teaching goals glass products · • different heat expansion coefficients of glass, adhesive and...

||Institute for Building Materials

Science and engineering of glass and natural stone in construction

Glass designF. Wittel

1


Teaching goals glass products:

You will … learn to categorize glass applications, glazing and support types

…get an overview on the present codes for glass design

…will see on simple examples how to design with glass



Golden rules when designing with glass:

Avoid contact of glass with harder materials under mechanical and thermal loading.

Avoid load by restraints from unconsidered load cases.

Choose an appropriate geometry of glass elements.

Choose an appropriate connection type.

Look for robustness of your glass construction.

Be sure that usability is granted.

Be sure durability is given.


Damage caused by ignoring design principles


Overview glass support types


General force support types

Code: DIN 18008-2• Free rotation of edges• EPDM layer of silicon profile• Clamped glass only in exceptions.

Code: DIN 18008-3 • Bore area, interlayer of soft Al-alloys, EPDM;POM;PA6• Stress concentration at bore holes need for pre-

stressed glass.• Statically determined support by combination of fixed and

movable supports (free of constraint forces)


Support types: Linear force transmission examples

Clamped support with wooden pressure cap

Linear clamped support with steel pressure cap

Linear clamped support with EPDM-integral profile

Linear clamped support

Simple glazing with glazing bead

Schüko FW50+ (Insolated post and rail facade)


Support types: linear blocking

bloc

ks

Dis

tanc

ebl

ocks

Constraint force free vertical support via blocks that transmit forces in frames and the construction.

Avoids contact between glass and frame.Materials: hardwood, polymers, elastomers.Durable, compliant and pressure resistant.80-100mm long, 2mm wider than glass.Placed about 100-250mm distant from edge.

rightwrong

1 setting blocks

Distance blocks

Fixed glazing Movable window


Support types: Point-fixed glazing

Glass clamps

Point mountingsBackcut anchorCountersunk bolt fixing

fixed

Hin

ge in

/out

side

of g

lass

pla

ne

fixed

Hin

ge o

utsi

de o

f gla

ss p

lane

VEGLA

Trösch

VEGLA

Sadev® Sadev®

Eckelt Glastechnik

Flachglas AG

Dorma Manet®

VEGLA VEGLA

Fa. Pauli + Sohn


Bolted glass assemblies

The bolts are designed to absorb:• wind and/or snow loading,• the weight of the glazing,• the differential movements between the glass and structure

The bolted glass assembly system requires finished glass products of the highest quality in terms of edge-work, drilling, toughening and heat soak testing.


Support types: Glass spider supports

Spider for 4 sheets

Simple / Double eccentric

Adjustable in all directions

Constrained free, statically determined point support

Alternative point bearing:


Load transmission: ConnectionsConnection techniques have to transmit load without contact to glass and metal.

Adhesive connections: PU; EP; SiDurability of adhesive critical (creep, UV-light, chemical influence, other polymers).Adhesive bonding ONLY under controlled conditions.

Bearing type shear connection: Plastic deformable interlayers avoid excess loads and distribute pressure uniformly onto the glass. Materials: soft Al, PTFE, PA

Friction type connection: Friction layers without relevant creep deformation, similar to high pressure seals. Problems with laminated glass due to creep of PVB interlayers.Needs to be evaluated in tests.

bushingspacer

bushing (elastomer)

Steel mounting plateFriction layer

Spring cap


Adhesive connections: Structural Glazing Adhesively bonded glazing (Structural-Sealant Galzing System (SSGS)Used in the USA since 40 years!!!

• Adhesive bonding with load carrying capability for wind loads.better heat and noise insolation and proof against driving rain.

• Factory made (DIN EN 13022) high quality.

• Different heat expansion coefficients of glass, adhesive and metal lead to constraining loads of linear connections

life expectancy proof needed.

• Mounting by clipping the module in post-rail structure.

• Material mainly silicon filled with char, silica, carbon black.

• Thickness >6mm Strength 1MPa

• Adhesion on coated surfaces needs to be tested

adhesive test with cohesive failure.

• Some organic coatings have to be removed before coating.


SSGS Types


Adhesive connection: DesignDesign value of action < Design value of capacity

Bondline width h=6-20mmBondline thickness 6mm min.Deflection of static foundation max. L/300

Capacity Rd:Rd=Ru,5/6 Design stress for tension (safety factor = 6)Rd=Ru,5/6 Design stress for shear (safety factor = 6)Rd,∞= Rd /c Design stress for shear under constant load (creep factor c>10)Ru,5 Strength 5% fractile

ActionEd:

Silicon adhesive Producer Typ Rd Rd Rd,∞

DC 993 Dow Corning 2K 0,14 0,11 0,11

SG 500 Sika 2K 0,14 0,105 0,0105

DC 895 Dow Corning 1K 0,14 0,14 -

Design stress for ETAG approved silicon adhesive [MPa]:

1Ed

Rd

2Ed d

aq

h

qd Design value for wind loada shorter edge / h bondline width


Watertight joints

1 glass sheet2 laminated glass3 wet sealing4 dry sealing

• Protect glass and frame durably from air and moisture ingress.• Avoid transmission of noise and heat.• Take module, support and temperature displacements (-20°-60°C), compensate swelling to

avoid constrain forces.• Permit movements of glass module and support from wind loads, oscillations, vibrations,

low frequency noise.• Minimum with: 4mm.• Wet- or/and dry sealing .• UV-resistant materials.• Chemical compatibility.

PIB liquefactionDue to missing chemicalcompatibility


Bearing type Frictional typePre-fabricated bushing Materials: POM; PEEK or cast resinsThickness ~ 4mmMinimum glass thickness ~ 12mm to avoid squeezing

Polymer layers for frictionAre not allowed to creepFriction coefficients and pre-stress are given by producer.Pre-stress needs to be maintained spring caps.

Nk

r t

tang. principal stress at the edgek factor for bushing materialsN bearing forcer hole radiust glass thickness


Glazing types: Classification

Overhead glazing (horizontal glazing)

Vertical glazing

Walk-on glazingFall protectionglazing

The glazing must be designed in accordance with regulations governing the safety of building users :• in the event of breakage, limiting of the risk of injury to persons • guarding to protect people from falling• safety of users and operatives during cleaning/maintenance operations.


Codes in German – the future

DIN 18008 Glass in Building - Design and construction rules -

12/10 Part 1: Terms and general bases

12/10 Part 2: Linearly supported glazings

13/7 Part 3: Point fixed glazing

13/7 Part 4: Additional requirements for barrier glazing

13/7 Part 5: Additional requirements for walk-on glazing

15/2 Part 6: Additional requirements for walk-on glazing in case of maintenance procedures

Teil 7 Special purpose constructions


Vertical glazing types

Post-rail construction

Space-framesystem

Stiff tether system

Post construction Rail construction with tethers

Soft tether system


Vertical glazing


Vertical glazing Pre-stressed cable net facade:


Entrance hall Uni Bremen

Vertical glazing


Vertical glazing with tempered glass

DIN 18516-4 (02.1990): Curtain wall facade

Tempered glass min. 6mm with heat soak test.

Edges at least edged, no edge defect >15% glass width (visual inspection)

Every glass element has to be mounted without constraints.

Linear support (2-4) or point support.

Clamping depth at least 10mm (all-sided support); 15mm (2-3 sided) or glass thickness + 1/500*post distance; 25mm (point support) clamping area larger 1000mm2/side

Design approved, when bending stress < 50MPa

Usability proof: Deflection of free edges <1/100*edge length (for all-sided support no limitation)

Loading in the plane of the glass is not considered.


Maximilian-Museum in Augsburg

Overhead glazing / horizontal glazing




Horizontal glazing with tempered glass (TRLV)

Glazing with inclination >10°.

Public areas underneath need protection from falling fragments remaining capacity after fracture.

Wire glass, laminated glass from annealed or heat strengthened glass with PVB interlayer>0.76mm.

Holes and cut-outs are not allowed.

Positive composite action (shear) can not be considered, negative one has to be considered.

Deflection limit 1/200*sheet length, max. 15mm.

Always linear support, from 1.2m post distance on all sided.

Aspect ratio 3:1 must not be exceeded.

No slipping of sheets allowed (use blocks).


Horizontal glazing: Component test

For laminated glass with tempered glass, the remaining capacity after fracture needs to be proven in a component test.

Pressure loading

Destruction of glass layers by hitting the edge in the statically worst case.

Documentation of crack pattern and lifetime. No fragments are allowed to fall during lifetime.

Tram stop Bellvue WM 2006


Free horizontal edge

Bad construction withoutdrainage edge

Good constructionwith drainage edge



Fall protection glazing

Protection against human impactBesides the ones of vertical glazing, puncture and free fall protection must be assured.

In case of fracture blunt fragments and no fragments released on public areas.

From 1m on free fall protection required.

Up to 12m height 0.9m, >12m height 1.1m

DIN 18008 Part 4:

1. Proof for static load

2. Proof for impact load


Category A: linear supported vertical glazing without supporting rail in relevant hight.

Category C1: Railing that is supported at least at 2 opposide sides.

Category C2: Vertical glazing below a load bearing rail, supported at least at 2 opposite sides.

Category C: Fall protection glazing.

Category C3: Glazing of type A but with forwardly spaced rail.

A

B

C2

C3

C1

C1

C1

Fall protection glazing

Category B: Clamped, linear supported, load bearing glass rails with continuous hand rail.



Walk-on glazing


Walk-on glazing

Stairs, platforms, brides, roofs that can be accessed by users.TRLV: all-sided, linear support with at least three edges and laminated glass

Non shear interaction Stair cases outside of regulations.

Wear layer made of ESG/TVG t>10mm, has to be ignored for calculations ( scratches, cracks )Mainly frosted wear layers

psychological reasons Sight protection Anti-slip protection (DIN 51130)


Sky Walk Tainmen Mountain, China, 1200m free fall


Shear interactionShear interaction in laminated glass via PVB-foils leads to less stress and deformation consideration would be advantageous.PVB foil hast strong temperature dependent behavior (stiffness) and tends to creep strongly. (Tab. G(MPa) of PVB-foil).

Loadduration

t<5s t<10min t<1d t<7d t<90d static

T<3°C 1.86 1.44 1.01 0.84 0.62 -

T<25°C 0.54 0.37 0.19 0.12 0.03 -

T<50°C 0.32 0.09 - - - -

T<70°C 0.15 - - - - -


Shear interactionDue to creep, no positive shear interaction is allowed to be used.For climatic load in insolation glazing with laminated glass the negative influence of shear interaction has to be considered.For impact loading the full shear interaction can be considered

Laminated glass can be considered as monolithic plate.Comparison between interaction/no interaction of an all side linear supported plate:

12,

2 2,

3 (1 2 / )

(1 ) 4v l

m l

w h t

w k

2,

2 2,

4 4 / 2

3(1 2 / ) 1v l

m l

h t k

h t k

21 1.35

4

a Ehtk

b Ga

Interaction parameter:

Deformation:

Stress:

Foil thickness hEdge ratio a/bOverall thickness t=to+tuThickness ratio to/tuStiffness glass EShear modulus PVB G

Plate with interaction vMonolithic plate m


Remaining capactiy

LG from float

LG from TG

LG from HSG

LG from HSG+TG

Wire glass

Remaining capacity after failure

All sided support

Two-sided support

Point mounting

Point mounting with countersunk hole

Remaining capacity of failed LG

Remaining capacity after glass failure via PVB foil foil creeps. The time to failure under dead load /live load determines capacity.

Glass and support types are essentialIn tempered glass, the small fragments practically can be ignored

slack membrane.Point mountings can break free – two-sided linear supports can slip out.

LG (laminated glass); TG (tempered glass); HSG (heat strengthened glass)


Case Studies:

Rear ventilated vertical glazing with tempered glass Over head glazing with laminated glass Vertical insolation glazing


1st case: Vertical glazing with tempered glass


Vertical galzing with tempered glass

DIN 18516-4 (02.1990): Cladding for external walls, ventilated at read, tempered safety glass: requirements, design, testing.

Only TG with heat soak test (ESG-H), min. 6mm thick.

Edges at least arris grinded, edge defects up to 15% of thickness (visual inspection before installation).

Every glass element has to be mounted by itself without constrains.

Linear support (2-4 sided) or point support (clamped).

Glass support depth min. 10mm (all-sided support); 15mm (2-3 sided support) or glass thickness + 1/500*post width; 25mm (point support) clamping area min. 1000mm2/side.

Requirement met, when bending stress<50MPa.

Usability: Deflection of free edges<1/100*edge length (no limitation for all-sided support).

Load in the plane of the glass is neglected.


1st case: Vertical glazing with tempered glass

Linear support with depth 15+1785/500=18.57mm < 20mm (wind pressure)

Point support with depth 25mm (Wind suction) Clamped area (65-15)/2*80=2000mm2 > 1000mm2

ESG-H 1785x2925

Design detail:

HEA 100 M10x40

Plain sheet10mm

M10x25

Riegel Schüco 162590

ESG-H 15mm

Point Bearing(clamped)

M5x40

55


1st case: Vertical glazing from tempered glass

Material properties soda-lime glass (DIN EN 572-1):ESG-H, 15mm; EESG = 70GPa; =0.23; = 24kN/m3 ; Zul. ESG = 50MPa (TRLV)

Action:Wind load (installation 3-13m above ground) (DIN 1991-1-4, Eurocode 1)w=cpꞏq cp : Pressure-(d) or suction coefficient q: velocity pressure

Pressure coefficient: cp = 0.8 <8m: q=0.5kN/m2

Suction coefficient center: cp : =-0.56 8m<height<20: q=0.8kN/m2

Suction coefficient building edge: cp : =-2.0

Relevant height>8m:Wind pressure: wd=eꞏcpꞏq=1.25ꞏ0.8ꞏ0.8=0.8kN/m2 (load increase 25% for local peaks)Wind suction center: wsm=cpꞏq=-0.56ꞏ0.8=-0.45kN/m2

Wind suction edge: wsk=cpꞏq=-2.0ꞏ0.8=-1.6kN/m2

Dead load is transferred by blocks.


Stress calculation wind pressure:Based on Kirchhoffs plate theory Beyles tables for 2 / 4-sided supported plates

(!!w<t to be correct)

Max. stress: ∙Atꞏqꞏl2 =1ꞏ3.33ꞏ0.8ꞏ1.7822=8.49MPa < 50MPa Max. deflection: wꞏCtꞏqꞏl4 =1ꞏ0.62ꞏ0.8ꞏ1.7824=5.0mm < 1785/100=17.85mm

At ,Ct dimensional coefficientq area load [kN/m2] l post distance[m]t glass thickness [mm] a/b long/short edge[m]=a/b edge ratio , coefficient depending on

t 3 4 5 6 8 10 12 15 19

At 83.33 46.88 30.00 20.83 11.72 7.5 5.21 3.33 2.08

Ct 77.5 32.7 16.74 9.69 4.09 2.09 1.21 0.62 0.31

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

w 0.31 0.37 0.43 0.49 0.54 0.59 0.64 0.68 0.72 0.75 0.78 0.8 0.83 0.85 0.87 0.88 0.9 0.91 0.92

s 0.37 0.43 0.49 0.54 0.59 0.64 0.68 0.72 0.75 0.78 0.81 0.83 0.84 0.86 0.88 0.9 0.91 0.92 0.93

2.9 3.0 3.1 3.2 3.4 3.5 3.6 3.7 3.8 3.9 4 5 6 10 50

w 0.93 0.94 0.95 0.95 0.96 0.96 0.97 0.97 0.98 0.98 0.98 1 1 1 1

s 0.94 0.95 0.96 0.96 0.96 0.97 0.97 0.98 0.98 0.98 0.99 1 1 1 1

But =for 2-sided support



Excursion: FEM calculation for glass

All load increasing influences have to be modeled exactly: Holes, cutouts, clamping, eccentricity, deformation of support, tolerances, MOE and thickness of interlayers.

Try to use contact elements and volume elements in the load transformation regions

Sheets can be modeled with shell elements

Load transfer has to correspond to reality

Elastic interlayers MOE: EPDM 400MPa POM 3GPa Silicon 10MPa Hilti HIT-HY 4GPa (cast mortar)


d,max=8.93MPawd,max=5.66mm

Stress calculation wind suction: FEM calculation, Linear, Volume elements

Pressure above 8m, quarter model with linear support

Suction above 8m, building edge quarter model with point support

d,max=16.97MPa < 50MPawd,max=10.55mm < 17.85mm

DetailElastic supportwith contact



2nd case: Overhead glazing with laminated glass (DIN 18008)


2nd case: Overhead glazing with laminated glass Problem: Overhead glazing of a station roof with laminated glass 2x8mm heat strengthened, 2190x1090mm, all-sided linear supported.

Use only glass products according to DIN 18008.2.

PVB interlayer has to be at least 0.76mm thick.

Positive effect of shear interaction can not be considered.

Deflection of support <l/200, max. 15mm

Material properties soda-lime glass (DIN 1249-10, TRLV):

EESG = 70GPa; =0.23; = 25kN/m3 ; Adm. TVG = 29MPa

1 LG from 2x8mm HSG2 Si-Sealing3 IPE 160, St37-24 IPE 80, St27-25 IPE 180, St 52-36 IPE 240, St 52-3

1 LG from 2x8mm HSG2 Elastomer, EPDM3 IPE 160, St37-24 IPE 80, St27-25 Stone cover6 IPE 180, St 52-37 2xM148 IPE 240, St 52-3


Action: Glass in the center with 2.6° inclinationWind load (DIN 1991-1-4, Eurocode 1):w=cpꞏq cp : Pressure(d) or suction coefficient q: velocity pressure

Inclination<30°no wind pressure <8m: q=0.5kN/m2

Suction coefficient lower surface: cp = -0.8Suction coefficient upper surface: cp = -0.6 (only use ½ since they work against the dead load)

ws,lower=cpꞏq=-0.8ꞏ0.5=-0.4kN/m2 ws,upper=cpꞏq=0.5ꞏ-0.6ꞏ0.5=-0.15kN/m2

Load always act simultaneously but in opposite directionws,total=ws,lower-ws,upper=0.25kN/m2

Snow load(DIN 1991-1-4, Eurocode 1, Snow zone III):Standard snow load s0=0.75kN/m2, up to 30° snow load=standard snow load

Dead load has to be considered for all overhead glazing:g=ꞏd=0.4kN/m2, specific weight =25kN/m3, thickness d=2x8mm

Total load (DIN 1991-1-4, Eurocode 1):Summation of all loads, however simultaneous wind and snow loads only the max. load of s+w/2 or w+s/2 has to be taken.

Loading case 1: g+s+w/2=0.4+0.75+0.25/2=1.275kN/m2 significant caseLoading case 2: g+s/2+w=0.4+0.75/2+0.25=1.025kN/m2

2nd case: Overhead glazing with laminated glass


Stress calculation: Calculate individual glass sheets without shear interaction with half of the load. Beyle table for 4-sided linear supported plates.

Max. stress: ∙Atꞏqꞏl2 =0.81ꞏ11.72ꞏ0.5ꞏ1.275ꞏ1.092=7.19MPa < 29MPa Max. strain: wꞏCtꞏqꞏl4 =0.78ꞏ4.09ꞏ0.5ꞏ1.275ꞏ1.094=2.87mm < 1090/100

=10.9mmAt ,Ct dimensional coefficientsq area load [kN/m2] l post distance[m]t thickness [mm] a/b long /short edge [m]=a/b edge ratio , coefficients depending on

t 3 4 5 6 8 10 12 15 19

At 83.33 46.88 30.00 20.83 11.72 7.5 5.21 3.33 2.08

Ct 77.5 32.7 16.74 9.69 4.09 2.09 1.21 0.62 0.31

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

0.31 0.37 0.43 0.49 0.54 0.59 0.64 0.68 0.72 0.75 0.78 0.8 0.83 0.85 0.87 0.88 0.9 0.91 0.92

0.37 0.43 0.49 0.54 0.59 0.64 0.68 0.72 0.75 0.78 0.81 0.83 0.84 0.86 0.88 0.9 0.91 0.92 0.93

2.9 3.0 3.1 3.2 3.4 3.5 3.6 3.7 3.8 3.9 4 5 6 10 50

0.93 0.94 0.95 0.95 0.96 0.96 0.97 0.97 0.98 0.98 0.98 1 1 1 1

0.94 0.95 0.96 0.96 0.96 0.97 0.97 0.98 0.98 0.98 0.99 1 1 1 1

= 2190/1090=2.012.0



Stress calculation: Calculate individual glass sheets without shear interaction with half of the load. Bachs plate equation for 4-sided loading.Max. stress: ∙pꞏ(b/2)2/d2=2.44ꞏ1.275/2ꞏ(1.09/2)2/0.0082ꞏ1e-3=7.22MPaMax. deflection: wꞏpꞏ(b/2)4/(Ed3)=1.77ꞏ1.275/2ꞏ(1.09/2)4/(7e7ꞏ0.0082)ꞏ1e3=2.78mm dimensional coefficients p area load[kN/m2]d thickness [mm] a/b long/short edge [m] E MOE [MPa]

a/b a/b a/b a/b a/b a/b 1.00 1.15 0.71 1.4 1.82 1.24 1.8 2.27 1.63 2.2 2.57 1.89 2.6 2.75 2.05 3.0 2.85 2.14

1.02 1.19 0.74 1.42 1.85 1.26 1.82 2.29 1.64 2.22 2.58 1.9 2.62 2.76 2.06 3.05 2.86 2.15

1.04 1.23 0.77 1.44 1.87 1.29 1.84 2.31 1.66 2.24 2.59 1.91 2.64 2.76 2.06 3.1 2.87 2.15

1.06 1.27 0.8 1.46 1.9 1.31 1.86 2.33 1.67 2.26 2.6 1.92 2.66 2.77 2.07 3.15 2.87 2.16

1.08 1.3 0.83 1.48 1.92 1.33 1.88 2.35 1.69 2.28 2.61 1.93 2.68 2.77 2.07 3.25 2.89 2.17

1.1 1.34 0.86 1.5 1.95 1.35 1.9 2.36 1.7 2.3 2.62 1.94 2.7 2.78 2.08 3.35 2.9 2.18

1.12 1.38 0.89 1.52 1.97 1.37 1.92 2.38 1.72 2.32 2.63 1.94 2.72 2.79 2.08 3.4 2.9 2.19

1.14 1.41 0.91 1.54 2.0 1.39 1.94 2.39 1.73 2.34 2.64 1.95 2.74 2.79 2.09 3.5 2.91 2.2

1.16 1.45 0.94 1.56 2.02 1.41 1.96 2.41 1.74 2.36 2.65 1.96 2.76 2.8 2.09 3.6 2.92 2.2

1.18 1.48 0.97 1.58 2.05 1.43 1.98 2.43 1.76 2.38 2.66 1.97 2.78 2.8 2.1 3.75 2.94 2.22

1.2 1.15 1.0 1.6 2.07 1.45 2.00 2.44 1.77 2.4 2.67 1.98 2.8 2.81 2.1 3.8 2.94 2.22

1.22 1.55 1.02 1.62 2.09 1.47 2.02 2.45 1.78 2.42 2.68 1.99 2.82 2.81 2.11 3.95 2.95 2.23

1.24 1.58 1.05 1.64 2.11 1.49 2.04 2.47 1.8 2.44 2.69 1.99 2.84 2.82 2.11 4.15 2.96 2.28

1.26 1.61 1.07 1.66 2.14 1.51 2.06 2.48 1.81 2.46 2.7 2.0 2.86 2.82 2.11 4.35 2.97 2.3

1.28 1.64 1.1 1.68 2.16 1.52 2.08 2.5 1.82 2.48 2.71 2.01 2.88 2.83 2.12 4.4 2.98 -

1.3 1.67 1.12 1.7 2.18 1.54 2.1 2.51 1.83 2.5 2.71 2.02 2.9 2.83 2.12 4.8 2.98 -

1.32 1.7 1.15 1.72 2.2 1.56 2.12 2.52 1.84 2.52 2.72 2.02 2.92 2.83 2.13 4.85 2.99 -


||Institute for Building Materialswmax=2.876mm

wmax=2.9mm

Linear calculation

Non-linear calculation

Form a/d>50 on the membrane effect of the plate can be used. Here a/d=1090/(2*8)68Shell elements, reduced integration, Kirchhoff shells (thin shell theory). Non-linear calculation brings here no significant advantage. All calculations show admissible bending stress <29MPa and deflection <l/100=10.9mm



3rd case: Vertical insolation glazing (DIN 18008)


• In general insolation glazing needs to be designed following the DIN 18008

• Additionally climatic loads have to be considered that originate from the closed glass filling (3K 1kN/m2 = 84m height)

• Deflections due to climatic loads in general smaller than thickness.

• Deflection limitation by producers (sealing of the edges) or l/100.

• Edges can be considered like a freely rotatable bearing.

• Coupling via the closed interspace leads to simultaneous loading of all glass sheets, depending on their thickness and the insolation glass factor

• Shear interaction in laminated glass can additionally introduce loads.

3rd case: Vertical insolation glazing DIN 18008



Vertical insolation glazing all-sided linear support. Freely rotatable support.

Window size 2977x2777 a/b=≈1.1• Consider wind / climatic loads

• Edge defects <15% window thickness

• Support depth for all-sided linear support >10mm

• Deflection of supporting profiles <l/200, max. 15mm

Position 136 glass sheets


Wind load (DIN 1991-1-4, Eurocode 1):w=cpꞏq cp : Pressure(d) or suction coefficient q: velocity pressure

8m<height<20m: q=0.8kN/m2

Pressure coefficient: cp = -0.8Suction coefficient: cp = -0.5 (DIN 1055-4 6.3.1, Tab. 11 Lfd. Nr. 1,2)

Load increase factor for local pressure peaks e=1.25

wD=eꞏcpꞏq=1.25ꞏ0.8ꞏ0.8=-0.8kN/m2 significant casews=cpꞏq=-0.5ꞏ0.8=-0.4kN/m2



Climatic loads (DIN18008-2):Climatic load of the isochoric system:

pi=±ꞏp0: Insolation glass factor p0: isochoric pressure in the interspace

p0=c1ꞏT-pmet+c2ꞏH, with c1=0.34 kPa/K and c2=0.012 kPa/mT Temperature difference between fabrication

and installation site Height difference between fabrication and

installation sitepmet Difference of the meteorological air pressure between fabrication and installation site

p0: +16kN/m2 summerp0: -16kN/m2 winter

Combinations T [K] pmet

[kN/m2]H* [m] p0t kN/m2]

Summer 20 -2 600 16

Winter -25 4 -300 -16

* If fabication and installation sites are known, real values can be considered.



Climatic loads (TRLV, Anhang A):Climatic load of an isochoric system: pi=±ꞏp0

: Insolation glass factor:

Climatic load pi=±ꞏp0=±0.00149ꞏ16=±0.0238kN/m2

For the outer glass, the winter is more critical- (+ꞏp0) while for the inner glass the summer condition (+ꞏp0) is more critical.

a smaller edgea* characteristic edge

dSZR interspace in mmda outside glass thickness in mmdi inside glass thickness in mmBV factor (a/b) DIN 18008-2 Tab. A1

Kirchhoff’s plate theory for =0.23

a smaller edgeb longer edgea/b =2777/2977=0.93

a/b 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

BV 0.00194 0.0237 0.0288 0.035 0.0421 0.0501 0.0587 0.0676 0.0767 0.0857

3 3

43 3

* 28.9( )

SZR a i

a i V

d d da

d d B

3 3

43 3

16 10 6* 28.9 546.05

(10 6 ) 0.0233a mm

4

1

1*

aa

142777

1 0.00149546.05



Coupling of sheets (TRLV, Anhang A):

• pa,ges=aꞏi)ꞏwa + ꞏp0 + ꞏaꞏwi Winter significant• pi,ges=) ꞏiꞏwa + ꞏp0 + ꞏai)ꞏwi Summer significant

Portion of the single sheets for the total bending stiffness:a=da

3/(da3+di

3)=103/(103+63)=0.8224i=di

3/(da3+di

3)=63/(103+63)=0.1776Here wi=0:

pa,tot=aꞏi)ꞏwa + ꞏp0 =(0.8224+0.00149ꞏ0.1776)ꞏ0.8+0.00149ꞏ16=0.682kN/m2

pi,tot=) ꞏiꞏwa + ꞏp0=(1-0.00149) ꞏ0.1776ꞏ0.8+0.00149ꞏ16=0.1658kN/m2

Load on sheet:

Action Portion of outer sheet

Portion of inner sheet

outer Wind wa (a+ꞏi)ꞏwa (1-) ꞏiꞏwa

Snow s (a+ꞏi)ꞏs (1+) ꞏiꞏs

inner Wind wi (1-)ꞏaꞏwi (ꞏa+i)ꞏwi

both Isochoric pressure p0 -ꞏp0 ꞏp0



t 3 4 5 6 8 10 12 15 19

At83.33 46.88 30.00 20.83 11.72 7.5 5.21 3.33 2.08

Ct77.5 32.7 16.74 9.69 4.09 2.09 1.21 0.62 0.31

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

0.31 0.37 0.43 0.49 0.54 0.59 0.64 0.68 0.72 0.75 0.78 0.8 0.83 0.85 0.87 0.88 0.9 0.91 0.92

0.37 0.43 0.49 0.54 0.59 0.64 0.68 0.72 0.75 0.78 0.81 0.83 0.84 0.86 0.88 0.9 0.91 0.92 0.93

= a/b=2977/27771.1

Stress calculation: Material properties soda-lime glass (DIN 1249-10;DIN 18008): EESG = 70GPa; =0.23; = 25kN/m3 ; Admissible HSG = 29MPa

Beyle table for 4-sided plates

Max. stress: ∙Atꞏqꞏl2 Max. deflection: wꞏCtꞏqꞏl4

Outer sheet:a=0.43ꞏ7.5ꞏ0.682ꞏ27772=16.96MPa ua=0.37ꞏ2.09ꞏ0.682ꞏ277724=31.36mm

Inner sheet:i=0.43ꞏ20.83ꞏ0.1658ꞏ27772=11.45MPa ui=0.37ꞏ9.69ꞏ0.1658ꞏ27774=35.35mm

At ,Ct dimensional coefficientsq area load [kN/m2] l post distance[m]t thickness [mm] a/b long/short edge[m]=a/b edge rations , coefficient depending on



No deflection limitationbut deflections of 1/88 or 1/78 have to be approved by producer.

For vertical insolation glazing 18MPa+15% = ad=20.7MPa 16.96MPa < 20.7MPa 11.45MPa < 20.7MPa

Glass typeStrength [MPa]

Overhead glazing

Vertical galzing

TG from float glass 50 50

TG from cast glass 37 37

Fritted TG 30 30

Float glass 12 18

Cast glass 8 10

LG from float 15 22.5

Insolation glass,10mm FG, 16mm inter spacing, 6mm FG

Support profile

Pressure cap with sealing

Outer sheet:a=0.43ꞏ7.5ꞏ0.682ꞏ27772=16.96MPaua=0.37ꞏ2.09ꞏ0.682ꞏ27772=31.36mm

Inner sheet:i=0.43ꞏ20.83ꞏ0.1658ꞏ27774=11.45MPa ui=0.37ꞏ9.69ꞏ0.1658ꞏ27774=35.35mm



Summary:

Glass in architectureGlass chemistryGlass physicsGlass forming and processingGlass products in civil engineeringGlass in constructions


Thank you for your attention.

09.09.2013 64


Glass type

Overhead glazing

Vertical galzing

TG from float glass

50 50

TG from cast glass

37 37

Fritted TG 30 30

Float glass

12 18

Cast glass 8 10

LG from float

15 22.5


teaching goals glass products · • different heat expansion coefficients of glass, adhesive and...

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