VULNERABILITY ASSESSMENT OF PRECAST CONCRETE CLADDING WALLS FOR POLICE STATIONS

VULNERABILITY ASSESSMENT OF PRECAST CONCRETE CLADDING

WALLS FOR POLICE STATIONS

Critical Infrastructures – 6C

Chair: Dörr / Gündisch

Giovino G, Olmati P, Bontempi F

Sapienza University of Rome

[email protected]

www.francobontempi.org- September 18, 2013 -

Giannicola Giovino1, Pierluigi Olmati2, Franco Bontempi3


1 Ph.D. Student, P.E., Capt. of Carabinieri Corps, Email: [email protected]

2 Ph.D. Candidate, P.E., Email: [email protected]

3 Full Professor, Ph.D., P.E., Email: [email protected]

2 Presentation outline

1 Introduction

2 Test matrix

3 Experimental results

4 Numerical investigation

5 Conclusions



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3Giovino G, Olmati P, Bontempi F


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3 Introduction

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improving the performances of the Italian

police stations against external explosions.

This study presents both experimental and numerical investigations on the

assessment of precast concrete wall panels, for using as exterior cladding

system, subjected to explosive detonations

The aim

of study

collect data in order to verify and validate both analytical and

numerical model

check with the experimental evidence the necessity of

properly design the cladding system of the Italian police

stations.

4Giovino G, Olmati P, Bontempi F


[email protected]


4 Introduction

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The Italian police stations have a widespread distribution on the national

territory

obviously an advantage for the

community

But often, these police stations are

no other than common civil

buildings adapted for police use

they do not have a structure with

adequate performance against man-

made attacks

Is not economical sustainable to retrofit these buildings for police use, but it is

necessary to design and build new police stations providing the adequate

resistance performance against man-made attack


1 Introduction

2 Test matrix



5 Conclusions



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6



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Experimental results

The experimental test took place the July 22 and 23, 2013 at the facility of the

R.W.M. ITALIA s.p.a. at Domusnovas (Sardinia – Italy).

Via Industriale 8/dGhedi (BS)

Tel: +39 030 9043 1

www.rwm-italia.com

Domusnovas (CI)

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Test matrix

Three specimens are tested, and each is subjected to a single detonation

Specimen A

Designed with a minimum amount of required reinforcement (0.15 %)

Specimens B and C

Designed to achieve a specific maximum deflection if subjected to a

specific blast demand

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Test matrix

Blast side

3500

1500

1750

3100

750

10804800

Explosive charge

Concrete support

Panel

500

Not to scale

Wall13

70

Sandbags

800

Entry and exit ramp

Rupture discs

NORTH

SOUTH

EA

ST

WE

ST

Specimen Length Width Thickness Stand-offExplosive

weightReinforcement

[mm] [mm] [mm] [mm] [kg TNTeq] Longitudinal/Transversal

A 3500 1500 150 1500 3.5 7 Φ8 / 10 Φ8B 3500 1500 200 1500 3.5 12 Φ10 / 10 Φ8C 3500 1500 200 1500 5.5 12 Φ10 / 10 Φ8

Planar view

Test matrix

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Test matrix

Concrete support

Panel

Explosive charge

400

t15

003500

3100

1080 4800

Comb device

Coaxial tubes device

Ground

Wall

Not to scale a

b

c

EA

ST

WE

ST

Panelt a b c

[mm] [mm] [mm] [mm]

A 150 1550

B 200 1160 1550

C 200 880 1550 2030

Longitudinal section

PBXN-109

Two kinds of

displacement meter

comb device coaxial tube

device

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Test matrix

specimen ready to be tested

large view with the explosive just armed

rupture disc

displacement meter

explosive charge

explosive charge

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Test matrix

specimen

operation for positioning

supports

specimen

rupture disc

charge supports

sand bags

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Test matrix

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1 Introduction

2 Test matrix



5 Conclusions

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Specimen A

The deflection of the

specimen A reached the

full scale value of the

coaxial tubes device.

maximum and residual

deflection = 108 mm.

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Specimen B

maximum and the residual deflection

= 70 mm and 35 mm

The specimen B shows a ductile

failure with a diffuse crack

patterns on the central one third

of the panel span

(max 3 mm width)

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Specimen C

maximum and the residual deflection

= 123 mm and 82 mm

Heavy crack patterns are

assessed. Along the mid-span of

the panel diffuse cracks are

present

(width until 10 mm)


1 Introduction

2 Test matrix



5 Conclusions



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Numerical investigation



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Blast side

35001

500

1750

31007

50

10804800

Explosive charge

Concrete support

Panel

500

Not to scale

Wall

137

0

Sandbags

800

Entry and exit ramp

Rupture discs

NORTH

SOUTH

EA

ST

WE

ST

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AB

C

Reflecting surface

Reflecting surface

Using the uncoupled approach the image charge provides acceptable results

without increasing the computational effort.

Elementary scenario of

reverberating shock waves

Image charge side

Stand-off α [m] [degrees]

West 6009 27 North 4705 35 South 4705 35 East 13505 13

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Concrete and steel specimen testing

Specimen Concrete Rebar steel Rebar steel N° Rc [MPa] fy [MPa] ft [MPa]

1 37.46 536 616 2 35.87 540 625 3 35.60 541 626 4 35.19 547 670 5 29.89 549 676 6 31.01 547 672

Average 34.17 543 647

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• yielding stress=543 MPa• Cowper and Symonds strain-rate model: D=500 s-1 q=6

• steel Young’s modulus=200 GPa

• Poisson coefficient=0.3

Density 2.248 lbf/in

4 s2 2.4*103 kg/m3

fcm 4060 psi

28 N/mm2 Cap

retraction active

Rate effect

active

Erosion none

Concrete model - the Continuous Surface Cap Model

Steel model – the kinematic hardening plasticity model

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Specimen

Experimental Numerical Experimental Numerical

δmax

[mm]δres

[mm]δmax

[mm]δres

[mm]θmax

[deg]θres

[deg]θmax

[deg]θres

[deg]

A 108* 108* 244 240 4.0* 4.0* 8.9 8.8B 70 35 58 50 2.6 1.3 2.1 1.8C 123 82 114 106 4.5 3.0 4.2 3.9

* Full scale value

Component damage levels θ [degree] µ [-]

Blowout >10° none Hazardous Failure ≤10° none

Heavy Damage ≤5° none Moderate Damage ≤2° none

Superficial Damage none 1

US Army Corps of Engineers (USACE). Methodology Manual for the Single-Degree-of-Freedom

Blast Effects Design Spreadsheets. The United States Army Corps of Engineers.


1 Introduction

2 Test matrix



5 Conclusions



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27 Conclusions

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- Three concrete cladding wall panels has been tested at the

testing site of the R.W.M. Italia.

- If designed for blast a concrete wall panel is able to withstand

the blast demand and it can be used as a protective cladding

wall.

- The carried out numerical simulations are able to predict

sufficiently the deflection of the wall panels.

- The image charge method can be used for taking account the

reverberating of the shock wave.

- The conducted test can be used as benchmark for the

Arbitrary Lagrangian Eulerian method.

Critical Infrastructures – 6C

Chair: Dörr / Gündisch



[email protected]


VULNERABILITY ASSESSMENT OF PRECAST CONCRETE CLADDING WALLS FOR POLICE STATIONS

Design

Transcript of VULNERABILITY ASSESSMENT OF PRECAST CONCRETE CLADDING WALLS FOR POLICE STATIONS