Clt mtb seminar_presentation_five

LVL Floor Panel Systems

Massive Timber Seminar18th June – Sydney

19th June – MelbourneAuthored and presented by Andy Van Houtte

LVL Flooring Panel Characteristics Design Solutions• Light weight structures• Flexible designs• Multiple geometries• Acoustic solutions• Fire rating solutions• Composite action

Construction Advantages• Speed of installation (less overall workers on site)• Smaller cranes or larger reach (multiple lifts)• Smaller supporting structures (1/5th the mass of concrete)

• Less truck movements• Smaller/less expensive foundations

• Cleaner work environment – dry site• Quieter work site• Easier to install services• Instant working platform

Panel options1. T-beam

• bottom flange2. Cassette

• Bottom flange fire rated3. Concrete top

• Partial composite action4. Hanging ceiling

• fire performance/acoustical

Top Skin SizesXband LVL 17, 21, 25, 36, 45mm

LVL JoistsThicknesses 35, 45, 63, 90mmWidths 150, 200, 240, 300, 360, 400, 460, 600mm

Length up to 18m

T-Panels1. Simple to fabricate2. Cost effective – glue and nail/screw3. Fast to install4. Full composite action with floor sheathing

can be achieved with long length xband LVL5. Residential and commercial applications

Cassette Floors

1. More expensive than T-beam to fabricate2. Not a total solution3. Dynamics can govern due to light weight

1. Good span to weight ratio2. Bottom flange can act as sacrificial fire

barrier3. Between joists can support services and

insulation.4. Can be used for hit and miss flooring

effectively.

Concrete toppingAdvantages• Thermal mass• Rigid diaphragm action• Dynamic damping• Acoustical absorption• Partial composite action possible• Potential for pre fabrication

Disadvantages• J2 factor 3-4 (composite action only)• lots of mechanical fasteners/notches for composite action• Concrete shrinkage• Wet trade on site

2 2( )ef c c t t c c c c t t t tEI E I E I E A a E Aa

Cost versus Span

Span (m)

$/m

2

4 5 6 7 8 9 10 11100

120

140

160

180

200

220

240

Cassette FRR60T Beam Polynomial (T Beam )T Beam FRR60

Design loadings:3kPa live load2kPa superimposed dead loadNo concrete composite action consideredConcrete cost not included

Panel DesignStrength

1. Bending strength limited by concrete capacity2. Bending strength limited by timber capacity3. Shear strength4. Shear Connector Capacity

Deflection

DynamicsTraditionally fundamental frequency greater than 8Hz was employed to provide a guideline for the measure of a suitable floor response. This was simplified in AS1684 – residential framing (based on research by Mackenzie and Juniper, 1997) to a maximum deflection of 2mm under a 1kN point load (in conjunction with the load distribution factor) for timber joists.

More recently a more relevant method of measuring dynamic acceptability is by the floor acceleration (RMS), with different response criteria given the intended purpose of the floor. A good resource is the UK Concrete Society CCIP-016 report – Design Guide for footfall induced vibration of structures or alternatively using the rigorous analysis (SCI P-354)

Spreadsheet design – makes it easyStress Skin Panels

Joist spacing 600 mm

MoE of system 11 GPa

Total thickness 720

Laminate count 12

Geometrical centroid of section 420.62

Structural centroid of section (Stiffness) 445.47

2nd moment of Inertia (Geometrical) 0.00019

2nd moment of Inertia (Structural) 0.00019

Note: Cross ply contributes 0.3E

Top Flange Web Bottom Flange

Laminate Depth (mm) Width (mm) Contribution for IContribution for

Z E (GPa) F'b (Mpa) Depth (mm)Width (mm) Contribution for IContribution for

Z E (GPa) F'b (Mpa) Depth (mm) Width (mm)

1 3.5 400 1 1 9 35

2 3.5 400 1 1 9 35

3 3.5 400 0.3 0 9 35

4 3.5 400 1 1 9 35

5 3.5 400 1 1 9 35

6 3.5 400 1 1 9 35

7 3.5 400 1 1 9 35

8 3.5 400 0.3 0 9 35

9 3.5 400 1 1 9 35 10 3.5 400 1 1 9 35

11 610 45 1 1 11 38

13 75 400

14

15

16

17

i

i

bhE

12

3

zE A z

E Ai i i

i i

__

EE I AE z z

I A z z

i i i i i

i i i

( )

( )

_ _

_ __

2

2

I I A z zi i i ( )_ __

2

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)( Siii zzEA LVL Floor joists (mm) kg/m2

Supporting floor loads only, also not including deck joists Bearer width 75 Floor Dead Load 40

E value 10700000000 f's 6000000 loads

f'b 42000000 f'p 12000000 DL DL LL LL LL LL LL LL LL

Joist spacing G1 G2 Q1 Q2 Q3 Q4 Q5 Q6 Q7

Member B D I Z Reference Estimated length (mm) (kN/m) (kN) (kN/m) (kN/m) (kN/m) (kN/m) (kN) (kN) (kN)

400x45 45 400 240000000 1200000 16 4.5 400 0.257 0.000 0.200 1.600 0.300 1.200 2.22 6.00 0.65

400x45 45 400 240000000 1200000 16 4.5 450 0.277 0.000 0.225 1.800 0.338 1.350 2.20 6.75 0.64

400x45 45 400 240000000 1200000 16 4.5 600 0.337 0.000 0.300 2.400 0.450 1.800 2.41 9.00 0.75

Bending Deflection Shear Bearing

1 2 3 hb hc g42 g41

300 0.20 0.05 0.24 0.17 0.15 0.52 28.18 120.9 0.82 0.65

450 0.22 0.06 0.27 0.17 0.17 0.59 28.18 131.4 0.82 0.64

600 0.29 0.07 0.36 0.20 0.22 0.78 28.18 55.4 0.89 0.75

Bending Deflection Shear Bearing All

300 OK OK OK OK TRUE



Acoustics and Fire PerformanceFire Resistance Ratings requires typically 60, 90 or 120mins in Australia,Options:1. Can be achieved with a fire rated plasterboard ceiling2. Can be achieved with LVL char rating of 0.7mm/min

Acoustics – impact and airborne transmission1. Best performance achieved with an acoustical

break – like a hanging ceiling2. Floor toppings3. Sound insulation internally between joists

Reference Material1. Potius Panels - www.potius.co.nz

2. STIC EXPAN Material (UTS) – Keith Crews, Rijun Shrestha, Christophe Gerber

3. A dynamic approach for timber floor design - Chui and Smith

4. Composite Concrete slab and LVL floor systems – Fragiacomo and Deam

5. Eurocode 5

6. Timber Designers Manual - Ozelton and Baird

7. Springiness and Human induced floor vibrations – Ohlsson

8. Timber Design Guide – Buchanan

9. Mackenzie and Juniper – timber framed housing – methodology and performance

criteria

Thank you