Figure 1
Reduction of mechanical properties of concrete and steel with temperature: (a) compressive strength of the concrete (siliceous aggregate), (b) modulus of elasticity of concrete, (c) concrete tensile strength, (d) Mode-I fracture energy of concrete, (e) modulus of elasticity of steel, (f) yield strength of prestressing steel
Figure 2
Predefined uniaxial behavior for total strain model [31[31] TNO. DIANA: Finite Element Analysis - User’s Manual i DIANA. Release 9.6, 1 ed., Netherlands: TNO DIANA, 2015.]: (a) tension softening; (b) compression
Figure 3
Finite element Q4HT [31[31] TNO. DIANA: Finite Element Analysis - User’s Manual i DIANA. Release 9.6, 1 ed., Netherlands: TNO DIANA, 2015.]
Figure 4
Finite element B2HT [31[31] TNO. DIANA: Finite Element Analysis - User’s Manual i DIANA. Release 9.6, 1 ed., Netherlands: TNO DIANA, 2015.]
Figure 5
Finite element CHX60 [31[31] TNO. DIANA: Finite Element Analysis - User’s Manual i DIANA. Release 9.6, 1 ed., Netherlands: TNO DIANA, 2015.]
Figure 6
Finite element BQ4HT [31[31] TNO. DIANA: Finite Element Analysis - User’s Manual i DIANA. Release 9.6, 1 ed., Netherlands: TNO DIANA, 2015.]
Figure 7
Cross-section of hollow core slab used in validation of the computational model [26[26] SHAKYA, A.M, KODUR, V.K.R. Response of precast prestressed concrete hollowcore slabs under fire conditions. Engineering Structures, v. 87, p. 126-138, 2015.]
Figure 8
Test setup of hollow core slab used in validation of the computational model [26[26] SHAKYA, A.M, KODUR, V.K.R. Response of precast prestressed concrete hollowcore slabs under fire conditions. Engineering Structures, v. 87, p. 126-138, 2015.]
Figure 9
Finite element mesh with heat flow in voids, from reference [26[26] SHAKYA, A.M, KODUR, V.K.R. Response of precast prestressed concrete hollowcore slabs under fire conditions. Engineering Structures, v. 87, p. 126-138, 2015.]
Figure 10
Mesh of hollow core slab with Q4HT elements with air in the voids included in computational model
Figure 11
Finite element mesh of the hollow core slab for thermo-mechanical modeling
Figure 12
Temperature profile in cross-section of hollow core slab - first strategy: a) 60 minutes; b) 120 minutes
Figure 13
Temperature profile in cross-section of hollow core slab - second strategy: a) 60 minutes; b) 120 minutes
Figure 14
Temperature profile in cross-section of hollow core slab - third strategy: a) 60 minutes; b) 120 minutes
Figure 15
Temperature-time curve applied to the upper area of voids in hollow core slab with 20 cm thickness and circular voids
Figure 16
Variation of temperature with fire exposure time: a) first strategy; b) second strategy; c) third strategy
Figure 17
(a) Variation of displacement with fire exposure time; (b) cracking pattern of slab after 60, 90 and 120 minutes
Figure 18
Flexural strength of hollow core slab with time of exposure to standard fire
Figure 19
Cross-section of shallow hollow core slab - dimensions in mm [36[36] SILVA, R.P.M. Resistência à força cortante de lajes alveolares preenchidas de pequena altura, Goiânia, 2015, Dissertação (mestrado) - Escola de Engenharia Civil e Ambiental, Universidade Federal de Goiás, 201p.]
Figure 20
Temperature-time curve applied to the upper area of voids in shallow hollow core slab
Figure 21
Cross-section of the shallow hollow core slab with finite element mesh
Figure 22
Temperature profile after 60 minutes - shallow hollow core slab: a) first modeling strategy; b) second modeling strategy
Figure 23
Variation of temperature with fire exposure time - shallow hollow core slab
Figure 24
Temperature of reinforcement as a function of the distance from the face exposed to fire [6[6] BRITISH STANDARDS. BS EN 1168:2005. Precast concrete products - Hollow core slabs. 2005.]
Figure 25
Variation of temperature with fire exposure time - hollow core slab with thickness of 20 cm
Figure 26
Test setup for mechanical testing of shallow hollow core slab [36[36] SILVA, R.P.M. Resistência à força cortante de lajes alveolares preenchidas de pequena altura, Goiânia, 2015, Dissertação (mestrado) - Escola de Engenharia Civil e Ambiental, Universidade Federal de Goiás, 201p.] - dimensions in cm
Figure 27
Load versus deflection for shallow hollow core slab at ambient temperature [36[36] SILVA, R.P.M. Resistência à força cortante de lajes alveolares preenchidas de pequena altura, Goiânia, 2015, Dissertação (mestrado) - Escola de Engenharia Civil e Ambiental, Universidade Federal de Goiás, 201p.]
Figure 28
Flexural strength of shallow hollow core slab with time of exposure to standard fire
Table 1
Minimum thickness (h) and axis distance from the reinforcement to the face exposed to fire (c1) for simply supported slabs [7[7] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15200: Fire design of concrete structures. Rio de Janeiro, 2012 (in Portuguese).]
Table 2
Minimum dimensions for simply supported ribbed slabs in a fire [7[7] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15200: Fire design of concrete structures. Rio de Janeiro, 2012 (in Portuguese).]
Table 3
Minimum slab thickness and axis distance for simply supported hollow core floors [9[9] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 9062: Design and execution of precast concrete structures. Rio de Janeiro, 2017 (in Portuguese).]
Table 4
Thermal and physical properties1 of concrete and reinforcing steel
Table 5
Thermal properties of the air