Fire resistance of composite slabs with steel deck under natural fire

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Paulo A.G. Piloto ◽  
Carlos Balsa ◽  
Felipe Macedo Macêdo Gomes ◽  
Bergson Matias
Keyword(s):  
Fire Resistance ◽  
Numerical Models ◽  
Three Dimensional ◽  
Composite Slab ◽  
Content Type ◽  
Natural Fire ◽  
Fire Scenario ◽  
Composite Slabs ◽  
Cooling Phase ◽  
Steel Deck

PurposeMost of the numerical research and experiments on composite slabs with a steel deck have been developed to study the effect of fire during the heating phase. This manuscript aims to describe the thermal behaviour of composite slabs when submitted to different fire scenarios, considering the heating and cooling phase.Design/methodology/approachThree-dimensional numerical models, based on finite elements, are developed to analyse the temperatures inside the composite slab and, consequently, to estimate the fire resistance, considering the insulation criteria (I). The numerical methods developed are validated with experimental results available in the literature. In addition, this paper presents a parametric study of the effects on fire resistance caused by the thickness of the concrete part of the slab as well as the natural fire scenario.FindingsThe results show that, depending on the fire scenario, the fire resistance criterion can be reached during the cooling phase, especially for the thickest composite slabs. Based on the results, new coefficients are proposed for the original simplified model, proposed by the standard.Originality/valueThe developed numerical models allow us to realistically simulate the thermal effects caused by a natural fire in a composite slab and the new proposal enables us to estimate the fire resistance time of composite slabs with a steel deck, even if it occurs in the cooling phase.

Investigation into effects of cooling rate on properties of polyamide 12 parts in the multi jet fusion process

2020 ◽  
Vol 26 (10) ◽  
pp. 1789-1795
Author(s):  
Mattia Mele ◽  
Giampaolo Campana ◽  
Gregorio Pisaneschi ◽  
Gian Luca Monti
Keyword(s):  
Cooling Rate ◽  
Three Dimensional ◽  
The Body ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Polyamide 12 ◽  
Body Of Knowledge ◽  
Cooling Phase ◽  
The Right ◽  
High Building

Purpose Multi jet fusion is an industrial additive manufacturing technology characterised by high building speed and considerable properties of the parts. The cooling phase represents a crucial step to determine productivity, since it can take up to 4.5 times the building time. The purpose of this paper is to investigate into effects of cooling rate on parts manufactured by multi jet fusion. Crystallinity, density, distortions and mechanical properties of specimens produced through an HP multi jet fusion 4200 are examined. Design/methodology/approach An experimental activity is carried out on specimens cooled down at three different rates. Properties of the parts are analysed by means of differential scanning calorimetry, optical microscopy, three-dimensional scanning and tensile testing. Originality/value The present work makes a contribution to the body of knowledge providing correlations between the cooling phase of multi jet fusion and part properties. These results can be used to choose the right balance between production time and product quality.

A novel quasi-3D thermodynamic model of oil film bearing with non-Newtonian and temperature-viscosity effects

2017 ◽  
Vol 69 (5) ◽  
pp. 638-644 ◽  
Author(s):  
Feng Liang ◽  
Quanyong Xu ◽  
Ming Zhou
Keyword(s):  
High Speed ◽  
Numerical Models ◽  
Thermal Analyses ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Content Type ◽  
Oil Film ◽  
Time Consumption ◽  
Simulation Speed ◽  
Viscosity Effects

Purpose The purpose of this paper is to propose a quasi-three-dimensional (3D) thermohydrodynamic (THD) model for oil film bearings with non-Newtonian and temperature-viscosity effects. Its performance factors, including precision and time consumption, are investigated. Design/methodology/approach Two-dimensional (2D), 3D and quasi-3D numerical models are built. The thermal and mechanical behaviors of two types of oil film bearings are simulated. All the results are compared with solutions of commercial ANSYS CFX. Findings The 2D THD model fails to predict the temperature and pressure field. The results of the quasi-3D THD model coincide well with those of the 3D THD model and CFX at any condition. Compared with the 3D THD model, the quasi-3D THD model can greatly reduce the CPU time consumption, especially at a high rotational speed. Originality/value This quasi-3D THD model is proposed in this paper for the first time. Transient mechanical and thermal analyses of high-speed rotor-bearing system are widely conducted using the traditional 3D THD model; however, the process is very time-consuming. The quasi-3D THD model can be an excellent alternative with high precision and fast simulation speed.

scholarly journals Fire Resistance of Axially Loaded Slender Concrete Filled Steel Tubular Columns – Development of a Three-Dimensional Numerical Model and Comparison with Eurocode 4

10.14311/1089 ◽  
2009 ◽  
Vol 49 (1) ◽  
Author(s):  
A. Espinós ◽  
A. Hospitaler ◽  
M. L. Romero
Keyword(s):  
Numerical Model ◽  
Fire Resistance ◽  
Numerical Models ◽  
Three Dimensional ◽  
Calculation Model ◽  
Construction Technology ◽  
Tubular Columns ◽  
Highly Nonlinear ◽  
Structural Engineers ◽  
Simplified Calculation

In recent years, concrete filled tubular (CFT) columns have become popular among designers and structural engineers, due to a series of highly appreciated advantages: high load-bearing capacity, high seismic resistance, attractive appearance, reduced column footing, fast construction technology and high fire resistance without external protection. In a fire, the degradation of the material properties will cause CFT columns to become highly nonlinear and inelastic, which makes it quite difficult to predict their failure. In fact, it is still not possible for analytical methods to predict with enough accuracy the behaviour of columns of this kind when exposed to fire. Numerical models are therefore widely sought. Many numerical simulations have been carried out worldwide, without obtaining satisfactory results. This work proposes a three-dimensional numerical model for studying the actual fire behaviour of columns of this kind. This model was validated by comparing the simulation results with fire resistance tests carried out by other researchers, as well as with the predictions of the Eurocode 4 simplified calculation model. 

scholarly journals Nonlinear finite element analysis of profiled steel deck composite slab system under monotonic loading.

2021 ◽  
Author(s):  
Shubhangi Attarde
Keyword(s):  
Finite Element ◽  
Mesh Size ◽  
Monotonic Loading ◽  
Nonlinear Finite Element ◽  
Experimental Results ◽  
Model Parameters ◽  
Element Analysis ◽  
Composite Slab ◽  
Composite Slabs ◽  
Steel Deck

This research concentrated on the nonlinear finite element (FE) modeling of one-way composite floor slab system comprising of profiled steel deck and two types of concrete namely, Engineered Cementitious Composites (ECC) and Self-Consolidating Concrete (SCC). Two FE models were developed based experimental results of composite slabs subjected to in-plane monotonic loading. The simulated load-deflection response, moment resistance, and shear bond capacity using two FE models were in reasonable good agreement with experimental results. The FE models were used in a comprehensive parametric study to investigate the effect of numerical model parameters such as mesh size, dilation angle, steel sheet-concrete interaction contact, material properties and composite slab span. In addition, FE models were used to determine shear bond parameters of ECC and SCC composite slabs that can be used for design purposes.

scholarly journals Structural behaviour of composite slab with high performance concretes

2021 ◽  
Author(s):  
Haile Mengistu
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
Experimental Investigations ◽  
Structural Behaviour ◽  
Interface Shear ◽  
Composite Slab ◽  
Composite Slabs ◽  
Energy Absorbing ◽  
Steel Deck ◽  
Bond Characteristics

Composite slabs with profiled steel deck and concrete toping have gained wide acceptance as they lead to faster, lighter and economical construction. Extensive research works have been conducted on the behaviour of composite slabs to study their structural behavior and steel-concrete interface shear bond resistance which primarily governs the failure. However, the use of emerging highly durable engineered cementitous composite (ECC) in composite slab is new and no research has been conducted yet. High strain hardening and intrinsic crack width characteristics of ECC can significantly improve structural performance of composite slabs through enhancing ductility, energy absorbing capacity and steel-concrete shear bond. In this study, experimental investigations are conducted to evaluate the shear bond characteristics of composite slabs made with ECC and conventional self-consolidating concrete (SCC) using Code based m-k method. Twelve slab specimens having variable shear span and two types of profiled steel deck were tested under four point loading. The performance of ECC and SCC composite slabs are compered based on load-deflection response, stress-strain development in concrete and steel, failure modes, energy absorbing capacity and steel-concrete shear bond parameters (m and k) and bond stress.

Adaptive finite element–discrete element analysis for stratal movement and microseismic behaviours induced by multistage propagation of three-dimensional multiple hydraulic fractures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yongliang Wang
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Three Dimensional ◽  
Fracture Propagation ◽  
Discrete Element ◽  
Hydraulic Fractures ◽  
Adaptive Finite Element ◽  
Fracture Networks ◽  
Content Type ◽  
Microseismic Events

Purpose Optimized three-dimensional (3D) fracture networks are crucial for multistage hydrofracturing. To better understand the mechanisms controlling potential disasters as well as to predict them in 3D multistage hydrofracturing, some governing factors, such as fluid injection-induced stratal movement, compression between multiple hydraulic fractures, fracturing fluid flow, fracturing-induced microseismic damaged and contact slip events, must be properly simulated via numerical models. This study aims to analyze the stratal movement and microseismic behaviours induced by multistage propagation of 3D multiple hydraulic fractures. Design/methodology/approach Adaptive finite element–discrete element method was used to overcome the limitations of conventional finite element methods in simulating 3D fracture propagation. This new approach uses a local remeshing and coarsening strategy to ensure the accuracy of solutions, reliability of fracture propagation path and computational efficiency. Engineering-scale numerical models were proposed that account for the hydro-mechanical coupling and fracturing fluid leak-off, to simulate multistage propagation of 3D multiple hydraulic fractures, by which the evolution of the displacement, porosity and fracture fields, as well as the fracturing-induced microseismic events were computed. Findings Stratal movement and compression between 3D multiple hydraulic fractures intensify with increasing proximity to the propagating fractures. When the perforation cluster spaces are very narrow, alternate fracturing can improve fracturing effects over those achieved via sequential or simultaneous fracturing. Furthermore, the number and magnitude of microseismic events are directly proportional to the stratal movement and compression induced by multistage propagation of fracturing fracture networks. Originality/value Microseismic events induced by multistage propagation of 3D multiple hydraulic fractures and perforation cluster spaces and fracturing scenarios that impact the deformation and compression among fractures in porous rock matrices are well predicted and analyzed.

scholarly journals Numerical simulation of the fire resistance of composite slabs with steel deck

2018 ◽  
Vol 7 (2.23) ◽  
pp. 83 ◽  
Author(s):  
Paulo A. G. Piloto ◽  
Lucas M.S. Prates ◽  
Carlos Balsa ◽  
Ronaldo Rigobello
Keyword(s):  
Numerical Simulation ◽  
Fire Resistance ◽  
Calculation Method ◽  
Simple Calculation ◽  
Concrete Layer ◽  
Composite Slabs ◽  
Composite Solution ◽  
Steel Deck ◽  
Loadbearing Capacity ◽  
Methods Numerical

This 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.  

Advanced analyses of the membrane action of composite slabs under natural fire scenarios

2018 ◽  
Vol 9 (1) ◽  
pp. 77-90 ◽  
Author(s):  
Lorenzo Lelli ◽  
Jonas Loutan
Keyword(s):  
Gas Temperature ◽  
Reinforced Concrete Structure ◽  
Membrane Action ◽  
Content Type ◽  
Natural Fire ◽  
Small Thickness ◽  
Composite Frame ◽  
Composite Slabs ◽  
Fire Scenarios ◽  
Definition Of

Purpose This paper aims to detail the advanced natural fire simulations that were carried out for the composite steel-reinforced concrete structure of the JTI Building in Geneva, Switzerland. The results of these analyses led to a significant reduction of in the fireproofing of the steel floor framing. Design/methodology/approach Several scenarios were studied considering different thermal behaviours of the peripheral cladding. Despite the small thickness of the resisting slabs, the analyses performed with SAFIR software showed that the typical wide storey bay (12 × 15.86 m) can resist to the design’s fire temperatures without the protection of the main and secondary beams while the spandrels remain protected. For study completeness, the composite frame-membrane model was also simulated with Hasemi-localized fire routines on SAFIR. Findings The analyses have showed that the membrane behaviour of composite slabs under fire allows a significant reduction of the fire protection, even in case of small thickness of the concrete topping. The increase of the reinforcement ratio to sustain the membrane forces is widely compensated by the savings related to the fireproofing of the steel framing. Practical/implications A natural fire approach is particularly advisable in case of fully glazed buildings. In fact when the façade collapses, the entry of a large cold air quantity limits the increase of the gas temperature inside the compartment. Originality/value The analyses were carried out with recent SAFIR routines for localized fires (Hasemi fire model) and represent one of the first applications in practice. The issue of the rebar orientation in mesh is raised out. The latest SAFIR release allows the definition of a global orientation of the rebars and amends the issue.

scholarly journals Structural behaviour of composite slab with high performance concretes

2021 ◽  
Author(s):  
Haile Mengistu
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
Experimental Investigations ◽  
Structural Behaviour ◽  
Interface Shear ◽  
Composite Slab ◽  
Composite Slabs ◽  
Energy Absorbing ◽  
Steel Deck ◽  
Bond Characteristics

Composite slabs with profiled steel deck and concrete toping have gained wide acceptance as they lead to faster, lighter and economical construction. Extensive research works have been conducted on the behaviour of composite slabs to study their structural behavior and steel-concrete interface shear bond resistance which primarily governs the failure. However, the use of emerging highly durable engineered cementitous composite (ECC) in composite slab is new and no research has been conducted yet. High strain hardening and intrinsic crack width characteristics of ECC can significantly improve structural performance of composite slabs through enhancing ductility, energy absorbing capacity and steel-concrete shear bond. In this study, experimental investigations are conducted to evaluate the shear bond characteristics of composite slabs made with ECC and conventional self-consolidating concrete (SCC) using Code based m-k method. Twelve slab specimens having variable shear span and two types of profiled steel deck were tested under four point loading. The performance of ECC and SCC composite slabs are compered based on load-deflection response, stress-strain development in concrete and steel, failure modes, energy absorbing capacity and steel-concrete shear bond parameters (m and k) and bond stress.

scholarly journals Experimental investigations on the load bearing behaviour of an innovative prestressed composite floor system in fire

2018 ◽  
Author(s):  
Patrick Meyer ◽  
Peter Schaumann ◽  
Martin Mensinger ◽  
Suet Kwan Koh
Keyword(s):  
Fire Resistance ◽  
Large Scale ◽  
Concrete Slab ◽  
Experimental Investigations ◽  
Load Bearing ◽  
Natural Fire ◽  
Fire Scenario ◽  
Standard Fire ◽  
Hollow Space ◽  
Floor System

In Germany, regulations for hollow spaces in slab systems require 30 minutes standard fire resistance of the load-bearing steel construction. Within a current national research project a natural fire scenario for the hollow space was developed based on realistic fire loads and ventilation conditions in the hollow space. Assuming this realistic fire scenario in the hollow space, two large scale tests on an innovative composite floor system were performed to evaluate the influence on the load bearing behaviour of the floor system. The integrated and sustainable composite floor system consists of a prestressed concrete slab, an unprotected, bisected hot rolled I-profile with composite dowels either in puzzle or clothoidal shape, and removable floor panels on the top of the I-profile. This floor system ensures the opportunity to adjust the technical building installations in accordance with the use of the building. This integrated and sustainable composite floor system was developed in several research projects. The standard fire resistance R90 for the fire scenario below the slab system has already been proven successfully. In this paper, experimental investigations regarding the heating and load bearing behaviour of the innovative composite floor system under the newly developed natural fire scenario of hollow spaces are presented. In doing so, the special test set-up to realise the fire tests for the fire scenario hollow space will be described in detail. After the fire scenario for the hollow space, the specimen was subjected to the ISO standard fire curve to establish the failure temperature of the unprotected I-profile. In addition to the temperature development and the load bearing behaviour inside the innovative floor during the heating phase, the cooling phase and the influence of a web opening on the load bearing behaviour will be discussed.

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