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system thus achieved a 60 minute fire resistance. The loaded floor test specimen similarly wasexpected to have a fire resistance of at least 60 minutes. However, there were voids in the core whichhad not been properly filled with mineral wool which led to very high temperature rises in part of thefloor and so the test had to be terminated after 47 minutes.3.3 Numerical studies3.3.1 Load-bearing structuresNested tubes (thermal analysis)The temperature development in the columns was modelled using the material properties given in EN1993-1-2 and compared with the temperature development using revised properties proposed byGardner and Ng [8] and also carbon steel properties. Gardner and Ng proposed an emissivity of 0.2 forstainless compared to 0.4 given in EN 1993-1-2, and a heat transfer coefficient of 35 W/m 2 K comparedto 25 W/m 2 K in EN 1993-1-2. These values were derived by analysing tests from 3 differentlaboratories in Finland, France and the UK. It is therefore thought that they are reliable parameters fordescribing behaviour in fire tests, but perhaps not for describing behaviour in real fires where soot islikely to build up on the surface after a short time. The issue of what should be used in design wasdebated by the project partners since there are a number of conservatisms already built into the designprocess (e.g. standard fire curve); adopting the more conservative value of 0.4 for emissivity may leadto unnecessarily uneconomic design for stainless steel.EN 1993-1-2 gives a value of 0.7 for the emissivity of carbon steel and 25 W/m 2 K for the heat transfercoefficient.Numerical analyses were carried out with a two-dimensional ABAQUS model. The insulation materialwas characterised by a temperature gradient and the outer and inner tubes showed approximatelyuniform cross-section temperatures. The cross-sections were exposed to the EN 1363-1 standard fireand the temperatures were measured at the corners of the tubes, as shown in Figure 3.6. Thetemperature difference obtained with the different sets of material properties is small, but it is observedthat the use of the Gardner and Ng values introduces an improvement in the fire resistance of stainlesssteel. Subsequent analyses were carried out using the material properties proposed by Gardner and Ng.1,000900800Temperature in °C7006005004003002001EN 1363-1 standard firestainless steel (EC3-1-2)stainless steel (Gardner)carbon steelCross-section12RHS 300×10Mineral woolRHS 200×8100020 10 20 30 40 50 60Time in minutesFigure 3.6Cross-sectional temperatures of nested tubes for varying material propertiesFigure 3.7 and Figure 3.8 compare the measured temperatures with the predicted temperatures in theouter and inner RHS respectively. There is a substantial variation in the measured temperatures aroundthe tube due to non-uniform heating effects. In both tubes the predicted temperatures are lower thanthose recorded during the test, although the difference is greater in the inner tube due to theuncertainties connected with modelling of the mineral wool.20
1,2001,100Temperature in °C1,000900800700600500400300200100041ABAQUSEC3-1-211 8ABAQUSGardner0 10 20 30 40 50 60Time in minutes25241511Cross-section8Figure 3.7Comparison between test data and numerical results for outer tube41Temperature in °C1,2001,1001,00090080070060050040030020010004120 23 14 170 10 20 30 40 50 60Time in minutes14ABAQUSEC3-1-21723Cross-sectionABAQUSGardner20Figure 3.8Comparison between test data and numerical results for inner tubeComparison of stainless steel and carbon steel column behaviour in fireThe structural performance of a stainless steel RHS column (200x200x8) from grade 1.4301 wascompared to the performance of an identical carbon steel column from grade S235 at differenttemperatures using finite element analysis (Figure 3.9). An imperfection factor of L/300 was assumed.The ultimate load-bearing capacity was calculated by incrementally increasing the applied load. For across-sectional temperature of 400°C, the stainless and carbon steel columns showed similar loadbearingcapacity. At 600°C, the stainless steel columns exhibited much higher load-bearing capacity21
Page 1 and 2: Research Programme of the Research
Page 3 and 4: CONTENTSPage No.ABSTRACT 5FINAL SUM
Page 5: ABSTRACTThe relatively sparse body
Page 9: 8. WP7: Design aids and softwareRat
Page 12 and 13: 1.2Stiffness E( ) retention / E(20
Page 15 and 16: 3 WP1: FIRE RESISTANT STRUCTURES AN
Page 17 and 18: ExposedMid-depth ofinsulationInnerp
Page 22 and 23: than the carbon steel columns; the
Page 24 and 25: For case 1 (pinned ends), the stain
Page 26 and 27: 10 68.5 10 61.5θg2= 20°C; α = 9
Page 28 and 29: of part of the cross-section being
Page 30 and 31: Load testing:1000 kN PressEnd plate
Page 32 and 33: Table 4.3 shows failure times, fire
Page 34 and 35: 4.3.3 Design method for composite c
Page 36 and 37: 4.3.5 Design method for composite b
Page 38 and 39: 4.3.6 Comparison between stainless
Page 41 and 42: 5 WP3: CLASS 4 CROSS SECTIONS IN FI
Page 43 and 44: FWater cooled steelload equipmentSu
Page 45 and 46: Table 5.4 Comparison of strength re
Page 47 and 48: 5.3.3 Development of design guidanc
Page 49 and 50: 6 WP4: PROPERTIES AT ELEVATEDTEMPER
Page 51 and 52: Table 6.3Test programme for transie
Page 53 and 54: The following procedure used to eva
Page 55: Table 6.4Material reduction factors
Page 58 and 59: T= 100 °C T=200°CT= 300 °C T=400
Page 60 and 61: Grade 1.4318: Welded (W) v.s. Base
Page 62 and 63: Figure 7.5Connection design for bol
Page 64 and 65: Table 7.2Detailed results of shear
Page 66 and 67: dilatation caused by heating may ca
Page 69 and 70:
8 WP6: PARAMETRIC FIRE DESIGNDetail
Page 71 and 72:
Table 8.1Cross-sectionTemperature f
Page 73 and 74:
analyses (Figure 8.2). The differen
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calculated according to EN 1993-1-4
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The following observations were not
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9 WP7: DESIGN AIDS AND SOFTWARE9.1
Page 81 and 82:
9.3 Design of stainless steel beams
Page 83 and 84:
Figure 9.4Column buckling tests at
Page 85 and 86:
The main assumptions made by the so
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Figure 9.7Fire design software: fir
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11 FINAL WORK PACKAGE REPORTSAll de
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12.2 Dissemination of project resul
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13 CONCLUSIONSThis report summarise
Page 100 and 101:
Figure 6.3 EN 1.4541 steel stress-s
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Table 8.5 Buckling resistance at ro
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[22] ECSC Final Report, Development
Page 106 and 107:
Table A.4Values of parameters L θ
Page 108 and 109:
Table B.1Experimental data on stain
Page 110 and 111:
EUROPEAN COMMISSIONRESEARCH DIRECTO
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
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