Incremental Dynamic Analysis of RC Frames
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This document presents an incremental dynamic analysis of reinforced concrete buildings with 7 and 11 stories. IDA involves applying earthquake ground motions of increasing intensity to structural models until collapse. The 7-story building was found to yield at 0.29g and collapse at 0.37g, while the 11-story building yielded at 0.61g and collapsed at 0.73g. The analysis was conducted using SeismoStruct to model the buildings and evaluate response parameters like interstory drift ratio and base shear.
Incremental Dynamic Analysis of RC Frames
- 1. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 697 INCREMENTAL DYNAMIC ANALYSIS OF RC FRAMES Vinod Tiwari1, Dr. Ashok Kasnale2 1PG Student, Department of Civil Engineering, Dr. D. Y. Patil School of Engineering & Technology, Pune-412105, India. 2Principal, Dr. D. Y. Patil School of Engineering & Technology Pune-412105 ,India. ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Structures subjected to force like earthquake must be resisted by structure as they are dynamic in nature. It causes unsafe condition. performance based analysis of structure is required. This can be achieved by incremental dynamic analysis(IDA) which can be done by SAP ( static pushover analysis) but in Incremental Dynamic analysis is more accurate .incremental dynamic analysis involves different intensity of ground motion which is selected for complete collapse. In present work increment dynamic analysis of reinforced concrete G+ 7 and G+ 11 building is carried out buildings susceptible ischeck, interstorydriftratio from IS 1893 : 2002 is checked. Basic baseshearcapacityof G+ 7 and G+ 11 are calculated base shear curve of top displacement is compared with SPA (static pushover analysis).pushover analysis is of two types Force control and displacement control. Force control in which lateral loads are applied in small increment. Distance by which structure is proportional to horizontal translation.This paper deals with the Incremental Dynamic analysis of G+7 and G+11building. Key Words: IDA; SAP; Earthquake analysis 1. INTRODUCTION IDA (Incremental Dynamic Analysis) is powerful mean to study the overall behaviour of structural earthquake of different intensity are applied on the model till the collapse. When slope of incremental dynamic analysis changes from linear to nonlinear yield is reached when incremental dynamic analysis curve become flat or slope less than 20% then we can say yield is reached. To start with incremental dynamic analysis earthquake applied from low intensity to high intensity. Structure collapse at very high intensity measure. Nonlinear dynamic analysis means combining ground motion records with the model. Static pushover analysis is the procedure in which loading increases in lateral direction with predefined failure pattern response from the structure in IDA(Incremental Dynamic Analysis) is actually response due to earthquake on the 1.1 Methodology Decide steel and concrete properties structural column components such as beam, column their size is selected. model is prepared with seismostruct.Columnareconsidered fixed, degree of freedom is fixed because column is considered as fixed. Earthquake is selected as input as intensity will vary depending upon zoning. Select response like inters tory drift ratio,baseshear.Selectgroundmotionas per zone. Generate incremental dynamic analysis curve for G+7 and G+11 building. Software used are Seismostruct and ETAB. Seismo Struct version 7.0.3 is used to carry out incremental dynamic analysis. Based on finite element and capable of predicting large displacement, behaviour of space frame due to static and dynamic loading. 1.2 . Incremental Dynamic AnalysisofG+7Building Floor Height = 3.5 m Column Dimension = (230 x650) mm Beam Dimension = (230 x 550) mm Building Location = Zone IV Boundary Condition = fixed on ground Material properties = M25, Fe415 G+7 building is designed in ETABS and parameters such as inter storey drift ratio, floor acceleration, and base shearare found out. For the building frame, seismic coefficient and response spectrum analysis is carried out along with dead load and live load combinations. Dead load and live load is applied as per IS 875. Load combinations given in IS 1893- 2000 are considered for the design of building. Incremental dynamic analysis is carried out in Seismo Struct for the designed reinforcement Table1 : Column and beam dimensions and reinforcement Member Size (mm) Steel Column 230 x 650 4#20 + 2#16 Beam 230 x 550 2#20 at top 2#20 at bottom
- 2. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 698 2. Building Plan Fig1: Odd Storey and Even Storey Fig2 : ETABS model Figure 3: SeismoStruct model of G+7 Building 2.1Incremental Dynamic AnalysisofG+11Building Floor Height = 3.5 m Column Dimension = (230 x650) mm Beam Dimension = (230 x 550) mm Slab thickness = 150 mm Building Location = Zone IV Boundary Condition = fixed on ground Material properties = M25, Fe415 Table2 : Column and beam dimensions and reinforcement Member Size(mm) Steel Column (base to storey6) 300 x 800 14#20 Column(storey7 to store12) 300 x 800 10#20 Beam 300 x 650 3#20 at top 3#20 at bottom Fig 4: Plan of G+11 building
- 3. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 699 Fig5: ETABS model of building G+11 Fig 6: SeismoStruct model Model of the building G+11 Table 3:Yield and collapse peak ground acceleration of G+7 building Time History Station PG A (g) Yield PGA(g) X directi on Collaps e PGA(g) X directi on Yield PGA(g) Y directi on Collaps e PGA(g) Y directi on 2001 Bhuj Bhuj L 0.1 1 0.32 0.42 0.29 0.38 1991 Uttarkas hi Uttarkas hi T 0.2 6 0.29 0.37 0.30 0.40 1967 Koyna Koyna L 0.3 4 0.18 0.26 0.19 0.28 1991 Uttarkas hi Bhatwari T 0.2 5 0.29 0.38 0.30 0.40 1967 Koyna Koyna T 0.4 0 0.21 0.30 0.24 0.34 1986 Dharmsh ala Dharmsh al L 0.1 7 0.38 0.44 0.40 0.45 1986 Dharmsh ala Dharmsh ala T 0.1 8 0.30 0.37 0.27 0.37 1995 Chamba Chamba L 0.1 4 0.27 0.36 0.29 0.39 1995 Chamba Chamba T 0.1 2 0.27 0.40 0.27 0.38 Median 0.29 0.37 0.29 0.38 G+7 building yields at the peak ground acceleration of 0.29g in both X and Y direction. Building collapse occurs at peak ground acceleration of 0.37g in X direction and 0.38g in Y direction. So, we can find out the building susceptibility for any other time history. If any time history has PGA less than 0.29g, we can say that building can sustain that earthquake otherwise building fails to sustain that earthquake and column dimensions need to be revised. Table 4:Yield and collapse peak ground acceleration of G+11 building Yield Collapse Yield Collapse Time History Station PGA PGA(g) PGA(g) PGA(g) PGA(g) (g) X X Y Y directiondirectiondirection direction 1995Chamba Chamba L 0.14 0.65 0.77 0.55 0.70 1995Chamba Chamba T 0.12 0.64 0.76 0.54 0.72 1986Dharmshala Dharmshala L 0.17 0.63 0.79 0.52 0.74 1986Dharmshala Dharmshala T 0.18 0.61 0.74 0.53 0.69 1995 India- Burma Katakhal L 0.14 0.61 0.72 0.56 0.68 border
- 4. International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 700 1995 India- Burma Katakhal T 0.16 0.63 0.75 0.58 0.70 border 1991Uttarkashi Bhatwari T 0.25 0.59 0.65 0.51 0.62 1967Koyna Koyna L 0.34 0.56 0.73 0.52 0.71 1967Koyna Koyna T 0.40 0.54 0.65 0.51 0.60 Median 0.61 0.74 0.53 0.70 3. Conclusion G+7 building yields at the peak ground acceleration of 0.29g in both X and Y direction. Building collapse occurs at peak ground acceleration of 0.37g in X direction and 0.38g in Y direction. So, we can find out the building susceptibility for any other time history. If any time history has PGA less than 0.29g, we can say that building can sustain that earthquake otherwise building fails to sustain that earthquake and column dimensions need to be revised. G+11 building yields at peak ground acceleration of 0.61g in X direction and 0.58g in Y direction. Building collapseoccurs at 0.73g in X direction and 0.71g in Y direction.So, any time history having peak ground acceleration lower than 0.53g, we can say that building can sustain that earthquake. 4. Acknowledgement This work is synergetic productofmanyminds.IamGrateful for the inspiration and wisdom of many thinkers and for the trans-generational sources and the roots. I hereby take this opportunity to express my profound gratitude and deep regards to my guide Dr. Ashok Kasnale Principal DYPSOET and staff for their exemplary guidance, monitoring and constant encouragement throughout the course of this work. 5. References 1. Camilleri M. (2010) “Structural Analysis” Nova Science Publishes, New York 2. Dolsek M. (2009) “Incremental dynamic analysis with consideration of modelling uncertainties” Earthquake Engineering and Structural Dynamics, 38(6), 805-825. 3. FEMA P-58-1, Volume 1– Methodology (2012) “Seismic Performance Assessment of Buildings”. 4. FEMA P-58-2, Volume 2– Implementation Guide (2012) “Seismic Performance Assessment of Building” 5. Mander J. and Dhakal R. (2007) “Incremental dynamic analysis applied to seismic financial risk assessment of bridges” Engineering Structures 29, 2662-2672. 4. Somes, N.F. and Corley, W.G. (1974). Circular openings in webs of continuous beams Shear in Reinforced Concrete, special Publication SP-42, American Concrete Institute, Detroit, 359-398. 5. IS 1893:2002.’Seismic Analysis” -Code of practice.’ 6. IS 456:2000.’Plain and Reinforced concrete-Code ofpractice.’ BIOGRAPHIES Vinod Tiwari(PG 2nd Year Student) Department of Civil Engineering Dr. D. Y. Patil School of Engineering& Technology Dr. D. Y. Patil School of Engineering& Technology. Dr. Ashok Kasnale(Guide & Principal) Department of Civil Engineering Dr. D. Y. Patil School of Engineering& TechnologyDr. D. Y. Patil School of Engineering& Technology