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UNIVERSITATEA TEHNIC DE CONSTRUC II BUCURE TI

BULETINUL TIIN IFIC


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BULETINUL TIINIFIC

AL

UNIVERSITII TEHNICEDE CONSTRUCII

BUCURETI

NR.2/2008


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CUPRINS

STUDII

Rspunsul structurilor cu un nivel dotate cu amortizori cu masacordatn condiiile seismice din Romnia - Ghindea Cristian ............................................................ 5

Legtura dintre managementul calitii n construcii i reducerea riscului

Nafees Ahmed Memon................................................................................................................. 16

Predicia strii mbrcmintei rutiere utiliznd metode numericeBogdan Tudor, Rodian Scnteie................................................................................................... 32

Modelele terenului de fundare pentru mbrcaminti rigide. Vasile Cornea...................... 41

Evaluarea calitii apei n zonele costiere Alexandra Crmizoiu........................................ 51

Realizarea bazei de date a unui sistem informatic cadastral din Republica MoldovaNistor Livia .................................................................................................................................. 59

Evaluri prin incercri de rezistenla solicitri termomecanice alealiajelor pentru structuri aerospaiale - Indira Andreescu ...................................................... 67

Reducerea emisiilor la motoarele ecologice pentru camioane si utilajede constructii (I) Srbu Laureniu............................................................................................ 74

Influena coninutului armonic al curenilor asupra sarcinii admisibile aconductoarelor electrice Mircea Roca................................................................................... 82

Un model fizic de ardere a particulei de rumegun suspensie Ioana Mogo .................... 97Modelarea hidraulica reelei de canalizare. Studiu de caz: municipiul Buzu

Alexandru Lungu, Victor Octavian Luca ..................................................................................... 105

Modelarea i optimizarea deciziilor pentru conducerea tiinifica activitii

operatorului de alimentare cu api canalizare - Claudiu Albu ........................................... 111


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Buletinul tiinific al UTCB nr.2 2008 5

Rspunsul structurilor cu un niveldotate cu amortizori cu masacordatn condiiile seismice dinRomnia

One Story Buildings Endowed WithTuned Mass Dampers SeismicResponse for Romanian EarthquakeCondition

Cristian Ghindea, asist. univ. ing., Universitatea Tehnica de Construcii Bucureti (Technical University ofCivil Engineering of Bucharest), Catedra de Rezistena Materialelor (Strength of Materials Department), e-mail:[email protected]

1. Introducere

Pentru obinerea unui nivel acceptabil deperforman al cldirilor, n cazul uneimicri seismice, n proiectareaconvenional se utilizeaz capacitateastructurii de rezistenta de a absorbi i disipaenergie. Aceasta disipare de energie nu se

poate produce fr admiterea unui anumitgrad de degradare a structurii. Un exemplu arfi apariia articulaiilor plastice la capetelegrinzilor i la bazele stlpilor, elemente careau un rol important nsi in sistemul pentru

preluarea ncrcrilor gravitaionale.La nivel mondial, tot mai multe cldiri sunt

proiectate s reziste la aciunea seismicutilizndu-se un concept relativ nou, ianume acela de a introduce n structurdispozitive speciale cu rolul de a absorbii/sau disipa energia indus n structur demicarea seismic.Dispozitivele de amortizare cu mas acordat(TMD - Tuned Mass Damper) se ncadreaznaceast categorie de dispozitive speciale. nalte ri, au fost folosite cu succes acestedispozitive pentru reducerea vibraiilorstructurilor cu rspuns dinamic caracterizat decontribuia unui anumit mod de vibraie [1].Studiul are in vedere urmrirea rspunsului

structurilor dotate cu sisteme de amortizarecu masa acordat n condiiile speciale datede seismicitatea teritoriului Romniei.Datorit necesitii acordrii dispozitivuluide amortizare cu un mod de vibraie

predominant al structurii [2] s-au analizat treistructuri cu un singur nivel, acestea fiindechivalate cu trei sisteme cu 1 GLD.Caracteristicile dinamice ale sistemelor cu 1GLD au fost determinate n funcie decaracteristicile dinamice ale micrilor

1. Introduction

To obtain a reasonable performance level,for conventional seismic design are used thedamping and dissipation capacities of thelateral resistant structure. This admits acertain degree of deterioration of thestructure. Such an example is the

appearance of plastic hinges in beams and atthe base of the columns, elements with animportant role in supporting the gravitationalloads.Globally, more buildings are designed to resistto seismic loads using a relatively new conceptwhich presupposes to include in the structuresome special devices to damp or/and dissipatethe earthquake induced energy.The Tuned Mass Damper (TMD) devices can

be included in this special category odevices. In other countries this devices weresuccessfully used for vibration reduction instructures with dynamic responsecharacterized by one vibration period [1].This paper pursues to obtain the dynamicresponse of buildings endowed with tunedmass dampers for the special earthquakeconditions of Romanias countryside.Because of the necessity of the device to betuned with the predominant vibration period

of the structures [2] three one story buildingswere analysed. All the buildings weremodeled as a SDOF system. The dynamiccharacteristics of the SDOF systems werechosen in accordance with the dynamiccharacteristics of the considered earthquakerecords.To characterize the response we took thefollowing cases:- the structure without the dampening systemwas equated with a SDOF system (fig. 1.1),

and


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6 Buletinul tiinific al UTCB nr.2 2008

Fig. 1.1Sistem cu 1 GLDSDOF system Fig. 1.2Sistem cu 2 GLD (sistem cu 1 GLD +

amortizor cu masa acordata)Two-DOF system (SDOF system + TMD)

seismice considerate.Pentru caracterizarea rspunsului s-au considerat:- structura frsistemul de amortizare, echivalatcu un sistem cu 1 grad de libertate dinamica(figura 1.1), i

- structura cu TMD, echivalatcu un sistem cudoua grade de libertate (figura 1.2). Un grad delibertate corespunznd sistemului iniial si cel deal doilea grad de libertate corespunzndsistemului de amortizare.Rezolvarea acestei probleme a pornit de laecuaia de echilibru dinamic caracteristic unuisistem cu 1 GLD i, respectiv, de la ecuaiile demicare ale sistemului cu masa acordata [3].Ecuaia de echilibru dinamic pentru 1 GLD:

( ) ( ) ( ) ( )tuMtKxtxCtxM g&&&&& =++ (1.1)Sistemul de ecuaii de echilibru dinamic pentru 2GLD:- pentru sistemul secundar:

( ) ( )[ ] ( ) ( ) ( )tumtyktyctxtym gdddd &&&&&&& =+++ (1.2)

- pentru sistemul principal:( ) ( ) ( ) ( ) ( ) ( )tuMtyktyctKxtxCtxM gdd &&&&&& =++

(1.3)unde:

dmM , - masa sistemului de bazi, respectiv,masa sistemului de amortizare;

dcC, - coeficientul de amortizare al sistemului

de bazi, respectiv, al sistemului de amortizare;

dkK, - rigiditatea sistemului de baz i,

respectiv, rigiditatea sistemului de amortizare;( ) ( ) ( )txtxtx ,, &&& - acceleraia, viteza i deplasarea

relativcorespunztoare sistemului de baz;( ) ( ) ( )tytyty ,, &&& - acceleraia, viteza i deplasarea

relativ corespunztoare sistemului de

amortizare;

- the structure with TMD was equated with aTwo-DOF. One degree of freedomsubstitutes the initial system and the secondDOF substitutes the dampening system.The response was obtained by starting from

the equation of motion of the SDOF and,from the equations of motion system for theTwo-DOF system [3] respectivelyThe equation of motion for SDOF system:

( ) ( ) ( ) ( )tuMtKxtxCtxM g&&&&& =++ (1.1)The equations of motion system for Two-DOF system:

- for the secondary system:( ) ( )[ ] ( ) ( ) ( )tumtyktyctxtym gdddd &&&&&&& =+++

(1.2)- for the principal system:

( ) ( ) ( ) ( ) ( ) ( )tuMtyktyctKxtxCtxM gdd &&&&&& =++

(1.3)where:

dmM , - the mass of the principal system

and, the mass of the damping system,respectively;

dcC, - the damping coefficient of the

principal system and, the dampingcoefficient of the damping system,respectively;

dkK, - stiffness of the principal system and,

the stiffness of the damping system,respectively;

( ) ( ) ( )txtxtx ,, &&& - relative acceleration, velocityand displacement of the main system;

( ) ( ) ( )tytyty ,, &&& - relative acceleration,velocity and displacement of the damping

system;


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( )tug&& - acceleraia terenului.

Rezolvarea ecuaiilor dinamice de echilibru s-arealizat cu ajutorul metodei Newmark deintegrare a ecuaiilor difereniale pas cu pas [4].Pentru integrare s-a considerat acceleraia liniar,

iar parametrii corespunztori, specifici metodeide integrare Newmark, au fost alei astfel:

5.0= i 61= .

2. Descrierea micrii seismice i alegereacazurilor de studiu

S-au analizat ase nregistrri corespunztoare atrei micri seismice importante din sursaVrancea. Caracteristicile nregistrrilor precum i

locaiile unde s-au efectuat acestea se regsesc ntabelul 2.1.n scopul determinrii perioadelor critice s-au realizat spectre Fourier pentru fiecarenregistrare n parte (figura 2.12.6).

( )tug&& - ground acceleration;

The time-stepping solution was reach usingthe Newmarks method of integration for thedifferential equation system [4]. In this casethe linear acceleration method is considered,

for which the Newmark integrationparameters were 5.0= and 61=

2. Earthquake Motion Characterizationand Studies

For three important earthquake motions fromVrancea source six corresponding recordswere analyzed. Table 2.1 shows the

characteristics of the records and therecording sites.To show the critical vibration period, foreach record, the Fourier Spectra were made(figure 2.12.6)

Tab. 2.1 nregistrri micri seismiceEarthquakes acceleration records

nregistrareRecord

LocaieRecording Site

Sursa, componentaSource, component

DataDate t

DuratDuration

Acc. 1 INCERC Bucureti Vrancea, NS 04.03.1977 0.005 s 65.37 sAcc. 2 INCERC Bucureti Vrancea, NS 30.08.1986 0.01 s 25.94 sAcc. 3 IMGB Bucureti Vrancea, NS 30.08.1986 0.005 s 42.92 sAcc. 4 Focani Vrancea, NS 30.08.1986 0.01 s 21.68 sAcc. 5 Mgurele Vrancea, NS 30.05.1990 0.01 s 57.56 sAcc. 6 INCERC Bucureti Vrancea, NS 30.05.1990 0.005 s 52.485 s

n tabelul 2.2 sunt redate caracteristicileimportante pentru fiecare din nregistrrileluate n discuie.

Urmrind rezultatele obinute n urmaanalizrii spectrelor Fourier pentru cele asenregistrri, s-au considerat trei sisteme cuun grad de libertate dinamic ale crorperioade proprii de vibraie sse gseascnvecintatea perioadelor de rspuns maximale micrilor seismice analizate. Pentruacestea s-a considerat ca masa ( ) icoeficientul de amortizare critic () suntconstante, singurele variabile fiind perioada

proprie de vibraie (T) i, implicit,

Table 2.2 shows the important dynamiccharacteristics for every record.

After the analyses of the Fourier Spectra

three SDOF systems resulted.Those systems have the fundamentalvibration period in the neighborhood of the

peak response period of the accountedearthquake records.

For those systems, the mass ( ) and thecritical damping coefficient () wereconsidered as constant, the only variables

being the vibration period (T) and, thestiffness of the system (K), respectively.


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Spectrul Fourier

0

50

100

150

200

250

300

350

400

0.5 1 1.5 2 2.5 3 3.5

T[s]

SFA

INCERCBucuresti , seism Vrancea 4.03.1977,component a NS

Fig. 2.1Spectrul Fourier pentru Acc. 1Fourier Spectra for Acc. 1

Spectrul Fourier

0

20

40

60

80

100

120

140

160

0.5 1 1.5 2 2.5 3 3.5

T [s]

SFA

INCERCBucuresti, seism Vrancea 30.08.1986,componenta NS


Spectrul Fourier

0

20

40

60

80

100

120

140

0.5 1 1.5 2 2.5 3 3.5

T[s]

SFA

IMGBBucuresti , seism Vrancea 30.08.1986,componenta NS


Spectrul Fourier

0

20

40

60

80

100

120

140

160

0.1 0.5 0.9 1.3 1.7 2.1 2.5 2.9 3.3 3.7

T[s]

SFA

Focsani, seism Vrancea 30.08.1986,componenta NS


Spectrul Fourier

0

20

40

60

80

100

120

140

0.5 1 1.5 2 2.5 3 3.5

T[s]

SFA

Magurele, seism Vrancea 30.05.1990,component aNS


Spectrul Fourier

0

10

20

30

40

50

60

70

80

90

0.5 1 1.5 2 2.5 3 3.5

T[s]

SFA

INCERCBucuresti, seism Vrancea30.05.1 990,componenta NS


rigiditatea sistemului (K). Aceste sistemesunt descrise n tabelul 2.3.

3. Studiu parametric

Prima etapa a studiului parametric a vizatdeterminarea influenei diverselorcaracteristici ale sistemului de amortizareasupra comportrii de ansamblu a structuriicu TMD. S-a analizat structura de tip A sub

Table 2.3 shows the properties of analyzedsystems.

3. Parametric Study

The purpose of the first stage of the studywas to determine the influence of differentcharacteristics of the damping system on thegeneral behavior of the system with TMD.Type A structure have been analyzed under a


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Tab. 2.2.Caracteristici importante ale micrilor seismiceImportant earthquake record characteristics

Caracteristici principalePrincipal characteristics

nregistrareRecord

T [s] ASF

Alte perioade importanteOther important vibration periods

Acc. 1 1.64 340.70 T=2.41s, ASF=261.8Acc. 2 1.36 139.39

Acc. 3 1.64 119.21 T=1.46 s, ASF=100.2Acc. 4 0.43 151.57 T=1.21 s (ASF=141.32);T=0.89 s, (ASF=131.26)Acc. 5 1.61 120.90 T=1.34 s, ASF=103.32Acc. 6 2.21 83.09 T=0.99 s (ASF=78.66); T=1.32 s (ASF= 70.83)

Tab. 2.3 Sisteme cu un GLDSDOF Systems

SistemSystem

T[s]

M[t]

Cazul ACase A

1.60 s 50 t 0.05

Cazul BCase B

1.35 s 50 t 0.05

Cazul CCase C

1.00 s 50 t 0.05

aciunea micrii seismice descrise deaccelerograma 1 (nregistrare INCERC Bucureti,seism Vrancea 4.03.1977, componenta NS),

parametrii sistemului de amortizare care au fostvariai, fiind masa ( dm ) i coeficientului de

amortizare critic( d ) al TMD-ului.

n tabelul 3.1 sunt prezentate denumirile cazurileanalizate n aceast etap, precum sicaracteristicile detaliate.

Comparaia rspunsurilor sistemului frTMD ia sistemului cu TMD s-a realizat prinreprezentarea variaiei n timp a deplasrilorrelative la nivelul sistemului cu 1 GLD cu sau frTMD.

load described by accelerograme 1 (recordedat INCERC Bucharest, Vrancea Source,4.03.1977, N-S component). The variables othe TMD system were the mass ( dm ) and the

critical damping coefficient ( d ).

Table 3.1 shows the titles of the analyzed

cases and the detailed description of thecharacteristics.

The comparison between the structurewithout TMD and the structure with TMDwas carried out by showing the time-historyof the relative displacement of the first DOFwith or without TMD.

Tab 3.1. Cazuri analizate pentru sistemul cu TMDAnalysis cases for TMD system

Sistem 1GLD TMDCaz Ms(t)

Ts(s)

s

(%)md

(%Ms)Td(s)

d

(%)nregistrare INCERC Bucureti, seism Vrancea 4.03.1977,componenta NS (Acc.1)INCERC Bucharest Record, source Vrancea, 4.03.1977, NS component (Acc. 1)1. A.I.1 50 1.60 5% 1% 1.60 5%2. A.I.2 50 1.60 5% 2% 1.60 5%3. A.I.3 50 1.60 5% 5% 1.60 5%4. A.II.1 50 1.60 5% 1% 1.60 10%5. A.II.2 50 1.60 5% 2% 1.60 10%6. A.II.3 50 1.60 5% 5% 1.60 10%7. A.III.1 50 1.60 5% 1% 1.60 15%

8. A.III.2 50 1.60 5% 2% 1.60 15%


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Urmrind variaia deplasrilor la nivelulstructurii pentru cele nou cazuri analizate,concluziile preliminare nu sunt diferite de celentlnite n literatur[1] ca fiind caracteristice sialtor tipuri de micri seismice:- O mai buncomportare o au sistemele avnd

masa adiionala de 2% si, respectiv, de 5%, dinmasa sistemului de baza. Mrirea maseiadiionale de la 2% la 5%, aduce un aport

benefic la reducerea amplitudinilor sistemuluide baz, dar acest lucru presupune o creteresemnificativ a ncrcrilor verticale careacioneazasupra structurii (figurile 3.13.3);- Creterea amortizrii sistemului TMD nu ajutla micorarea amplitudinilor maxime, ci doar lao atenuare a micrii mai rapid, n numitelimite ale amortizrii

(figurile 3.43.6).

From the representation of the structuredisplacements in all nine analyzed cases, theconclusions were no different from the onesmet in the literature [1] for other types ofearthquake motions:

- The systems with 2%, respectively, 5%TMD mass are more suitable than the others.Increasing the mass from 2% to 5% brings afavorable contribution to the reduction of theamplitudes of the main system displacement,

but also presumes a significant increase othe vertical loads acting on the structure(figures 3.13.3);- TMD damping rise does not help to reducethe peak amplitudes, it only attenuates fasterthe motion at certain levels of the damping

(figures 3.43.6).INCERCBucuresti, seism Vrancea 4.03.1977,componenta NS

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

16 18 20 22 24 26 28 30

t [s]

Deplasarestructura[m]

GLD A.I.1 A.I.2 A.I.3


-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

16 18 20 22 24 26 28 30

t [s]


GLD A.II.1 A.II.2 A.II.3

Fig. 3.1 Sistem frTMD i sistemele cu %5=d

System without TMD and systems with %5=d

[A.I.1 ( Mmd %1= ), A.I.2 ( Mmd %2= ),

A.I.3 ( Mmd %5= )]



[A.II.1 ( Mmd %1= ), A.II.2 ( Mmd %2= ),

A.II.3 ( Mmd %5= )]


-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

16 18 20 22 24 26 28 30

t [s]

Deplasarestructur

a[m]

GLD A.III.1 A.III.2 A.III.3


-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

16 18 20 22 24 26 28 30

t [s]

Deplasarestru

ctura[m]

GLD A.I.1 A.II.1 A.III.1



[A.III.1 ( Mmd %1= ), A.III.2 ( Mmd %2= ),

A.III.3 ( Mmd %5= )]

Fig. 3.4 Sistem frTMD i sistemele cu Mmd %1=

System without TMD and systems with Mmd %1=

[A.I.1 ( %5=d ), A.II.1 ( %10=d ),

A.III.1 ( %15=d )]


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Mgurele Record, source Vrancea, 30.05.1990, NS component (5)13. A.I.2 50 1.60 0.05 2 1.60 0.0514. B.I.2 50 1.35 0.05 2 1.35 0.0515. C.I.2 50 1.00 0.05 2 1.00 0.05nregistrare INCERC Bucureti, seism Vrancea 30.05.1990,componenta NS (6)INCERC Bucharest Record, source Vrancea, 30.05.1990, NS component (6)16. A.I.2 50 1.60 0.05 2 1.60 0.05

17. B.I.2 50 1.35 0.05 2 1.35 0.0518. C.I.2 50 1.00 0.05 2 1.00 0.05

n tabelul 3.2 sunt prezentate cazurilestudiate in etapa a II-a a studiului parametric.Cele mai importante rezultate sunt prezentaten figurile 3.7 3.12.

Table 3.2 shows the cases analyzed in thesecond stage of the study.Figures 3.7 3.12 shows the representativeresults of the analysis.


-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

16 18 20 22 24 26 28 30

t [s]


fara tMD cu TMD


-0.3

-0.2

-0.1

0

0.1

0.2

0.3

16 18 20 22 24 26 28 30

t [s]


fara TMD cu TMD

Fig. 3.7 Sistem fr/cu TMD [ sTT ds 60.1== ];System without/with TMD [ sTT ds 60.1== ]

INCERC Bucureti, Vrancea 4.03.1977, NS (1.64s)

Fig. 3.8 Sistem fr/cu TMD [ sTT ds 30.1== ];

System without/with TMD [ sTT ds 30.1== ]



-0.15

-0.1

-0.05

0

0.05

0.1

0.15

16 18 20 22 24 26 28 30

t [s]


fara TMD cu TMD


-0.1

-0.075

-0.05

-0.025

0

0.025

0.05

0.075

0.1

3 6 9 12 15 18 21

t [s]

Deplasare

structura[m]

f ar a TM D cu TM D








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-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

2 4 6 8 10 12 14 16 18 20

t [s]


fara TMD cu TMD

Focsani, seism Vrancea 30.08.1986,componenta NS

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

8 10 12 14 16 18 20

t [s]


fara TMD cu tMD






Focani, Vrancea 30.08.86, NS (0.43s; 1.21s; 0.89s)Focsani, seism Vrancea 30.08.1986,componenta NS

-0.18

-0.16

-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

8 10 12 14 16 18 20

t [s]

Deplasarestructura[m

]

fara TMD cu tMD


-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

15 17 19 21 23 25 27 29 31 33 35

t [s]

Deplasarestructura[m

]

fara TMD cu TMD



Focani, Vrancea 30.08.86, NS (0.43s; 1.21s; 0.89s)



INCERC Bucureti, Vrancea 30.05. 90, NS (2.21s; 0.99;1.32s)

4. Concluzii i direcii de studiu

Dup analiza comparativa a rspunsuluistructurilor analizate n cazurile expuseanterior se pot trage urmtoarele concluzii:- Raportat la rspunsul sistemului frTMDse observ c sistemul de amortizare nuintr in lucru, n mod semnificativ, dectdup ocul maxim al seismului. Reducereade amplitudine a deplasrii n momentul

ocului maxim este neglijabil(maxim 5%).Exist ns anumite cazuri n care ocurilemaxime apar cu o scurta ntrziere, acesteafiind precedate de o micare importantcareactiveazTMD-ul (figura 3.13). n acest cazreducea rspunsului dinamic este deaproximativ 25%;- Dup ocul principal, care n majoritateamicrilor studiate se produce nc de lanceput, reducerea amplitudinilor oscilaiiloridepinde de coninutul de frecvene al

micrii seismice. Dac micarea seismic

4. Conclusion and Future Studies

After the analysis of the structural responsefor the studied cases, the conclusions are:- Referring to the response of the systemwithout TMD, we may observe that thedamping device runs significantly only afterthe peak impulse of the earthquake.Displacement amplitude reduction at the

peak earthquake impulse can be neglected

(maximum 5%).There are some cases in which the peakimpulses are delayed being preceded by animportant oscillation which acts on the TMD(figure 3.13). In this case the peak reductionis about 25%;- After the first impact, which in almost allcases occurs at the beginning of motion,amplitude reduction depends on thefrequency content of the earthquake motion.If the earthquake has the important response

near the tuned period of the system with


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are un rspuns important in apropierea perioadeide acordare a sistemului cu TMD atuncireducerea deplasrilor dup ocul iniial esteconsiderabil ntre (20-50%) (de exemplu:figurile 3.7, 3.10, 3.13, 3.14);- n cazul n care micarea seismic nu se

acordeazla rndul su cu sistemul i cu TMD-ul, rspunsul sistemului cu TMD poate s fieaproximativ acelai sau mai mare in comparaiecu sistemul frTMD (de exemplu: figurile 3.8,3.9, 3.12). Un caz deosebit este prezentat nfigura 3.12 unde aproape pe toata durataexcitaiei seismice, structura cu TMD are unrspuns mai mare dect cel al structurii frTMD.- Comparnd cazurile analizate mai sus, se mai

poate observa banda ngust de frecvente in

care sistemul cu TMD se poate acorda cumicarea seismica (pentru o diferen deaproximativ 0,20 s 0,30 s rspunsul sedenatureaz drastic) (de exemplu aa cum se

poate observa n figurile 3.8, 3.11,3.12)Structurile reale au mai mult de un grad delibertate dinamic. Pentru obinerea unorconcluzii mai acoperitoare trebuie studiatefectul sistemelor de amortizare cu masacordat asupra unor sisteme cu mai multegrade de libertate. Astfel rezult necesitateadezvoltrii unui studiu n aceast direcie. nsdatoritgradului de incertitudine din punctul devedere al micrii seismice trebuie avut invedere ca la o evaluare mai amnunit amodului de comportare a sistemelor deamortizare cu masacordat, pe lngmicrilenregistrate care ne stau la dispoziie s sefoloseasc i o serie de micri generateartificial, compatibile cu spectrul de proiectaredescris n normativele n vigoare.

Studiul a fost realizat cu finanare UEFISCU-CNCSIS n cadrul programului PNII, contractnr. 67/2007

TMD then the reduction can be taken intoaccount (20-50%) (for example: figures3.7, 3.10, 3.13, 3.14);

- For the case in which the earthquakemotion is not tuned with the main system

and with the TMD the response can besimilar or greater than the response of thestructure without TMD (for example:figures 3.8, 3.9, 3.12). In figure 3.12 aspecial case is showed for which theresponse of the structure with TMD isgreater than the response of the structurewithout TMD almost from the start to theend of motion.

- By comparing the presented cases one

can notice the thin frequency domain inwhich the TMD system can be tuned withthe earthquake motion (for about 0.20 s 0.30 s the response can be drasticallytainted)( for example: figures 3.8,3.11,3.12).

Real structures have more than one degree of freedom. For a more generalconclusion it is necessary to study theeffect of the tuned mass damper on someMDOF systems. So the necessity todevelop the study results also in thisdirection. Regarding the incertitude of theearthquake motion, for the TMD systemstudies it is necessary to take into account,

besides the recorded accelerograms, someartificial generated accelerograms also, thatare compatible with the design spectraavailable.This study was made with resources from

UEFISCU-CNCSIS, as a part of a PNIIProgram, contract no. 67/2007.

La rponse des structures un tage dotes damortisseurs avec masse accorde dans les conditionssismiques de Roumanie

Rsum

Les dispositifs damortissement avec masse accorde font partie de la catgorie des dispositifs spciauxdattnuation des effets du mouvement sismique ou des structures. Ils sont constitus, en principe, dun poids, dunressort ainsi que dun amortisseur, relis une structure, et dont le rle est la rduction de la rponse dynamique. Lafrquence de lamortisseur est accorde une frquence de la structure ; par consquent, quand celle-ci est stimule


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Legtura dintre managementulcalitii n construcii i reducereariscului

Linking quality management inconstruction with seismic riskreduction

Nafees Ahmed Memon, dr. ing., Universitatea Tehnic de Construcii Bucureti (Technical University ofCivil Engineering Bucharest), e-mail: [email protected]

1. Introducere

Daunele cauzate de recentele cutremure dinPakistan, Indonezia, Iran, India i Turcia au atrasatenia asupra vulnerabilitii sociale ieconomice n continua cretere datoratriscurilor seismice. Numrul mare de pierderiumane continu s existe, iar pierderile

economice sunt ntro cretere dramatic. nurmtorii 20 de ani este de ateptat ca populaiaunora dintre cele mai srace orae ale lumii sajungegalcu cea a Indiei i Chinei, nsumate,iar oamenii sfie nevoii striasc, snvee, ismuncescn aceste aglomerri urbane. Avndn vedere lipsa resurselor i caracterul imperiosde a construi, calitatea construciilor va continuas scad dac nimic nu se va schimba rapid.Acest lucrare face legtura dintreimplementarea Sistemelor de Management al

Calitii n societile de construcii precum iprocesele de construcie, pe de-o parte, ireducerea riscului seismic, pe de cealaltparte.Ea sugereaz msurile necesare ce trebuieadoptate n diferite stadii ale duratei unui proiectde construcii pentru a mbuntii calitateaconstruciilor i a reduce, n consecin, riscul

pierderilor mai sus menionate. Ea subliniazdeasemenea i avantajele implementrii sistemelorde management al calitii n organizareaconstruciei.

2. Importana studiului

Lumea s-a confruntat de nenumrate ori cuimense pierderi din cauza cutremurelor.Seismele au cauzat pe lng imense pierderiomeneti, i importante pierderi financiare subform de structuri prbuite. Daunelerecentelor cutremure din Pakistan, Indonezia,Iran, India i Turcia au atras atenia asupra

vulnerabilitii sociale i economice n

1. Introduction

The damages caused by recentearthquakes in Pakistan, Indonesia, Iran,India and Turkey have brought attentionto the increasing social and economicvulnerability to seismic risks. Therecontinue to be large human losses from

earthquakes and the economic losses arerising dramatically. In the next 20 yearsthe combined population of todays Indiaand China is expected to appear in someof the worlds poorest cities and will need

places to live, learn, and work. Given thelack of resources and the urgency to build,the quality of construction will, unlesssomething changes quickly, continue todecline. This paper links theimplementation of Quality Management

Systems in construction companies andconstruction process with seismic riskreduction. It suggests necessary measuresto be taken at different stages in the lifecycle of a construction project in order toimprove the quality of constructions andconsequently reduce the risk of damages.It also highlights the advantages ofimplementing quality managementsystems in construction organization.

2. Importance of study

The world has been facing huge losses onaccount of earthquakes time by time. Theearthquakes not only cause huge losses ofhuman lives but a significant financialloss also results in the shape of collapsedstructures. The damages caused by recentearthquakes in Pakistan, Indonesia, Iran,

India and Turkey have brought attention


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Prpastia dintre rile dezvoltate i n cursde dezvoltare se lrgete: n secoluldouzeci, patru din cinci decese cauzate decutremure au avut loc n rile n curs dedezvoltare. n anul 1950, dou din trei

persoane proveneau din oraele din zone

seismice, n curs de dezvoltare, n timp cen 2000, raportul era de nou la zece(Geohazards International, 2004). Odatcucreterea populaiei globale, n special nrile n curs de dezvoltare, aceastvulnerabilitate devine din ce n ce mai

pronunat. Potrivit Naiunilor Unite, n2000, o jumtate din populaia globuluitria n zone urbane ce acoper 3% dinteritoriu, o alarmant cretere a densitii.Pnn 2015, Naiunile Unite estimeazc

23 de orae vor avea o populaie ce vadepi zece milioane, i din acestea 6 vor filocalizate n ri n curs de dezvoltare. Din

primele zece aglomerri urbane preconizatepentru 2015, opt sunt orae cu risc seismicde la moderat la ridicat. Cele zece sunt:Tokio, Mumbai, Dhaka, Karachi, MexicoCity, New York, Jakarta i Calcutta [23].

Un cutremur major n unul dintre acesteorae, n special ntrun ora cuinfrastructur fragil i cldiri vulnerabile,

poate cauza distrugeri majore i un numrmare de mori. n rile n curs dedezvoltare nu numai populaia urbandevine din ce n ce mai vulnerabil, dar esten cretere i numrul de dezastre. Avnd nvedere creterea numrului de locuitori, avulnerabilitii i a numrul de dezastre nntreaga lume este necesar pentru rile n cursde dezvoltare s ia msuri de micorare a

dezastrelor seismice. Una dintre aceste msurieste sfie mbuntitcalitatea construciiloraa cum este subliniat n acest articol.

3. Calitatea precar a construciilor principal cauza a pierderilor umane ifinanciare

Literatura de specialitate n domeniul mai susmenionat arat c precara calitate a

construciilor a fost principala cauza a

this goal. The gap between developed anddeveloping countries is widening: four ofevery five deaths caused by earthquakes inthe twentieth century occurred indeveloping countries. Of people living inearthquake threatened cities in 1950, two of

every three were in developing countries; in2000, nine of ten were in developingcountries (Geohazards International, 2004).As the worlds population grows,

particularly in developing countries, thisvulnerability becomes even more

pronounced. According to the UnitedNations, in 2000, one-half of the worldspopulation lived in urban areas crowdedinto 3% of the land area, an alarmingincrease in population density. By 2015, the

United Nations estimates that 23 cities willhave populations exceeding ten million, andof those, all but 4 will be in less developedcountries. Of the top ten urbanagglomerations projected for 2015, eightare cities with a known moderate to highseismic risk, including Tokyo, Mumbai,Dhaka, Karachi, Mexico City, New York,Jakarta, and Calcutta [23].

A major earthquake in one of these cities,particularly in a city with a vulnerablebuilding stock and fragile infrastructure,could cause major devastation and asignificant number of deaths. Not only areurban populations in developing countries

becoming increasingly more vulnerable, butalso the number of disasters is increasing.Considering the increase in population,vulnerability and number of disastersaround the world it is necessary for the

developing countries to take proactivemeasures for earthquake disaster mitigation.One of the important proactive measures inthis perspective is to improve the quality ofconstructions as emphasized in this article.

3. Poor construction quality- the majorcause of human & financial losses

Literature review in the above mentionedarea reveals that poor construction quality

was the major cause of human and financial


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pierderilor umane i financiare n cutremureledevastatoare ce au avut loc n Pakistan, India iTurcia. Studiile i rapoartele de cercetarereferitoare la zona afectatde ctre cutremuruldin Pakistan dezvluie faptul c principalacauza deceselor i a pierderilor de proprieti

i imobile n cutremurul din Kashmir a fostcalitatea precar a construciilor [12][24][28].Raportul pentru Cutremure Speciale (RaportulEERI Special Earthquake) (December 2005) cu

privire la cutremurul din Kashmir relateazurmtoarele: practic calitatea precar aconstruciilor a cauzat numrul mare decalamiti.

Avnd n vedere acest adevr, este o imens

nevoie sse aplice Practicile de Management alCalitii n sectorul construciilor pentru ambunti calitatea construciilor i nconsecinpentru a reduce riscul unor viitoare

pierderi umane i financiare.

4. Obiective

Principalul obiectiv al acestei lucrri este dea evidenia aspectele legate de cum pot fimicorate riscurile n construcii. n acestcontext, lucrarea de faface legtura dintreimplementarea sistemelor de managemental calitii n companiile de construcii i

procesul de construcie,pe de-o parte, ireducerea riscului seismic, pe de altparte.

5. Durata de via a unui proiect deconstrucii

Institutul de Management al Proiectelor

(Project Management Institute) (PMI2000) definete durata de via aproiectului (Project Life cycle) (PLC)astfel: succesiunea continu a fazelorunui proiect de la nceput sau pn lafinalizare [2]. Din punct de vedere al

beneficiarului, durata de via aproiectului unei construcii poate fiilustrat schematic ca n figura 1.

losses in devastating earthquakes whichoccurred in Pakistan, India and Turkey.The surveys and research reports ofearthquake affected area in Pakistanreveal that one of the major causes ofheav death toll and property loss in

Kashmir earthquake is poor constructionquality [12][24][28]. The EERI SpecialEarthquake Report (December 2005) onKashmir earthquake describes that:basically the poor quality buildingconstruction caused the large number offatalities.

Considering the above fact, there is an

immense need to apply QualityManagement Practices in the constructionsector in order to improve the constructionquality and consequently reduce the risk ofhuman and financial losses against futureearthquakes.

4. Objective

The main objective of this paper is tohighlight the aspect that how risk can bereduced in construction. In this context, this

paper links the implementation of QualityManagement Systems in constructioncompanies and construction process withseismic risk reduction.

5. Life cycle of a construction project

The Project Management Institute (PMI2000) defines the Project Life cycle (PLC)as: the steady progression of a project fromits beginning to its completion [2]. Fromthe perspective of an owner, the project lifecycle for a constructed facility may beillustrated schematically in figure 1.


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Fig. 1: Principalele stadii din durata de viaunui proiect de construciiMain stages of the life cycle of a construct project

n esen, un proiect este conceput n timputil pentru a corespunde cererilor pieeisau nevoilor. Mai multe posibiliti pot fi

considerate n faza de planificareconceptual a proiectului, iar fezabilitateatehnologic i economic a fiecreialternative este evaluat i comparat nvederea selectrii celui mai bun proiect.Schemele financiare ale fiecrei variante

propuse trebuie analizate, i proiectul esteplanificat n concordancu timpul necesarfinalizrii lui i cu circuitul financiardisponibil. Dup ce scopul proiectului afost definit cu precizie, proiectarea

detaliat va furniza planul proiectului, iarestimarea costului final va sta la bazacontrolului costurilor. n fazele de achiziiei construcie, furnizarea de materiale iridicarea construciei pe antier trebuie

planificate i controlate cu atenie. Dupterminarea construciei, exist o scurt

perioad de funcionare sau testare aconstruciei cnd aceasta este ocupat

pentru prima dat. n cele din urm,managementul facilitii este lsat n

atribuiile beneficiarului ce va deine totala

Essentially, a project is conceived to meetmarket demands or needs in a timelyfashion. Various possibilities may be

considered in the conceptual planningstage, and the technological and economicfeasibility of each alternative is assessedand compared in order to select the best

possible project. The financing schemesfor the proposed alternatives must also beexamined, and the project is programmedwith respect to the timing for itscompletion and for available cash flows.After the scope of the project is clearlydefined, detailed engineering design will

provide the blueprint for construction, andthe definitive cost estimate will serve asthe baseline for cost control. In the

procurement and construction stage, thedelivery of materials and the erection ofthe project on site must be carefully

planned and controlled. After theconstruction is completed, there is usuallya brief period of start-up or shake-down ofthe constructed facility when it is firstoccupied. Finally, the management of the

facility is turned over to the owner for full

Cererea pieii sau Alte nevoi/Market demands or Precieved needs

Planificarea conceptuali Studiu de fezabilitate/Conceptual planning and Feasibility study

Definirea obiectivelor proiectului i a scopului su/Definition of project objectives and Scope

Proiectare i Inginerie/

Design and Engineering

Plan conceptual i Proiectare preliminar/Conceptual plan or Preliminary Design

Achiziie i ExecuieProcurement and Construction

Darea in Folosin/Startup for occupancy

Utilizarea i ntreinerea/Operation and maintenance

ncheierea funciunii/Disposal of facility

Planuri de Proiectare i Prescripii /Construction plans and specification

Finalizarea construciei/Completion of Construction

Luarea n primire a facilitii/Acceptance of facility

ndeplinirea duratei de via/Fullfilment of Useful Life


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posesiune pe tot restul vieii cldirii, pncnd aceasta va fi demolatsau destinaiai va fi schimbat[2].

6. Legtura dintre ManagementulCalitii n durata de viaa unui proiect

de construcii i reducerea riscurilorseismice

Managementul Calitii n durata de viaaunui proiect de construcii reprezint

procesele necesare pentru a asigura faptulc acel proiect va satisface nevoile pentrucare a fost iniiat. El cuprinde planificareacalitii, asigurarea i controlul la niveluldiferitelor faze ale duratei de via a

proiectului. Caliatea precar a construcieipoate fi cauzat de nerespectareaprocedurilor de management al calitii ndiferite stadii ale duratei de via a

proiectului. inta acestei seciuni este de arelaiona proiectul de management alcalitii cu reducerea riscului seismic.

6.1 Managementul Calitii n analizacererilor pieii sau a nevoilor

Scopul acestei faze este de a definiobiectivele proiectului i scopul su. Odat ce proprietarul a identificat nevoileunei noi faciliti, beneficiarul trebuie s-idefineasc cerinele i a conturezeconstrngerile bugetare. Aceasta implicstabilirea n linii mari a caracteristicilor

proiectului ca de exemplu locaia, criteriilede performan, mrimea, configuraia,forma, echipamentul, serviciile i alte

cerine ale proprietarului necesare pentru astabili aspectele generale ale proiectului.

Caracteristicile proiectului ca de exemplulocaia i performana sunt importante din

punctul de vedere al managementului derisc seismic. n timpul seleciei locaieitrebuie avute n minte aspecte legate deamplasmentul geotehnic i de zonaseismic. Nevoile societii includ, pelng altele, structuri cu rezisten

seismic. De aceea atenia acordata

occupancy until the facility lives out itsuseful life and is designated for demolitionor conversion [2].

6. Linking Quality Management in thelife cycle of a construction project with

seismic risk reduction

Quality management in the life cycle of aconstruction project means the processesrequired to ensure that the project willsatisfy the needs for which it wasundertaken. It covers quality planning,assurance and control at various stagesof a project life cycle. Poor construction

quality may be caused due tooverlooking quality management

practices at different stages of projectlife cycle. This section aims to link

project quality management with seismicrisk reduction.

6.1 Quality management in analyzing

market demands or perceived needs

The aim of this stage is to defineprojectobjectives and scope. Once an owner hasidentified the need for a new facility, theowner must define the requirements anddelineate the budgetary constraints. Itinvolves establishing broad projectcharacteristics such as location,

performance criteria, size, configuration,layout, equipment, services and otherowner requirements needed to establish

the general aspects of the project.

Project characteristics like location andperformance are important from seismicrisk management point of view. Whileselecting the location geotechnical siteconsideration and seismic zone of the siteshould be kept in mind. The perceivedneeds of the society include safe structuresagainst earthquakes besides other needs.

Therefore consideration of above


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parametrilor de mai sus are o importanexceptionaln aceastfaza proiectului.

parameters is of paramount importance inthis phase of project.

Fig. 2: Legtura dintre Managementul Calitii n durata de viaa unui proiect de construcii i reducereariscurilor seismice

Linking Quality Management in life cycle of a construction project with seismic risk reduction

Aplicarea practicilor de management alcalitii folosete la realizarea obiectivuluide mai sus. Paii recomandai pentru a

ndeplini acest obiectiv includ i:

- Angajarea de profesional calificat i cuexperien

- Asigurarea preciziei datelor n cadrulanalizei nevoilor societii/comunitii

- Luarea n calcul a aspectelor legate deamplasamentul geotehnic i a zonelorseismice

- Aplicarea principiilor de managemental calitii n procesul de mai sus

Application of quality managementpractices can help in achieving the aboveobjective. Recommended steps to achieve

this objective include:

- Employment of qualified andexperienced professionals.

- Assuring the accuracy of data inanalyzing the needs ofsociety/community.

- Consideration of geotechnical siteconsiderations and earthquake zone.

- Application of total qualitymanagement principles in the above

process.

(6)Managementul Calitii n

nciunii i ntreinerii /Quality Managementduring operation and

maintenance

(5)Managemntul Calitii la

stadiul de execuie /Quality Management at

construction stage

(4)Managementul Calitii la

nivelul achiziiilor /Quality Management

at procurement stage


nivelul proiectrii iingineriei /

Quality Management atthe design and engineering

stage


nivelul Planificriiconceptuale i a studiului de

fezabilitate /Quality Management atconceptual planning and

feasibility study stage

(1)Managementul Calitii n

analiza cererilor pieei sau anevoilor /

Quality Management inanalyzing market demands

or perceived needs

Legtura dintreManagementul Calitii n

durata de viaa unui proiectde construcii i reducerea

riscurilor seismice /

Linking Quality Managementin the life cycle of a

construction project withseismic risk reduction


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6.4. Managementul calitii la nivelulachiziiilor

Achiziiile se refer la comandarea ilivrarea echipamentelor i materialelornecesare, n special a celor care implicun

interval mare de timp pentru livrare.Selectarea celei mai adecvate forme deorganizare a proiectrii i a lucrrilor deteren reprezint astzi un aspectfundamental al procesului de achiziie.(Turner, 1997; Ashworth, 2002). Din ce nce mai mult, echipa beneficiarului includespecialiti n domeniul managementuluifacilitilor (n special cei menii ssoluioneze nelmuririle clientului legatede organizare) care trebuie sfie familiari

cu amplitudinea de extindere a opiunilorachiziiilor [5] [29]. n cadrul acestui

proces, muli cercettori sunt de acord cproiectarea, managementul, i execuia pot fi teoretic considerate pridistincte, dei n realitate existo oarecaresinergie i suprapunere. (Best and deValence, 1999; Masterman, 2002; Walkerand Hampson, 2003). Pentru acest motiv,categoriile metodelor de achiziie au fostclasificate n trei activiti distincte:

(1)Sisteme tradiionale (includ costuriestimate prin adaos, cantiti

provizorii);(2)Sisteme proiectare-execuie (includ

proiectarea, managementul iexecuia); i

(3)Sisteme bazate pe management(includ proiectare i administrare;managementul contractrii i

managementul construciei).6.4.1 Selectarea criteriilor adecvate de

achiziie

Selecia unei ci adecvate de achiziie esteo sarcincomplexatt pentru client ct i

pentru consultantul clientului (n specialmanagerilor de faciliti strategice celucreazpentru client) i rmne o enigm

pentru muli cercettori, dupcum o arat

volumul mare de cercetri efectuate n

6.4. Quality management at procurement

stage.

Procurement refers to the ordering,expediting and delivering of key projectequipment and materials, especially those

that may involve long delivery periods.Selecting the most appropriateorganization for design and constructionwork represents a fundamental aspect ofthe modern building procurement

process (Turner, 1997; Ashworth, 2002).Increasingly, the integrated client teamincludes facilities management

practitioners (particularly those concernedwith client strategic issues in theorganization) who need to be familiar with

the expanding range of procurementoptions [5] [29]. Within this process, manyresearchers agree that design,management and construction cantheoretically be viewed as discrete parts,although in reality some synergy andoverlap does exist (Best and de Valence,1999; Masterman, 2002; Walker andHampson, 2003). For this reason,categories of procurement methods have

been classified around three distinctactivities:

(1)traditional systems (including cost-plus, provisional quantities);

(2)design and build systems(including design, management andconstruction); and

(3)management-oriented systems(including design and manage;management contracting and

construction management).6.4.1 Selection of appropriate

procurement criteria

Selecting an appropriate procurement pathis a complex and daunting task for both theclient and the clients advisers(particularly client strategic facilitiesmanagers) and remains an enigma formany researchers, as evidenced by the

volume of research conducted in this


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acest domeniu (Franks, 1984; Bennett andGrice, 1990; Chan et al., 2001; Cheung,2001; Masterman, 2002). Este adeseorirecomandat ca alegerea traseului deachiziii s se bazeze pe prioritile iobiectivele clientului (Turner, 1997) ct i

pe consideraii de rezisten i siguran,economice, de mediu i sociale (Love,1996). Cel mai des ntlnit criteriu nliteratura de specialitate, dedicat alegeriimetodelor de achiziie include timpul,

precizia preului, flexibilitatea, calitatea,complexitatea, riscul, concurena,responsabilitatea, disputa i arbitrajul(NEDO, 1985; Skitmore and Marsden,1988; Love, 1998).

Din punct de vedere al managementuluiriscului seismic, calitatea managementuluin procesul de achiziie este importantodat ce acest proces va asigura cea maiadecvat organizare a proiectrii iexecuiei. n afar de asta va ajuta laasigurarea criteriilor de calitate n seleciaechipei tehnice a proiectului, aechipamentului i a materialelor. Paiirecomandai n procesul de achiziie din

punct de vedere al managementului de riscseismic sunt:- Adoptarea unui Criteriu de Evaluare a

Achiziiei (Procurement AssessmentCriteria (PAC)) adecvat lund nconsiderare factorii: viteza (timp),

precizia preului, flexibilitatea, nivelulcalitii, complexitatea, evitarea riscul,concurena preului, responsabilitatea,disputa i arbitrajul.

- Selectarea celei mai adecvate organizri

pentru a prelua aceste sarcini- Asigurarea criteriilor de calitate nselectarea echipei tehnice a proiectului, aechipamentului i a materialelor.

6.5 Managemntul calitii la stadiul deexecuie

Execuia este procesul de punere naplicare a proiectului i de punere n lucrua materialelor i echipamentelor. Ea

implic obinerea de mn de lucru,

subject area (Franks, 1984; Bennett andGrice, 1990; Chan et al., 2001; Cheung,2001; Masterman, 2002). It is oftenrecommended that the choice of

procurement route should be based on theclients objectives and priorities (Turner,

1997) as well as engineering, economic,environmental and social considerations(Love, 1996). The most common criteriafound in literature concerning the choiceof procurement methods include time,

price certainty, flexibility, quality,complexity, risk, price competition,responsibility, and dispute and arbitration(NEDO, 1985; Skitmore and Marsden,1988; Love, 1998).

From the seismic risk management pointof view quality management in the

procurement process is important as thisprocess will ensure the most appropriateorganization for design and construction.Besides this it will help in ensuring thequality criteria in the selection of key

project technical staff, equipment andmaterials. The recommended steps in the

procurement process from the seismic riskmanagement point of view are:- Adoption of the appropriate

Procurement Assessment Criteria(PAC) considering the factors: speed(time), price certainty, flexibility,quality level, complexity, riskavoidance, price competition,responsibility, and dispute andarbitration.

- Selection of most appropriateorganizations to undertake the work.

- Ensuring the quality criteria in theselection of key project technical staff,equipment and materials.

6.5 Quality management at the

construction stage

Construction is the process of physicallyerecting the project and putting thematerials and equipment into place and

this involves providing the manpower,


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structuri. n aceast faz sunt incluse deasemenea i posibilele restaurri alecldirii.Din punct de vedere al managementului derisc seismic, aplicarea managementuluicalitii n acest stadiu este foarte

important. Lipsa controlului calitii ntimpul fazei de ntreinere i funciune afacilitilor poate mri riscul apariieidaunelor n timpul cutremurelor. Paiirecomandai din punct de vedere alcontrolului calitii n timpul funciunii intreinerii sunt:

- Asigurarea la intervale regulate detimp a calitii n timpul ntreineriistructurii.

- Consolidarea structurii pentru a crete/mbuntii stabilitatea la cutremure,daceste necesar.

- Studierea deteriorrilor/comportriistructurii n timpul cutremurelor iluarea de msuri de remediere.

- Analiza din timp n timp a funciuniistructurii i conversia funciunii sale

pentru a reduce riscul apariieideteriorrilor cauzate de cutremur dace necesar.

- Dac se observ c o viitoarentreinere sau conversie a facilitilornu va fi util, atunci structura va trebuidezasamblat iar prile i materialeleaflate ncn stare bun, refolosite.

7. Legtura dintre Sistemele deManagement al Calitii n organizaiilede construcii i reducerea risculuiseismic

Trei principali participani/organizaii suntimplicai de obicei n contracteletradiionale de construcii: beneficiarul,

proiectantul i antreprenorul.Implementarea sistemelor de managemental calitii la nivelul acestor participani

poate fi folositoare n mbuntirea imeninerea calitii construciei i nconsecin n reducerea riscului seismic.Principalele avantaje ale implementrii

sistemelor de management al calitii (ISO

building/structure. In this stage thepossible renovations of the building arealso included.From the seismic risk management pointof view application of quality managementis very important during this stage. Lack of

quality control during maintenance andoperation phase of the facility can increasethe risk of damage on account ofearthquakes. The recommended step fromquality management point of view duringthe operation and maintenance stage are:

- Assuring quality during themaintenance of structure at regularintervals.

- Retrofitting of the structure to increase/

improve its stability againstearthquakes if required.

- Study of the structural losses/behaviorin the event of earthquakes and takingremedial measures.

- Analyzing the function of structuretime by time and converting thefunction of structure to reduce the riskof damages due to earthquakes ifrequired.

- If it is observed that furthermaintenance or conversion of thefacility will not be useful then thestructure should be dismantled and

possible parts and materials of thestructure should be recycled.

7. Linking Quality ManagementSystems in construction organizationswith seismic risk reduction

Three main participants/organizations areusually involved in traditional constructioncontracts: client, designer and contractor.Implementation of quality managementsystem in these organizations can be usefulin improving and maintaining the qualityof construction and consequently reducingseismic risk. The main advantages ofimplementing quality managementsystems (ISO 9000 & TQM) in

construction organization from seismic


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9000 & TQM) n organizaiile deconstrucii din punct de vedere almanagementului riscului seismic suntmenionate mai jos:

risk management point of view are givenbelow

Fig.3: Legtura dintre Sistemele de Management al Calitii n organizaiile de construciii reducerea riscului seismic

Linking Quality management systems in construction organizations with seismic risk reduction /

7.1 Avantajele implementrii sistemelorde management al calitii la nivelulbeneficiarului:

- Angajai calificai i motivai.- Accentuarea mbuntirii continue a

calitii.- Luarea n considerare a standardelor

seismice n faza de proiectare.- Selectarea consultanilor calificai.- Luarea n considerare a criterilor de

calitate n timpul selectriiconsultanilor i a antreprenorilor.

- Transparena n procesul de licitaie.- Monitorizare adecvat a calitii

construciei.- Detectarea non-conformitiilor.- Redresarea non- conformitiilor.

7.1 Advantages of implementing Quality

management systems at client level:

- Qualified and motivated employees.- Emphasis on continuous quality

improvement.- Consideration of seismic standards in

design.- Selection of qualified consultants.- Consideration of quality characteristics

during selection of consultants andcontractors.

- Transparency in bidding process.- Proper monitoring of construction

quality.- Detection of non-conformances.- Rectifying the non-conformances.

3. Avantajele implementrii sistemelor demanagement al calitii la nivelulantreprenorilor / Advantages ofimplementing QM systems at contractorlevel

Legtura dintre Sistemele de Management al Calitiin organizaiile de construcii i reducerea risculuiseismic / Linking Quality Management Systems inconstruction organizations with seismic risk reduction

1. Avantajele implementrii sistemelor demanagement al calitii la nivelulbeneficiarului / Advantages of implementingQuality management systems atclient level

2. Avantajele implementrii sistemelor demanagement al calitii la nivelulproiectantului (consultantului) / Advantagesof implementing Quality Managementsystems atdesigner/consultant level


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- Asigurarea calitii n timpulntreinerii i a funcionrii.

- Conversia/organizarea din timp afacilitilor i reciclarea prilor sau amaterialelor refolosibile.

7.2 Avantajele implementrii sistemelor

de management al calitii la nivelulproiectantului/consultantului:

- Echipa tehnic calificat, motivatpentru o mbuntire continu acalitii.

- Acuratee n a colecta datele necesareproiectrii.

- Luarea n considerare a celor mairecente coduri i standarde seismice.

- Acuratee n prescripiile i desenele de

proiectare.- O mai bunsupraveghere a execuiei i

a calitii.- Control eficient i msuri luate

mpotriva corupiei.- Relaii bune de lucru cu beneficiarii i

antreprenorii.

7.3 Avantajele implementrii sistemelorde management al calitii la nivelulantreprenorilor:

- Echipa tehnici muncitori calificai.- Utilizarea tehnologiei i metodei de

execuie adecvat.- Detectarea adecvat a non-

conformitilor.- Rectificarea din timp a non-

conformitilor.- Punerea accentului pe efectuarea corect

a sarcinilor din prima ncercare.

- Producerea construciilor de calitate nconformitate cu prescripiile existente.- Finalizarea n timp a proiectului.- Luarea de msuri de siguranadecvate

pe antier.

8. Concluzii

Prbuirea structurilor n recentelecutremure din ri ca Turcia, India, iPakistan au dezvluit faptul cunul dintre

motivele principale ale producerii daunelor

- Ensuring quality during maintenanceand operation phase.

- Timely conversion/disposal of thefacility and recycling of possible partsand materials.


management systems atdesigner/consultant level:

- Qualified technical staff withmotivation for continuous qualityimprovement.

- Accuracy in data collection for design.- Proper consideration of updated

seismic codes and standards.- Accuracy in design drawings and

specification.

- Better supervision of the constructionprocess and quality.

- Good control and measures againstcorruption.

- Good working relation with clients andcontractors.


management systems at contractor level:

- Qualified technical and skilledworkers.

- Use of appropriate technology andconstruction method.

- Proper detection of non-conformances.- Timely rectification of non-

conformances.- Emphasis on doing the things right the

first time.

- Producing the quality constructionaccording to specification.- Timely completion of the project.- Provision of proper construction safety

measures on construction site.

8. Conclusion

The failures of structures in recentearthquakes in countries like Turkey, Indiaand Pakistan reveal that poor construction

quality is one of the most important


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a fost calitatea precar a construciilor.Aceasta poate fi cauzatde nerespectareacriteriilor de management al calitii ndiferite stadii ale duratei de via a

proiectului. Acest lucrare a relaionatmanagementul calitii unui proiect de

construcii i implementarea efectiv asistemelor de managementul calitii nsocietiile de construcii cu reducereariscului seismic. Ea sugereaz luareamsurilor necesare n diferite stadii aleduratei de via a unui proiect deconstrucii cu scopul de a mbunticalitatea construciei i implicit de areduce riscul pierderilor umane ifinanciare cauzate de obicei de calitatea

precarn cazul unui cutremur.

reasons in the failure of structures. Poorconstruction quality may be casued due tooverlooking quality management practicesat different stages of project life cycle.This paper has linked quality managementin life cycle of the construction project and

effective implementation of Qualitymanagement systems in constructioncompanies with seismic risk reduction. Itsuggests necessary measures to be taken atdifferent stages in the life cycle of aconstruction project in order to improvethe quality of constructions andconsequently reduce the risk of human andfinancial losses which is usually causeddue to poor construction quality in theevent of earthquakes

La relation entre quality management in construction et la rduction du risque

RsumLes endommagements causs par des sismes rcents au Pakistan, en Indonsie, en Iran, en Inde et en Turquie ont attirlattention sur la vulnrabilit accrue aux risques sismiques, dun point de vue social et conomique. On continue avoirdes pertes humaines cause des sismes. Aussi les pertes conomiques sont importantes. Dans les prochaines 20 annes, onsattend ce que la population combine des Indes et de la Chine daujourdhui fasse partie des plus pauvres du monde.Cette population sera demandeuse de logements, de possibilits denseignement et de travail. En tenant compte delabsence des ressources et de lurgence de construire continuellement, la qualit des constructions se rduira, si deschangements ne sont pas effectus. Ce projet-ci fait la liaison entre la mise en place des systmes de management de laqualit dans les entreprises de construction et le processus de rduction du risque sismique. Nous ferons des suggestionsncessaires d tre appliques pour amliorer la qualit des constructions et, par consquent, aptes rduire le risque

dendommagement. Dans le mme temps, on souligne les avantages de la mise en place des systmes de management de laqualit dans lorganisation des constructions.

BibliografieReferences

[1]. BRIAN E. TUCKER (2004): Trends in Global Urban Earthquake Risk: A Call to the International Earth Scienceand Earthquake Engineering Communities, Seismological Research Letters November/December 2004Volume75,Number6.[2]. CHRIS HENDRICKSON (2003): Project Management for Construction- Fundamental Concepts for Owners,Engineers, Architects and Builders,2003.[3]. C.M. TAM, Z.M. DENG, S.X. ZENG AND C.S. HO. (2000): Performance assessment scoring system of publichousing construction for quality improvement in Hong Kong, international Journal of Quality & ReliabilityManagement, Vol. 17, Nos. 4/5, 2000.

[4]. DAVID ARDITI AND H. MURAT GUNAYDIN (1997): Total quality management in the construction process,International Journal of Project Management Vol. 15, No. 4, pp. 235-243, 1997.

[5]. DENNIS LOCK (2004): Project Management in Construction, Gower Publishing Limited, U.K, 2004.[6]. FLORIN ERMIL DABIJA AND RUXANDRA ERBASU (2002): Building Design-1 (Chapter 2, section 2.4,Quality in Constructions, page 145 to 173), Technical University of Civil Engineering, Bucharest, 2002.

[7]. H. ABDUL-RAHMAN, P.A THOMPSON AND I.L WHYTE (1996): Capturing the cost of non-conformance onconstruction sites (An application of the quality cost matrix), International Journal of Quality & ReliabilityManagement, Vol. 13, No. 1, 1996.

[8]. HONG XIAO AND DAVID PROVERBS (2002): The performance of contractors in Japan, the UK and the USA-An evaluation of construction quality, International Journal of Quality & Reliability Management, Vol. 19, No. 6, 2002.[9]. LOW SUI PHENG, TAN BOON KEE AND ALLEN ANG AIK LENG (1999): Effectiveness of ISO 9000 inraising construction quality standards: Some empirical evidence using CONQUAS scores, Structural Survey Volume17, Number 2, 1999.


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++= bVaYj

ijji , (2)

S-a efectuat analiza multiliniar pornind dela premisa unei multiplicri a efectelor fiecruifactor de influen:

Multi-linear analysis hasbeen performedbased on the idea of a multiplicative effect ofeach influence factor:

++= bVaYj

ijji , (3)

A fost evaluatrelaia dintre valorile prezisei valorile msurate; A fost selectatforma corespunztoare, daca rezultat una acceptabil.

2.1. Modelul de evoluie pentru IRI

Variabil dependenta fost variaia uniformit-ii( IRI ) pe diferite perioade. n final, s-a adoptat oabordare incremental. Astfel, dac se doretecalculul variaiei pentru un numr de ani, se facecalculul pentru fiecare an considernd modificrilerezultate n parametri n anii anteriori.Variabilele independente luate n calcul au fost: IRI (valoarea la nceputul fiecrui intervalanalizat); Timpul; Temperatura la 20 mm n sol;

Precipitaiile medii anuale; Grosimea mbrcmintei bituminoase, Grosimea straturilor de balast; Grosimea totala structurii rutiere;Traficul a fost luat n calcul ca valoare medieanualdar i ca valoare cumulat. Deoarece s-adovedit c grosimile straturilor de balast igrosimea total a structurii rutiere nu prezintsemnificaia dorit n analiz, a fost introdus nlista datelor numrul structural modificat (SNP)care ine cont nu doar de geometrie ci i de

natura materialelor.Pentru calcul s-a avut n vedere ecuaia propuspentru HDM-4:

Correlation between predicted values andmeasured values has been evaluated; The appropriate form has been selected if anacceptable one resulted.

2.1. Evolution Model for IRI

The dependent variable has been the variation of

evenness ( IRI ) for different periods. Finally,an incremental approach has been adopted. If thevariation should be estimated for more years, thecalculation is performed for each yearconsidering the modifications resulted in the

previews years.Independent variables have been: IRI (value at the beginning of the analysisinterval); Time; Temperature at 20 mm in soil; Average annual precipitation; Thickness of the bituminous pavement, Thickness of the ballast layers; Total thickness of the road system.The traffic has been considered as annualaverage daily traffic but also as cumulatevalue. Because it has been proved that ballastand total thickness are not significant in theanalysis the modified structural number (SNP)has been included on the list of independent

variables. SNP includes not only the geometrybut also the nature of the materials.For calculation, the equation proposed byHDM4 has been used:

63.02.3 = BenkSNP (4)

Unde:Benk este deflexiunea Benkelman n mm.Pentru modelul multiplicativ s-a pornit de laincluderea tuturor variabilelor (att simplcti logaritmul) i s-au reinut cte au fostsemnificative (p-value mai mic dect un

prag).

Where:Benk is Benkelman deflexion in mm.For the multiplicative effect the analysis hasstarted by including all available variables(both simple and their logarithm) and retainingas many are significant (p-value less than athreshold).


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De exemplu: timpul, logaritmul traficuluicumulat, IRI iniial, precipitaiile medii,logaritmul temperaturii, logaritmul grosimiitotale, grosimea straturilor bituminoase au fostreinute:

As an example: time, logarithm of cumulatedtraffic, initial IRI, average precipitation,logarithm of temperature, logarithm of totalthickness, thickness of bituminous layers have

been retained.

Tab.1Ieirea LIMDEP pentru IRI

LIMDEP output for IRICoeff. Std.Err. t-ratio P-value

ONE 313.06 74.5733 4.19802 0.0247

TIMP -0.46644 0.078136 -5.96955 0.0094

L_TC 1.1754 0.22665 5.18597 0.0139

IRI 0.144089 0.051425 2.8019 0.0677

PRECMED -0.01036 0.00153 -6.77093 0.0066

L_K -61.9839 13.3428 -4.64551 0.0188

L_GT 13.2503 1.61811 8.18876 0.0038

GROSB -0.26763 0.036959 -7.24129 0.0054

Pe baza rezultatului analizei a fost construitecuaia de evoluie. Aceastecuaie are forma:

Based on the analysis the evolution equation hasbeen constructed. It has the following form:

( ) ( ) ( )

( )GrosBGrosTotTEMP

UMIDIRITRAFtCIRI

GrosBK

UMIDIRIcumt

GrosTotTEMPK

TRAFcum

exp

expexpexp 00

=

(5)

Unde:IRI Variaia IRI n intervalul de timp,

t timpul n ani;

cumTRAF Traficul cumulat,

0IRI Valoarea IRI la nceputul intervalului,

UMID Precipitaiile anuale medii;GrosTotGrosimea totala structurii rutiere;GrosB Grosimea straturilor asfaltice;

KTEMP Temperatura medie n sol (K).Din cauza condiiilor privind semnificaiastatistic acest rezultat nu a putut fi reinut( 0.72 R ).Pentru parametrii selectai au fost analizatediferite combinaii. Dintre acestea s-a reinuturmtoarea dependena variaiei anuale a IRI:

Where:IRI variation of IRI on the interval,

t time in years;

cumTRAF cumulated traffic,

0IRI IRI at the beginning of the interval,

UMID average annual precipitation;GrosTottotal thickness of the road structure;GrosB thickness of the bituminous layers;

KTEMP average temperature in soil (K).Due to the statistical significance of the test

predicted vs. measured values ( 0.72 R ) theresult could not be retained.For the selected parameters different combi-nationshave been analyzed. The following equation for thevariation of IRI has been finally obtained:

KTkKprecGPavKGrosPavSNPKSNPTRAFbKtraf TkUmideeeaIRI = 20 (6)

Unde:TRAFb Traficul mediu pe band;SNP Numrul structural modificat;GPav Grosimea mbrcmintei;Umid Precipitaiile anuale medii;Tk Temperatura la 20mm n sol ;

0a , Ktraf , KSNP, KGrosPav , Kprec , Tk

sunt coeficieni obinui n analizei de regresie.

Where:TRAFb average traffic on lane;SNP modified structural number;GPav pavement thickness;Umid average annual precipitations;Tk temperature at 20mm in soil ;

0a , Ktraf , KSNP, KGrosPav , Kprec , Tk

are coefficients resulted after the regression

analysis.


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A fost efectuat verificarea corelaiei dintrevalorile prezise i valorile msurate i s-aobinut urmtoarea imagine:

The correlation between the predicted andmeasured values has been verified as

presented in the following picture:

y = 1.054x - 0.0406

R2= 0.9621

0.0

0.5

1.0

1.5

2.0

2.5

0.0 0.5 1.0 1.5 2.0 2.5

Valori masurate

Valoriprezise

Fig. 1 Verificarea corelaiei dintre valorile msurate i valorile prezise pentru IRIVerification of the correlation between predicted and measured values for IRI

2.2. Modelul de evoluie pentru HS

Ca variabil dependent studiat a fost impusvariaia HS pe diferite perioade.Pentru modelul cumulativ al HS s-a pornit de laincluderea tuturor variabilelor. Pentru fiecaredintre ele s-a considerat variabila ca atare ilogaritmul ei. n anumite cazuri selectate intuitivau fost utilizate combinaii de variabile.Un exemplu, n care au fost incluse HS itraficul mediu anual este prezentat n continuare:

2.2. Evolution Model for HS

The dependent variable has considered variation ofHS for different periods.The cumulative model for HS started by includingall the variables. For each variable the logarithmwas also considered. In certain cases combinationsof variables have been used. The insignificantvariables have been eliminated.An example of a result including the HS and theannual average daily traffic is presented in thefollowing table:

Tab.2. Ieirea LIMDEP pentru HSLIMDEP output for HS

Coeff. Std.Err. t-ratio P-valueONE -0,11286 0,047133 -2,3945 2,56%

HS 0,352883 0,078165 4,51457 2E-04

TRAF 1,95E-05 7,57E-06 2,57111 0,017

Pe baza rezultatului analizei a fost construit

urmtoarea ecuaia de evoluie:

Based on the result of the analysis the

following equation was constructed:medTRAFCHSCCHS ++= 210 (7)

Unde:HS Variaia HS n intervalul de timp,

HS Valoarea HS la nceputul intervalului,

medTRAF Traficul mediu,

0C , 1C , 2C Coeficienii dezvoltai n analiza

de regresie.

Verificarea corelaiei:

Where:HS variation of HS in the interval,

HS value of HS at the beginning ofinterval,

medTRAF average traffic,

0C , 1C , 2C coefficients resulted from

regression analysis.Verification of the correlation:


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y = 0.6294x + 0.0459

R2= 0.6447

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0 0.1 0.2 0.3 0.4 0.5

Valori masurate

Valoriprezise

Fig. 2 HS; Relaia dintre valorile msurate i cele prezise

HS; relation between predicted and measured valuesp-valueare valoare acceptabilpentru fiecareparametru inclus, dar 2R nu este suficient demare i aceast formul explic doar ~63%din variaia HS . Rezultatul nu a fost reinut.Urmnd procedura specificat s-au obinutmai multe variante de dependen. Totui, nus-a reinut nici-una.De aceea s-a considerat cnu sunt suficientedate pentru a obine o formul satisfctoare.n consecin s-a trecut la adaptarea uneiecuaii cunoscute. deja folosite n practic, i

s-a efectuat calibrrii coeficienilor lacondiiile specifice reelei rutiere pe care s-aufcut msurtorile.Ecuaia are urmtoarea formfinal:

p-value has an acceptable value for eachparameter, but 2R is not big enough and thisformula doesnt explain more than 63% of thevariation of HS . The result has not beenretained. Following the specific procedure, morevariants of dependence equations have beenobtained. However, none of them could beretained. Therefore, it has been considered that notsufficient data are available to obtain a satisfactoryequation. As a result, a known equation, which hasalready been used in practice, has been selected

and the calibration of the coefficients has beenperformed to adapt it to the specific conditionsfrom Romania. The equation has the final form asfollows:

( ) KTrafBTRAFbTRAFbHSaHS += 1ln*0 (8)

Unde:

HS este valoare la nceputul fiecrui an;TRAFb Traficul mediu pe band;

0

a , KTrafB sunt coeficieni obinui n

analiza de regresie.n urma analizei rmne o parte a variaieineexplicat. Acest lucru se corecteaz princalculul unui coeficient de scal.

3. Modelul de evoluie pentru deflexiune

Aa cum am observat mai sus avem deja doumodele de calcul a evoluiei din dateledisponibile.

Where:

HS value at the beginning of each year;TRAFb average traffic on lane;

0

a , KTrafB coefficients have resulted from

the regression analysis.Following the analysis a part of the variationstill remains unexplained. This might becorrected calculating a scale coefficient.

3. Evolution Model for Deflection

As presented earlier, two calculation methodsare available for the calculation of theevolution from available data.


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y = 0.8487x + 5.8866

R2= 0.8531

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140 160

Valoare masurata

Valoareprezisa

Fig. 4 Verificarea corelaiei dintre valorile msurate i cele prezise ale variaiei deflexiunii

Verification of the correlation between predicted and measured values for the variation

Se poate observa o valoare 85.02

=R careeste la limitdar acceptabilpentru cazul dat.

4. Concluzii

Prezenta lucrare ia n studiu o tem de mareimportan din domeniul ingineriei rutiere ianume analiza sistemic a evoluiei striimbrcminilor suple utiliznd informaiilestocate n banca de date. Studiul analizeaz

parametrii care influeneaz performanele

mbrcmintei: indici de stare tehnic, IRI, HS ideflexiune. Studiul s-a efectuat pe date culese de

pe sectoare experimentale pe o duratde peste 7ani. Acolo unde nu au existat suficiente valori aufost utilizate date de pe alte sectoare similare.Analiza pornete de la premisa c structurisimilare, n condiii similare vor aveacomportament similar. De aceea rezultateleobinute pentru anumite condiii (clim, traficetc.) vor putea fi folosite n evaluarea

performanelor altor sectoare cu structursimilardin alte zone cu condiii asemntoare.Stabilirea cu acuratee a strii tehnice i ariscurilor structurale se constituie ntr-un prim

pas spre dezvoltarea i implementarea unuisistem de management al mbrcmintei rutiereeficient. Rezultatele obinute sunt utilizate

pentru calibrarea actualei metodologii de lucrubazate pe utilizarea HDM-4, dar i pentrurealizarea unui program de simulare i prediciea evoluiei strii mbrcmintei rutiere adaptatcondi

iilor specifice din Romnia.

A value 85.02

=R might be observed whichis at limit but still acceptable.

4. Conclusions

The present paper takes into account a veryimportant problem for highway engineeringnamely the systemic analysis of the evolutionof the pavement condition using informationfrom the databank. The study analyzes the

parameters that influence the performance of

the pavement: technical condition indices, IRI,HS and deflection. The study has been

performed on data collected on experimentalsector over a 7 years period. Where nosufficient values have been available otherdata from similar sectors have been used. Theanalysis starts from the postulate that similarstructures, in similar conditions will performsimilarly. Hence, the results derived forcertain conditions (climate, traffic etc.) could

be used to evaluate performances of othersimilar structures from other areas with similarconditions.Assessment of the accurate prediction modelsand the structural risks represents a first stepfor the development and implementation of aneffective pavement management system. Theresults are used to calibrate the presentmethods based on HDM4, but also todevelopment of a simulation and predictionsoftware for pavements, better adapted toRomanian conditions.


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Rsum

Larticle prsente une tude dune grande importance pour le domaine dingnierie routire : lanalyse systmatique

dvolution de la condition technique des systmes routiers souples en utilisant les informations prsentes dans la base dedonnes. Ltude analyse les paramtres qui peuvent influencer les performances des routes : conditions techniques, IRI, HS,dflexion. Ltude a t effectue sur des donnes collectes auprs de secteurs exprimentaux au cours de 7 annes. On autilis lanalyse de rgression multi-linale, avec deux hypothses : des effets additifs et des effets multiplicatifs. Lvolutiona t vrifie selon les conditions de trafic, la gomtrie des routes et les conditions climatiques.Les rsultats seront utiliss afin de calibrer HDM4 et pour le dveloppement dun logiciel de simulation et de prdiction desconditions.

BibliografieReferences

[1] J. B. Odoki, Henry G. R. Kerali, HDM4 Highway Development & Development, Volume Four, AnalyticalFramework and Model Descriptions; World Road Association, World Bank, 1999

[2] William H. Greene,Econometric Analysis/LimDep Users Manual, www.prenhall.com/greene/ealimdep.doc


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Modelele terenului de fundarepentru mbrcaminti rigide.

Foundation Models for RigidPavements.

Vasile Cornea, drd. Ing, S.C. TELOXIM CON SRL Bucuresti, e-mail: [email protected]

1. Introducere

Dei n literatura de specialitate existmulte modele elaborate , majoritatea pentrumbuntirea modelului Winkler( Filonenko Borodici, 1940; Heteny,1946; Pasternak, 1954; Reisner, 1958;

Vlasov si Leontiev, 1960; Kerr,1964; Loof,1965; Jones i alii care completeazmodelul Vlasov i Leontiev, 1977;Vallabhan i alii care modific imbunataete modelul Vlasov i Leontiev,1988; ) n practic, s-au folosit n modobinuit modelele Winkler(Dens Lichid) (DL) i modelul SoliduluiElastic (SE), vezi Fig.1.i respectivFig.2[1], [2]].

1. Introduction

Although in the specialty literature thereare many elaborated models, the majorityfor the improvement of the Winkler model(Filonenko Borodici, 1940; Heteny,1946; Pasternak, 1954; Reisner, 1958;

Vlasov and Leontiev, 1960; Kerr, 1964;Loof, 1965; Jones et al. which completethe model of Vlasov and Leontiev, 1977;Vallabhan et al. whichmodify and improve the model of Vlasovand Leontiev, 1988 ;) in practice, themodel of Winkler (Dense Liquid) andthe model of Elastic Solid (ES) have beencommonly used, see Fig.1.and respectiveFig.2[1], [2].

Fig.1. Modelul de fundare Dens Lichid (DL)Foundation model Dens Liquid (DL)

Fig.2. Modelul de fundare al Solidului Elastic (SE)

Foundation model Elastic Solid (ES)


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2. Comparaii intre modelul DL i SE

Totui att modelul DL ct i modelul SE

nu sunt total adecvate, pentru a fi aplicateterenurilor de fundare existente [3] i [4].Astfel n modelul DL se consider crezistena la forfecare este neglijabil ncomparatie cu capacitatea de forfecare aterenului de fundare i cn mod idealizatterenul de fundare este reprezentat de unset de resoarte independente caracterizatprin parametrul K [kPa/m] (coeficientulpatului).n modelul SE se asum c terenul de

fundare prezint un grad nalt deinteraciune la forfecare fat deinteraciunea uzual a terenurilor defundare aflate n situ iar prin aplicareaacestuia rezult eforturi infinite pentrumarginile i colturile mbrcminii rigide.Oricum prediciile celor dou modeleatunci cnd sunt aplicate terenurilor defundare reale prezint discrepane vizavide observaiile comportrii n situ.

3. Consideraii recente privind cea maibuna alternativfaa de modelele DLi SE.

n ultimii ani tot mai muli cercettoriafirmccele doumodele ar trebui sfienlocuite cu modelul Pasternak generalizatde Vlasov i dezvoltat de Kerr, vezi Fig.3i Fig 4.

2. Comparison Between DL and SEModel

However, both model DL and model SE

are not totally proper to be applied to theexistent foundation ground [3], [4].Thus, in the DL model it is assumed thatshear strength can be neglected incomparison with shear

buletin_stiintific_nr2_2008

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