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Building with base isolation techniques exhibit less lateral deformation if exposed to seismic load.

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- 1. BUILDINGS WITH BASEISOLATION TECHNIQUESMahmoud SAYED AHMEDm.sayedahmed@ryerson.ca
- 2. Overview Introduction Literature Review Case Study: Base Isolated Building Case Study: Fixed Base Building Conclusions and Recommendations
- 3. IntroductionNBCC 2010 specifies thatbuildings and theirstructural members shall bedesigned by one of thefollowing methods: analysis based on generally established theory, evaluation of a given full-scale structure or a prototype by loading tester or studies of model analogues .
- 4. Literature review Earthquake Structural bearing Base Isolation Design requirements Construction of base isolated building
- 5. EarthquakeTectonic plate movement
- 6. Cont. 0.8 0.7 Spectral Response Acceleration,S 0.6 0.5 Toronto 0.4 Alexandria 0.3 White River 0.2 0.1 0 0 0.5 1 1.5 2 2.5 Period, T Seismic map in Canada The four Sa 0.2, 0.5, 1.0 and 2.0 seconds (equivalent to frequencies of 5, 2, 1, and 0.5 Hertz) [Source: www.earthquakescanada.nrcan.gc.ca]
- 7. Structural bearing The CHBDC standards recognized the bearing as follows: Plain elastomeric Natural Rubber Neoprene Steel reinforced elastomeric Roller bearing Elastomeric Roller Rocker bearing Pot bearing Disc bearing Spherical and cylindrical bearing Other (require approval)Rapolla seismic isolated building, Potenza, ItalyLBRtest Rocker Pot
- 8. Rubber bearing Lift-off: bearing behavior assumed in :Internal forces which act to displace the rubber from the vertical height “seismic linear model” lost in deflection to the unloaded sides Load-deflection for one and three layer units reinforced with steel plate [Farat]
- 9. Base isolation Add your procedure here Key assumptions Add your assumptions here Building movementBase-Isolation Building [Lu et al 2012]
- 10. Building movementPress to run Video Press to run Video
- 11. Damping 0.001 g (0.01 m/s²) – perceptible by people 0.02 g (0.2 m/s²) – people lose their balance 0.50 g – very high; well-designed buildings can survive if the duration is short
- 12. Design requirements
- 13. Cont.,
- 14. Construction of base isolation Friction Pendulum System Pasadena City Hall
- 15. Pasadena City Hall
- 16. Parametric study Finite element modeling Gravity loads Isolated base building Fixed base building Results
- 17. Finite element modelingTable 3. 1 High damping bearing Properties Vertical (axial) stiffness 10,000 k/in (linear) Initial shear stiffness in each 10 K/in direction Shear yield force in each 5 kips direction B.1 Ratio of post yield shear 0.2 stiffness to initial shear stiffness Figure 3. 1 3D Finite element model
- 18. Gravity loads & forces Moment 3-3 Diagram Axial Force Diagram Figure 3. 3 Combo (Dead plus live load) effect on the N-S for Grid A.1 or A.4
- 19. Isolated base building Response histories (a) displacement of column (joint 15, 13), (b) displacement of column w.r.t. base, (c) displacement of base shear
- 20. MODAL 1 Moment 3-3 Diagram (MODAL) Model 1 – Period 2.81065 Deformation shape (MODAL) – Mode 1 – Period 2.81065
- 21. MODAL 2 Moment 3-3 Diagram (MODAL) Model 2 – Period 2.7975 Deformation shape (MODAL) – Mode 2 – Period 2.7975
- 22. MODAL 3 Moment 3-3 Diagram (MODAL) Model 3 – Period 2.42137 Deformation shape (MODAL) – Mode 3 – Period 2.42137
- 23. MODAL 4 Moment 3-3 Diagram (MODAL) Model 4 – Period 0.32664 Deformation shape (MODAL) – Mode 4 – Period 0.32664
- 24. MODAL 5 Moment 3-3 Diagram (MODAL) Model 5 – Period 0.24728 Deformation shape (MODAL) – Mode 5 – Period 0.24728
- 25. Fixed base building Response histories (a) displacement of column (joint 15, 13), (b) displacement of column w.r.t. base, (c) displacement of base shear
- 26. MODAL 1 Moment 3-3 Diagram (MODAL) Model 1 – Period 0.49310 Deformation shape (MODAL) – Mode 1 – Period 0.49310
- 27. MODAL 2 Moment 3-3 Diagram (MODAL) Model 2 – Period 0.35973 Deformation shape (MODAL) – Mode 2 – Period 0.35973
- 28. MODAL 3 Moment 3-3 Diagram (MODAL) Model 3 – Period 0.35117 Deformation shape (MODAL) – Mode 3 – Period 0.35117
- 29. MODAL 4 Moment 3-3 Diagram (MODAL) Model 4 – Period 0.19916 Deformation shape (MODAL) – Mode 4 – Period 0.19916
- 30. MODAL 5 Moment 3-3 Diagram (MODAL) Model 5 – Period 0.14006 Deformation shape (MODAL) – Mode 5 – Period 0.14006
- 31. ResultsModal participating mass ratio (MPMR) Period, T [seconds] Frequency, ƒ [Hz] Modal Fixed Base Isolated Base Fixed Isolated Mode Base Base 1 0.49310 2.81065 2.0279 0.35578 2 0.35973 2.79750 2.7799 0.35746 3 0.35117 2.42137 2.8476 0.41298 4 0.19916 0.32664 5.0211 3.06147 5 0.14006 0.24728 7.1397 4.04399 Where ƒ ≥ 1 Hz for rigid building, ƒ < 1 Hz for flexible building 6 5 MODAL, mode 4 3 Fixed base 2 Isolated base 1 0 0 2 4 6 8 frequency, Hz
- 32. Modal moment and shear values for edge column B.1 Modal 1 Modal 2 Modal 3 Modal 4 Modal 5 H Moment Shear Moment Shear Moment Shear Moment Shear Moment Shear Minor (V3 , M2) 288 10.95 -0.146 -0.012 2.4E-4 -3.452 0.047 1104.155 -15.399 -423.458 5.990 144 -10.06 -0.146 0.022 2.4E-4 3.375 0.047 -1110.116 -15.399 437.875 5.990Isolated-Base 144 29.27 -0.411 -0.035 5.2E-4 -8.186 0.115 1431.488 -20.376 -536.685 7.627 0 -29.27 -0.411 0.040 5.2E-4 8.403 0.115 -1502.657 -20.376 561.644 7.627 Major (V2, M3) 288 4.5E-3 2.3E-4 14.804 -0.19 22.168 -0.28 -0.246 0.022 2765.094 -37.176 144 0.038 2.3E-4 -12.55 -0.19 -18.120 -0.28 2.864 0.022 -2588.261 -37.176 144 -0.086 1.4E-3 32.193 -0.457 49.083 -0.698 -4.993 0.072 3107.763 -45.283 0 0.112 1.4E-3 -33.644 -0.457 -51.388 -0.698 5.389 0.072 -3413.022 -45.283 288 562.661 -7.645 245.464 -3.435 1.067 -0.023 -2586.53 38.47 944.549 -13.976 Minor (V3 , M2) 144 -538.23 -7.645 -249.23 -3.435 -2.209 -0.023 2921.005 38.47 -1068.03 -13.976 144 1133.21 -16.52 403.782 -5.849 2.217 -0.023 1862.977 -25.378 -691.367 9.451 0 -1245.9 -16.52 -438.537 -5.849 -1.082 -0.023 -1791.469 -25.378 669.645 9.451Fixed-Base 288 -0.315 0.021 -1569.76 20.652 -1477.36 19.656 3.372 -0.038 -6329.895 94.133 Major (V2, M3) 144 2.776 0.021 1404.12 20.652 1353.073 19.656 -2.092 -0.038 7225.272 94.133 144 -3.192 0.031 -2430.91 37.054 -2251.60 34.076 0.841 -8.2E-3 4966.383 -66.903 0 1.321 0.031 2904.87 37.054 2655.291 34.076 -0.348 -8.2E-3 -4667.693 -66.903
- 33. Lateral displacement for B.1Modal Mode Joint Fixed Base Isolated Base [Height] U1 U2 U3 U1 U2 U3 15 [288] -9.2E-14 -0.7459 -0.0032 -2.2E-11 -0.4699 -0.0001 1 14 [144] -5.4E-14 -0.4597 -0.0025 -2.2E-11 -0.4642 -0.0001 13 [0.00] 0.00 0.00 0.00 -2.2E-11 -0.4518 -4.8E-5 15 [288] 0.8412 -0.2804 -0.0026 -0.4659 1.9E-11 2.3E-5 2 14 [144] 0.4806 -0.1602 0.0021 -0.4625 1.8E-11 2.1E-5 13 [0.00] 0.00 0.00 0.00 -0.456 1.8E-11 1.1E-5 15 [288] 0.7684 1.6E-13 -0.0013 -0.5141 0.1714 6.7E-5 3 14 [144] 0.4362 9.0E-14 -0.001 -0.5088 0.1696 6.0E-5 13 [0.00] 0.00 0.00 0.00 -0.4987 0.1662 2.9E-5 15 [288] 1.19E-14 0.5858 0.0073 -3.3E-14 -0.6543 -0.0086 4 14 [144] -1.03E-14 0.5853 0.0043 -1.8E-15 -0.1044 -0.0073 13 [0.00] 0.00 0.00 0.00 2.6E-14 0.5306 -0.0031 15 [288] 0.6114 -0.2038 -0.0062 -0.727 0.2423 0.0066 5 14 [144] -0.6612 0.2204 -0.0034 -0.1064 0.0355 0.0056 13 [0.00] 0.00 0.00 0.00 0.0025 -0.1926 0.5778 Where U1, U2, U3 are displacement in x, y, z directions respectively in [in]; Height in [in]
- 34. Cont., 350 350 300 300 250 250 Mode 1 200 200Height, in Height, in Mode 2 Mode 1 150 150 Mode 3 Mode 2 Mode 4 Mode 3 100 100 Mode 5 Mode 4 50 50 Mode 5 0 0 -1 -0.5 0 0.5 1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 Displacment, in Displacement, in Movement in U2 direction for fixed & isolated base buildings under the first five MODAL modes
- 35. Base shear SRSS; square root of sum of squares
- 36. Cont., Structure Joint reaction @ B.1 [kip] Type Type 1 2 3 Modal1 0.000 0.678 0.480 Modal 2 0.684 0.000 -0.108 Isolated Modal 3 0.748 -0.249 -0.291 Base Modal 4 0.000 -0.796 31.454 Modal 5 -0.867 0.289 -24.722 Gravity 0.000 0.000 361.487 Modal 1 -3.134E-2 16.522 13.514 Modal 2 37.054 5.849 10.948 Modal 3 -34.076 2.291E-2 5.603Fixed Base Modal 4 8.258E-3 25.378 -22.900 Modal 5 66.903 -9.451 18.251 Gravity 0.179 0.404 360.799
- 37. Conclusions The main observation from the modeling study on the accuracy of seismic effect and lateral load patterns utilized in the Multi-Modal Pushover analysis (MPA) in predicting earthquake effect showed that the accuracy of the pushover results depends strongly on the load path, properties of the structure and the characteristics of the ground motion. The lateral deflection for MDOF for multi-story building can be represented as SDOF once the equivalent mass and stiffness is obtained. The plastic hinge location varies by the type of loading, and the change in MODAL period. It can be located at any point along the span of member as well as the end of the member. Drift index and inter-story drift should be predicted using the multi-modal (SRSS) and the elastic first mode with long period for the lateral load pattern which corresponds to the average in most cases. Base-isolated structure exhibit less lateral deflection, as the lateral displacement at the base never equals to zero, and less moment values than the fixed base structure.
- 38. Cont., The base isolation decouples the building from the earthquake-induced load, and maintain longer fundamental lateral period than that of the fixed base. Base-isolated structure exhibit less lateral deflection, as the lateral displacement at the base never equals to zero, and less moment values than the fixed base structure. The base isolation decouples the building from the earthquake-induced load, and maintain longer fundamental lateral period than that of the fixed base.
- 39. Recommendations Study the influence of the structural bearing properties and the stresses generated from tilting of the superstructure due to lateral loading. Study the potential for liquefaction of the soil and its consequences on base-isolated buildings. Establish design procedures and guidelines for Base-Isolation structure.
- 40. References Chopra, A.R., “Dynamics of structures,” Prentice-Hall, New Jersy, USA, 2001. CSI, “base reactions for response spectrum,” website: https://wiki.csiberkeley.com/display/kb/Base+reactions+fo r+response+spectrum+analysis, accessed March 2012. Eggert, H., Kauschke, W., “Structural Bearings,” Ernst & Sohn, Germany, 2002. NRCC, “National Building Code of Canada,” Associate Committee on the National Building Code, National Research Council of Canada, Ottawa, ON, 2005. Tedesco, J.W., McDougal, W.G., and Ross C.A., “Structural dynamics: Theory and applications,” Prentice Hall, USA, 1998.
- 41. DRAMATIC BUILDING COLLAPSE CAUGHT ON TAPE! http://www.youtube.com/watch?v=tzGJs- uyaSY&feature=related Earthquake causes building to collapse http://www.youtube.com/watch?v=NqRN63iDTqA Rapolla seismic isolated building, Potenza, Italy http://www.youtube.com/watch?v=1oGkM1QpL3M LBRtest http://www.youtube.com/watch?v=2yXgu4aS8HE
- 42. Questions and Discussion

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i am writing a book about seismic isolation , i don't have much information about modelling seismic isolation in etabs and sap , can you help me anyway ? i need etabs and sap 2000 files , any help will extremely appreciated.

thanks a lot

god bless you and your family

please contact with me via: sillencejaguar@yahoo.com