Parasiya et al., International Journal of Advanced Engineering Research and Studies E-ISSN

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1 Review Article A REVIEW ON COMPARATIVE ANALYSIS OF BRACE FRAME WITH CONVENTIONAL LATERAL LOAD RESISTING FRAME IN RC STRUCTURE USING SOFTWARE Ashik S. Parasiya 1 Paresh Nimodiya 2 Address for Correspondence 1 PG student, Civil Engineering Department, Veerayatan Group Of Institution Faculty Of Engineering And Faculty Of Management, Jakhaniya, Kutch, Gujarat, India 2 Assistant Professor, Applied Mechanics Department, Vishwakarma Government Engineering College, ABSTRACT: Chandkheda, Ahmedabad, Gujarat, India In General, the structure in high seismic areas may be susceptible to the severe damage. Along with gravity load structure has to withstand to lateral load which can develop high stresses. Now a day, shear wall in R.C. structure and steel bracings in steel structure are most popular system to resist lateral load due to earthquake, wind, blast etc. The shear wall is one of the best lateral load resisting systems which is widely used in construction world but use of bracing will be the viable solution for enhancing earthquake resistance. So there is a need of precise and exact modeling and analysis using software to interpret relation between brace frame parameters and structural behavior with respect to conventional lateral load resisting frame. There are various softwares used for analysis of different type of lateral load resisting system such as, E-TABS, SAP2000, STADPRO, etc. In this paper, a few of the past research work has been discussed for modeling and analysis of brace frame RC structure and conventional lateral load resisting frame structures, co-relation of efficiency and various parameters are compared. It is found from the analysis in software, The type of bracing, location of bracing, bracing stiffness and bracing material, etc. have significant effects to the lateral capacity of the structure. In this paper comparative study of RC brace frame structure with conventional lateral load resisting frame has been carried out with different type of bracing, various parameters of bracing and property of bracing by different researchers discussed. KEY WORD: RC frame, braced frame, lateral load resisting frame, nonlinear dynamic analysis, response spectrum analysis lateral displacement, storey shear, storey drift, Base shears, etc. INTRODUCTION The primary purpose of all kinds of structural systems used in the building type of structures is to transfer gravity loads effectively. The most common loads resulting from the effect of gravity are dead load, live load and snow load. Besides these vertical loads, buildings are also subjected to lateral loads caused by wind, blasting or earthquake. Lateral loads can develop high stresses, produce sway movement or cause vibration. Therefore, it is very important for the structure to have sufficient strength against vertical loads together with adequate stiffness to resist lateral forces. Most RC buildings with shear walls also have columns; these columns primarily carry gravity loads (i.e., those due to self-weight and contents of building). Shear walls provide large strength and stiffness to buildings in the direction of their orientation, which significantly reduces lateral sway of the building and thereby reduces damage to structure and its contents. Since shear walls carry large horizontal earthquake forces, the overturning effects on them are large. There are two types of bracing systems, Concentric Bracing System and Eccentric Bracing System. The braces are usually placed in vertically aligned spans. This system allows obtaining a great increase of stiffness with a minimal added weight, and so it is very effective for existing structure for which the poor lateral stiffness is the main problem. The concentric bracings increase the lateral stiffness of the frame, thus increasing the natural frequency and also usually decreasing the lateral drift. However, increase in the stiffness may attract a larger inertia force due to earthquake. Further, while the bracings decrease the bending moments and shear forces in columns, they increase the axial compression in the columns to which they are connected. Since reinforced concrete columns are strong in compression, it may not pose a problem to retrofit in RC frame using concentric bracings. HIERARCHY The previous study devoted to evaluate, using nonlinear dynamic analyses, the seismic behavior of reinforced concrete moment resisting chevron braced framed buildings (RC-MRCBFs) (E. A. Godínez-

2 Domínguez et. al. 2010, Ugur Akpinar 2010). The behavior of Special Concentrically Braced Frame (SCBF) systems have been compared with Eccentric Braced Frame (EBF) for different stories buildings (Mohsen Tehranizade et. al.). The study is also carried out on R.C.C. building in different Parts I) Model without bracing and shear wall II) Model with different shear wall system III) Model with Different bracing system(m.d. Kevadkar et. al. 2013, Mrugesh D. Shah 2011). Also the seismic performance of reinforced concrete buildings using concentric steel bracing is investigated (Nabin Raj.C et. al. 2012). The study of, seismic propensity of knee braced frames as weigh against concentric braced frames was investigated (Mohammad Eyni Kangavar 2012). REVIEW OF LITERATURE Following are the parameters that mostly affect in the analysis of brace frame RC structure, such as type of bracing, material of bracing, stiffness of bracing, etc. Mohsen Tehranizade et. al. concluded that increase in no of story, EBF frames with moment link-beams under near-field strong motions represent large inter story drifts and large roof displacements. The hysteric energy to input energy ratio is more in EBFs than the SCBF systems. The difference of this ratio for EBFs (Eccentric braced frame) and SCBFs (Special concentric braced frame) reduced by increasing in PGA values. The maximum base shear is increasing in SCBF systems with increase in braced spans and reduced in order in SCBF systems with decreasing braced spans. By increasing the PGAs the maximum base shear increases too. The shear link-beam EBF systems have less drifts than moment link-beam EBF systems, therefore the probability to form the flexible story in moment link-beam EBFs is more. Increasing in number of braced spans controlled lateral displacements in upper stories more than bottom stories. A.A Adedeji et. al. (2011) concluded that the displacement of the frame has been drastically reduced by a concentric application of shape memory alloy wires in reinforced concrete frame seismic prone areas. Fig. 1 Displacement-time graph at first floor (A.A Adedeji et. al. (2011)) Fig 2 Displacement-time graph at roof (A.A Adedeji et. al. (2011))

3 Under time history analysis method, the maximum top story displacement exhibited by the reinforced concrete frame with the straw bale infill has significant effect. The computed force-deformation response can be used to assess the overall structural damage of a structure with the composition shape memory alloy braces. Figure-4 Performance Point of Bare frame model (Push Y) (M.D. Kevadkar et. al. (2013)) Fig-3 Comparison of all frames under time history analysis (A.A Adedeji et. al. (2011)) Ugur Akpinar (2010) concluded that infill wall effect should be included to have a better estimation of seismic behavior. So, for design purposes neglecting infill walls would not always lead safe design or assessment results. Braced frame results showed that buckling of braces has significant importance on performance of this retrofitting method. After buckling occurs, lateral load capacity of the system may drop dramatically. Performance limit states determined by deficient RC members and they found to be nearly independent from brace slenderness whereas dependent from axial load on columns. Time history analysis showed that including correct boundary conditions can dramatically affect the response of these systems. According to the analysis results, keeping system under low deformations can lead RC members to take any significant damage. However, high axial forces can be transferred from upper story braces to first story columns due to overturning effects. That may increase damages on the first story columns. ISF (internal steel frame) could be improved by using alternative boundary conditions and results could be matched better in terms of loading stiffness and cyclic behavior. M.D. Kevadkar et. al. (2013) concluded that (1) The concept of using steel bracing is one of the advantageous concepts which can be used to strengthen structure 2) Steel bracings reduce flexure and shear demands on beams and columns and transfer the lateral load through axial load mechanism. 3) The lateral displacement of the building is reduced by use of shear wall and steel bracing system. Figure-5 Performance Point of shear wall model (Push Y) (M.D. Kevadkar et. al. (2013) Figure-6 Performance Point of Steel Bracing (Push Y) (M.D. Kevadkar et. al. (2013)) (4) Storey drift is controlled by use of the Shear wall and steel brace. 5) Steel bracings can be used as an alternative to the other strengthening techniques available as the total weight of structure changes significantly. 6) Shear wall has more storey shear as compare to steel bracing but there is a difference in lateral displacement between shear wall and steel bracing. 7) Shear wall and steel bracing increases the level of safety since the demand curve intersect near

4 the elastic domain. 8) Capacity of the steel braced structure is more as compare to the shear wall structure. 9) Steel bracing has more margin of safety against collapse as compare with shear wall. Nabin Raj.C et. al. (2012) concluded that the bracing in bare frame increases the overall stiffness of the structure. The lateral displacement in bare frame is more in comparison to the frame with bracings.the bracings prevent the excessive damage in non structural elements. Significant reduction in moment in case of frame with bracings in comparison to bare frame. Significant reduction in reinforcement demand by the frame members other than the one associated with bracings. The performance of frame with bracings is better and within the limit. Maximum inter story drift for frame without bracings is in storey just above the GF. For frame with bracings maximum ISD is found at height nearly to one third height of the building.deflection pattern is of flexure shape at lower heights in which rate of deflection increase and follows the shear configuration in upper heights. E. Salajegheh et. al. (2008) concluded that performance-based criteria could be implemented not only for retrofitting existing structures but also for design of new buildings. It is shown by this study that the developed program Snap GA is capable of motivating the decision maker to choose the best design from a wide range of valid alternatives with regards to any performance objective. capacity increases but with the increase in bays corresponding displacement is not increases. Fig-8 Force V/s Deformation curve (Mrugesh D. Shah (2011)) Also conclude that as the no of storey increases lateral load carrying capacity does not increase but corresponding displacement increases. Mohammad Eyni Kangavar (2012) concluded that the seismic performances of without braced frames are weak. The strength capacity of reinforced concrete frames can be enhanced to a desired level using either concentric bracing or knee bracing. Figure-9 Hysteretic Behavior of Concentric Braced Frame (1-Storey) (Mohammad Eyni Kangavar (2012)) Figure-7 Configuration of model structure (E. Salajegheh et. al. (2008)) Mrugesh D. Shah (2011) concluded from the results that the bare frame without infill having lesser lateral load capacity (Performance point value) compare to bare frame with infill as membrane and bare frame with infill having lesser lateral load capacity compare to bar frame with equivalent strut. Also conclude that as the no of bays increases lateral load carrying Figure-10 Hysteretic Behavior of Knee Braced Frame (1-Storey) (Mohammad Eyni Kangavar (2012)) The ductility is highest for a frame without brace. While in the Concentric Braced Frame and Knee Braced Frame, stiffness is highest among other properties. Stiffness is higher in Concentric Braced Frame compare to the Knee Braced Frame. Ductility

5 is higher in the Knee Braced Frame compared to the Concentric Braced Frame. Energy absorption is highest in the Knee Braced Frame. Both concentric bracing and knee bracing systems can be employed to increase the yield capacity of a reinforced concrete frame. Substantial increases may be obtained using concentric bracing. The global displacements of a reinforced concrete frame can be reduced to a desired level by providing either a concentric or a knee steel bracing system. Both concentric bracing and knee bracing systems may be utilized to design or retrofit for a damagelevel earthquake. Concentric bracing is more suitable for a strength-based design. Knee bracing, on the other hand, is suitable for both the strength-based and ductility-based designs. Nitendra G Mahajan et. al. (2011) concluded that dampers are more significant to reduce seismic quantities with same direction of placement as brace. Dampers placed in the upper levels had little to no effect on the structural response. There were significant reductions in deflection and acceleration response under all earthquake records. The results showed that there was a correlation between the amount of rigidity cut out of the system and the stiffness and damping coefficients of the damper replacing this. Figure-11 Base Shear v/s Time of Koyna Earthquake 22 Story. (Nitendra G Mahajan et. al. (2011)) The investigations showed that significant reduction in structure acceleration, deformation and Base shear can be achieved by strategically placing the dampers within the periphery of structure. Figure-12 Base Shear v/s Time of El Centro Earthquake for 22 Story. (Nitendra G Mahajan et. al. (2011)) CONCLUSION bracing system, stiffness of different kind of bracing, Right now, whatever work has been done with bracing properties, etc. If the bracing system is respect to seismic dynamic response, covers effects incorporated for resisting a lateral load it serves of brace frame, effect of shear wall, types of bracing better than conventional lateral load resisting system system as lateral load resisting system, material of when dynamic loads are acting to the structure.

6 Bracing system also increases the stiffness and ductility of the structure on the application of the seismic force. Bracing system is good practice of retrofitting scheme for high rise RCC structure to strengthen against the seismic exication. So it can be said that bracing system is good practice for implementation in high rise RCC structure for controlling and reducing the damage in RCC structure during dynamic loading by increasing the lateral load resisting capacity of the structure due to strengthening characteristic. REFERENCE Mohsen Tehranizade et. al. Comparative Study On Seismic Behavior Of Special Concentric Braced Frames With Eccentric Braced Frames A.A Adedeji et. al. (2011) Comparative Study Of Seismic Analysis For Reinforced Concrete Frame Infill With Masonry and Shape Memory Alloy Wires, Trends in Applied Sciences Research 6(5): , 20, ISSN /DOI: /tasr Ugur Akpinar (2010), Nonlinear Analysis Of RC Frames Retrofitted With Structural Steel Element M.D. Kevadkar et. al. (2013), Lateral Load Analysis of R.C.C. Building, International Journal of Modern Engineering Research (IJMER), Vol.3, Issue.3, May- June pp ISSN: Nabin Raj.C et. al. (2012), Analytical Study on Seismic Performance of Hybrid (DUAL) Structural System Subjected To Earthquake, International Journal of Modern Engineering Research (IJMER), Vol.2, Issue.4, July-Aug pp ISSN: E. Salajegheh et. al. (2008), Optimum Performance Based Design of Concentric Steel Braced Frames, World Conference on Earthquake Engineering. Mrugesh D. Shah (2011), Performance Based Analysis Of R.C.C. Frames, National Conference on Recent Trends in Engineering & Technology. Mohammad Eyni Kangavar (2012), Seismic Propensity of Knee Braced Frame (KBF) As Weighed Against Concentric Braced Frame (CBF) Utilizing ETABS and OPENSEES, International Journal of Engineering and Advanced Technology (IJEAT), ISSN: , Volume-5 (2012). Nitendra G Mahajan et. al. (2011), Seismic Response Control Of A Building Installed With Passive Dampers, International Journal of Advanced Engineering Technology, E-ISSN