Browsing by Author "Prates, Lucas"
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- Fire resistance of composite slabs with profiled steel decking: trapezoidal and reentrant numerical simulationPublication . Piloto, P.A.G.; Prates, Lucas; Balsa, Carlos; Rigobello, RonaldoABSTRACT This work investigates the thermal behaviour of composite slabs with steel deck under fire from the bottom. This composite solution is widely used in every type of buildings and requires fire resistance, in accordance to regulations and standards. The scope of this investigation concerns the fire rating for insulation (I). Numerical simulation was performed through Matlab PDE toolbox for the thermal effects of standard fire exposure. The results are also compared with the simplified method proposed by Eurocode, which seems to be unsafe.
- Fire resistance of composite slabs with steel deck: experimental analysis and numerical simulationPublication . Piloto, P.A.G.; Prates, Lucas; Balsa, Carlos; Rigobello, RonaldoThis work investigates the thermal behaviour of composite slabs with steel deck under controlled test conditions corresponding to a fire from the bottom. This composite solution consists of a concrete topping cast on the top of a steel deck. The concrete is typically reinforced with a steel mesh and may also contain individual rebars. The deck also acts as reinforcement and may be exposed to accidental fire conditions from the bottom. This composite solution is widely used in every type of buildings and requires fire resistance, in accordance to regulations and standards. Composite slabs need to meet fire-safety requirements according to building codes. The fire assessment of this type of elements is normally made using standard fire tests. Two samples are being prepared to be tested and should take into account the criterion for stability (R), Integrity (E) and insulation (I). The scope of this investigation concerns the fire rating for insulation (I). Numerical simulation was performed through Matlab PDE toolbox for the thermal effects of standard fire exposure. The results are also compared with the simplified method proposed by Eurocode, which seems to be unsafe.
- Fire resistance of composite slabs with steel deck: from experiments to numerical simulationPublication . Piloto, P.A.G.; Prates, Lucas; Balsa, Carlos; Rigobello, RonaldoThis work investigates the thermal insulation behaviour of composite slabs with steel deck under standard fire test conditions. This composite slab consists of a concrete topping cast on the top of a steel deck. The concrete is usually reinforced with a steel mesh on the top and may also be reinforced using individual rebars. The steel deck also acts as reinforcement and may be directly exposed to fire conditions. This composite solution is widely used in every type of buildings which require fire resistance, in accordance to regulations and standards. The fire rating of this type of elements is determined by standard fire tests. Two samples were tested using standard fire conditions ISO834 to evaluate the Integrity (E) and insulation (I). The scope of this investigation concerns the fire rating for insulation (I). Numerical thermal simulation was also developed using Matlab PDE toolbox and ANSYS to compare the results and to find out the thermal effects of standard fire exposure. The results are also compared with the simplified method proposed by Eurocode 4-part 1.2, which seems to be unsafe.
- Fire resistance of composite slabs withp rofiled steel decking: trapezoidal and reentrant numerical simulationPublication . Piloto, P.A.G.; Prates, Lucas; Balsa, Carlos; Rigobello, RonaldoThis work investigates the thermal behaviour of composite slabs with steel deck under standard fire conditions corresponding to a fire from the bottom. This composite solution consists of a concrete topping cast on the top of a steel deck. The concrete is typically reinforced with a steel mesh and may also contain individual rebars. The deck also acts as reinforcement and may be exposed to accidental fire conditions from the bottom. This composite solution is widely used in every type of buildings and requires fire resistance in accordance to regulations and standards. Composite slabs need to meet fire-safety requirements according to building codes. The fire resistance is specified by the loadbearing capacity (R), insulation (I) and integrity (E). The fire rating for (R) and (E) is not in the scope of this investigation. The fire rating for insulation (I) is evaluated by two different methods (numerical simulation and simple calculation). Numerical simulation was performed using Matlab PDE toolbox for the thermal effects of standard fire exposure. The fire rating is calculated for 196 different geometric configurations, in order to evaluate the effect of the thickness of the concrete layer and the thickness of steel deck. The fire resistance (I) increases with the thickness of the concrete, according to the results of both methods. The numerical results are also compared with the simplified method proposed by Eurocode, which appears to be unsafe.
- Numerical simulation of the fire resistance of composite slabs with steel deckPublication . Piloto, P.A.G.; Prates, Lucas; Balsa, Carlos; Rigobello, RonaldoThis investigation is related with the fire resistance of composite slabs with steel deck. This composite solution consists of a concrete topping cast on the top of a steel deck. The concrete is typically reinforced with a steel mesh and may also contain individual rebars. The deck also acts as reinforcement and may be exposed to accidental fire conditions from the bottom. This composite solution is widely used in every type of buildings and requires fire resistance, in accordance to regulations. The fire resistance is specified by the loadbearing capacity (R), insulation (I) and integrity (E). The fire rating for (R) and (E) is not in the scope of this investigation. The fire rating for insulation (I) is evaluated by two different methods (numerical simulation and simple calculation). The fire rating is calculated for 32 different geometric configuration, in order to evaluate the effect of the thickness of the concrete layer and the thickness of steel deck. The fire resistance (I) increases with the thickness of the concrete when using both methods, but the simple calculation method seems to be unsafe for all the cases, requiring a revision for the formulae presented in Annex D of EN1994-1-2. A new proposal is presented.
- Simulação numérica do comportamento ao fogo de estruturas mistas (lajes)Publication . Prates, Lucas; Balsa, Carlos; Piloto, P.A.G.; Rigobello, RonaldoEste trabalho investiga o comportamento térmico de lajes mistas de aço e concreto com perfil de chapa colaborante sob condições controladas de acidente, correspondendo a um incêndio a atingir a superfície inferior. Esta solução mista consiste em uma cobertura de concreto no topo de um perfil de aço. O concreto é normalmente reforçado com uma malha de aço e também pode conter vergalhões individuais. O deck ou chapa colaborante também atua como reforço e consequentemente pode ser exposto a condições acidentais de incêndio. Esta solução mista é amplamente utilizada em todos os tipos de edifícios e requer resistência ao fogo, de acordo com os regulamentos e normas. As lajes mistas precisam atender aos requisitos de segurança contra incêndio de acordo com os códigos de construção. A avaliação ao fogo deste tipo de elementos é normalmente feita utilizando testes de incêndio padrão. Duas amostras foram preparadas para serem testadas e devem levar em consideração os critérios de estabilidade (R), Integridade (E) e isolamento (I). O objetivo desta investigação diz respeito à classificação de incêndio para o isolamento (I). A classificação de incêndio para isolamento (I) é avaliada por três métodos diferentes (simulação numérica, método simplificado e ensaios experimentais). A simulação numérica foi realizada através da biblioteca de equações as derivadas parciais do Matlab e também através do programa ANSYS, considerando os efeitos térmicos da exposição a um fogo padrão. A resistência ao fogo é calculada para 196 configurações geométricas diferentes, sendo assim, 394 simulações numéricas foram realizadas a fim de avaliar o efeito da espessura da camada de concreto e da espessura da chapa colaborante de aço. A resistência ao fogo (I) aumenta com a espessura do concreto, de acordo com os resultados obtidos em ambos os métodos. Os resultados numéricos também são comparados com os ensaios experimentais e comparados com o método simplificado proposto no anexo D do Eurocódigo 4 e pela NBR 14323, que parecem estar inseguros.
- The air gap effect on the fire resistance of composite slab with steel deckPublication . Piloto, P.A.G.; Balsa, Carlos; Prates, Lucas; Rigobello, RonaldoThe fire resistance of composite slabs with steel deck may be defined by experimental tests or using simple calculation methods available in standards, such as EN1994-1-2. The composite slab is made by a concrete topping cast on the top surface of a steel deck, presenting a combination of two different materials (steel and concrete). This work presents the results and the validation of a two dimensional finite element model, used for comparison with experimental results developed by the authors. Results are also compared with the simple calculation method of EN1994-1-2, which seems to be unsafe. The numerical model considers perfect contact between materials, but investigates the effect of the air gap between the concrete slab and the steel deck. The existence of the air gap is usually justified by different expansion coefficients and by the thermal bowing caused by the thermal gradient across the thickness, which leads to the separation of both materials during experimental tests.