EASIE Congress 23092011 Retrofitting of Sandwich Panels€¦ · EASIE Congress 23092011 Retrofitting of Sandwich Panels ... the service life of the sandwich panel wall and ... the

EASIE Congress 23092011

Retrofitting of Sandwich Panels

Actions to return the resistance

Cladding of sandwich panels

Paavo Hassinen

EASIE MC, Roma September 21, 20112

Repairing of a wall or roof made of sandwich panels- Cleaning and painting of the surfaces and improving or replacing of the fasteners

- Repairing of defects- Covering the panels with new cladding

- New architectural appearance of old and new facades

- Improvement of mechanical and physical behaviour and resistance

- Extension of the service life of the sandwich panel wall and roof


Returning of resistance of panels exposed to blisters or accidential attacts

Artificial defects- simulation of real defects and faults

Development of repairing actions- four different technigues- suitability to conditions on site

Experimental verification

B / 1

D1 one circular dent

- diameter D1 = 200 mm - depth d1= 10 mm

R

Photo; Eric Rustemeijer


Returning the resistance of panels exposed to blisters or accidential attacts

Development of repairing actionsExperimental verificationTesting of the suitability of the techniques on site

Photo; Eric Rustemeijer


Returning of resistance of panels Artificial defects in the tests in IsMainz


Wrinkling stress of PU-foam cored sandwich panels before and after reparation actions (I, II, III and IV) of artificial defects (A, B, C), results by Anton Kull, IsMainz

Simulation of a wrinkling failureRelative wrinkling stress [N/mm²]

1

0.540.58

0.63

0.38

0.72 0.74

0.90

0.48

0.86

0

0.2

0.4

0.6

0.8

1

1.2

Initi

al Te

st 1

A befo

re rep

airing

A af

ter re

pairi

ng T

ype I

A after

repa

iring

Typ

e IV

B be

fore

repair

ing

B aft

er rep

airing

Typ

e IV

C aft

er rep

airing

Tes

t 15 T

ype I

C aft

er rep

airing

Tes

t 17 T

ype I

I

C aft

er rep

airing

Tes

t 19 T

ype I

II

C aft

er rep

airing

Tes

t 21 T

ype I

V


Wrinkling stress of PU-foam cored sandwich panels before and after reparation actions (I, II, III and IV) of artificial defects (D1, D2, E1, E2), results by Anton Kull, IsMainz

Simulation of a local faultRelative wrinkling stress [N/mm²]

1

0

0.2

0.4

0.6

0.8

1

1.2

Initi

al Te

st 1

D1 befo

re rep

airing

D1 a

fter r

epair

ing T

ype I

D1 afte

r rep

airing

Typ

e IV

D2 befo

re rep

airing

D2 a

fter r

epair

ing T

ype I

D2 afte

r rep

airing

Typ

e IV

E1 be

fore

repair

ing

E2 be

fore

repair

ing


Returning the resistance of face layers with faults and damages

- technigues to return the resistance partially

- full returning of the wrinkling strength is a demanding task

- knowledge about the level of the return is highlyimportant in practice


Retrofitting, new to old concept

Tests at IsMainz and Aalto University


Retrofitting; Cladding based on thin-walled purlins and sheetingspu-foam cored and steel sheet faced ordinary panels, screw fasteners

Photos: Jessica Kochenbach


Cladding based on thin-walled purlins and sheetingsWrinkling failure along the plane of the web of Z- and hat profile

Reduction of the load bearing capacity



Cladding based on thin-walled purlins and sheetings

Compression failure of the profile and face sheetImprovement of the load bearing capacity



Cladding based on thin-walled purlins and sheetingspu-foam cored and steel sheet faced panels, screw fasteners

A) Ordinary sandwich panelB) Sinusoidal sheet directC) two hat-profiles longitudinalD) hat-profiles transverseE) Z-profiles transverse

0.6

0.8

1.0

1.2

1.4

A B C D E

Rel

ativ

e to

tal l

oad

and

stiff

ness

Relative resistanceRelative stiffness

Resistance and stiffness depend on the span


Cladding based on thin-walled purlins and sheetingsDesign using analytical or numerical modelsShear flexibility of the transverse purlins and fasteningsVerification of the resistance of the panel, purlins, sheetingand fastenings

X

Z

Y


Repair and retrofittingCladding based on additional sandwich panels

EPS foam cored and steel sheet faced additional panel

EPS foam cored and steel sheet faced ordinary

sandwich panel

Screw and rivet

fasteners


Metal sheet faced additional panel

0

5

10

15

20

25

0 5 10 15 20 25 30 35 40 45 50 55 60

Deflection [mm]

Load

[kN]

F1b-1, IR2, k500 A1-1 FEM (no cladding)

FEM (spring IR2 k500) FEM (no slip) FEM (frictionless slip)

Repair and retrofittingCladding based on additional sandwich panels

EPS foam cored and steel sheet faced additional panel fixed to EPS cored and steel sheet faced ordinary panel

Comparison between

experimental and

calculated results


Cladding with additional panelsFlange normal forces

Steel sheet faced panel + steel sheet faced additional panel

Original panel:upper facelower face

Additional panel:uppr face

lower face

Steel sheet faced panel + additional mono panel


Cladding with additional panelsComparison of experimental load-bearing capacity and stiffness to those of the ordinary sandwich panel

Sandwich panels covered with additional elements

0,0

0,5

1,0

1,5

2,0

A B C D E F G H

specimen

rela

tive

tota

l loa

d

0,0

0,5

1,0

1,5

2,0

rela

tive

tota

l stif

fnes

s

relative total loadrelative total stiffness Repeated load

of 5000 cycles no noticeable

effects

Additional panels

Additional monopanels


Repair and retrofitting

Ordinary sandwich

panel

Four normal forcesin the faces

Three normal forcesin the faces

Monopanel fixed to the

external face

Additional thin sandwich panel fixed to

the external face

Mechanical fastening

Verification of the resistance of the ordinary sandwich pneland the additional sandwich panel


Cladding based on additional sandwich panelsVisual appearance

Effect and visibility of the fastenings of the

additional element


Repair and retrofittingAdhesive joints between the cladding

componentsBenefits

- fluent flow of stresses without local stress concentrations- no holes through the external face of the sandwich panels- no visible fastenings in the cladding

Challenges- cleaning and primary coating of the surfaces in contact,methods and technique depends strongly on the coatings

- possible prestress during the hardening of the joint- work to be made on site


Product of EASIE project; Practical guidelines on cladding and repairing of Sandwich panels

- distributions of the external mechanical pressure load- distribution and effects of the temperature on the components of thecladding systems and the ordinary sandwich panel

- local stresses and effects caused by the of self-weight of the additionalcladding

- static interactions between the ordinary sandwich panel and theadditional cladding

- effects of the local damages- long-term effects caused by ageing and repeated loads- influence of the cladding on the other properties of the panel such as thethermal insulation etc.

- good practice, including the return of resistance, also

Documents

EASIE Congress 23092011 Retrofitting of Sandwich Panels€¦ · EASIE Congress 23092011 Retrofitting of Sandwich Panels ... the service life of the sandwich panel wall and ... the