BRE/TSLAB Vulcan Comparisons - University of Sheffieldfire-research.group.shef.ac.uk/steelinfire/downloads/RP_09_07.pdf · BRE/TSLAB – Vulcan Comparisons Roger Plank Anthony Abu

BRE/TSLAB – VulcanComparisons

Roger Plank

Anthony Abu & Ian Burgess

25-Sep-07 © The University of Sheffield - Structural Fire Engineering Group

Tensile Membrane Action

Peripheral compression

Tensile Area


• Rigid – plastic theory with large change of geometry

• Yield line capacity

• Membrane enhancement to yield line capacity

• Panels are horizontally unrestrained

• Vertical support at the boundaries

• Tensile strength of concrete is ignored

BRE – Bailey Method


φ

nL

L

l

SS


T1

T2

T2’ T2

’

T2

C C

T2 T2

T1

CC


• Allowable deflection

( )

8

35.0

2.19

22

12L

E

f

h

lTTv

y×+

−=

α

T2-T1 = 770°C for Time ≤ 90 mins T2-T1 = 900°C for Time > 90 mins



• Do protected beams provide adequate vertical support?

• Effect of reinforcement ratios on failure

• Effect of tensile strength of concrete

• Effect of edge continuity

Comparison between Vulcan and



• 9.0m x 6.0m, 7.5m x 9.0m, 9.0m x 9.0m, 9.0m x 12.0m

• S275 beams

• Trapezoidal deck profile

• Normal weight concrete

• Strength (fcu = 40N/mm2, fck = 35N/mm2)

• S500 Reinforcement mesh

• Average mesh position (from top surface) = 45mm

Slab-Panel Properties


Slab-Panel Properties


7.5m x 9.0m Slab-Panel

9.0m

7.5m

Corner vertical supportDifferent protection regimes

and support conditions

A193 Mesh

• Load ratios and limiting temperatures

• Secondary beams = 0.44 and 631°C

• Primary beams = 0.40 and 646°C


-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)

Vertical Displacement (mm)60 mins

Span/20

( )8

35.0

2.19

77022

L

E

f

h

lCv

y×+=

oαBRE Limit

( )

8

35.0

2.19

22

12L

E

f

h

lTTv

y×+

−=

αTSLAB



-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)

Vertical Displacement (mm)


Bailey - BRE Method




















-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)



Vulcan – edge support

Vulcan – corner support

– Generic Protection


-1000

-900

-800

-700

-600

-500

-400

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-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)



Vulcan – Displacement of slab panel

centre relative to secondary beam

Vulcan – Displacement of slab panel

centre relative to primary beam


-1000

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-700

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-500

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-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)




-1000

-900

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-700

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-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)


Vulcan – Cold Perimeter Beams – Edge

support - Tensile strength of concrete

included

Vulcan – Cold Perimeter Beams –

Edge support - Tensile strength of

concrete ignored



• Maximum absolute vertical displacements

• Deflection plots (mesh sizes)

• A142 – Navy blue

• A193 – Red

• A252 – Green

• A393 - Black

• Analytical approaches

• BRE Method – Solid lines

• Vulcan – Broken lines

Main Study


Typical slab panel Secondary beam failure Primary beam failure

Type 1

Typical slab panel Secondary beam failure Primary beam failure

Type 2

Proposed Failure Criteria


-1000

-900

-800

-700

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-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)

Maxim

um

Dis

pla

cem

ent

(mm

)

Vulcan Results

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)M

axim

um

Dis

pla

cem

ent

(mm

)

Plastic Failure


Type 2

Type 1


-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)

Maxim

um

Dis

pla

cem

ent

(mm

)

Vulcan Results

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)M

axim

um

Dis

pla

cem

ent

(mm

)

Plastic Failure


Type 2

Type 1


-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)

Maxim

um

Dis

pla

cem

ent

(mm

)

Vulcan Results

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)M

axim

um

Dis

pla

cem

ent

(mm

)

Plastic Failure


Type 2

Type 1


• Reinforcement ratios

• 142, 166, 193, 221, 252, 318, 393 (mm2/m)

• Additional ratios for 9.0m x 9.0m slab panel

• 153, 179, 206, 236, 284, 354 (mm2/m)

• Comparison of failure times

Comparison of Failure Times


-1000

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-800

-700

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-500

-400

-300

-200

-100

0

0 10 20 30 40 50 60 70 80 90

Time (min)

Maxim

um

Dis

pla

cem

ent

(mm

)

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

0

0 60 120 180 240 300 360

Time (min)M

axim

um

Dis

pla

cem

ent

(mm

)

Vulcan failure times BRE failure times

Increasing

reinforcement ratio

Increasing

reinforcement ratio



0

30

60

90

120

150

180

210

240

270

140 170 200 230 260 290 320 350 380

Area of Reinforcement (mm2/m)

Failu

re T

ime (

min

)

TSLAB

Span/20

BRE Limit

9.0m x 6.0m comparison

0

30

60

90

120

150

180

210

240

270

140 170 200 230 260 290 320 350 380

Area of Reinforcement (mm2/m)F

ailu

re T

ime (

min

)

TSLAB

Span/20

BRE Limit

9.0m x 12.0m comparison

Failure Times


Conclusions

• Significant influence of edge support & continuity

• Bailey Method sensitive to mesh size and temperature

• Conservative for

• Smaller mesh sizes

• Larger slab panels

• As ‘collapse’ condition for slab

• Failure criteria - relative or absolute displacements?

• Reinforcement temperatures


Thank You

Documents

BRE/TSLAB Vulcan Comparisons - University of Sheffieldfire-research.group.shef.ac.uk/steelinfire/downloads/RP_09_07.pdf · BRE/TSLAB – Vulcan Comparisons Roger Plank Anthony Abu