LVR_POSTELNICU_12

SAFERR

Izolarea Bazei Studiu de caz Structur cu perei de beton armat: P+8E (Bucureti)

Nivel Curent Base

PresenterPresentation NotesI wiil trea only the siesimic base-islation so all over the paper seismic is missingThe idea of seismic base isolation emerged in the early 1970 in New Zealand [1] Traditional seismic approach implies the design of the building in order to be strong enough to resist the horizontal forces induced by the ground shaking.A more modern approach is to try to minimize the effects of the ground shaking. This can be realized by introducing an isolation layer between the ground and the building. An ideal isolation implies that no motion will be transmitted from the ground to the building (Fig.1 a) Unfortunately, the weight of the building and its containment must be transmitted to the ground. The solution is to introduce an isolation layer (Fig.1 b) that has to be very stiff vertically (to constrain the vertical movement) and very soft in horizontal movement (to allow relative displacements between the ground and building). Suitable devices having such properties are, for example, natural rubber bearings (NRB) (Fig.2). The main components of the isolation layer are the isolators or bearings as stated in the previous paragraph. The usual NRB isolators posses no or very low damping. In order to reduce the relative displacement between the ground and building, and to stop the horizontal motion as soon as possible once initiated, dampers are added to the isolation layer. Very many kinds of dampers are presently available. Widely used types are hysteretic dampers (Fig. 3 & 4) and viscous hydraulic dampers (fig.5). The hysteretic ones damp the motion through plastic deformations of the steel rods (Fig.3) or lead sticks (Fig.4). The hydraulic ones consist of oil dampers that damp the motion through viscous behavior of the oil (Fig.5).

SAFERR

Etapele studiului

1. Proiectarea structurii neizolate (metoda clasic)

2.1 Dimensionarea nivelului de izolare - metoda simplificat ( Teff, Keff );

2.2 Verificarea metodei simplificat (calcul dinamic neliniar pe sistemul cu 1GLD);

2.3 Proiectarea structurii la eforturile rezultate;

2.4 Verificarea soluiei printr-un calcul dinamic neliniar (time history);

2. Proiectarea structurii izolate

PresenterPresentation NotesSeismic LoadsDesign spectraThe significant effect of the local soil condition was greatly emphasized by the 1995 Kobe earthquake. Buildings located at approximately the same distance from the epicenter had experienced very different ground acceleration levels [15], [16], [17]. One of the explanations was found to be the effect of the local soil properties. Consequently, in BSL [18] an explicit consideration of the local soil effect on the design spectrum is provided (Eq. 3):were: SA 5% damping acceleration response spectrum; Z seismic zoning factor (Z takes values from 0.7 to 1, but is equal to unity for approximately 80% of Japans territory); Gs local soil amplification factor; S0 5% damping acceleration response spectrum at exposed engineering bedrock (Eq. (4) and fig. 7 a.). The L-1 corresponding spectrum is obtained by dividing the L-2 associated spectrum values to a coefficient equal to 5. The engineering bedrock is defined as a layer with more than 400 m/s in shear wave velocity.The soil effect can be assessed using a program code like SHAKE [19], if the accelerogram at the engineering bedrock is given and the local soil profile is known. Fig. 7 a. approximates the expected amplified acceleration spectra corresponding to L-2 intensity level for stiff, medium stiff and soft soil profiles, for the cases where the soil properties are not precisely defined [20].Ground motionsThe Japanese design practice for seismic isolated buildings involves time-history analysis. The analytical model should be checked against two groups of accelerograms. The first group should consist of standard accelerograms like El CENTRO 1940, TAFT 1952 and HACHINOHE 1968 (fig. 7 b.). HACHINOHE ground motion is preferred mainly due to the long period components. The second group must consider the characteristics of the local site. Natural accelerograms recorded in the vicinity of the building site may be used, if available. Alternatively, synthetic accelerograms can be constructed. Two types of procedures for the construction of the artificial ground motions are used. The first one ([21], [22], [23], [24]) starts from the fault rupture and the effect is estimated at the seismic bed rock through convolution. Finally, the amplification of the waves over the bedrock and from the engineering bedrock to the surface is assessed. The second starts from the engineering bedrock with the generation of artificial ground motions, compatible with the spectrum defined at paragraph 4.2.1, and the effects of the local soil are determined using SHAKE type program codes. The most debatable aspect in the case of the synthetic accelerograms is the adopted phase spectra. The common solution is to consider the phase spectra similar to the recorded accelerogram or alternatively, white noise distribution.The standard accelerograms are scaled for PGV equal to 0.25 m/s2 and 0.5 m/s2 corresponding to L-1 and L-2 levels defined in paragraph 4.1. The peak ground velocity of recorded accelerograms is determined by proper integration of the acceleration time-history. There is a deliberate contradiction between the ratios of the L-2 to L-1 intensity (2 to 1) recommended for the scaling of the standard accelerograms and the ratio of the same intensity levels provided by BSL 2000 (5 to 1 paragraph 4.2.1). 5 to 1 ratio has been a design concept for common buildings, but for special structures that require peer-review through the BCJ committees (presented in paragraph 4.5) a conservative measure of 2 to 1 ratio is adopted. L2 intensity level is the same, meaning that L1 intensity level is much larger for peer-review ones. The seismic demand is decided by taking the maximum time-history response values resulted from all considered ground motions.Design Methods. Analysis Model of the Structure and Isolation Layer Simplified models for time-history analysis, like lumped mass model (stick model), are accepted and commonly used in the design process of base-isolated structures. First, a preliminary design of the upperstructure is completed. The preliminary design will be enhanced according to the dynamic response of the structure but initially a value of the base-shear coefficient is assumed (usually between 0.1 and 0.2). Then a nonlinear push-over analysis of the structure is carried out in order to estimate the force-deformation relationship for each story. Elements with concentrated plastic hinges are usually adopted for analysis. Often, a spatial model is constructed to check the sensitivity of the structure to torsion and bi-directional actions. Based on the story shear-deformation relationship the story stiffness and strength characteristics of the stick model are developed. The chosen hysteretic model is usually degrading triliniar (Takeda model) for RC structures and triliniar or bilinear for steel structures. The analysis models of the isolation layer depend on the types of seismic isolators and dampers. The common models are elastic springs for NRB, bilinear hysteretic for lead and steel dampers, modified bilinear for HDRB or LRB and viscous springs for oil dampers.General Requirements. Results of AnalysisTo achieve an effective reduction of the earthquake demands, the ratio of the fixed base period to the base-isolated period of the structure is recommended to be greater than 3. The period in the large displacement domain computed on tangential isolators stiffness, is commonly greater than 3.5 s. The placement and number of the isolators are determined by the tributary gravitational loads. The vertical average stress of the isolators is set to be about 10 N/mm2 for NRB and LRB and a little lower for HDR. The number of dampers is assessed in order to obtain an equivalent damping for L-2 earthquake of about 15-20%. The hysteretic dampers, if used, are designed to resist the frequent lateral loads in the elastic domain. The common yield threshold of the hysteretic dampers is in the range of 3-9% of structure weight and is determined by wind load. After the time-history analysis of the stick model subjected to the chosen ground motion is performed, the maximum values of the response parameters are determined. The most important response parameters are:Maximum displacement of the isolation layer. The demand (L-2 performance level) is checked against the linear limit deformation of natural rubber bearing (300-400 mm for common devices) that corresponds to a shear strain of 200-250%. The safety factor against buckling or failure is in the range of 2. The dampers are chosen to be able to sustain a significantly larger number of cycles of maximum amplitude than the ones resulted from the analysis. The clearance (isolation gap) and the stroke of the hydraulic dampers are determined using a safety factor in the range of 1.5 with respect to the determined maximum displacement. The upperstructure is limited to elastic response for L-1 intensity level. Accidental yielding is accepted for L-2 earthquakes but full formation of plastic hinges is avoided. Maximum drift angles are limited to 2% and 1% for L-1 and L-2, respectively. The maximum floor acceleration is limited to 3 m/s2.Regulatory Environment in JapanThe seismic isolated buildings in Japan require a special license from the Ministry of Construction. The Building Center of Japan (BCJ) is mandated by the Ministry to organize review committees that act as a third party review and administer the building approvals for special types of structures. Each committee is delegated for reviewing one type of special structures, for example, there are committees for high-rise, base-isolated, special concrete or steel structures. The committee for reviewing base-isolated buildings is composed of about 20 university professors and, additionally, of structural engineers that represent the professional design and structural associations from Japan (Japan Structural Consultants Association JSCA, Building Constructors Society - BCS, Japan Society of Base Isolation - JSSI).Seismic base isolated committee must review every isolated building submitted by the designers or by the construction companies. The designer provides an essence of the design documents consisting of a binder of about 50 mm. Two members of the committee are assigned for each design project. On the average, one or two months are necessary for the completion of the review and during this time the assigned reviewers meet one or two times. In addition to administering the approvals process, the BCJ publishes a journal [2], which contains the design data for all the licenses granted by the various committees and periodically includes design recommendations that, taken together, define a sort of informal code (for example [6]). Designers tend to follow these recommendations to speed the review process.

Structur neizolat - P+8E Bucureti

Metoda de calcul a structurii este Metoda forelor echivalente

- proiectarea unui mecanism favorabil de disipare a energiei seimice;

- detaliere constructiv pe baza prevederilor din P100-2006;

- Considerarea unei distribuii liniare pe nlime a forei seismice;

- Factor de comportare q=4;

1. Proiectarea structurii neizolate;

SAFERR

Structur izolat - P+8E Bucureti Se propune utilizarea urmtoarelor dispozitive :

Izolatori din cauciuc natural (NRB) Amortizori histeretici din plumb (U180)

Model de comportare:

Sistem biliniar

0

10002000

3000

40005000

6000

0 0.1 0.2 0.3 0.4

Deplasare (m)

Fort

a (K

N)

PresenterPresentation NotesNRB consist of many layers of natural rubber with thickness in the range of 3 - 9 mm, intercalated with stiff slender steel plates of 2.5 - 4.5 mm. The main parameter that controls the vertical stiffness is the S1 shape factor, defined as the ratio of the loaded area to the force free area. S1 represents a dimensionless measure of the aspect ratio of a single layer of rubber. For a circular isolator of diameter D and rubber layer thickness tR, S1 = D/4tR [9]. The usual S1 values are in the range of 30 to 40 with maximum values of about 45. The vertical stiffness associated with stated S1 shape factors is between 2.5 - 3.0 106 kN/m. The second shape factor S2 is defined by the aspect ratio of the rubber included in the isolator S2 = D/ntR (n is the number of rubber layers). S2 value has an important impact on the buckling behavior of isolators. The usual values for S2 are around 5 due to the fact that no significant buckling effect is expected for S2 > 5.The manufacturers usually offer three types of bearings according to the properties of rubber. The rubber shear modulus can be chosen from 0.35, 0.4 or 0.45 N/mm2. The long term compressive stress ranges from 10 to 15 N/mm2 and the short term compressive stress (under earthquake loading) varies from 20 to 30 N/mm2.The diameter varies from 500 to 1550 mm with usual values between 600 ~ 1200 mm. The design deformation is set to about 250-300% shear strain (450 550 mm, for 800 mm diameter) and the ultimate deformation corresponding to buckling or collapse to approximately 400% (550 to 800 mm), respectively.Dependency of the vertical and lateral stiffness on creep, ageing, vertical stress, shear strain, temperature, load history, frequency of loading cycles is specified in the product data sheet. The main parameters variation depending on one factor is in the range of 10%. Up to 20% total variation for the lateral properties and 10% for the vertical ones is specified by the manufacturer as normal. NRB can be modeled for analytical computation as linear springs. After the design displacement limit is attained (250-300% strain) the rubber isolators present a significant strain hardening effect until collapse. The stiffness in this domain reaches up to 6-8 times the design stiffness and the computation model beyond the design limit can be properly modeled as bilinear elastic spring.Because NRB do not posses any significant damping properties it is compulsory to be coupled with dampers.

SAFERR

Raportul intre perioada izolata si fixata la baza > 3 ;

Efortul unitar mediu de compresiune in izolatori ~ 15 N/mm2 ;

Amortizori realizeaza o amortizare echivalenta 20-30% ;

Amortizori histeretici reziste ncarcarilor din vnt;

Amortizori astfel dispusi incat sa nu existe torsiune;

Suprastructura sa ramana in domeniul elastic

(q=1.5);

Structur izolat - P+8E Bucureti

( )effeffejj ,TSmf =

Reguli de predimensionare



2.1 Dimensionarea stratului de izolare : Ipotez de calcul: sistem liniar echivalent

Sistem liniar-elastic

0

1000

2000

3000

4000

5000

6000

0 0.1 0.2 0.3 0.4

Deplasare (m)

Fort

a (K

N)

Sistem liniar-elasticSistembiliniar


Dimensionare izolatori: Limitarea efortului unitar axial de compresiune pentru grupare de lunga durata

Limitarea efortului axial de intindere

Limitarea deplasarii orizontale pentru SLU (IMR=100 ani)

215 /LD adm N mm =

2int 1 /indere adm N mm =

minint 2.5 izcer a adm h =


Dimensionare amortizori: Acestea se dimensioneaza pentru a obtine o amortizare cuprinsa intre 20-30% Se recomanda aceste valori de amortizare din urmatoarele considerente

a) Reducerea deplasarilor orizontale

b) Pentru valori mai mari de amortizare cresc eforturile orizontale aduse la structura

Determinarea amortizarii efective se face printr-un calcul iterativ (metoda simplificata):

conditie de oprire:

2( ) ( ) ( )2

effu De eff d eff

TS T S T

= =

1 1 11

2 ( ) ; 2i

eff

uy yi i ieff effi i

u u u eff

F F MK TF K

+ + ++

= = =

1

1 1 1 2( ) ( ) ( )2

eff

u eff eff

ii i i

De d

TS T S T

+

+ + + = =

21.89% ~ 0.609neff =

1 5%i iu u+


Solutia adoptata (metoda simplificata): 16 izolatori NRB (d=65cm, h=17cm, G=3.5 Kgf/cm2, S2=D/ntR ~ 4 )

20 amortizori din plumb U-180 (Fy=100 KN, y=0.0083 m, k1=12 t/cm,

k2=0 t/cm)

2 212.5 / 15 /LD admN mm N mm = =

2 2int 0.74 / 1 /indere admN mm N mm = =

minint 0.3191 2.5 0.425izcer a admm h m = = =

21.89% ~ 0.609neff =


Ipoteze de calcul: Structura are o comportare de solid rigid

(sistem cu 1GLD echivalent);


Izolatorii au o comportare biliniar ; Sistem biliniar

0

10002000

3000

40005000

6000

0 0.1 0.2 0.3 0.4

Deplasare (m)

Forta

(KN)


Calculul s-a efectuat cu ajutorul unui program de calcul spectral (Sinel);

n calcul s-au considerat dou accelerograme nregistrate (Martie1977) i cinci accelerograme artificiale compatibile cu spectrul de proiectare;

S-a urmrit determinarea cerinei de deplasare pentru sistemul considerat att pentru SLU (IMR=100 ani) ct i pentru Seismul maxim credibil(IMR= 475 ani);

Deplasrile obinute din calcul au fost comparate cu cele obinute din metoda simplificat precum i cu deplasrile admisibile ale sistemului de izolare;


simplifica cerinta zolator( ) 2.5 /1.2

(0.3199 )0.31183 0.354ih

m m m

Starea limit ultim - SLU (IMR=100 ani)

Starea Precolaps (IMR=475 ani)

cerinta zolator4 /1.20.4921 0.57

ihm m


2.3 Proiectarea i dimensionare structurii izolate.

Distribuia forei seismice este constant pe nlimea cldirii (modul 1 = mod de translaie);

Dimensionarea elementelor structurale se face la valorile maxime obinute din aciunea ncrcrilor gravitaionale i a ncrcrilor seismice;

Detalierea elementelor structurale se face n mod similar cu situaia cldirilor supuse strict la aciuni gravitaionale;

Structur izolat - P+8E Bucureti Deplasarea relativ de nivel (drift)

Drift

0 0.005 0.01 0.015

PARTER

ETAJ1

ETAJ2

ETAJ3

ETAJ4

ETAJ5

ETAJ6

ETAJ7

ETAJ8Et

aje

Drift

Str.Iz.SLU

Str.Neiz.SLU

Str.Neiz.SLS

Izolarea bazei vs. proiectare traditionala

Structura neizolat:

Structura izolat:

SAFERR

0.241 2,75 0.85 0.140254

0.14025 42335.96 5927.032 25927.03 273 3

106686.54

b

b tot

c

F KN

Mr F H

KNm

= =

= =

= =

=

..

1 ) 1, 2 0.0786

0.0786 45854.93 3604.151 13604.15 272 2

48656.025

gstr iz ef ef

str iz

b

b tot

ac T

qF KN

Mr F H

KNm

= ( =

= =

= =

=

Structur izolat - P+8E Bacu

Structura neizolat: Structura izolat:

SAFERR

0.1646918

2 1245243

b

b tot

cF KN

Mr F H kNm

=

=

= =

. 0.0572653

1 358102

str iz

b

b tot

cF kN

Mr F H kNm

=

=

= =

Izolatori NRB: 12buc. (d=55cm, h=13.5cm) 4 buc. (d=65cm, h=16cm)

Amortizori U-180:16 buc. 0.593


2.4 Calcul dinamic neliniar (Time History);

Calculul s-a fcut cu ajutorul programului ETABS

Sistem biliniar

0

10002000

3000

40005000

6000

0 0.1 0.2 0.3 0.4

Deplasare (m)

Fort

a (K

N)

Model biliniar de comportare Model de calcul -Link Plastic1 (Wen)


Aciunea seismic a fost modelat cu ajutorul accelerogramei nregistrate INCERC N-S 1977 4 Martie


Verificarea deplasrii cerin la nivelul izolatorilor:

DeplasareBASE

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50

Time (s)

Dep

lasa

rea

(m)

Time HistoryMetoda Simplif.Metoda Simplif.Depl.Capabila SLUDepl.Capabila SLU

Structur izolat - P+8E Bucureti Verificare ipoteza de solid rigid:

U1top-U1base

-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

0 10 20 30 40 50

Time (s)

U1t

op-U

1Bas

e

TimeHistory

D*c*q

D*c*q


Comportarea Link Plastic1:

Structur izolat - P+8E Bucureti Energia disipata de link

Structur izolat - P+8E Bucureti Eforturi grinzi ax 11:

Obs: Eforturile capabile au fost determinate cu rezistene de calcul.

Momente M33

-500-400-300-200-100

0100200300

ET

AJ8

ET

AJ8

ET

AJ7

ET

AJ6

ET

AJ6

ET

AJ5

ET

AJ4

ET

AJ4

ET

AJ3

ET

AJ2

ET

AJ2

ET

AJ1

PA

RT

ER

ET

AJ8

ET

AJ8

ET

AJ7

ET

AJ6

ET

AJ6

ET

AJ5

ET

AJ4

ET

AJ4

ET

AJ3

ET

AJ2

ET

AJ2

ET

AJ1

PA

RT

ER

Etaj

M33

(KN

m)

TimeHistory Mcap+ Mcap- Menve*qel

Structur izolat - P+8E Bucureti Eforturi perete ax 11:

Obs: Eforturile capabile au fost determinate cu rezistene de calcul.

Moment Perete

-25000-20000-15000-10000-5000

05000

10000150002000025000

0 10 20 30 40 50

Time (s)

M33

(KN

m) M33-Time History

Mcap (KNm)Mcap (KNm)Msimplif.(KNm)Msimplif.(KNm)

Structur izolat - P+8E Bucureti Concluzii:

Soluia de izolarea a bazei la aciunea seismic este foarte eficient pentru zona Bacu (Tc=0.7s) i eficient pentru zona Bucureti (Tc=1.6s)

Coeficientul seismic este redus cu : 65 % Bacu 44 % Bucureti Momentul de rsturnare este redus cu : 71 % Bacu 54 % Bucureti Drift-ul structurii este mult redus (degradrile n

elementele nestructurale scad) Metoda simplificat ofer rezultate similare cu cele obinute prin

calculul dinamic neliniar

Att P100-2006 ct i EC8 nu prevd o verificare explicit la Starea limit de supravieuire (IMR=475 ani) cu toate acestea autorii acestui studiu consider c o astfel de verificare se impune (Mecanismul de cedare asociat SLU se poate modifica la Starea Limita de supravieuire)

SAFERR

Structura n cadre de beton armat P+5E (Bucureti)

PresenterPresentation NotesI wiil trea only the siesimic base-islation so all over the paper seismic is missingThe idea of seismic base isolation emerged in the early 1970 in New Zealand [1] Traditional seismic approach implies the design of the building in order to be strong enough to resist the horizontal forces induced by the ground shaking.A more modern approach is to try to minimize the effects of the ground shaking. This can be realized by introducing an isolation layer between the ground and the building. An ideal isolation implies that no motion will be transmitted from the ground to the building (Fig.1 a) Unfortunately, the weight of the building and its containment must be transmitted to the ground. The solution is to introduce an isolation layer (Fig.1 b) that has to be very stiff vertically (to constrain the vertical movement) and very soft in horizontal movement (to allow relative displacements between the ground and building). Suitable devices having such properties are, for example, natural rubber bearings (NRB) (Fig.2). The main components of the isolation layer are the isolators or bearings as stated in the previous paragraph. The usual NRB isolators posses no or very low damping. In order to reduce the relative displacement between the ground and building, and to stop the horizontal motion as soon as possible once initiated, dampers are added to the isolation layer. Very many kinds of dampers are presently available. Widely used types are hysteretic dampers (Fig. 3 & 4) and viscous hydraulic dampers (fig.5). The hysteretic ones damp the motion through plastic deformations of the steel rods (Fig.3) or lead sticks (Fig.4). The hydraulic ones consist of oil dampers that damp the motion through viscous behavior of the oil (Fig.5).

SAFERR

Etapele studiului

1. Proiectarea structurii neizolate (metoda clasic)

2.1 Dimensionarea nivelului de izolare - metoda simplificat ( Teff, Keff );


2.3 Proiectarea structurii la eforturile rezultate;

2.4 Verificarea soluiei printr-un calcul dinamic neliniar (time history);

2. Proiectarea structurii izolate


Structur neizolat - P+5E Bucureti

Metoda de calcul a structurii este Metoda forelor echivalente

- proiectarea unui mecanism favorabil de disipare a energiei seimice;

- detaliere constructiv pe baza prevederilor din P100-2006;

- Considerarea unei distribuii liniare pe nlime a forei seismice;

- Factor de comportare q=6.75;

1. Proiectarea structurii neizolate;


2.1 Dimensionarea stratului de izolare : Ipotez de calcul: sistem liniar echivalent

Sistem liniar-elastic

0

1000

2000

3000

4000

5000

6000

0 0.1 0.2 0.3 0.4

Deplasare (m)

Fort

a (K

N)

Sistem liniar-elasticSistembiliniar

SAFERR

Solutia adoptat : 16 izolatori NRB (d=65cm h=16.25cm G=3.5 Kgf/cm2, S2=D/ntR ~ 4 )

20 amortizori din plumb U-180 (Fy=100 KN, y=0.0083 m, k1=12 t/cm, k2=0 t/cm)

2 28.95 / 15 /LD admN mm N mm = =

2 2int 0 / 1 /indere admN mm N mm = =

minint 0.394 2.5 0.4062izcer a admm h m = = =

20.47% ~ 0.627neff =



Deplasare

0.1

0.2

0.3

0.4

cerinta zolator4 /1.20.4028 0.5416

ihm m

Starea limit ultim - SLU (IMR=100 ani)

Starea Precolaps (IMR=475 ani)

simplifica cerinta zolator( ) 2.5 /1.2

(0.328 )0.238 0.3385ih

m m m


Deplasare

0.1

0.2

0.3

0.4

0.5

0.6


2.3 Proiectarea i dimensionare structurii izolate.

Distribuia forei seismice este constant pe nlimea cldirii (modul 1 = mod de translaie);

Dimensionarea elementelor structurale se face la valorile maxime obinute din aciunea ncrcrilor gravitaionale i a ncrcrilor seismice;

Detalierea elementelor structurale se face n mod similar cu situaia cldirilor supuse strict la aciuni gravitaionale;


Deplasarea relativ de nivel (drift)

Drift

0 0.01 0.02 0.03

STORY1

STORY2

STORY3

STORY4

STORY5

STORY6

Etaj

e

Drift

Str.Iz.SLU

Str.Neiz.SLU

Str.Neiz.SLS

Izolarea bazei vs proiectare traditionala

Structura neizolat:

Structura izolat:

SAFERR

0.0832185.5426226.48

b

cFMr KNm

==

=

. 0.12163751.3433762.06

str iz

b

cFMr KNm

=

=

=

Structura neizolat:

Structura izolat:

SAFERR

0.0962581.8630982.32

b

cF KNMr KNm

==

=

. 0.0722261.6920355.21

str iz

b

cFMr KNm

=

=

=

Structur izolat - P+5E Bacu

Izolatori NRB: 16buc. (d=65cm, h=17cm) Amortizori U-180: 20 buc. 0.632


2.4 Calcul dinamic neliniar (Time History);

Verificarea deplasrii cerin la nivelul izolatorilor:

DeplasareaBASE

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0 10 20 30 40 50

Time (s)

Dep

lasa

re (m

) Time HistoryMet.Simplif.

Met.Simplif.

McapSLU

McapSLU

Structur izolat - P+5E Bucureti Verificare ipoteza de solid rigid:

U1top-U1base

-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

0 10 20 30 40 50

Time (s)

U1t

op-U

1Bas

e

TimeHistory

D*c*q

D*c*q

Structur izolat - P+5E Bucureti Comportarea Link Plastic1:

Structur izolat - P+5E Bucureti Energia disipata de link:

Structur izolat - P+5E Bucureti Eforturi grinzi ax 44:

Moment Incovoietor

-800-600-400-200

0200400600800

STO

RY

6

STO

RY

6

STO

RY

5

STO

RY

4

STO

RY

3

STO

RY

2

STO

RY

1

STO

RY

6

STO

RY

5

STO

RY

4

STO

RY

3

STO

RY

2

STO

RY

1

STO

RY

6

STO

RY

5

STO

RY

4

STO

RY

3

STO

RY

2

STO

RY

1

Etaje

M33

(KN

m)

Time History

Calc.Simplif.

Structur izolat - P+5E Bucureti Concluzii:

Soluia de izolarea a bazei la aciunea seismic este relativ eficient pentru zona Bacu (Tc=0.7s) i puin eficient pentru zona Bucureti (Tc=1.6s)

Coeficientul seismic : se reduce cu 25 % Bacu creste cu 46 % Bucureti Momentul de rsturnare : se reduce cu 34 % Bacu crete cu 29 % Bucureti Drift-ul structurii este mult redus (degradrile n

elementele nestructurale scad) Metoda simplificat ofer rezultate similare cu cele obinute prin

calculul dinamic neliniar

Att P100-2006 ct i EC8 nu prevd o verificare explicit la Starea limit de supravieuire (IMR=475 ani) cu toate acestea autorii acestui studiu consider c o astfel de verificare se impune (Mecanismul de cedare asociat SLU se poate modifica la Starea Limita de supravieuire)

V mulumesc pentru atenie!

Izolarea Bazei Studiu de cazEtapele studiuluiStructur neizolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiIzolarea bazei vs. proiectare traditionala Structur izolat - P+8E BacuStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiStructur izolat - P+8E BucuretiSlide Number 26Etapele studiuluiStructur neizolat - P+5E BucuretiStructur izolat - P+5E BucuretiSlide Number 30Structur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiIzolarea bazei vs proiectare traditionala Slide Number 35Structur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiStructur izolat - P+5E BucuretiSlide Number 42

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