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Published byCharla Lang Modified over 9 years ago
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SCHEDULE 8:30 AM 10:30 AM Session I 11:00 AM Break 12:15 PM Session II 1:30 PM Lunch 2:45 PM Session III 3:15 PM 4:30 PM Session IV
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ENERGY DIAGRAM
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ENERGY DIAGRAM w/ HYSTERETIC
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IMPLIED NONLINEAR BEHAVIOR
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STEEL STRESS STRAIN RELATIONSHIPS
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INELASTIC WORK DONE
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HYSTERETIC BEHAVIOR
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MOMENT ROTATION RELATIONSHIP
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IDEALIZED MOMENT ROTATION
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DUCTILITY LATERAL LOAD Partially Ductile Ductile Brittle DRIFT
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CAPACITY DESIGN STRONG COLUMNS & WEAK BEAMS IN FRAMES
REDUCED BEAM SECTIONS LINK BEAMS IN ECCENTRICALLY BRACED FRAMES BUCKLING RESISTANT BRACES AS FUSES RUBBER-LEAD BASE ISOLATORS HINGED BRIDGE COLUMNS HINGES AT THE BASE LEVEL OF SHEAR WALLS ROCKING FOUNDATIONS OVERDESIGNED COUPLING BEAMS OTHER SACRIFICIAL ELEMENTS
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SHEAR LINKS FOR ENERGY DISSIPATION
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PERFORMANCE LEVELS Operational Immediate Occupancy Life Safety
Collapse Prevention Less Damage More Damage Ref: FEMA 451 B
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PERFORMANCE LEVELS
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IDEALIZED FORCE DEFORMATION CURVE
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ASCE 41 BEAM MODEL
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STRENGTH vs. DEFORMATION
ELASTIC STRENGTH DESIGN - KEY STEPS CHOSE DESIGN CODE AND EARTHQUAKE LOADS DESIGN CHECK PARAMETERS Stress/BEAM MOMENT GET ALLOWABLE STRESSES/ULTIMATE– PHI FACTORS CALCULATE STRESSES – Load Factors (ST RS TH) CALCULATE STRESS RATIOS INELASTIC DEFORMATION BASED DESIGN -- KEY STEPS CHOSE PERFORMANCE LEVEL AND DESIGN LOADS – ASCE 41 DEMAND CAPACITY MEASURES – DRIFT/HINGE ROTATION/SHEAR GET DEFORMATION AND FORCE CAPACITIES CALCULATE DEFORMATION AND FORCE DEMANDS (RS OR TH) CALCULATE D/C RATIOS – LIMIT STATES
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ASCE 41 ASSESSMENT OPTIONS
Linear Static Analysis Linear Dynamic Analysis (Response Spectrum or Time History Analysis) Nonlinear Static Analysis (Pushover Analysis) Nonlinear Dynamic Time History Analysis (NDI or FNA)
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STRUCTURAL COMPONENTS
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F-D RELATIONSHIP
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BACKBONE CURVE
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HYSTERESIS LOOPS
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ASCE 41 BACKBONE CURVES This can be used for components of all types.
It can be used if experimental results are available. ASCE 41 gives capacities for many different components. .
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ASCE 41 MOMENT HINGE AUTOMATED
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HYSTERESIS LOOPS AUTOMATED
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IMPORTANCE OF DUCTILITY
LATERAL LOAD Partially Ductile Ductile Brittle DRIFT
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ASCE 41 – DUCTILITY
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FORCE AND DEFORMATION CONTROL
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ASCE 41 BEAM MODEL
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STEEL COLUMN AXIAL-BENDING
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COLUMN AXIAL-BENDING MODEL
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CONCRETE COLUMN AXIAL-BENDING
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STEEL STRESS STRAIN RELATIONSHIPS
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STEEL COLUMN FIBER MODEL
SECTION FIBERS
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MATERIAL STRESS-STRAIN CURVES
Unconfined and Confined Concrete ( Compared ) Confined Concrete Steel
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CONCRETE COLUMN FIBER HINGE MODEL
Reinforced Concrete Column Steel Rebar Fibers Confined Concrete Fibers Unconfined Concrete Fibers
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MATERIAL STRESS-STRAIN CURVES
Unconfined and Confined Concrete ( Compared ) Confined Concrete Steel
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SHEAR WALL FIBER HINGE MODEL
Reinforcement Layout Steel Fibers Confined Concrete Fibers Unconfined Concrete Fibers
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SHEAR WALL FIBER HINGE MODEL
Shear Wall Cross Section Rebar Fibers Confined and Unconfined Concrete Fibers
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STRAIN AS A PERFORMANCE MEASURE
Concrete Tension Compression IO 0.0001 LS 0.0005 -0.003 CP 0.001 Rebar Tension Compression IO 0.02 -0.02 LS 0.06 -0.06 CP 0.09 -0.09
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STRAIN AND ROTATION MEASURES
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CONCRETE WALL MODELING
P-M Action With No Shear Coupling Nonlinear Fiber Model P-M Action With Shear Coupling (Multi-layered Nonlinear Darwin-Pecknold Concrete Shell Model )
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ENERGY DISSIPATION DEVICES
Buckling-Restrained Brace (BRB) Friction Isolator Rubber Isolator Viscous Damper Friction Damper
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SHEAR HINGE MODEL
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PANEL ZONE ELEMENT
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LINEAR vs. NONLINEAR
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NONLINEAR SOLUTION SCHEMES
∆ ƒ u 1 2 iteration CONSTANT STIFFNESS ITERATION 3 4 5 6 ∆ ƒ u 1 2 iteration NEWTON – RAPHSON ITERATION
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NONLINEAR EVENT TO EVENT ANALYSIS
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STEP BY STEP DYNAMIC ANALYSIS
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EQUATIONS FOR CAA METHOD
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THE POWER OF RITZ VECTORS
APPROXIMATELY THREE TIMES FASTER THAN THE CALCULATION OF EXACT EIGENVECTORS IMPROVED ACCURACY WITH A SMALLER NUMBER OF VECTORS CAN BE USED FOR NONLINEAR ANALYSIS TO CAPTURE LOCAL RESPONSE
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FAST NONLINEAR ANALYSIS (FNA)
DISCRETE NONLINEARITY FRAME AND SHEAR WALL HINGES BASE ISOLATORS (RUBBER & FRICTION) STRUCTURAL DAMPERS STRUCTURAL UPLIFT STRUCTURAL POUNDING BUCKLING RESTRAINED BRACES
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RITZ VECTORS
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FNA ADVANTAGES MODAL SOLUTION - NO STIFFNESS REDUCTION
CLOSED FORM SOLUTION – VERY FAST TIME STEP INDEPENDENT CAPTURES HIGH FREQUENCY RESPONSE RITZ VECTORS CALCULATED ONCE MULTIPLE TIME HISTORIES ARE FAST
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FNA KEY POINT The Ritz modes generated by the nonlinear deformation loads are used to modify the basic structural modes whenever the nonlinear elements go nonlinear.
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DYNAMIC EQUILIBRIUM EQUATIONS
g u - = w + x 2 M Ku C t . .. M C .. .. K .. .. ..
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RESPONSE FROM GROUND MOTION
A B t u g = + - . 2 x w .. ug .. 2 ug2 ug1 1 t1 t2 t
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CLOSED FORM DAMPED RESPONSE
{ [ . ] cos ( )] sin } e u B t A d = - + xw w 1 2 Bt x [u ) 3
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BASIC DYNAMICS WITH DAMPING
u & - = w + x 2 M Ku C t C K g u &
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RESPONSE MAXIMA u t ) cos( w = 2 - & sin( max
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Displacement Response Spectrum
RESPONSE SPECTRUM GENERATION -0.40 -0.20 0.00 0.20 0.40 1.00 2.00 3.00 4.00 5.00 6.00 TIME, SECONDS GROUND ACC, g Earthquake Record -4.00 -2.00 DISPL, in. -8.00 8.00 T= 0.6 sec T= 2.0 sec 2 4 6 8 10 12 14 16 PERIOD, Seconds DISPLACEMENT, inches Displacement Response Spectrum 5% damping
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SPECTRAL PARAMETERS S PS w = d V a v DISPLACEMENT, in. PERIOD, sec
4 8 12 16 2 6 10 PERIOD, sec DISPLACEMENT, in. 20 30 40 VELOCITY, in/sec 0.00 0.20 0.40 0.60 0.80 1.00 ACCELERATION, g d V S PS w = v a
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Spectral Acceleration, Sa
THE ADRS SPECTRUM ADRS Curve Spectral Displacement, Sd Spectral Acceleration, Sa 2.0 Seconds 1.0 Seconds 0.5 Seconds Period, T RS Curve
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THE ADRS SPECTRUM
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THE LINEAR PUSHOVER
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EQUIVALENT LINEARIZATION
How far to push? The Target Point!
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ARTIFICIAL EARTHQUAKES
CREATING HISTORIES TO MATCH A SPECTRUM FREQUENCY DOMAIN & TIME DOMAIN MATCHING
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SPECTRAL MATCHING IN FREQUENCY DOMAIN
FFT Inverse FFT Scaled Cyclic Signals for Each Frequency of Interest De-aggregated Cyclic Signals for Each Frequency of Interest Scale Amplitudes for Each Freq. (Scale factor = At/As) Seed Acceleration Time History Acceleration Time History Matched to Target Spectrum As At Target Spectrum and Spectrum for Seed Acceleration Time History Target Spectrum and Spectrum for Matched Acceleration Time History
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SPECTRAL MATCHING IN TIME DOMAIN
B C D E F G H I Seed Acceleration Time History Target Spectrum and Spectrum for Seed Acceleration Time History Adjust Wavelet No Yes Misfit < Tol Adjust Wavelet Wavelet for Freq. Band A No Yes Misfit < Tol ADD Wavelet for Freq. Band B ADD Misfit < Tol for all Freq. Bands Target Spectrum and Spectrum for Matched Acceleration Time History Acceleration Time History Matched to Target Spectrum
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CONSEQUENCE BASED DESIGN
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RATING FOR SEISMIC PERFORMANCE
CoRE Rating Safety Reparability Functionality 5-Star Life Safe Loss <5% Occupiable Immediately Functional < 72 hours 4-Star Loss <10% Occupiable Immediately Functional < 1 month 3-star Loss <20% Occupiable < 1 month Functional < 6 months Certified Not estimated Not Certified Life Safety Hazard
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