About the use of semi-continuity in simply supported composite steel and concrete beams, to remove fireproof coatings for standard-fire resistance requirement of less than 30 minutes

Previous studies of the behavior under fire conditions of composite steel and concrete beams, not subjected to local buckling (compact steel profile), showed that it’s not possible to justify, by design code methods, the absence of fire coating for 30 minutes standard-fire resistance requirement, even when considering the support rotational stiffness provided by the upper longitudinal slab reinforcement (semi-continuity). The purpose of this work is to verify the viability of this proposal for lower standard-fire resistance time, which, although rare, may occur with the use of the equivalent time method.

Keywords:
fire; composite steel concrete beam; semi-continuous

Authorship

L. C. ROMAGNOLI

Escola Politécnica da Universidade de São Paulo, São Paulo, SP, Brasil. lucas.romagnoli@usp.br valpigss@usp.brUniversidade de São PauloBrazilSão Paulo, SP, Brazil Escola Politécnica da Universidade de São Paulo, São Paulo, SP, Brasil. lucas.romagnoli@usp.br valpigss@usp.br

http://orcid.org/0000-0002-3693-1128

V. P. SILVA

http://orcid.org/0000-0003-3302-8520

SCIMAGO INSTITUTIONS RANKINGS

Figures | Tables

Figures (7)
Tables (7)

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Figure 1
Composite connection (adapted from ABNT NBR 8800 [¹¹[11] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 8800: Projeto de estruturas de aço e de estruturas mistas de aço e concreto de edifícios. Rio de Janeiro, 2008.])

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Figure 2
Temperature as function of the slab height, 30 minutes

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Figure 3
Temperature as function of the slab height, 60 minutes

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Figure 4
Temperature as function of the slab height, times less than 30 minutes

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Figure 5
Semi-continuous case fire resistance time (for 0.7 load factor) as function of the analyzed profile (Gerdau W200 series)

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Figure 6
Semi-continuous case fire resistance time (for 0.7 load factor) as function of the analyzed profile

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Figure 7
Reinforcement ratio as function of the analyzed profile, for the semi-continuous case fire resistance time (for 0.7 load factor)

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Table 1
Concrete slab temperature distribution [ºC] for standard fire resistance requirement of less than 30 minutes

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Table 2
Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W150-W360

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Table 3
Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W150-W360 (continuation)

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Table 4
Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W410-W610

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Table 5
Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W410-W610 (continuation)

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Table 6
Reinforcement ratio as function of the standard fire resistance requirement for development of the maximum negative bending moment, for composite beams with 10 cm slabs and Gerdau profiles series W150-W360

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Table 7
Reinforcement ratio as function of the standard fire resistance requirement for development of the maximum negative bending moment, for composite beams with 10 cm slabs and Gerdau profiles series W410-W610

Figure 1 Composite connection (adapted from ABNT NBR 8800 [¹¹[11] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 8800: Projeto de estruturas de aço e de estruturas mistas de aço e concreto de edifícios. Rio de Janeiro, 2008.])

Figure 2 Temperature as function of the slab height, 30 minutes

Figure 3 Temperature as function of the slab height, 60 minutes

Figure 4 Temperature as function of the slab height, times less than 30 minutes

Figure 5 Semi-continuous case fire resistance time (for 0.7 load factor) as function of the analyzed profile (Gerdau W200 series)

Figure 6 Semi-continuous case fire resistance time (for 0.7 load factor) as function of the analyzed profile

Figure 7 Reinforcement ratio as function of the analyzed profile, for the semi-continuous case fire resistance time (for 0.7 load factor)

Table 1 Concrete slab temperature distribution [ºC] for standard fire resistance requirement of less than 30 minutes

Slice	Height (y) mm	Standard fire resistance requirement (min)
Slice	Height (y) mm	15	20	25
1	0 to 5	424	506	565
2	5 to 10	318	394	453
3	10 to 15	238	308	363
4	15 to 20	178	240	291
5	20 to 25	133	186	233
6	25 to 30	102	145	186
7	30 to 35	81	114	149
8	35 to 40	64	92	120
9	40 to 45	51	75	100
10	45 to 50	42	62	83
11	50 to 55	35	51	70
12	55 to 60	30	44	60
13	60 to 80	25	38	48
14	≥ 80	23	31	44

Table 2 Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W150-W360

Standard fire resistance requirement (30 to 23 minutes), series W150-W360, tc = 10 cm
Name	30		29		28		27		26		25		24		23
Name	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC
W 150x18.0	0.11	0.20	0.11	0.21	0.12	0.21	0.12	0.22	0.13	0.23	0.13	0.24	0.14	0.26	0.15	0.28
W 150x24.0	0.12	0.22	0.12	0.23	0.13	0.24	0.14	0.25	0.15	0.26	0.16	0.28	0.17	0.31	0.19	0.35
W 150x37.1	0.14	0.26	0.15	0.28	0.16	0.29	0.17	0.32	0.19	0.35	0.22	0.40	0.24	0.44	0.27	0.49
W 200x22.5	0.11	0.20	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28
W 200x31.3	0.12	0.22	0.13	0.23	0.13	0.24	0.14	0.26	0.15	0.27	0.16	0.29	0.17	0.32	0.19	0.35
W 200x41.7	0.14	0.25	0.15	0.27	0.15	0.28	0.16	0.30	0.18	0.34	0.20	0.38	0.23	0.42	0.25	0.47
W 200x59.0	0.18	0.33	0.19	0.36	0.22	0.40	0.24	0.44	0.26	0.49	0.30	0.55	0.33	0.61	0.36	0.67
W 200x71.0	0.24	0.44	0.26	0.48	0.29	0.53	0.32	0.59	0.35	0.65	0.39	0.72	0.43	0.80	0.48	0.90
W 200x86.0	0.31	0.57	0.34	0.63	0.37	0.69	0.40	0.76	0.44	0.84	0.49	0.94	0.55	1.04	0.60	1.16
W 250x22.3	0.11	0.20	0.11	0.21	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.27
W 250x25.3	0.11	0.21	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28
W 250x28.4	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28	0.16	0.30
W 250x38.5	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28	0.16	0.30	0.18	0.33	0.20	0.37
W 250x44.8	0.13	0.25	0.14	0.26	0.15	0.27	0.15	0.29	0.17	0.31	0.19	0.35	0.21	0.39	0.23	0.43
W 250x89.0	0.24	0.45	0.27	0.50	0.30	0.55	0.32	0.61	0.36	0.67	0.39	0.74	0.43	0.82	0.48	0.93
W 250x101.0	0.30	0.56	0.32	0.61	0.35	0.67	0.39	0.73	0.42	0.80	0.47	0.90	0.52	1.01	0.58	1.12
W 250x115.0	0.35	0.67	0.38	0.73	0.41	0.79	0.45	0.88	0.50	0.98	0.56	1.09	0.61	1.20	0.66	1.31
W 310x23.8	0.11	0.20	0.11	0.21	0.11	0.21	0.12	0.22	0.12	0.22	0.13	0.23	0.13	0.24	0.14	0.26
W 310x28.3	0.11	0.21	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28
W 310x32.7	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28	0.16	0.30
W 310x44.5	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28	0.16	0.30	0.18	0.33	0.20	0.37
W 310x52.0	0.13	0.25	0.14	0.26	0.14	0.27	0.15	0.29	0.17	0.32	0.19	0.35	0.21	0.39	0.23	0.43
W 360x32.9	0.11	0.21	0.11	0.21	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28
W 360x39.0	0.11	0.22	0.12	0.22	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.27	0.15	0.29	0.16	0.31
W 360x51.0	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28	0.16	0.30	0.18	0.33	0.19	0.37
W 360x57.8	0.13	0.24	0.13	0.25	0.14	0.27	0.15	0.28	0.16	0.30	0.18	0.33	0.20	0.37	0.22	0.41
W 360x64.0	0.14	0.26	0.14	0.27	0.15	0.29	0.17	0.31	0.18	0.34	0.20	0.38	0.22	0.42	0.25	0.47
W 360x72.0	0.15	0.28	0.16	0.30	0.17	0.32	0.19	0.36	0.21	0.39	0.23	0.43	0.25	0.48	0.28	0.53
W 360x79.0	0.16	0.31	0.18	0.33	0.20	0.37	0.21	0.40	0.24	0.44	0.26	0.49	0.29	0.55	0.32	0.60
W 360x91.0	0.18	0.34	0.20	0.37	0.22	0.41	0.24	0.45	0.26	0.50	0.29	0.55	0.32	0.61	0.35	0.67
W 360x101.0	0.21	0.39	0.23	0.43	0.25	0.48	0.28	0.53	0.31	0.58	0.33	0.64	0.37	0.70	0.42	0.80
W 360x110.0	0.24	0.45	0.26	0.49	0.28	0.54	0.31	0.59	0.34	0.65	0.37	0.71	0.42	0.81	0.47	0.91
W 360x122.0	0.27	0.51	0.29	0.56	0.32	0.61	0.35	0.67	0.38	0.73	0.43	0.83	0.48	0.93	0.53	1.04

*SS = Simply Supported; SC = Semi-continuous; Highlighted values shows load factors greater than 0.7.

Table 3 Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W150-W360 (continuation)

Standard fire resistance requirement (22 to 15 minutes), series W150-W360, tc = 10 cm
Name	22		21		20		19		18		17		16		15
Name	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC
W 150x18.0	0.17	0.31	0.18	0.33	0.20	0.36	0.22	0.40	0.25	0.45	0.28	0.50	0.31	0.56	0.36	0.63
W 150x24.0	0.21	0.39	0.24	0.43	0.27	0.48	0.30	0.54	0.34	0.62	0.39	0.70	0.45	0.80	0.52	0.91
W 150x37.1	0.31	0.56	0.34	0.62	0.38	0.70	0.44	0.79	0.50	0.91	0.56	1.03	0.64	1.16	0.72	1.31
W 200x22.5	0.17	0.31	0.18	0.33	0.20	0.37	0.22	0.41	0.25	0.45	0.27	0.50	0.31	0.55	0.35	0.62
W 200x31.3	0.21	0.39	0.24	0.44	0.27	0.49	0.30	0.55	0.34	0.62	0.39	0.72	0.45	0.83	0.51	0.95
W 200x41.7	0.28	0.52	0.32	0.59	0.36	0.65	0.40	0.75	0.46	0.86	0.52	0.98	0.59	1.11	0.67	1.27
W 200x59.0	0.40	0.75	0.45	0.85	0.51	0.96	0.57	1.08	0.64	1.22	0.72	1.37	0.80	1.53	0.89	1.68
W 200x71.0	0.53	1.01	0.59	1.12	0.65	1.24	0.72	1.38	0.80	1.54	0.88	1.71	0.95	1.83	1.02	1.94
W 200x86.0	0.66	1.27	0.72	1.41	0.80	1.56	0.87	1.71	0.95	1.85	1.02	1.97	1.09	2.05	1.14	2.11
W 250x22.3	0.16	0.29	0.17	0.31	0.18	0.33	0.19	0.36	0.22	0.39	0.24	0.42	0.26	0.46	0.29	0.51
W 250x25.3	0.16	0.31	0.18	0.33	0.19	0.36	0.21	0.40	0.24	0.44	0.26	0.48	0.29	0.53	0.34	0.60
W 250x28.4	0.18	0.33	0.19	0.36	0.21	0.40	0.24	0.44	0.26	0.49	0.30	0.55	0.34	0.62	0.39	0.71
W 250x38.5	0.22	0.41	0.25	0.46	0.27	0.51	0.31	0.57	0.35	0.65	0.40	0.75	0.46	0.86	0.52	0.99
W 250x44.8	0.26	0.48	0.29	0.53	0.32	0.59	0.36	0.67	0.42	0.78	0.47	0.89	0.54	1.01	0.62	1.17
W 250x89.0	0.54	1.04	0.60	1.16	0.66	1.28	0.73	1.43	0.82	1.61	0.90	1.78	0.97	1.92	1.05	2.03
W 250x101.0	0.63	1.24	0.69	1.36	0.77	1.51	0.84	1.68	0.93	1.86	0.99	1.99	1.06	2.08	1.12	2.14
W 250x115.0	0.73	1.45	0.80	1.60	0.88	1.76	0.94	1.91	1.00	2.04	1.05	2.11	1.11	2.17	1.13	2.19
W 310x23.8	0.15	0.28	0.16	0.30	0.18	0.32	0.19	0.34	0.21	0.37	0.23	0.40	0.25	0.43	0.27	0.47
W 310x28.3	0.16	0.30	0.18	0.33	0.19	0.36	0.21	0.39	0.23	0.43	0.26	0.47	0.29	0.52	0.33	0.59
W 310x32.7	0.18	0.33	0.19	0.36	0.21	0.40	0.24	0.44	0.26	0.49	0.29	0.55	0.34	0.62	0.39	0.71
W 310x44.5	0.22	0.41	0.24	0.45	0.27	0.50	0.30	0.56	0.34	0.63	0.39	0.73	0.45	0.84	0.51	0.96
W 310x52.0	0.25	0.48	0.28	0.53	0.31	0.59	0.36	0.67	0.41	0.78	0.47	0.89	0.53	1.01	0.61	1.17
W 360x32.9	0.16	0.31	0.18	0.33	0.19	0.36	0.21	0.40	0.23	0.44	0.26	0.48	0.28	0.54	0.33	0.60
W 360x39.0	0.18	0.34	0.20	0.38	0.22	0.41	0.24	0.46	0.27	0.51	0.31	0.57	0.35	0.66	0.40	0.76
W 360x51.0	0.21	0.40	0.24	0.45	0.26	0.50	0.29	0.55	0.33	0.63	0.38	0.73	0.44	0.83	0.50	0.96
W 360x57.8	0.24	0.45	0.27	0.50	0.30	0.56	0.33	0.63	0.39	0.73	0.44	0.84	0.50	0.96	0.58	1.12
W 360x64.0	0.28	0.52	0.31	0.58	0.34	0.64	0.39	0.74	0.45	0.86	0.51	0.97	0.58	1.11	0.66	1.28
W 360x72.0	0.31	0.59	0.35	0.66	0.40	0.76	0.45	0.86	0.51	0.98	0.58	1.11	0.66	1.28	0.75	1.46
W 360x79.0	0.36	0.68	0.40	0.77	0.46	0.88	0.51	0.99	0.58	1.12	0.66	1.28	0.74	1.45	0.83	1.63
W 360x91.0	0.40	0.76	0.45	0.87	0.51	0.98	0.57	1.10	0.64	1.25	0.72	1.42	0.81	1.61	0.90	1.77
W 360x101.0	0.47	0.91	0.52	1.02	0.58	1.14	0.65	1.27	0.73	1.45	0.82	1.63	0.90	1.79	0.97	1.94
W 360x110.0	0.52	1.02	0.58	1.14	0.64	1.27	0.72	1.43	0.81	1.61	0.89	1.78	0.95	1.92	1.02	2.00
W 360x122.0	0.58	1.15	0.65	1.28	0.72	1.44	0.80	1.61	0.88	1.78	0.94	1.91	1.00	2.00	1.07	2.07

*SS = Simply Supported; SC = Semi-continuous; Highlighted values shows load factors greater than 0.7.

Table 4 Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W410-W610

Standard fire resistance requirement (30 to 23 minutes), series W410-W610, tc = 10 cm
Name	30		29		28		27		26		25		24		23
Name	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC
W 410x46.1	0.12	0.22	0.12	0.23	0.12	0.24	0.13	0.25	0.14	0.26	0.14	0.27	0.15	0.29	0.17	0.32
W 410x60.0	0.13	0.24	0.13	0.25	0.14	0.26	0.14	0.27	0.15	0.29	0.17	0.32	0.18	0.35	0.20	0.39
W 410x67.0	0.13	0.25	0.14	0.26	0.14	0.27	0.16	0.30	0.17	0.32	0.19	0.35	0.21	0.39	0.23	0.43
W 410x75.0	0.14	0.27	0.15	0.28	0.16	0.30	0.17	0.33	0.19	0.36	0.21	0.39	0.23	0.44	0.26	0.48
W 410x85.0	0.15	0.29	0.17	0.32	0.18	0.34	0.20	0.38	0.22	0.41	0.24	0.46	0.27	0.51	0.29	0.56
W 460x52.0	0.12	0.22	0.12	0.23	0.12	0.24	0.13	0.25	0.13	0.26	0.14	0.27	0.15	0.29	0.17	0.32
W 460x60.0	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.15	0.28	0.16	0.30	0.17	0.33	0.19	0.36
W 460x68.0	0.13	0.24	0.13	0.26	0.14	0.27	0.15	0.28	0.16	0.31	0.18	0.34	0.20	0.37	0.22	0.41
W 460x74.0	0.13	0.25	0.14	0.26	0.14	0.27	0.15	0.29	0.17	0.32	0.18	0.35	0.20	0.39	0.22	0.43
W 460x82.0	0.14	0.26	0.15	0.28	0.16	0.30	0.17	0.32	0.19	0.35	0.20	0.39	0.22	0.43	0.25	0.48
W 460x89.0	0.15	0.28	0.16	0.30	0.17	0.33	0.19	0.36	0.21	0.39	0.23	0.43	0.25	0.48	0.28	0.53
W 460x97.0	0.16	0.30	0.17	0.33	0.19	0.36	0.20	0.39	0.22	0.43	0.25	0.47	0.27	0.52	0.30	0.58
W 460x106.0	0.17	0.33	0.19	0.36	0.20	0.39	0.22	0.43	0.25	0.47	0.27	0.53	0.30	0.58	0.34	0.65
W 530x66.0	0.12	0.23	0.12	0.23	0.13	0.24	0.13	0.25	0.14	0.26	0.14	0.28	0.16	0.30	0.17	0.33
W 530x74.0	0.12	0.24	0.13	0.24	0.13	0.25	0.14	0.27	0.15	0.28	0.16	0.30	0.17	0.33	0.19	0.37
W 530x85.0	0.13	0.25	0.14	0.26	0.14	0.27	0.16	0.30	0.17	0.32	0.18	0.35	0.20	0.39	0.22	0.43
W 530x92.0	0.14	0.26	0.14	0.27	0.15	0.29	0.16	0.31	0.18	0.34	0.19	0.37	0.21	0.41	0.24	0.45
W 530x101.0	0.14	0.28	0.15	0.29	0.17	0.32	0.18	0.35	0.20	0.38	0.22	0.42	0.24	0.46	0.26	0.51
W 530x109.0	0.15	0.29	0.17	0.32	0.18	0.34	0.20	0.37	0.21	0.41	0.24	0.46	0.26	0.50	0.29	0.56
W 610x101.0	0.13	0.25	0.14	0.27	0.14	0.28	0.15	0.30	0.17	0.32	0.18	0.35	0.20	0.39	0.22	0.43
W 610x113.0	0.14	0.27	0.15	0.29	0.16	0.31	0.18	0.34	0.19	0.37	0.21	0.41	0.23	0.45	0.26	0.50
W 610x125.0	0.16	0.30	0.17	0.32	0.18	0.35	0.20	0.38	0.22	0.42	0.24	0.47	0.27	0.51	0.29	0.57
W 610x140.0	0.18	0.34	0.19	0.37	0.21	0.41	0.23	0.44	0.25	0.49	0.28	0.54	0.31	0.60	0.35	0.69
W 610x174.0	0.21	0.40	0.22	0.44	0.24	0.48	0.27	0.53	0.29	0.58	0.32	0.64	0.37	0.73	0.42	0.83

*SS = Simply Supported; SC = Semi-continuous; Highlighted values shows load factors greater than 0.7.

Table 5 Load factors as function of the standard fire resistance requirement for composite beams with 10 cm slab and Gerdau profile series W410-W610 (continuation)

Standard fire resistance requirement (22 to 15 minutes), series W410-W610, tc = 10 cm
Name	22		21		20		19		18		17		16		15
Name	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC	SS	SC
W 410x46.1	0.19	0.35	0.20	0.39	0.22	0.43	0.25	0.47	0.28	0.53	0.31	0.60	0.36	0.69	0.41	0.79
W 410x60.0	0.22	0.43	0.25	0.47	0.28	0.52	0.31	0.58	0.36	0.68	0.41	0.78	0.46	0.89	0.54	1.04
W 410x67.0	0.25	0.48	0.28	0.53	0.31	0.59	0.36	0.68	0.41	0.79	0.47	0.90	0.54	1.04	0.62	1.21
W 410x75.0	0.28	0.54	0.31	0.59	0.36	0.69	0.41	0.78	0.47	0.90	0.53	1.02	0.61	1.19	0.70	1.35
W 410x85.0	0.33	0.63	0.38	0.72	0.42	0.82	0.48	0.92	0.55	1.06	0.63	1.23	0.71	1.39	0.81	1.53
W 460x52.0	0.18	0.35	0.20	0.38	0.22	0.42	0.24	0.46	0.27	0.51	0.30	0.57	0.35	0.65	0.40	0.74
W 460x60.0	0.21	0.40	0.23	0.44	0.26	0.49	0.28	0.54	0.33	0.62	0.37	0.71	0.42	0.82	0.49	0.95
W 460x68.0	0.24	0.45	0.26	0.50	0.29	0.56	0.34	0.64	0.39	0.74	0.44	0.84	0.50	0.97	0.59	1.13
W 460x74.0	0.25	0.47	0.28	0.52	0.30	0.58	0.35	0.67	0.40	0.78	0.46	0.88	0.53	1.03	0.62	1.20
W 460x82.0	0.28	0.53	0.30	0.58	0.35	0.67	0.40	0.76	0.45	0.88	0.52	1.01	0.60	1.17	0.69	1.33
W 460x89.0	0.31	0.59	0.35	0.67	0.40	0.77	0.45	0.87	0.51	1.00	0.59	1.15	0.68	1.33	0.77	1.48
W 460x97.0	0.34	0.66	0.39	0.75	0.44	0.85	0.49	0.96	0.57	1.11	0.65	1.28	0.74	1.43	0.83	1.57
W 460x106.0	0.38	0.75	0.43	0.84	0.49	0.95	0.55	1.08	0.64	1.26	0.72	1.41	0.81	1.55	0.90	1.68
W 530x66.0	0.19	0.35	0.21	0.39	0.23	0.42	0.25	0.46	0.28	0.51	0.31	0.58	0.37	0.66	0.43	0.77
W 530x74.0	0.21	0.40	0.23	0.45	0.26	0.49	0.28	0.54	0.33	0.62	0.38	0.71	0.44	0.82	0.52	0.95
W 530x85.0	0.25	0.47	0.27	0.52	0.31	0.59	0.35	0.68	0.40	0.78	0.46	0.90	0.54	1.04	0.63	1.18
W 530x92.0	0.26	0.50	0.29	0.56	0.33	0.63	0.37	0.72	0.43	0.83	0.49	0.96	0.57	1.13	0.67	1.28
W 530x101.0	0.29	0.56	0.33	0.64	0.38	0.73	0.43	0.83	0.49	0.96	0.57	1.12	0.66	1.28	0.75	1.43
W 530x109.0	0.32	0.63	0.37	0.72	0.42	0.82	0.47	0.92	0.54	1.07	0.63	1.24	0.72	1.39	0.81	1.53
W 610x101.0	0.25	0.48	0.27	0.53	0.30	0.59	0.35	0.68	0.40	0.78	0.47	0.91	0.54	1.06	0.64	1.21
W 610x113.0	0.28	0.55	0.32	0.62	0.37	0.71	0.41	0.81	0.48	0.94	0.56	1.10	0.64	1.26	0.74	1.40
W 610x125.0	0.33	0.65	0.38	0.74	0.43	0.84	0.48	0.95	0.56	1.11	0.64	1.29	0.74	1.43	0.82	1.56
W 610x140.0	0.40	0.78	0.44	0.88	0.50	0.99	0.57	1.13	0.66	1.32	0.74	1.46	0.81	1.58	0.89	1.69
W 610x174.0	0.46	0.93	0.51	1.04	0.58	1.19	0.66	1.36	0.75	1.55	0.82	1.68	0.90	1.81	0.98	1.89

*SS = Simply Supported; SC = Semi-continuous; Highlighted values shows load factors greater than 0.7.

Table 6 Reinforcement ratio as function of the standard fire resistance requirement for development of the maximum negative bending moment, for composite beams with 10 cm slabs and Gerdau profiles series W150-W360

Reinforcement ratio (%) for standard fire resistance requirement (30 to 15 minutes), series W410-W610 - tc = 10 cm
Name	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15
W 150x18.0	0.07	0.08	0.08	0.08	0.09	0.09	0.10	0.11	0.12	0.13	0.14	0.16	0.19	0.21	0.24	0.28
W 150x24.0	0.11	0.12	0.12	0.13	0.14	0.15	0.17	0.19	0.21	0.24	0.28	0.31	0.36	0.42	0.48	0.54
W 150x37.1	0.21	0.22	0.24	0.27	0.30	0.35	0.39	0.44	0.50	0.57	0.64	0.73	0.82	0.91	1.02	1.11
W 200x22.5	0.09	0.10	0.10	0.10	0.11	0.12	0.12	0.14	0.15	0.16	0.18	0.20	0.23	0.26	0.30	0.35
W 200x31.3	0.14	0.15	0.16	0.17	0.19	0.20	0.22	0.26	0.29	0.33	0.37	0.43	0.49	0.56	0.64	0.71
W 200x41.7	0.23	0.24	0.26	0.29	0.33	0.37	0.42	0.47	0.54	0.61	0.69	0.78	0.88	0.97	1.08	1.18
W 200x59.0	0.44	0.50	0.56	0.63	0.70	0.79	0.89	0.99	1.10	1.22	1.35	1.48	1.63	1.75	1.89	2.04
W 200x71.0	0.74	0.82	0.92	1.03	1.14	1.26	1.38	1.52	1.66	1.81	1.95	2.08	2.24	2.40	2.54	2.69
W 200x86.0	1.17	1.29	1.42	1.56	1.70	1.85	2.01	2.18	2.35	2.50	2.67	2.85	3.04	3.21	3.40	3.58
W 250x22.3	0.09	0.09	0.10	0.10	0.10	0.11	0.12	0.12	0.13	0.15	0.16	0.17	0.19	0.22	0.25	0.28
W 250x25.3	0.10	0.11	0.11	0.12	0.12	0.13	0.14	0.15	0.16	0.18	0.20	0.22	0.26	0.29	0.33	0.38
W 250x28.4	0.12	0.13	0.13	0.14	0.15	0.16	0.17	0.19	0.20	0.23	0.26	0.29	0.34	0.38	0.44	0.51
W 250x38.5	0.18	0.20	0.21	0.22	0.24	0.26	0.30	0.34	0.38	0.43	0.49	0.56	0.65	0.73	0.82	0.92
W 250x44.8	0.24	0.25	0.27	0.29	0.33	0.37	0.42	0.47	0.53	0.60	0.68	0.77	0.88	0.97	1.08	1.20
W 250x89.0	0.97	1.08	1.21	1.34	1.48	1.63	1.78	1.95	2.12	2.31	2.46	2.63	2.84	3.04	3.21	3.41
W 250x101.0	1.34	1.49	1.63	1.79	1.94	2.12	2.31	2.50	2.70	2.85	3.04	3.24	3.47	3.66	3.86	4.08
W 250x115.0	1.82	1.99	2.15	2.33	2.53	2.74	2.96	3.13	3.32	3.53	3.76	3.98	4.20	4.42	4.66	4.77
W 310x23.8	0.10	0.10	0.10	0.11	0.11	0.11	0.12	0.13	0.14	0.15	0.16	0.18	0.20	0.22	0.24	0.27
W 310x28.3	0.12	0.12	0.13	0.13	0.14	0.15	0.16	0.17	0.18	0.20	0.22	0.25	0.28	0.32	0.36	0.42
W 310x32.7	0.14	0.15	0.15	0.16	0.17	0.18	0.20	0.21	0.24	0.27	0.30	0.34	0.39	0.44	0.51	0.58
W 310x44.5	0.21	0.23	0.24	0.26	0.28	0.30	0.34	0.39	0.44	0.50	0.56	0.64	0.74	0.84	0.93	1.04
W 310x52.0	0.28	0.30	0.32	0.34	0.39	0.44	0.50	0.56	0.63	0.71	0.80	0.91	1.03	1.14	1.26	1.39
W 360x32.9	0.13	0.14	0.14	0.15	0.16	0.17	0.18	0.19	0.21	0.23	0.26	0.29	0.33	0.37	0.42	0.49
W 360x39.0	0.17	0.18	0.19	0.20	0.21	0.22	0.24	0.26	0.30	0.34	0.38	0.43	0.49	0.56	0.65	0.73
W 360x51.0	0.24	0.26	0.27	0.29	0.31	0.34	0.39	0.44	0.49	0.56	0.63	0.72	0.82	0.93	1.04	1.17
W 360x57.8	0.29	0.31	0.33	0.35	0.40	0.45	0.51	0.57	0.64	0.73	0.82	0.93	1.05	1.17	1.29	1.45
W 360x64.0	0.36	0.38	0.41	0.47	0.53	0.59	0.66	0.75	0.85	0.96	1.07	1.20	1.34	1.48	1.62	1.77
W 360x72.0	0.44	0.49	0.55	0.62	0.69	0.77	0.87	0.98	1.10	1.22	1.36	1.50	1.66	1.81	1.96	2.13
W 360x79.0	0.57	0.64	0.71	0.79	0.88	1.00	1.12	1.24	1.38	1.53	1.68	1.84	2.01	2.16	2.34	2.53
W 360x91.0	0.74	0.83	0.93	1.03	1.16	1.30	1.44	1.59	1.75	1.92	2.11	2.30	2.46	2.66	2.86	3.06
W 360x101.0	0.99	1.09	1.22	1.36	1.51	1.67	1.83	2.01	2.19	2.39	2.59	2.75	2.97	3.19	3.40	3.61
W 360x110.0	1.22	1.36	1.51	1.67	1.84	2.00	2.19	2.39	2.60	2.81	2.97	3.18	3.43	3.66	3.87	4.12
W 360x122.0	1.55	1.71	1.87	2.05	2.23	2.43	2.65	2.87	3.09	3.27	3.51	3.76	4.03	4.26	4.53	4.81

Table 7 Reinforcement ratio as function of the standard fire resistance requirement for development of the maximum negative bending moment, for composite beams with 10 cm slabs and Gerdau profiles series W410-W610

Reinforcement ratio (%) for standard fire resistance requirement (30 to 15 minutos), series W410-W610 - tc = 10 cm
Name	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15
W 410x46.1	0.20	0.21	0.22	0.24	0.25	0.27	0.29	0.33	0.37	0.42	0.47	0.53	0.61	0.69	0.79	0.88
W 410x60.0	0.30	0.31	0.34	0.36	0.39	0.44	0.50	0.56	0.63	0.71	0.81	0.91	1.04	1.16	1.28	1.45
W 410x67.0	0.36	0.39	0.41	0.46	0.51	0.58	0.65	0.73	0.82	0.93	1.04	1.17	1.31	1.45	1.63	1.78
W 410x75.0	0.44	0.47	0.52	0.59	0.66	0.73	0.82	0.93	1.04	1.16	1.31	1.44	1.61	1.78	1.95	2.14
W 410x85.0	0.57	0.64	0.71	0.79	0.88	0.99	1.11	1.24	1.38	1.53	1.68	1.85	2.05	2.23	2.43	2.65
W 460x52.0	0.22	0.24	0.25	0.26	0.28	0.30	0.32	0.35	0.40	0.45	0.51	0.57	0.65	0.74	0.85	0.96
W 460x60.0	0.28	0.30	0.32	0.34	0.36	0.40	0.45	0.51	0.57	0.64	0.73	0.82	0.94	1.06	1.17	1.32
W 460x68.0	0.36	0.38	0.40	0.44	0.49	0.55	0.62	0.69	0.78	0.88	0.98	1.11	1.25	1.38	1.55	1.72
W 460x74.0	0.40	0.42	0.45	0.50	0.56	0.63	0.71	0.79	0.90	1.01	1.13	1.28	1.43	1.58	1.77	1.94
W 460x82.0	0.47	0.51	0.57	0.63	0.71	0.79	0.88	1.00	1.12	1.25	1.40	1.55	1.73	1.92	2.10	2.31
W 460x89.0	0.58	0.64	0.71	0.79	0.88	0.99	1.11	1.24	1.38	1.54	1.70	1.87	2.06	2.26	2.46	2.69
W 460x97.0	0.69	0.76	0.85	0.94	1.05	1.18	1.31	1.46	1.62	1.79	1.96	2.15	2.37	2.58	2.82	3.06
W 460x106.0	0.84	0.93	1.03	1.14	1.28	1.43	1.58	1.75	1.93	2.12	2.32	2.53	2.78	3.03	3.29	3.56
W 530x66.0	0.29	0.30	0.32	0.34	0.35	0.38	0.41	0.46	0.52	0.59	0.66	0.74	0.85	0.96	1.10	1.28
W 530x74.0	0.35	0.37	0.40	0.42	0.45	0.50	0.57	0.64	0.71	0.80	0.90	1.02	1.17	1.30	1.49	1.70
W 530x85.0	0.45	0.48	0.52	0.58	0.64	0.71	0.80	0.90	1.01	1.13	1.27	1.42	1.58	1.76	1.98	2.19
W 530x92.0	0.52	0.55	0.60	0.68	0.75	0.84	0.94	1.06	1.20	1.34	1.50	1.66	1.85	2.07	2.29	2.53
W 530x101.0	0.63	0.69	0.77	0.86	0.95	1.07	1.20	1.34	1.50	1.67	1.84	2.03	2.25	2.48	2.72	2.99
W 530x109.0	0.75	0.84	0.93	1.02	1.14	1.28	1.43	1.59	1.77	1.95	2.14	2.35	2.60	2.84	3.11	3.38
W 610x101.0	0.54	0.58	0.62	0.69	0.77	0.87	0.97	1.09	1.23	1.38	1.54	1.72	1.93	2.17	2.44	2.70
W 610x113.0	0.69	0.77	0.85	0.94	1.04	1.17	1.32	1.47	1.64	1.83	2.02	2.23	2.48	2.74	3.01	3.31
W 610x125.0	0.91	1.01	1.12	1.23	1.38	1.54	1.71	1.89	2.10	2.30	2.53	2.76	3.03	3.31	3.62	3.93
W 610x140.0	1.22	1.34	1.49	1.65	1.83	2.02	2.23	2.44	2.68	2.92	3.17	3.42	3.75	4.08	4.40	4.77
W 610x174.0	1.89	2.09	2.30	2.54	2.79	3.03	3.31	3.61	3.92	4.19	4.53	4.90	5.33	5.72	6.16	6.62

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IBRACON - Instituto Brasileiro do Concreto Instituto Brasileiro do Concreto (IBRACON), Av. Queiroz Filho, nº 1700 sala 407/408 Torre D, Villa Lobos Office Park, CEP 05319-000, São Paulo, SP - Brasil, Tel. (55 11) 3735-0202, Fax: (55 11) 3733-2190 - São Paulo - SP - Brazil
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Leia a Declaração de Acesso Aberto

Métricas

About the use of semi-continuity in simply supported composite steel and concrete beams, to remove fireproof coatings for standard-fire resistance requirement of less than 30 minutes

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[TFN1] *SS = Simply Supported; SC = Semi-continuous; Highlighted values shows load factors greater than 0.7.