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Publicada porTiburcio Espejo Modificado hace 9 años
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Torsion in buildings the Mexican research experience after the 1985 earthquake Gustavo Ayala
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TORSION Causes No coincidence of acting and resisting forces in structures with asymmetric plan distibutions of masses, stiffnesses and/or strengths. Kinematic effects Coupling between lateral and rotational displacements of the levels. Consequences Non-contemplated damage in asymmetric structures subjected intense earthquakes.
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DAMAGE STATISTICS 19th SEPTEMBER 1985, MEXICO EARTHQUAKE
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DESIGN PHYLOSOPHY Torsion Design Elastic models of single storey shear buildings. DESIGN RECOMMENDATIONS FOR TORSION It is formally accepted that under intense seismic events structural damage (non-linear behaviour) may occur.
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SPATIAL VARIATION OF THE TORSION CENTRE IN MULTI-STOREY BUILDINGS WITH IN-PLAN AND ELEVATION ASYMMETRY ( SHEAR AND BENDING MODELS)
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CENTRE OF TORSION “ The Centre of Torsion of a buuilding is defined as the loci on its levels or inter-storeys at which the seismic force or shear must be applied to produce only translations with no rotations “ PARAMETERS WHICH DEFINE THE LOCATION OF THE CENTRE OF TORSION. Stiffness Location of the elements Distribution of lateral loads “ The CENTRE OF TORSION is not an INVARIANT“
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SHEAR MODELS EXACT. Infinite stiffnesses of beams Plane frames TRADITIONAL. Bending on beams Inter-storey stiffnesses of plane frames THREE DIMENSIONAL MATRIX FORMULATION LOCATION OF THE CENTRE OF TORSION
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BUILDING MODELS 4 levels
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BUILDING MODELS 15 levels
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BUILDING MODELS 4 levels
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BUILDING MODELS 15 levels
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Location of the torsion centre 4 levels Model I Model II
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Location of the torsion centre 4 levels Model III Model IV
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Location of the torsion centre 15 levels 4 levels Model V Model I
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Location of the torsion centre 15 levels Model II Model III
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Location of the torsion centre 15 levels Model IV Model V
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Location of the torsion centre 15 levels Model VI Model VII
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Location of the torsion centre 15 levels Model VIII
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INELASTIC TORSION
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Parametric studies based on single storey models Distribución en planta de las rigideces y resistencias. Excentricidad estática Relación de aspecto de la planta Cociente Rr/ Rn Periodo fundamental de vibrar ( T ) Relación de frecuencias desacopladas ( W ) Evaluación del criterio de diseño por Torsión del RCDF BACKGROUND
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1 ) Gómez, Ayala and Jaramillo, 1987 2) Barrón, Ayala and Zapata, 1991
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BACKGROUND 3) García and Ayala, 1991 4) Zapata and Ayala,1993
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Relationships of Maximum Ductility Ratios vs. Strength Distribution in shear models with resisting elements in two orthogonal directions. SOME RESULTS OBTAINED FROM SINGLE STOREY MODELS
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Relationships of Maximum Ductility Ratios vs. Strength Distribution SOME RESULTS OBTAINED FROM SINGLE STOREY MODELS
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STUDY OF THE RESPONSE OF 3D BUILDING MODELS TORSIONALLY COUPLED
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INVESTIGATED MODEL
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CONSIDERED PARAMETERS MASS AND STIFFNESS ASYMMETRIC. DYNAMICA AMPLIFICATION FACTOR. FA din = Mt Me Design Eccentricity : e d1 = e s + b e d2 = e s - b
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MASS ASYMMETRIC MODELS TYPES AND LEVELS OF STRUCTURAL ASYMMETRY STIFFNESS ASYMMETRIC MODELS mean values
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Symmetric Model INSTANTANEOUS CENTRE OF SEISMIC SHEAR (CICS) Model I Mass Asymmetric Interstorey 01
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Symmetric Model Model I Mass Asymmetric Interstorey 01 INSTANTANEOUS CENTRE OF SEISMIC SHEAR (CICS)
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Model III Mass Asymmetric Model II Mass Asymmetric Interstorey 01 INSTANTANEOUS CENTRE OF SEISMIC SHEAR (CICS)
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Modelo II Asimétrico en Rigidez Modelo I Asimétrico en Rigidez Interstorey 01 INSTANTANEOUS CENTRE OF SEISMIC SHEAR (CICS)
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Model III Stiffness Asymmetric Interstorey 01 INSTANTANEOUS CENTRE OF SEISMIC SHEAR (CICS)
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SYMMETRIC MODEL INSTANTANEOUS CENTRE OF STIFFNESS (CIR) Interstorey 01
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MODEL I MASS ASYMMETRIC Interstorey 01 INSTANTANEOUS CENTRE OF STIFFNESS (CIR)
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MODEL II MASS ASYMMETRIC Interstorey 01 INSTANTANEOUS CENTRE OF STIFFNESS (CIR)
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MODEL III MASS ASYMMETRIC Interstorey 01 INSTANTANEOUS CENTRE OF STIFFNESS (CIR)
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MODEL I STIFFNESS ASYMMETRIC Interstorey 01 INSTANTANEOUS CENTRE OF STIFFNESS (CIR)
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MODEL II STIFFNESS ASYMMETRIC Interstorey 01 INSTANTANEOUS CENTRE OF STIFFNESS (CIR)
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MODEL III STIFFNESS ASYMMETRIC Interstorey 01 INSTANTANEOUS CENTRE OF STIFFNESS (CIR)
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SYMMETRIC MODEL Interstorey 01 SHEAR - TORSIONAL MOMENT HISTORY SUPERPOSED ON THE SUCT
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MODEL I MASS ASYMMETRIC Interstorey 01 SHEAR - TORSIONAL MOMENT HISTORY SUPERPOSED ON THE SUCT
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Interstorey 01 MODEL II MASS ASYMMETRIC SHEAR - TORSIONAL MOMENT HISTORY SUPERPOSED ON THE SUCT
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Interstorey 01 MODEL III MASS ASYMMETRIC SHEAR - TORSIONAL MOMENT HISTORY SUPERPOSED ON THE SUCT
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MODEL I STIFFNESS ASYMMETRIC Interstorey 01 SHEAR - TORSIONAL MOMENT HISTORY SUPERPOSED ON THE SUCT
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Interstorey 01 MODEL II STIFFNESS ASYMMETRIC SHEAR - TORSIONAL MOMENT HISTORY SUPERPOSED ON THE SUCT
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Interstorey 01 MODEL III STIFFNESS ASYMMETRIC
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DYNAMIC AMPLIFICATION FACTOR
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EEFECT OF FUNDAMENTAL PERIOD
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STRUCTURAL MODELS Group 1 (Models 4 levels) Group 2 (Models 8 levels) Group 3 (Models 15 levels)
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SIMÉTRICOS Y ASIMÉTRICOS EN MASAS
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ASIMÉTRICOS EN RIGIDECES
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STIFFNESS ASYMMETRIC
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CONSIDERACIONES PARA EL ANÁLISIS NO LINEAL 4 4Se asume que los modelos poseen base rígida 4 4Se desprecian los efectos P-Delta 4 4Se asume que el sistema de piso es indeformable en su plano 4 4Las uniones viga-columna se suponen rígidas 4 4La masa del nivel se supone concentrada en un punto (CM) 4 4La estructura no pierde su geometría inicial durante el análisis y hasta antes del colapso 4 4 Excitación sísmica
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* * CIR (Instantaneous Stiffness Centre) Centro instantáneo de torsión de entrepiso obtenido en cada paso de análisis * * CICS (Instantaneous Sismic Shear Centre) Es un punto que define la ubicación en planta de la demanda de fuerza cortante en cada paso de análisis. * * SUCT (Últimate Shear - Torsion Surface) Locus de las combinaciones de fuerza cortante y momento torsionante de entrepiso, que aplicadas estáticamente a la estructura, producen su colapso. BEHAVIOUR PARAMETERS
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RESULTS Interstorey 01 4 levels MEM411 MEM402 CICSCIR
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RESULTS Interstorey 01 4 levels MEM402 MEM411
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RESULTS Interstorey 01 8 levels MEM802 MEM822 CICS CIR
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RESULTS Interstorey 01 8 levels MEM802 MEM822
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RESULTS Interstorey 01 15 levels MEM1502 MEM1522 CICS CIR
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RESULTS Interstorey 01 15 levels MEM1522MEM1502
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Universidad Nacional Autónoma de México POR MI RAZA HABLARA EL ESPIRITU
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