Browsing by Author "Rigobello, Ronaldo"
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- Balanced summation model for the calculation of the buckling resistance of partially encased columns under fire: new improvementsPublication . Calió, Leonardo Jorge; Piloto, P.A.G.; Rigobello, RonaldoThe fire resistance of partially encased columns (HEB and IPE) depends on the temperature evolution under fire. This paper aims to assess de effect of the balanced summation model into the design of the axial buckling load of partially encased columns under fire, according to EN 1994-1-2. New improvements will be proposed to evaluate the fire resistance, based on new simple formulas to determine the flange temperature, the residual height and temperature of the web, the residual cross section and temperature of concrete, the reduced stiffness and strength of reinforcement. The new proposal is based on the validation of a numerical simulation using ANSYS.
- Buckling resistance of partially encased columns embedded on walls under fire from one sidePublication . Piloto, P.A.G.; Gonçales, Nathália; Rigobello, Ronaldo; Vaz, Mário; Guedes, Rui M.; Baptista, João S.Partially encased columns (PEC) have better fire resistance when compared to bare steel columns, due to the existence of concrete between the flanges. The aim of this study is to develop a new proposal for the calculation of the buckling strength of partially encased columns, embedded on walls, under fire conditions. This proposal is based on the current calculation method proposed in Annex G of EN 1994-1-2. This study uses the finite element method to calculate the average temperature of seven components. The average temperature is then used to find the buckling resistance of composite columns when submitted to fire from one side. This solution method is carried out using 30 different cross sections. All cross sections are exposed to the standard fire curve ISO834 from one side, assuming the specific fire rating of 30, 60, 90 and 120 min.
- Buckling resistance of partially encased columns under firePublication . Piloto, P.A.G.; Hoffstaeter, Ricardo Anderson; Rigobello, Ronaldo; Soufyane, Amari; Benlakehal, Nourredine O.The fire resistance of partially encased columns depends on the temperature evolution during fire exposure. This work aims to evaluate the effect of the balanced summation model on the design of the buckling load of Partially Encased Columns under fire situation. New improvements will be presented to assess fire resistance, suggesting some modification in the Annex G of Eurocode EN 1994-1-2. The advanced calculation method is based on the 3D modelling of the Partially Encased Column, using steel profiles ranging from IPE200 to IPE500 and HEB160 to HEB500, and using different buckling lengths. An incremental and interactive procedure is used to solve the geometric and material non-linear behaviour. The temperature effect is taken into account, using the uncouple thermal-structural analysis. The results obtained by the numerical simulations are in good agreement with the new simple calculation method and are also useful to prescribe the buckling curve that best fits the 3D simulation results.
- Computational simulation of the thermal effects on composite slabs under fire conditionsPublication . Piloto, P.A.G.; Balsa, Carlos; Ribeiro, Fernando; Rigobello, RonaldoA computational model is presented to evaluate the thermal effects on composite slabs with still deck, originated by standard fire exposure. Composite slabs with profiled steel deck are widely used in buildings which require fire resistance. Computational simulations are of great importance in this field and consist of an alternative to experimental fire tests that are expensive, time-consuming and require semi-specialized technical equipment. However, computational simulations must be reliable and realistic. The resulting transient and non-linear thermal problem is solved by the Finite Element Method in ANSYS and Matlab. The finite element models are three-dimensional, full scale, and multi-domain. Additionally, the models also include an air gap between the steel deck and the concrete part of the slab, in order to simulate the thermal effects induced by the debonding between the steel deck and the concrete, verified in previous experimental investigations. The results of the numerical simulations are validated against the results of experimental fire tests. The fire resistance of the composite slabs determined computationally is also compared with simplified calculation methods available in standards
- Critical temperature for the components of composite slabs with steel deck under fire for load-bearing ratingPublication . Piloto, P.A.G.; Balsa, Carlos; Ribeiro, Fernando; Santos, Lucas Manoel Cunha; Rigobello, Ronaldo; Kimura, Érica Fernanda AikoComposite slab made with concrete and steel deck are widely used in building structures. They also include other components, such as steel rebars for positive bending and a steel mesh for negative bending. The fire rating of this type of elements can be determined by standard fire tests, accounting for load (R), Integrity (E) and Insulation (I). This investigation deals with the fire resistance for load (R) and insulation (I), using a numerical model validated with experimental tests. This model considers material and geometric non-linear behaviour, using perfect contact between materials. The 3D finite element mesh uses solids, shells and bars, to model a simple supported composite slab with 3.2m long, 0.65 m wide and total height of 143mm, using a trapezoidal steel deck PRINS PSV73. Different load levels are simulated (live load ranging from 1.0 K/m2 to 21 kN/m2) in addition to the dead load (2.8 kN/m2). The fire resistance is determined according to standards, looking for the maximum displacement or the rate of displacement. The critical temperature of each steel component decreases with the load level. A new proposal is presented for the critical temperature of each steel component.
- Critical temperature for the components of composite slabs with steel deck under fire for load-bearing ratingPublication . Piloto, P.A.G.; Balsa, Carlos; Ribeiro, Fernando; Santos, Lucas Manoel Cunha; Rigobello, Ronaldo; Kimura, Érica Fernanda AikoComposite slabs made with concrete and steel deck are widely used in building structures. They also include other components, such as steel rebars for positive bending and a steel mesh for negative bending, preventing cracks in concrete. The fire rating of this type of elements can be determined by standard fire tests, accounting for load (R), Integrity (E) and Insulation (I). This investigation deals with the fire resistance for load (R) and insulation (I), using a numerical model validated with experimental tests. This model considers material and geometric non-linear behaviour, using perfect contact between materials. The 3D finite element mesh uses solids, shells and bars, to model a simply supported composite slab with 3.2m long, 0.65 m wide and total height of 143mm, using a trapezoidal steel deck PRINS PSV73. Different load levels are simulated (live load ranging from 1.0 kN/m2 to 21 kN/m2) in addition to the dead load (2.8 kN/m2). The fire resistance (R) is determined according to standards, looking for the maximum displacement or the rate of displacement, while the fire resistance (I) looks for the average or for the maximum temperature increase at the unexposed side. The critical temperature of each steel component decreases with the load level. A new proposal is presented for the fire resistance depending on the load level.
- 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.
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