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EUROPEAN COMMISSIONDIRECTORATE-GENERAL JRC JOINT

RESEARCH CENTRE

GOVERNMENT OF ROMANIAMINISTRY OF EDUCATION AND

RESEARCH

JRC Information Day and S&T Workshops11 May 2006

SITON SOLUTIONS TO INCREASE NEW OR EXISTING NPP’s RELIABILITY & SAFETY BY CONTROLLING, LIMITTING AND DAMPING

SHOCKS, VIBRATIONS & SEISMIC MOVEMENTS

V. Serban1, A. Panait1, I. Prisecaru2,1SITON - Subsidiary of Technology and Engineering for Nuclear Projects

2UPB - University “Politehnica” Bucharest

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1. GENERAL PRESENTATION OF SITON – SIGMA – UPB

CONSORTIUM ACHIEVEMENTS

2. CONTROL, LIMITATION & DAMPING OF SHOCKS,

VIBRATIONS & SEISMIC MOVEMENTS AS PER SERB-

SITON SOLUTION

3. DOMAINS IN WHICH SITON – SIGMA - UPB CONSORTIUM

CAN PARTICIPATE IN EUROPEAN RESEARCH

PROGRAMS FOR THE DEVELOPMENT OF NEW TYPES OF

ADVANCED NPP’S

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1. GENERAL PRESENTATION OF SITON – SIGMA – UPB CONSORTIUM ACHIEVEMENTS

SITON – SIGMA – UPB Consortium has conceived, designed, manufactured and experimented SERB devices with non-linear elasticity and controlled damping for shock, vibration and seismic movement control and attenuation.

The devices are capable to elastically overtake large permanent loads over which spatial dynamic loads may overlap and be damped .

The non-linear behavior of a device is geometric type, given by the modification of the internal geometry of the device structure function of the device distortion.

The device allows the displacements due to thermal expansions, with pre-set reaction forces.

The stiffness and damping characteristics of the device are independent of the temperature variation within very large ranges, from -50 to +350 degrees Celsius in case of common devices.

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The device can be installed in high radiation areas due to the component materials. The integrated fast neutron flux upto which the performances of the device can be guaranteed, is 2x1019 neutrons/cm2.

The devices can be made in very small sizes (60 mm diameter and 20 mm high) having the stiffness and damping characteristic pre-set for large operation ranges.

The device damping capacity is practically independent from the dynamic action frequency.

By now, the new devices have been employed:• to isolate equipment which generate shocks and vibrations;• to reduce the stress and vibrations conditions in pipe networks;• to control, limit and damp the building seismic movements.

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2. CONTROL, LIMITATION & DAMPING OF SHOCKS, VIBRATIONS & SEISMIC MOVEMENTS AS PER SERB-SITON SOLUTION

The first application related to shock & vibration reduction was in the year 2003. It was aimed to isolate a 1250Kg forging hammer and the inlets and outlets pressurized air pipe [2].

The next solution was to reduce the vibrations in the pipe networks.

At present, a ground-floor and 5 - storey building with reinforced concrete frame structure is strengthened by SERB devices now in progress of application.

SERB supports & devices are certified in Romania by TECHNICAL AGREMENT 016-03/144-2005 [3].

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Fig. 2.1.1. SERB 1 support testing. Fig. 2.1.2. SERB 3 support. Elongation – compression testing.

Fig. 2.1.3. SERB 3 support – balancing testing.

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Fig. 2.1.4. SERB 1 support. Force - displacement characteristics.

Damping 27,8%. Prestress force 1500 daN.

Fig. 2.1.5. SERB 3 – support. Force - distortion characteristics.

Damping 23,2%.

Fig. 2.1.6. SERB 3 – support. Force - distortion characteristics.

Damping 25,24%.

Figs. 2.1.1 – 2.1.6 illustrate the experimental testing developed on SERB prototypes supports for pipe networks and experimental diagrams.

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Fig. 2.1.7 illustrates installed support and fig 2.1.8 illustrates the effect of the support on the pipe PL1056.

Fig. 2.1.7. SERB 3 support. Setting pipe

PL1056 .Fig. 2.1.8. Fourier spectra vibration displacement before & after SERB

installation.

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To reduce the shocks & vibrations for forging hammers at Tool & Devices Factory (IUS – Brasov, Romania) SERB-SITON isolation solution was applied in two alternatives.

A. As per the Constructive Alternative 2003, 6 boxes symmetrically arranged were installed (fig.2.2.1) each having 4 SERB-194C supports (fig 2.2.2).

Fig.2.2.1. CM1250 foundation SERB-

194-C support

Fig.2.2.2. SERB-194C support type.

Fig.2.2.3. Hysteresis curves for SERB-194-C

support.

Fig.2.2.4. Variation of stiffness for SERB- 194C

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SIMULTANEOUS MESUREMENTS ON THE FOUNDATION VAT AND AT 5M AWAY FROM CM1250 FOUNDATION

Fig. 2.2.5. Wave shape recorded on the foundation vat and the spectral density

on the old location in point 1’

Fig. 2.2.6. Wave shape recorded on the foundation vat and the spectral density on the

new location in point 1

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B. Isolation alternative 2005 is different from isolation alternative 2003 by that the forging hammer bed plate support is resting on 5 boxes (fig. 2.2.7). One box is made up of one SERB-375C device see fig. 2.2.7 – 2.2.12.

Fig. 2.2.7. CM1250 foundation as per SERB-

SITON solution 2005

Fig. 2.2.8. Hysteresis characteristic for

SERB-375C.

Fig. 2.2.9. Bed plate installation at CM1250

solution 2005

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Fig. 2.2.10. Detail of SERB-375C boxes installed under the bed plate

Fig. 2.2.11. Time history on foundation and bed plate

Fig. 2.2.12. Time history acceleration on vat and bed plate

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SERB-SITON isolation solution is highly efficient because the average isolation coefficient experimentally obtained, is 97,6% for shocks generated by the operation of the forging hammer (isolation alternative 2005) as per table 2.1.

Table 2.1 No. Crt.

Bed plate (location 1) a1, m/s2

Foundation (location 2) a2, m/s2

A = a1/a2 T = a2/a1 % I = │1 -T│ %

1 6,9 0,185 37,30 2,68 97,31 2 3,4 0,067 50,75 1,97 98,03 3 3,0 0,071 42,30 2,36 97,63 Average value 97,65

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Washer type SERB device (see fig. 2.2.13 – 2.2.14) can be used to isolate equipment & pipe networks.

Fig. 2.2.13.1SERB-BS washer type device Fig. 2.2.14. SERB-BS washer type device. (e. g. pipe supports or equipment slabs

connected to structures)

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Reduction of shocks, vibrations and seismic movements at buildings

Here below is a presentation of two alternatives of SERB-SITON solution for reducing shocks, vibrations and seismic movements at buildings. The alternative solutions my be applied both for new buildings and for strengthening the old buildings to make them withstand severe future seismic events.

ALTERNATIVE 1- Building Isolation

For buildings, usually massive, the strengthening solution consists in making some openings in the basement or ground floor walls of the building (see fig. 2.3.1 – 2.3.4) located at 4 m to 6 m and about l m high and 1.2 m wide.

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j'

Fig. 2.3.1. Building isolation - stage 1. Fig. 2.3.2. Building isolation - stage 2.

Fig. 2.3.3. Building isolation – stage 3. Fig. 2.3.4. Building isolation - stage 4.

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Fig. 2.3.6 – 2.3.7 illustrate the force-displacement characteristic for seismic movements on vertical direction and vertical and horizontal direction, respectively.

Fig. 2.3.5. Dynamic testing of a SERB-I device element subject to vertical and

horizontal dynamic loads applied simultaneously.

Fig. 2.3.6. Force –vertical characteristics SERB-I device Relative damping 46,1%.

Fig. 2.3.7. Force - horizontal distortion characteristic for a SERB-I device element with a

permanent vertical load of 100 KN

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For the seismic isolation of buildings, over which dynamic loads on three directions may overlap, device box 0.5 x 1.2 x 0.7 m only one may be used. The device lateral displacements are 20-30 cm or even larger and are capable to overtake static and dynamic loads upto 2000 kN.

ALTERNATIVE 2 – Building Distortion Control.

The strengthening solution consists in the insertion of some SERB-B mechanical devices into the flexible building structure (usually steel frames or reinforced concrete).

The devices are installed in the telescopic braces into the walls by means of which the relative level distortions are controlled. The telescopic braces allow a relative level displacement of 0.3% - 0.5% of the storey hight (function of the building type) so that an overload of the beams and columns should not occur but for the entire building as an assembly, a low transfer of the seismic energy to the building, is resulting.

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Fig. 2.3.8. SERB-B devices for control, limiting and damping relative building

distortion.

Fig. 2.3.9. SERB-B-194 device experimental testing.

-8 -6 -4 -2 0 2 4 6 8 10

x 10-3

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1x 10

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Fig. 2.3.10. SERB-B-194. Force – distortion. Damping 43,3%.

-12 -10 -8 -6 -4 -2 0 2 4 6

x 10-3

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1x 10

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Fig. 2.3.11. SERB-B-194. Force – distortion Hysteresis loop. Prestressing

force 0 and 10 kN. Damping 41,9%

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Fig. 2.3.12 SERB-B experimental testing and Force – distortion Hysteresis loop-UTCB Lab

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3. DOMAINS IN WHICH SITON – SIGMA - UPB CONSORTIUM CAN PARTICIPATE IN EUROPEAN RESEARCH PROGRAMS FOR THE DEVELOPMENT OF NEW TYPES OF ADVANCED NPP’S

a. New solution for seismic isolation of the integrated nuclear building as to a the general basement;

b. Solution for pipe network anchoring which allow displacements due to thermal expansion, attenuate shocks and vibrations and minimize load due to the earthquakes;

c. Solution to reduce shocks and vibrations at equipment due to eccentric mass or misalignment;

d. Isolation of electric and instrumentation cabinets or of sensitive equipment installed on a common platform against shocks, vibrations and seismic movements.

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For further information, please contact PhD Viorel Serban phone mobil: +40-722.615.672, phone +40-21.404.60.06, fax: +40-21-457.44.31, e-mail: serbanv@router.citon.ro; serbv@rdslink.ro.

Bibliography:

[1] Serban Viorel Patent no. 119845/29.04.2005 “Sandwich structure, device including the sandwich structure and device network for taking over and damping the loads for structure behavior control”;[2] Serban Viorel, “Damping of Vibrations generated by the CM 1250 kgf forging hammer, located in Forging Shop SC IUS SA Brasov, Romania”, Contract SITON nr. 209/17.07.2003.[3]Technical Agreement 016-03/144-2005. Permanent Technical Council for Buildings, Bucharest, Romania.