Upload
carlosrobles147741
View
222
Download
0
Embed Size (px)
Citation preview
8/11/2019 4_Pushover.pdf
1/6
Diseo Ssmico por DesempeoDr. Jos Restrepo, Dr. Mario Rodrguez
INSTITUTO DE LA CONSTRUCCION Y GERENCIA - ICGTelefax: (01) 4217896 / [email protected] / www.construccion.org
Curso Internacional Pre IV Congreso de Estructuras
Diseo SsmicoDiseo Ssmico
por Desempeopor Desempeo
Lima, 21 al 23 de Junio 2010Lima, 21 al 23 de Junio 2010
Dr. Jos RestrepoDr. Jos Restrepo
Curso Internacional: Diseo Ssmico por Desempeo, Junio 2010
Pushover AnalysisPushover Analysis
8/11/2019 4_Pushover.pdf
2/6
Diseo Ssmico por DesempeoDr. Jos Restrepo, Dr. Mario Rodrguez
INSTITUTO DE LA CONSTRUCCION Y GERENCIA - ICGTelefax: (01) 4217896 / [email protected] / www.construccion.org
Classification
Force-basedat each step force increments are assigned,
Displacement-basedat each step displacement increments are assigned,system is solved for force increments
CONTROLLEDPARAMETER
Fixed-vector
vary during analysis
Adaptiverelative magnitude of increments varies step by step,increments are proportional to an instantaneous mode shape
VECTORSHAPE
Force-Based Fixed-Vector
Pushover Typical of building codes
Force increments prop. to a fixed approx. mode shape
en nver e - r angu ar s ape s assume or s mo e
i(3)i(2)i(1)
Vb(3)
Vb(2)
Fi(1)Fi(2)Fi(3)
Vb,maxVb
analysis stopswhen peak load
calculated=KT
-1Fr(3)
Vb(1)
r(1) r(2)
Vb(1)
givenfixed
Vb(2)Vb(3)
r
s near y reac e
8/11/2019 4_Pushover.pdf
3/6
Diseo Ssmico por DesempeoDr. Jos Restrepo, Dr. Mario Rodrguez
INSTITUTO DE LA CONSTRUCCION Y GERENCIA - ICGTelefax: (01) 4217896 / [email protected] / www.construccion.org
Force-Based Fixed-Vector
Pushover Typical of building codes
Force increments ro . to a fixed a rox. mode sha e
Often inverted-triangular shape is assumed for 1st mode
Advantages Easy implementation
Low computational effort
Drawbacks Cannot determine full-mechanism response (KT=0) Does not account for significant changes in the mode
shape (e.g. intermediate soft-story mechanism)
Force-Based Adaptive Pushover
Force increments prop. to an instantaneous mode shape
Eigenvalue solution required when KT changes
i(3)i(2)i(1)Fi(1)Fi(2)Fi(3)
Vb(3)
Vb(2)
Vb,maxVb
analysis stopswhen peak load
calculated=KT
-1F
Vb(1)
given byinstantaneouseigenvalue
Vb(2)Vb(3)
r(3)
Vb(1)
r(1) r(2)
r
s near y reac e
8/11/2019 4_Pushover.pdf
4/6
Diseo Ssmico por DesempeoDr. Jos Restrepo, Dr. Mario Rodrguez
INSTITUTO DE LA CONSTRUCCION Y GERENCIA - ICGTelefax: (01) 4217896 / [email protected] / www.construccion.org
Force-Based Adaptive Pushover Force increments prop. to an instantaneous mode shape
Eigenvalue solution required when KT changes
Advantages Changes in the mode shapes can be included
Drawbacks Cannot determine full-mechanism response (KT=0) High computational effort (repeated eigenvalue solutions)
Displacement-Based
Adaptive Pushover Opposite to force-based
Displ. increments prop. to instantaneous mode shape
Eigenvalue solution required when KT changes
i(3)i(2)i(1)Fi(2) Fi(1)Fi(3) i(4)
Vb(3)
Vb(2)
Vb,maxVb
analysis does not
given byinstantaneouseigenvalue
Vb(2)
calculatedF=KT
Vb(1)Vb(3)
r(3)
Vb(1)
r(1)r(2)
r
load is reached
r(4)
8/11/2019 4_Pushover.pdf
5/6
Diseo Ssmico por DesempeoDr. Jos Restrepo, Dr. Mario Rodrguez
INSTITUTO DE LA CONSTRUCCION Y GERENCIA - ICGTelefax: (01) 4217896 / [email protected] / www.construccion.org
Displacement-Based
Adaptive Pushover Dual to force-based
Displ. increments prop. to instantaneous mode shape
genva ue so u on requ re w en T c anges
Advantages Changes in the mode shapes can be included
Full-mechanism response can be evaluated
Drawbacks High computational effort (repeated eigenvalue solutions)
Simplified Pushover for Hw #1
Suitable for cantilever walls (only one plastic hinge at the
base)
orce s r u on s assume xe as an nver e
triangle
Vb Mb = Vb * heff
VbVb
Mb
Mb
V Mp.h.
eff
8/11/2019 4_Pushover.pdf
6/6
Diseo Ssmico por DesempeoDr. Jos Restrepo, Dr. Mario Rodrguez
INSTITUTO DE LA CONSTRUCCION Y GERENCIA - ICGTelefax: (01) 4217896 / [email protected] / www.construccion.org
Simplified Pushover for Hw #1
Base moments at
significative stages of M-
M
re a ons p or e ase
section are taken
Corresponding base shears and moment profiles are
calculated based on the assumed force distribution
Curvature profiles are determined knowing moment and
-
Curvatures are integrated to find the roof displacementat each stage
Roof displacements are associated to the corresponding
base shears and the pushover curve is found