Design projects and research activities

Athens, Greece, 2013Athens, Greece, 2013

DESIGN PROJECTS AND RESEARCH ACTIVITIES

Dr. Isabella Vassilopoulou

STRUCTURAL ENGINEER, Ph.D. NTUA, GREECE

ASSOCIATE AT ODOTECHNIKI Ltd

DESIGN PROJECTS AND RESEARCH ACTIVITIESDr. ISABELLA VASSILOPOULOU

STRUCTURAL ENGINEER, Ph.D. N.T.U.A. and ASSOCIATE AT ODOTECHNIKI Ltd 2

CONTENTSCONTENTSPROJECT NAME: Pages

A. Entrance Canopies of the Athens Olympic Sports Complex 3-11

B. Railway bridge (integral system) 12-15

C. Viaduct of 14 spans 16-21

D. Doctoral Thesis: Nonlinear Dynamic Response and Design of Cable Nets

22-32

A

C

B

D



Entrance Canopies of the Athens Olympic Sports ComplexLocation: Athens, GreeceArchitectural and structural report: CALATRAVA S.A.Design verification: Associate Professor C. J. Gantes, I. VassilopoulouConstruction: Joint Venture TERNA S.A. – PANTECHNIKI S.A.Client: Hellenic Ministry of Culture – General Secretariat of SportDates: design and construction - 2004

ENTRANCE CANOPIESENTRANCE CANOPIES

Areas of responsibilityStructural design of superstructure and foundation

•Modeling•Permanent, variable and seismic loads•Loading combinations•Static and dynamic analysis



Plan view (dimensions in m)




Section A-A (dimensions in m)




Model for analysis


Finite Element Software: SOFiSTiK



Vibration modes



1st 2nd 3rd

4th 5th 6th



Installation of the two arches


The canopies under construction



Installation of the beams





Installation of the outer ring






General view



RAILWAY BRIDGERAILWAY BRIDGE

Railway bridge over the river “Dervenios”Location: Derveni (Railway line Corinth – Patras), GreeceGeotechnical and Structural Design: ODOTECHNIKI LtdConstruction: MICHANIKI S.A.Client: ERGOSE S.A.Dates: design - 2006, construction - 2008Type: Prestressed frame (integral system) – Total length ~49m

Areas of responsibilityFinal design of superstructure and foundation

•Modeling•Pretension•Permanent, variable and seismic loads•Loading combinations•Static and dynamic analysis•Foundation bearing capacity•Preparation of construction drawings



Elevation view


Cross section

2.80

7.80

2.00 8.70 2.00

48.70 4.004.00

(dimensions in m)



Model for analysis and design





Bridge under construction




VIADUCTVIADUCT

Viaduct from Km 13+774.54 to Km 14+270.40 Location: Tsakona (Tripoli – Kalamata Highway), GreeceGeotechnical and Structural Design: ODOTECHNIKI LtdConstruction: ALPINE BAU Gmbh – GEK TERNA GROUPClient: Hellenic Ministry of Infrastructure, Transport and NetworksDates: design - 2008, construction - 2010Type: 14 spans with post-tensioned/precast beams – Total length 492mAreas of responsibilityFinal design of superstructure and foundation

•Modeling•Pretension•Permanent, variable and seismic loads•Loading combinations•Static and dynamic analysis•Foundation bearing capacity•Supervision of construction drawings



Model for seismic design


Model for deck designPrestressed/precast beams of a typical span

VIADUCTVIADUCT



Detail of beam reinforcements from the construction drawings(dimensions in m)

VIADUCTVIADUCT

0.750.75

0.25 0.25 0.25

1O12

8O18 /320 10 10 L= 0.90

0.12

0.66

0.12

/404 10 10[(34+19)x2+96]x2L= 1.00

0.29

0.58

0.13

/330 10 10 L=

0.140.66

0.10

/540 10 10L= 0.80

0.10

0.44

0.26

/168 10 10(84x2)L= 0.45

0.12

0.20 0.13

/140 14 100L= 0.65

0.25

0.15

0.25

1.97 2.03

L= 5.00

0.15

2.19

0.16

2.18

0.16

0.16

/110 12 10

/10 10

/10 10/10 10

/10 12 20 /10 12 20

/12 10

/10 10/10 10

/14 100

/10 10



Pretension of beamsConstruction of foundationand pilecaps

VIADUCTVIADUCT




Construction of piers

VIADUCTVIADUCT

Placement of beams




Finished bridge

VIADUCTVIADUCT

Construction of concrete slab




Nonlinear Dynamic Response and Design of Cable NetsSupervisor: Associate Professor C. J. GantesDate: November 2011http://odotechniki.gr/siteen/pages/publications/associates-research.php

DOCTORAL THESISDOCTORAL THESIS

… the Raleigh ArenaNorth Carolina, U.S.A. (1953)

…the VelodromeLondon, UK (2011)

From … … to …

Vassilopoulou, I., “Nonlinear dynamic response and design of cable nets”, Structural Engineering International (SEI) – Recent PhD Abstracts, Vol. 22, No. 3, pp. 422-423.



Geometry of a cable net


Nonlinear Dynamic Response and Design of Cable Nets



SDOF Cable net

4 (L/2,0,-f) 2 (-L/2,0,-f)

L/2 L/2

L/2

L/2

L: cable span, f/L: sag-to-span ratio

Plan view Perspective view



I. Vassilopoulou and C.J.Gantes“Nonlinear dynamic phenomena in a SDOF model of cable net”Archive of Applied Mechanics, Vol. 82, No. 10, pp. 1689-1703.



SDOF Cable net: Simplified equation of motion

)tΩcos(M

)P(w

LM

)EA(16w

M

Kw

MC

wm

m03m3

mm

mm

m

mm

mm

Linear termNonlinear term

Duffing equation

2εμ=2ζωm

)tΩcos(pwεαwωwεμ2w m3mm

2mmm

2m

2m

m

m0

m

m02m

2m

mm

mm

L

f

)EA(

)N(4

)EA(

)N(2

L

f8

LM

)EA(4ω

3mm

m

LM

)EA(16εα

m

m0m M

)P(p where







(2A)

(1A) (1A)

(1S)

3

20

2S1 fL

EA

T

Lρ

EgLf

7ω

5.2

20

2A1 fL

EA

T

Lρ

EgLf

7ω

Aρ

gT

L7

ω 0A2

I. Vassilopoulou and C. J. Gantes, “Vibration modes and natural frequencies of saddle form cable nets”, Computer and Structures, Vol. 88, pp.105-119, 2010.

MDOF cable net: natural frequencies





MDOF cable net: natural frequencies

2

0

2

Lf

TEA

λ

ω1S ≤ ω1A <

ω2A

λ2≤0.8

0.8 < λ2 ≤ 1.0ω1A < ω1S

≤ ω2A

1.0 < λ2 ≤ 1.17

ω1A ≤ ω2A <

ω1S

1.17 < λ2ω2A < ω1A

< ω1S

Ε: Elastic modulusΑ: Cross-sectional area

T0: initial pretension

f/L: Sag-to-span ratio





MDOF cable net: Dynamic response to harmonic loads

P(t)=P0cosΩt

Steady-state response(fundamental resonance Ω≈ω1S)

node 15

0

1

2

3

0.90 1.00 1.10 1.20 1.30 1.40

Ω/ω1S

defle

ctio

n (m

)

node 15

0

1

2

0.30 0.40 0.50 0.60

Ω/ω1S

defle

ctio

n (m

)

Steady-state response (superharmonic resonance Ω<ω1S)

I. Vassilopoulou and C. J. Gantes, “Nonlinear dynamic behavior of saddle form cable nets under uniform harmonic load”, Engineering Structures, Vol. 33, pp. 2762-2771, 2011

Uniform loading




Approximate method

Similarity

relations

PROTOTYPE (p)MODEL (m)

prototype

pmodel

mnumber of cables per direction

N

2

m

pp0m0 1N

1N)P()P(

I. Vassilopoulou and C. J. Gantes, “Cable nets with elastically deformable edge ring”,

International Journal of Space Structures, Vol. 20, No.1, pp. 15-34, 2005.





Estimation of MDOF cable net response with an equivalent SDOF model

Similarity

relations

PROTOTYPE (p)MODEL (m)

Numerical analysisAnalytical solution


I. Vassilopoulou and C.J.Gantes, “Nonlinear dynamic response of MDOF cable nets estimated by equivalent SDOF

models”, Computational Methods in Earthquake Engineering, Vol. 2, M. Papadrakakis, M. Fragiadakis, V. Plevris (Eds.), Springer Verlag, 2012 (in press).




Estimation of MDOF cable net response with an equivalent SDOF model Fundamental Resonance

0

1

2

3

4

0.9 1 1.1 1.2 1.3

Ω/ωp

Stea

dy s

tate

am

plitu

de (

m)

Ω/ ωp=1.08

-4.0

-2.0

0.0

2.0

4.0

0 5 10 15 20 25time (sec)

defle

ctio

n (m

)

Ω/ ωp=1.08

-4.0

-2.0

0.0

2.0

4.0

0 5 10 15 20 25time (sec)

defle

ctio

n (m

)


SDOF responseMDOF response with initial conditionsMDOF response with zero initial conditions




MDOF cable net: Dynamic response to wind action


f/L N0/(Aσy) [%]

λ2 ω1S[sec-

1]f1S[Hz

]

1/20 10 2.59

7.696 1.225

1/20 19 1.35

6.654 1.059

1/20 30 0.86

6.085 0.968

f/L: sag/span ratio, Ν0: initial cable pretensionA: cross-sectional area σy: yield stress

2

0

2

Lf

TEA

λ

λ2 2.59 1.35 0.86

Athens, Greece, 2013Athens, Greece, 2013

Dr. Isabella Vassilopoulou

STRUCTURAL ENGINEER, Ph.D. NTUA, GREECEASSOCIATE AT ODOTECHNIKI Ltd

[email protected][email protected]

Documents

Design projects and research activities