Seismic performance of adjacent building using fluid viscous dampers

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This presentation highlights the effect of Fluid Viscous Dampers (FVDs) on the seismic performance of adjacent buildings connected through a ped-way. A part of this project also deals with the Qualitative Damage Analysis of the structure during an earthquake, with and without FVDs.

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Seismic performance of adjacent building using fluid viscous dampers

  1. 1. STUDY ON SEISMIC PERFORMANCE OFADJACENT BUILDINGS USING FVDsCIV E 661- Dynamics of StructuresUNIVERSITY OF ALBERTAGroup MembersCourse IDAyaz MalikLuong Hongistookphoto.com
  2. 2. OBJECTIVES To study the effect of Fluid Viscous Dampers (FVDs)on response of adjacent buildings during a pastearthquake (El Centro). To perform Qualitative Damage Analysis of thestructure under earthquake excitation, with andwithout FVDs.
  3. 3. SPECIFICATIONS FOR ANALYSISAND DESIGN ACI 318-08, Building Code Requirements forStructural Concrete AISC 360-05, Specification for Structural SteelBuildings IBC (International Building Code), 2009 ATC-40 Report on Seismic Evaluation and Retrofit ofConcrete Buildings, Volume 1COMPUTER SOFTWARE USED: SAP 2000 Ver. 14
  4. 4. BUILDING MODEL Number of Stories = 11 Storey height = 14 ft Bay width = 20 ft fc’ (Columns) = 4000 Psi fc’ (Beams/Slabs) = 3000 Psi fy (Reinforcement) = 60, 000 Psi fy (Steel beams) = 250 MPa Typical Beam Size = 18 x 21 in Typical Column Size = 24 x 24 in Slab Thickness = 6 in
  5. 5. LOADINGS FOR ANALYSIS Partition load = 20 lb/ft2 Live Load = 80 lb/ft2 Earthquake load = El CentroStep size = 0.1 sec , Number of steps = 3000 (Chopra)-0.4-0.3-0.2-0.100.10.20.30.40 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32Acceleration(g)Time (sec)
  6. 6. ANALYSIS CASESCase 1 Case 2Case 3 Case 4Building 2Building 1
  7. 7. ANALYSIS CASESCase 5 Case 6Case 7
  8. 8. FVDs consist of a closed cylinder filled with viscous fluid.The movement of a piston in that cylinder causes afriction and energy of the motion can be dissipated. Fornon-linear FVDs, the force (𝑓𝐷) - velocity (𝑢) relation is;𝒇 𝑫 = 𝒄 𝜶 𝒔𝒈𝒏(𝒖) 𝒖 𝜶 (Lin & Chopra, 2002)Where: 𝒄 𝜶 – damping coefficient (571 Kips-sec/in)𝜶 – positive exponent, 0.35 – 1.0 (0.5 in model)sgn(𝑢) – signum function𝜶 = 1.0 represents the linear FVDs and 𝜶 = 0 representsthe pure friction damper.FLUID VISCOUS DAMPERS (FVDs)
  9. 9. SAN FRANCISCO CIVIC CENTER DAMPER INSTALLATION(Tylor, Duflot)
  10. 10. Sa(g)Performance Point (Sd, Sa, D)SdFamily of Demand Spectra fordifferent values of dampingSingle Demand Curve withvariable dampingCapacity CurveAcceleration Displacement Response SpectrumCAPACITY SPECTRUM METHODATC-40 Report on Seismic Evaluation and Retrofit of Concrete Buildings
  11. 11. Performance point;(T = 2.85sec, D = 6.5in)CAPACITY-DEMAND CURVES FORMODEL BUILDING
  12. 12. ANALYSIS RESULTS FOR CASESCaseDeflection (in) No. ofDampersBuilding 1 Building 21 12.93 12.93 02 7.58 10.95 303 6.58 12.39 364 5.45 11.54 665 7.38 7.39 606 6.76 6.78 727 5.91 5.9 132COMPARISONBetween1and6
  13. 13. -15-10-50510150 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32RoofDisplacement(in)Time (Sec)Without DampingWith DampingROOF DISPLACEMENT VS TIME
  14. 14. -40-30-20-10010203040500 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32Velocity(in/sec)Time (sec)With dampingWithout DampingVELOCITY VS TIME
  15. 15. -250-200-150-100-500501001502002500 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32Acceleration(in/sec2)Time (sec)With dampingWithout DampingACCELERATION VS TIME
  16. 16. -5000-4000-3000-2000-10000100020003000400050000 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32BaseShear(Kips)Time (sec)With DampingWithout DampingBASE SHEAR VS TIME
  17. 17.  Immediate Occupancy, SP-l: A stage where very limitedstructural damage has occurred. Damage Control, SP-2: A range of post-earthquake damagestates that could vary from SP-I to SP-3. Life Safety, SP-3: At this level the risk of life-threatening injury from structural damage is very low. Limited Safety, SP-4: A range of post-earthquake damagestates that are less than SP-3 and better than SP-5. Structural Stability, SP-5: A level at which structure is onthe verge of experiencing partial or total collapse.SEISMIC PERFORMANCE LEVELSATC-40 Report on Seismic Evaluation and Retrofit of ConcreteBuildings, Volume 1
  18. 18. CASE 1Roof Displacement > 10 inchAs expected from performance pointdisplacement, at displacements greaterthan 6.5 inch the performance of thestructure became poor. Damage-levelhinges were formed for displacementsgreater than 10in which means that thestructure is on the verge of global orlocal failure under the given earthquakeload.
  19. 19. As the maximum displacement, i.e.6.8 inch, was very close toperformance point displacement (6.5inch), Only Immediate Occupancylevel hinges were formed fordisplacements lesser than 7 inch.Thus, for case-6, structure is safefrom stability as well as life safetypoint of view under the givenearthquake load.CASE 6Roof Displacement < 7 inch
  20. 20. • Results showed a significant reduction in lateraldeflection and velocity of the structures when viscousdampers were added. However, not much improvementwas observed in Acceleration and base shear.• Their was a significant improvement in performancelevel of the structure under earthquake when damperswere added.• Optimum level of performance depends on the type ofstructure and the level of performance required bythe place holder.CONCLUSIONS
  21. 21. (A California Structural Engineer)“ WHEN IN DOUBT ……DAMP IT OUT !! ”
  22. 22. ANY QUESTIONS

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