Search results

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.

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.

There are rising issues with the delivery performance of Malaysian low-cost housing (LCH) because the occupants are inclined to perceive safety hazards. Among the safety issues raised during the occupancy period in LCH are structural instability and falling building fragments. Without defining the occupants’ requirements in the early housing development, it is hard to determine the prevailing safety factors. Hence, this paper emphasises the application of post occupancy evaluation (POE) that incorporates participation from the occupants as a tool to assess the safety performance of Malaysian LCH. The purpose of this study is to develop a framework of POE integrated with safety elements for Malaysian LCH.

This research was carried out with a quantitative method using questionnaires as the survey instrument involving safety inspection survey and satisfaction surveys. The inspection survey and Occupants’ Satisfaction Survey were carried out based on 24 LCH projects located in the federal territory of Kuala Lumpur, Malaysia. In total, 380 samples were used for both surveys. Statistical correlation was used to affirm the incorporation of occupants’ participation towards safety performance in the POE approach. The Spearman’s rho (r) correlation was used in the analysis for variables in both surveys which consisted of an ordinal scale.

The correlation result revealed that there was a significant relationship among all safety attributes between safety performance and occupants’ satisfaction. Therefore, a framework consisting of POE and safety elements has been proposed based on the significance of both variables. The development process of the framework used the vital phases of POE and inputs of safety elements which consisted of three main stages: planning phase as safety input, conducting phase as safety process and applying phase as safety output.

The surveys were limited to the rented People’s Housing Programme located in Kuala Lumpur and not extensively to all LCH programmes in Malaysia. The surveys were also not carried out to other LCH programmes such as the Hardcore Poor Housing Programmes and the low- to medium-cost housing because of the limitations of time and resources.

This research has introduced a new dimension for safety performance assessment in LCH using the POE as the safety performance tool. By allowing the participation of occupants for safety assessment, this study stresses the fundamental concept of POE by highlighting the importance of obtaining feedback from the building occupants.

As a proactive measure, the proposed framework was introduced as an improved procedure to inspect safety performance in LCH during occupancy, in lieu of the current assessment process. Receiving complaints from the occupants after the occurrence of incidents is demarcated as a reactive approach, whereas the current inspection survey does not incorporate the occupants’ participation. Feedback from occupants is not a routine of building assessment during occupancy; hence, using POE is generally a new dimension of safety performance in Malaysian LCH.