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SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Eurocode EN 1993-1-2
Clause
4.2.5
Reasons for improvement
The EN 1993-1-2 for fire design, does not take into account the case of steel elements
embedded in walls, presenting only a formulation considering uniform temperature. Thus
the thermal gradients observed within the cross-section are neglected.
Proposed changes
The proposal consists of a new simplified calculation method to evaluate the
temperature distribution on steel columns embedded in walls. The method is based on Finite
Element Analysis and Fire Resistance Tests. Steel columns totally or partially embedded in
walls, with the web perpendicular or parallel to the wall surface, were studied.
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Innovation in Structural Engineering
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
|2
SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
1.
2.
3.
4.
5.
6.
3D restraining steel frame;
Hydraulic jack of 1MN;
2D reaction frame;
LVDT’s;
Furnace;
Safety structure;
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Innovation in Structural Engineering
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
|3
SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Preparation of the tests on steel columns embedded on walls
The columns in test were placed on the centre
of a 3D restraining frame.
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Walls on both sides of the columns were
built. The furnace applies the thermal
action, following the standard ISO curve.
The column was instrumented with
thermocouples and LVDT’s.
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
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SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
|5
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Experimental tests on steel columns embedded on walls
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
400ºC
Institute for Sustainability and
Innovation in Structural Engineering
400ºC
400ºC
400ºC
400ºC
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
800
700
600
500
400
300
200
100
0
Web parallel to the wallsEA
Exposed
flange
web
Unexposed
t (min)
0
5
10
15
20
25
30
flange
Mean Steel
Temperature
800
700
600
500
400
300
200
100
0
Exposed halfflange
web
Unexposed
Half-flange
t (min)
0
t(min)
Exposed
flange
Web
Unexposed
flange
0.0
20
20
20
1.8
100
49
20
3.2
200
87
20
4.5
300
127
20
5.9
400
170
21
7.6
500
220
23
10
600
280
28
14.6
700
362
42
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T (ºC)
T (ºC)
Thermal Gradients Web perpendicular to the walls
5
10
15
20
Mean Steel
Temperature
t(min)
Exposed
half-flange
Web
Unexposed
half-flange
0
20
20
20
2.25
100
80
37
4.16
200
159
72
6.1
300
244
119
8.3
400
329
174
11.1
500
417
245
15.5
600
513
333
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
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SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Reduction factors
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FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
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SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Analytical Proposals
Temperature evolution in unevenly heated columns, embedded on walls
Model 1
Model 4
Model 2
Model 3
Model 5
Institute for Sustainability and
Innovation in Structural Engineering
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
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SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Analytical Proposals
Model 2 – HEA 160
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Model 5 – HEA 160
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
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SIMPLIFIED CALCULATION METHOD FOR TEMPERATURE EVALUATION OF STEEL COLUMNS
EMBEDDED ON WALLS
António Moura Correia, João Paulo Rodrigues, Valdir Pignatta e Silva
Conclusion
Concerning the assessment of the temperature evolution in the steel
profiles embedded on walls
The EN 1993-1.2 (2005) formulation using the section factor can be used, although
it was proven to be valid only for the exposed flange engulfed in fire (cases of wall
thickness smaller than web height). In all other cases, the temperature in each zone of the
cross-section can be calculated in function of the temperature of the exposed area.
Several reduction factors were defined in such a way that multiplying the temperature of
the exposed area of the steel profile by them, the temperature in the corresponding zone
is obtained.
Another aproach was proposed considering different formulae for the different
cases.
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Innovation in Structural Engineering
FCTUC
Faculdade de Ciências e Tecnologia
Universidade de Coimbra
| 10