Faris Ali, Ali Nadjai and S. Choi
The first part of this paper represents the results of an experimental research executed on 42 high strength concrete columns. The parametric study investigated high strength…
Abstract
The first part of this paper represents the results of an experimental research executed on 42 high strength concrete columns. The parametric study investigated high strength concrete columns under 3 loading levels 0.2, 0.4 and 0.6 subjected to high degree of axial restraint = 0.2 and exposed to two heating rates with a special attention directed to explosive spalling. The second part of the paper represents a three-dimensional finite element model of the reinforced concrete columns taking into account exposure to high temperatures. The effects of tension softening is included in the model and based on Hordijik, Cornelissen and Rienhardt curve. The concrete columns were modeled taking into account the embedded reinforcement and cracks formation and propagation using smeared cracks model which allowed a non-linear transient structural analysis to be conducted. The comparison of the results of the FE and the performed tests showed a reasonable agreement and a divergence in some cases due to concrete spalling. An assessment of the stresses generated in the high strength concrete columns under fire using the FEM model is also presented in the paper. The experimental and the FEM study showed that imposing axial restraint against concrete columns expansion may reduce explosive spalling of concrete during fire.
Ashti Yaseen Hussein and Faris Ali Mustafa
Spaciousness is defined as “the feeling of openness or room to wander” that has been affected by various physical factors. The purpose of this paper is to assess the spaciousness…
Abstract
Purpose
Spaciousness is defined as “the feeling of openness or room to wander” that has been affected by various physical factors. The purpose of this paper is to assess the spaciousness of space to determine how spacious the space is. Furthermore, the study intends to propose a fuzzy-based model to assess the degree of spaciousness in terms of physical parameters such as area, proportion, the ratio of window area to floor area and color value.
Design/methodology/approach
Fuzzy logic is the most appropriate mathematical model to assess uncertainty using nonhomogeneous variables. In contrast to conventional methods, fuzzy logic depends on partial truth theory. MATLAB Fuzzy Logic Toolbox was used as a computational model including a fuzzy inference system (FIS) using linguistic variables called membership functions to define parameters. As a result, fuzzy logic was used in this study to assess the spaciousness degree of design studios in universities in the Iraqi Kurdistan region.
Findings
The findings of the presented fuzzy model show the degree to which the input variables affect a space perceived as larger and more spacious. The relationship between parameters has been represented in three-dimensional surface diagrams. The positive relationship of spaciousness with the area, window-to-floor area ratio and color value has been determined. In contrast, the negative relationship between spaciousness and space proportion is described. Moreover, the three-dimensional surface diagram illustrates how the changes in the input values affect the spaciousness degree. Besides, the improvement in the spaciousness degree of the design studio increases the quality learning environment.
Originality/value
This study attempted to assess the degree of spaciousness in design studios. There has been no attempt carried out to combine educational space learning environments and computational methods. This study focused on the assessment of spaciousness using the MATLAB Fuzzy Logic toolbox that has not been integrated so far.
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Bushra Mawlood Sabir and Faris Ali Mustafa
This paper aims to investigate the potential role of the Emergency Department (ED) layout in enhancing its functionality. It applies a performance-based building design (PBBD…
Abstract
Purpose
This paper aims to investigate the potential role of the Emergency Department (ED) layout in enhancing its functionality. It applies a performance-based building design (PBBD) approach to evaluate emergency department functionality and efficiency as the most important criterion behind the success of the hospital service.
Design/methodology/approach
A quantitative approach based on space syntax theory was adopted through four syntactic maps (isovist, axial, convex, and visibility graph analysis VGA), to depict three case studies in Erbil city hospitals by analyzing three different layout typologies of ED such as Podular, Ballroom and Linear through measuring wayfinding, accessibility, privacy, visibility, time spend-length of stay and corridor circulation as layout factors.
Findings
This paper provides empirical insights on how the ED layout typology factors significantly affect producing functionally efficient EDs, whereas the Ballroom ED layout typology is the most effective compared to others. Given the importance of ED in enhancing a healthy environment for patients and staff, study findings are valuable resource for health designers, who play a critical role in ensuring patients enjoy a healthy and safe environment.
Originality/value
This paper has attempted to identify the appropriate layout of ED for effective functional performance in hospitals. A syntactical analysis between three different ED layout typologies based on the layout variables has been analysed using the PBBD approach. There has been no attempt carried out so far to analyse the functional performance of the PBBD approach in different ED layouts using layout variables.
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Michael Quinn, Ali Nadjai, Faris Ali and Abid Abu-Tair
Breakage and fallout of glazing systems create openings in an enclosure that affect the fire growth and the development of post flashover flames emerging outside of the openings…
Abstract
Breakage and fallout of glazing systems create openings in an enclosure that affect the fire growth and the development of post flashover flames emerging outside of the openings. The behaviour of glazing is the result of its thermally induced stress response to the heat fluxes from the fire in an enclosure. In recent times building façade designs have evolved and now incorporate many different shapes, orientations and materials. The conventional single and double glazing panels have been surpassed by composite type glazing systems including glazing and transparent resins. This paper presents experimental testing of these comp osite glazing panels having different orientations subjected to localized fires, which have the same fire load. The experimental findings of interest include the varying first crack times for both scenarios as well as the variable final crack patterns on the glazing panels. The effect of localized fire on the materials tested as seen in the final char patterns on both glazing systems is also note worthy. The paper also includes details of three-dimensional finite element modeling completed for the prediction of response of the glazing panels at different orientations to the elevated temperatures of the localised fire scenario as tested in the laboratory. This finite element analysis allows for an assessment of glazing thermal stresses at various times throughout each test.
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Muhammad Rafi, Ali Nadjai, Faris Ali and Paul O'Hare
Fibre reinforced polymer (FRP) bars are made of innovative materials and establishment of the fire resistance of FRP reinforced concrete (RC) is necessary for their widespread…
Abstract
Fibre reinforced polymer (FRP) bars are made of innovative materials and establishment of the fire resistance of FRP reinforced concrete (RC) is necessary for their widespread application. Experimental behaviours of Carbon FRP (CFRP) and Glass FRP (GFRP) bar RC beams at elevated temperatures have been investigated in this paper. Data are presented from fire tests of six simply supported beams that were fabricated using normal-weight concrete. The effects of varying load levels and FRP bar type were studied. The beams were designed over-reinforced and were tested in a floor furnace. A steel bar reinforced beam was used as control specimen. A rebar temperature of 500°C was selected as failure criterion for the beam. Non-linear temperature distribution across the beam cross section was observed. Temperature rise in the compression concrete was found insignificant and its mechanical properties were nearly unaffected. All beams met the failure criterion of critical rebar temperature of 500°C. The stiffness reduction in the GFRP and steel RC beams was nearly the same at elevated temperatures and was independent of load levels and/or bar modulus. The CFRP bar reinforced beams showed better stiffness characteristics compared to other beams.
Ali Nadjai, Nathan Goodfellow, Kong Fah Tee, Faris Ali and Sengkwan Choi
The growing popularity of the use of cellular steel beams in composite floors comes at the same time as an increasing attention to the fire safety engineering design. The…
Abstract
The growing popularity of the use of cellular steel beams in composite floors comes at the same time as an increasing attention to the fire safety engineering design. The recommendation for their design in fire limit states remains very primitive and this is due to the lack of general research in this area. Four composite cellular steel beams were tested at the University of Ulster with two models of different steel geometries and loading conditions under monotonic loading and at elevated temperatures. This paper presents a finite element model and simple hand calculation methods to calculate the shear buckling at the web post, the bending resistance in fire, deflection and temperature distribution in the cross section of composite cellular beams.
El-Hadi Naili, Ali Nadjai, Sanghoon Han, Faris Ali and Sengkwan Choi
This paper describes an experimental and numerical study at elevated temperatures on the behaviour of full scale composite floor cellular steel beams with circular and elongated…
Abstract
This paper describes an experimental and numerical study at elevated temperatures on the behaviour of full scale composite floor cellular steel beams with circular and elongated web openings. A total of three specimens, comprising three different steel geometries and loading conditions were tested at elevated temperatures. Finite element models were established with both material and geometrical non-linearity to compare with the experimental results. This paper also demonstrates the capability of a developed simple design approach in comparison with numerical modelling, experimental tests and existing design software used by the Steel Construction Institute (SCI).
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Sengkwan Choi, Faris Ali, Ali Nadjai, Sanghoon Han and Joungyoon Choi
This paper presents a numerical study to predict the in-fire performance of slim floor system, composed of asymmetric steel beam, deep steel decking and in-situ concrete slab. The…
Abstract
This paper presents a numerical study to predict the in-fire performance of slim floor system, composed of asymmetric steel beam, deep steel decking and in-situ concrete slab. The reliability of the proposed numerical model was verified by comparison with experimental results obtained for 4.2m beam tests. A pilot study was also conducted to examine the effect of the cross sectional modification of the steel section on performance enhancement of the model in fire.
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Lasław Kwaśniewski, Faris Ali and Marcin Balcerzak
This work presents a coupled structural-thermal numerical analysis of restrained steel columns under elevated temperatures. The modeling is based on the experimental tests carried…
Abstract
This work presents a coupled structural-thermal numerical analysis of restrained steel columns under elevated temperatures. The modeling is based on the experimental tests carried out on a series of open section ‘I-shaped’ columns, tested experimentally under different loading. The parametric study of a chosen case investigated following problems: geometrical imperfections, reduction of heated column area, variation of temperature along the length of the column, variation of applied force and variation of constraints properties. For the comparison with experimental the following quantities were used: axial force, vertical displacement and midspan deflection. The comparison showed that including more details and uncerteinties give the numerical results closer to reality. The last paragraph presents results for the same steel column under different loading, comparing only the maximum applied load, which is a crucial quantity for the behavior of the structure.
This paper presents the results from two supervised Artificial Neural Networks (ANN) developed for the spalling classification and failure prediction of high strength concrete…
Abstract
This paper presents the results from two supervised Artificial Neural Networks (ANN) developed for the spalling classification and failure prediction of high strength concrete columns (HSCC) subjected to fire. The experimental test data used for the ANN are based on the HSCC tests undertaken at the Fire Research Laboratories at the University of Ulster. 80% of the chosen experimental test data was used to train the network with the remaining 20% used for testing. In the spalling classification example the key ANN input parameters were; furnace temperature, restraint, loading level, force, spalling degree, failure time and spalling type. This was also the case for the failure prediction example except for spalling type. The networks were trained using the resilient propagation algorithm. A 6-10-3 and 5-10-1 ANN architecture gave the best results for the classification and failure prediction times respectively. The results demonstrate that HSCC can be assessed using ANN.