges beyond the collapse prevention level is formed in the SSW system.       1  7  13  19  25  31  37  43  49  55  61  67  73  79  85  91  97  103  109  115  121  127  133  139  145  151  157  163  169  175  181  187  193 Chart Title A-IO IO-LS LS-CP >CP The smoothness of the curve shows the accuracy of modelling and analysis. In SSW system the curve seems to be heading constantly upward with the increasing in the base shear & displacement values till its reached the collapse point though in this system the collapse point didn't formed. In CBF system the curve is also observed to be smooth but at the later stages the downward kink is observed in the curve that downward kink is the collapse point in the analysis. In BRBF system the curve is also observed to be smooth and we also have a collapse point in the analysis.

CONCLUSION
This paper proposes the study to obtain a structural system which is more efficient, reliable and strong in its nature and strength. For this purpose, the investigation is carried out for 3 different structural system i.e. moment resisting frame with SSW, CBF & BRBF. The sizes of the members and loads on the building are kept same in all the systems. The conclusion on the evaluated results for the parameters such as target displacement, inter story drift, pushover curve and life expectancy level.
The maximum target displacement and story drift is obtained in the SSW system as compared with CBF & BRBF system but the maximum number of hinges formed beyond the collapse prevention level is formed in BRBF system although we also encountered a collapse point in CBF & BRBF system. From the investigation it can be concluded that moment resisting frame with SSW system is more efficient, reliable and strong in its nature and strength as compared with CBF & BRBF system.

SOURCES OF FUNDING
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.