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This paper aims to present a reliability analysis of the slab panel method (SPM) for the design of composite steel floors in severe fires. Rather than seeking to accurately define failure levels, this paper highlights areas of uncertainty in design and their effect on design results, whilst providing approximate reliability levels.

A Monte Carlo simulation has been conducted using the SPM design procedure to produce probability density functions of floor capacity for various floor layouts. Statistical input variables were obtained from the literature. Different configurations, geometries and fire severities are included to demonstrate how predicted floor capacities are influenced.

From the research presented, it is clear that the predicted reliability of SPM systems varies relative to a large number of criteria, but especially parameters related to fire loading. Predicted capacities are shown to be conservative compared to results of furnace and large-scale natural fire tests, which exhibit higher fire resistance. Due to distinct fire hazard categories with associated input values, there are step discontinuities in capacity graphs.

Limited research has been done to date on the reliability of structures in fire as discussed in this paper. It is important to verify the reliability levels of systems to ensure that partial and global factors of safety are adequate. Monte Carlo simulations are shown to be effective for calculating the average floor capacities and associated standard deviations. The presentation of probability density functions for composite floors in severe fires is novel.

This paper aims to provide a parametric investigation into the behaviour of steel, concrete and composite beams exposed to fire. This investigation gives insight into the structural behaviour of elements experiencing thermal and mechanical loading illustrating reasons for observed global structural behaviour, and identifying how selected design parameters influence results obtained. Non-linear heating/thermal bowing behaviour is specifically considered.

Cross-sectional stresses and strains, resultant thermal forces, bending stiffness, axial stiffness and deflections are plotted for beams subjected to different fire regimes or input values. The impact of changes in input parameters on beam section properties is illustrated. Unusual structural responses, localised effects and general trends are identified in relation to variations in thermal gradients, concrete tensile capacity, standard fire exposure time and the assumed concrete flange widths of composite beams.

Stress-strain plots highlighting cross-sectional structural behaviour, trends in beam properties and the influence of design parameters are provided. Some counter-intuitive behaviour is explained, such as increased member stiffness being offset by increased thermal effects, leading to this parameter having negligible impact on global behaviour but a significant effect on local stresses and strains. Increased concrete strengths may lead to increased thermal deformations, whilst the inclusion of concrete tensile capacity typically has a minimal influence.

The research focusses on cross-sectional properties, although results generated illustrate how global behaviour is affected.

Design engineers are made aware of how selected input values influence predicted structural response. Also, localised stress and strain behaviour relative to imposed loads and thermal effects can be identified.

This paper provides novel insight into the (sometimes counter-intuitive) behaviour of beams exposed to fire, highlighting trends and the influence of important input parameters on predicted response.

The present study is based on finding the structural response of a tensile membrane structure (TMS) through deformation. The intention of the present research is to develop a basic understanding of reliability analysis and deflection behavior of a pre-tensioned TMS. The mean value first-order second-moment method (MVFOSM) method is used here to evaluate stochastic moments of a performance function with random input variables. Results suggest the influence of modulus of elasticity, the thickness of the membrane, and edge span length are significant for reliability based TMS design.

A simple TMS is designed and simulated by applying external forces (along with prestress), as a manifestation of wind and snow load. A nonlinear analysis is executed to evaluate TMS deflection, followed by calculating the reliability index. Parametric study is done to consider the effect of membrane material, thickness and load location. First-order second moment (FOSM) is used to evaluative the reliability. A comparison of reliability index is done and deflection variations from μ − 3s to μ + 3s are accounted for in this approach.

The effectiveness of deflection is highlighted for the reliability assessment of TMS. Reliability and parametric study collectively examine the proposed geometry and material to facilitate infield design requirements. The estimated β value indicates that most suitable fabric material for a simple TMS should possess an elasticity modulus in the range of 1,000–1,500 MPa, the thickness may be considered to be around 1.00 mm, and additional adjustment of around 5–10 mm is suggested for edge length. The loading position in case of TMS structures can be a sensitive aspect where the rigidity of the surface is dependent on the pre-tensioning of the membrane.

The significance of the parametric study on material and loading for deflection of TMS is emphasized. Due to the lack of consolidated literature in the field combining reliability with deflection limits of a TMS, this work can be very useful for researchers.

The present work outcome may facilitate practitioners in determining effective design methodology and material selection for TMS construction.

The significance of parametric study for serviceability criteria is emphasized. Parameters like pre-stress can be included in future parametric studies to witness in depth behavior of TMS. Due to lack of consolidated literature in the field combining reliability with deflection limits of a TMS, this work can be very useful for the researchers. The present work outcome may facilitate practitioners in determining effective design methodology and material selection for TMS construction.

The Southern African Institute of Steel Construction has developed a novel cellular beam structure (CBS) for multi-storey buildings that is entirely devoid of concrete. Channel sections between the cellular beams support a complex sandwich flooring system, which contains a fire-resistant ceiling board, metal sheeting, an interior fibre-cement board and an access-flooring system. As for all structures, the CBS requires a fire rating. This paper aims to investigate the thermal behaviour of the CBS using numerical modelling and experimental fire testing, as it has a unique setup.

Experimental fire tests on the flooring system were conducted to validate finite element models, which were developed in ABAQUS. These models were then extended to include floor beams and the structural steelwork.

Good correlations were found between the experimental and numerical results, with temperature variations typically in the range of 0-5%, although with localised differences of up to 20%. This allowed larger finite element models, representing the sandwich floor system of the CBS, to be developed and analysed. A 1-hour rating can be obtained by the system in terms of insulation and integrity requirements.

The CBS allows for more economical steel structures, due to the rapid construction of its modular panels. A suitable fire resistance will ensure the safety of the occupants and prevent major structural damage. Steelwork and flooring temperatures are determined which has allowed for global structural analyses to be carried out.

The originality of this study lies in thermal analysis and testing of a new cellular beam flooring system, through determining behaviour in fire, along with beam temperatures.

In this study, the behavior of a multi-story flat plate structure during fire exposure is investigated using numerical simulations conducted with using ABAQUS software.

A three-dimensional finite element model is then carried out on the RC flat slab structure exposed to standard ISO-834 fire at different location arrangements. The model examines mid-span deflection, shear demand on the columns, bending moment and the membrane action of the floor slab.

The latter plays a main role to increase the capability and ductility of the slab at longer fire exposure to compensate the reduction in the flexural capacity. Also, shear demand in columns becomes bigger in cases of more than one surrounding slab exposed to fire at the same time.

This work focuses on the influence of the horizontal force on columns due to thermal expansion of slab which should be taken into account in the design of multistory multi-bay building considering it the same as the resulted horizontal force from the wind and seismic effect, the traveling fire and the restraint effect.

This paper presents a comparison, based on real practical case studies, between the simple analytical BRE-Bailey method (BRE-BM) and the advanced finite element model (FEM) Vulcan for the membrane action of composite slab panels with unprotected secondary beams at elevated temperatures. Both approaches predicted the membrane behaviour of the composite slabs, comprising compressive membrane action around the slabs' perimeter and tensile membrane action in the central span region of the slabs. This paper mainly studies the effects of the orientation of unprotected secondary beams and the boundary conditions on tensile membrane action of composite slab panels. The results show that the application of the BRE-BM is generally restricted by the conservative assumption of the maximum allowable vertical displacement. In contrast, the FEM estimates higher load-carrying capacities as well as providing a full displacement-time relationship throughout the heating of the slabs. For slab panels with unprotected secondary beams with an orientation in the short span, tensile membrane action can be easily mobilised without increasing fire protection to the boundary supporting beams. However, the FEM predictions on the slab capacities and deflections in fire are very sensitive to the continuity of the reinforcement over the protected boundary beams.

A simple folding mechanism, which considers the contributions of internal unprotected beams and protected edge beams, has been proposed for isolated slab panels in fire conditions. The current study extends the mechanism to include the reinforcement in the slab as well as continuity across the protected edge beams. Structural failure of the panel depends on the applied loads, the relative beam sizes, their locations within the building, their arrangement in the slab panel, the panel's location and the severity of fire exposure. These factors are considered in the development of a number of collapse mechanisms for verification so they may eventually serve as an additional check within the Bailey-BRE design method, to make it more robust for routine design of composite floors in fire. Comparisons are made with the finite element software Vulcan and other design acceptance criteria.

The aim of the research was to investigate the effect of concrete strength on the fire resistance of structures. At first, it may seem contradictory that higher concrete strengths can decrease the fire resistance of building structures. However, if the strength of the concrete exceeds a maximum value, the risk of spalling (the detachment of the concrete surface) significantly.

Prefabricated structural elements are often produced with higher strength. The higher concrete strengths generally do not cause a reduction in the load bearing capacity, but it can have serious consequences in case of structural fire design. Results of two prefabricated elements, namely, one slab (TT shaped panel) and one single layer wall panel, were examined. Results of the specimen with the originally designed composition and a specimen with modified concrete composition were examined, were polymer fibres were added to prevent spalling.

As a result of the experiments, more strict regulations in the standards the author is suggested including more strict regulations in the standards. It has been proved that to ensure the fire safety of the reinforced concrete structures, it is required after polymer fibres even in lower concrete strength class than prescribed by the standard. In addition, during the classification and evaluation of structures, it is advisable to introduce an upper limit of allowed concrete strength for fire safety reasons.

As a result of the experiments, the author suggests including more strict regulations in the standards. It has been proved that to ensure the fire safety of the reinforced concrete structures, it is necessary to require the addition of polymer fibres even in lower concrete strength class than prescribed by the standard. In addition, during the classification and evaluation of structures, it is advisable to introduce an upper limit of allowed concrete strength for fire safety reasons.

This study aims to investigate the influence of tendon layout, pre-stressing force, bond condition and concrete spalling on the structural behaviour of two-way post-tensioned flat slabs at elevated temperatures.

Fire tests of four scale specimens of two-way post-tensioned concrete flat slabs were performed and analysed. Three of them were provided with bonded tendons, while the other was unbonded for comparison. The fabrication of specimens, phenomena observed during testing, temperature distributions, deflections and occurrence of concrete spalling were examined.

Different degrees of concrete spalling observed at the soffit had significant effects on the temperature distribution and stress redistribution. This was the major reason for the progressive concrete spalling observed, resulting in loss of structural integrity and stiffness.

The structural behaviour of two-way post-tensioned concrete flat slabs at elevated temperatures is less understood compared to their one-way counterparts. Therefore, the present study has focused on the structural behaviour of two-way post-tensioned concrete flat slabs with bonded tendons in fire, a field in which relatively little information on experimental work can be found.

Nowadays, residential buildings have become increasingly important due to the growing communities. The purpose of this study is to investigate the behavior of a steel structural framing system that incorporates lightweight load-bearing walls and slabs, and to compare the weight of materials used in cold-formed and hot-finished steel structural systems for affordable housing.

Four types of models consisting of 243 members were simulated. Model 1 is a cold-formed steel structural framing system, while Model 2 is a hot-finished steel structural framing system. Both Models 1 and 2 use lightweight wall panels and lightweight composite slabs. Models 3 and 4 are made with brick walls and precast reinforced concrete systems, respectively. These structures use different wall and slab materials, namely, brick walls and precast reinforced concrete. The analysis includes bending behavior, buckling resistance, shear resistance and torsional rotation analysis.

This study found that using thinner steel sections can increase the deflection value. Meanwhile, increasing member length and the ratio of slenderness will decrease buckling resistance. As the applied load increases, buckling deformation also increases. Furthermore, decreasing shear area causes a reduction in shear resistance. Thicker sections and the use of lightweight materials can decrease the torsional rotation value.

The weight comparison of the steel structures shows that Model 1, which is a cold-formed steel structure with lightweight wall panels and lightweight composite slabs, is the most suitable model due to its lightweight and affordability for housing. This model can also be used as a reference for the optimal design of modular structural framing using cold-formed steel materials in the field of civil engineering and as a promotional tool.