Structural and Spatial Minimal Requirement Efficacy of Emergency Shelters for Different Emergencies

Natural and human-induced disasters have become more frequent in recent years, and this has increased the need for effective, high-quality, quick, easy-to-assemble, and affordable emergency housing solutions. The purpose of this study is to create a knowledge base for researchers and developers working in the structural and structural-related fields to favour the development of relevant and most appropriate assistance for emergency housing that could meet the anticipated future rising demands. The focus of the research is emergency shelters for the Global South, an area of research sparsely addressed within the structural-related field. The emergency sheltering process has so many variabilities in its duration and unfolding that many agencies suggest relying on the resilience of those in need. This can have dramatic human repercussions and eventually further burden natural resources. To reach its goal, the paper shifts the attention to information from field actors and global agencies and employs a multiple case studies approach, conducted through a grounded theory methodology. The process has allowed identification of a list of structural-related issues faced by users, acting as codes in the grounded theory methodology, the associated challenges for authorities in addressing them, acting as categories, and some ideal solutions, derived from the theoretical coding. The research concludes that the challenges of the sheltering process shall be read through sustainability housing indicators and that the constraints of the former may be stimuli to the application of innovative and more inclusive procedures within the latter. The study fosters a new theoretical approach in post-disaster housing, which encourages more interdisciplinary collaborations and empirical investigations that will potentially enhance post-disaster housing sustainability and facilitate the development of emergency shelter construction schemes

Shear Capacity of Cold-Formed Stainless Steel Beam with Elliptical Web Openings: Numerical Analyses

Cold-formed stainless-steel sections are increasingly being used in the construction industry, for both architectural and structural applications. The excellent combination of mechan-ical properties and corrosion resistance makes stainless steel a very good material for structural applications. Due to the lack of design rules for stainless steel, the design rules for carbon steel have been generally adopted in the stainless-steel design. However, the prominent non-linear be-haviour of stainless steel, which is the main difference with carbon steel, makes the standards for carbon steel not always accurate in the stainless-steel design. The provision of web openings at appropriate locations in such sections is also important to avoid cutting holes at an inappropriate location during the implementation stage. The type of section and the shape of opening were primarily chosen based on the application. The scope of this study is however limited to stainless steel Lipped Channel Beams (LCB) with elliptical web openings. The provision of openings in web affects the shear behaviour and shear capacity of LCB sections, but only very limited re-searches have been conducted so far. Hence, a numerical analysis was undertaken to investigate the shear behaviour and strength of cold-formed stainless steel LCB section with elliptical web openings. Finite element models of cold-formed ferritic stainless steel LCB with centered web openings were developed under the simply supported loading condition. They were validated with currently available shear test results and a detailed parametric study was undertaken to develop an extensive shear strength database. Numerical results showed that the currently available reduc-tion factor equations of circular web opening are either conservative or unsafe to use for the non-circular openings. Hence, numerical results were then used to develop a reduction factor to the shear capacities of cold-formed stainless steel LCBs with elliptical web opening

Web Crippling Behaviour of Cold-Formed Stainless Steel LCB with Non-Circular Web Opening Under ETF Load Case

Cold-formed stainless steel beams are often subjected to concentrated, localised loads or reactions. These concentrated forces acting on flexural members cause localised bearing failures. This bearing failure, generally known as web crippling, is one of the critical failure modes of cold-formed stainless steel members. The provision of web opening at an appropriate location in such section is also important to avoid holes being cut at an inappropriate location during the construction stage. Different shapes and sizes of web openings are made on the web panel of such sections to facilitate building services. The scope of this study is however limited to stainless steel Lipped Channel Beams (LCB) with square and rectangular web openings. Presence of opening in the web directly influences the web crippling behaviour and also considerably reduces web crippling strength of stainless steel LCBs, but very limited researches have been undertaken to predict the web crippling capacity of stainless steel LCBs. Hence, a detailed finite element analysis was undertaken to investigate the web crippling behaviour and web crippling strength of cold-formed stainless steel LCBs with centered non-circular web opening under the exterior-two-flange (ETF) loading condition. Finite element models of cold-formed stainless steel beams with web opening under web crippling actions were developed to investigate the ultimate web crippling strength behaviour of cold-formed stainless steel beams with web opening including their elastic and post-buckling characteristics. They were validated with currently available web crippling test results. A detailed parametric study based on validated finite element model was undertaken to develop an extensive web crippling strength database and were then used to develop the new design equations for the reduction factor of web crippling capacities of cold-formed stainless steel beams with non-circular (i.e. Square or rectangle) web opening. Appropriate web crippling design rules within the framework of European and International Standards were developed based on obtained FEA results

Development of Affordable Steel-Framed Modular Buildings for Emergency Situations (Covid-19)

This paper presents the development of novel affordable steel-framed modular units for construction with enhanced overall (healthcare, structural, fire, and lightweight) performance, which ideally suits for emergency response situation, such as current covid-19 pandemic. The nature of quick response and well-prepared strategies are essential to cope with the demand of quicker construction for emergency response structures and if similar situation continues or arises in the future as well. Off-site oriented modular construction is ideal to provide these requirements at very short notice for emergencies. Modular units made of steel components are a leading choice due to the exceptional strength and rigidity for lightweight construction. A new weight optimisation procedure was developed for Cold-Formed Steel (CFS) joists in varying shapes of and results show that weight for per unit length of the joists can be reduced up to 24% without compromising structural capacity. This was verified with validated Finite Element (FE) models. In order to improve the faster jointing method, a novel cut and bend intra-module connection was also introduced. In addition, strap bracing is used for the lateral stability of steel-framed modular buildings. Modular breathing panels are proposed to be employed in corner post modules as sidewalls to improve the indoor air quality and reduce the spread of disease. Based on the comprehensive assessment and numerical results conceptual design of performance improved steel-framed corner post modular unit was proposed to offer short-to-medium (in response to emergencies), as well as long-term solutions for the construction industry

Numerical Investigation on Fire Performance of LSF and Steel Modular Floor Panels

The steel Modular Building Systems (MBSs) that have been influenced by the Light-gauge Steel Frame (LSF) techniques have become a prominent culture in the industry. However, the detrimental behaviour of steel structural components at high temperatures has elevated the risk of fatal accidents in the event of a fire. Although several research investigations have addressed the fire performance of steel modular wall systems, the behaviour of modular floor systems has not been adequately addressed in the state of the art. Hence, to promote the fire safety and optimum design techniques in the modular construction industry by addressing the aforementioned research gap, this study investigated 48 conventional LSF and MBS floors for their structural and insulation Fire Resistance Levels using Finite Element Modelling (FEM) and Heat Transfer Analyses (HTA) techniques. Initially, full-scale experimental fire tests were modelled using FEM methods, and the validity of the techniques was verified prior to the analyses of parametric floor systems. Furthermore, the structural behaviour of the channel section joists in the elevated temperatures was studied, and hence a correlation was established to determine the critical steel temperature at the structural fire failure with respect to the applied Load Ratio (LR). An additional 12.5 mm thick plasterboard sheathing on single plasterboard sheathed floors resulted a 30 min improvement in structural and insulation FRLs. In addition, the modular floor systems demonstrated enhanced structural and insulation Fire Resistance Levels (FRLs) against the corresponding conventional LSF floor designs due to double LSF skin build-up. The incorporation of rockwool insulation and the increase in the insulation volume implied increased structural and fire performances. However, insulation material in the modular designs was more effective. The fire-rated conventional and modular LSF floor systems are expected to be practised in the construction industry to achieve required fire resistances with optimum material usage

Evaluation of inter-modular connection behaviour under lateral loads: An experimental and numerical study

This study focuses on a comprehensive investigation of the inter-modular connection shear behaviour under lateral load using theoretical, experimental, and numerical analyses. Initially, three design configurations of proposed inter-modular connection with varying bolt sizes and hole tolerances were tested in shear, and their load-deformation behaviours were studied. Finite element models were then developed in ANSYS and validated against the test results obtained from the experiments. The connections were identified as slip critical connections for serviceability design, as they tend to fail in slippage even at a very small lateral load. Further, evaluation of combined tension and shear effects on the connections confirmed that the failures were due to the combined effect not purely by shear, and therefore connections of this type should consider this as the most critical design check. Based on findings, this paper then describes a methodology for estimating the overall stiffness of inter-modular connections, such that those stiffness values can be employed in modelling the inter-modular connections as a link or spring type elements in the global model of modular buildings. This paper also presents recommendations and suggestions for future enhancement of inter-modular connection designs highlighting the shear slip behaviour and onsite installation constraints

Sustainable Performance of a Modular Building System Made of Built-Up Cold-Formed Steel Beams

Modular Building Systems (MBS) offer numerous benefits in terms of productivity, sustainability and safety. Therefore, MBSs are considered as a viable option to sort out the housing crisis in Britain as well as to drive Britain towards sustainable construction. Development in materials, manufacturing techniques, connection types and structural designs with respect to offsite construction is essential to achieve sustainable goals. Recent advancements in steel manufacturing, including Cold-Formed Steel (CFS), have showed potential benefits in structural performance compared to concrete and timber. Meanwhile, research was conducted to enhance the structural capacities of CFS sections by introducing different cross-sections, composite sections and techniques including optimization. Built-up sections were developed by connecting more than one channel section, and various research studies were conducted to assess their structural performances. However, sustainable performance of built-up sections in modular constructions is still unknown. Hence, this paper intends to develop an MBS using built-up sections for better sustainable performance. Literature review was carried out on the sustainability benefits of MBSs in terms of economic, environmental and social aspects. In addition to that, numerical analysis was performed to investigate the flexural capacity of built-up sections with different screw arrangements to address the sustainable aspects of modular construction by introducing novel sections. The numerical description, results and validations are also stated. Numerical results revealed that flexural capacities of built-up sections are improved up to 156 than those of single sections. Finally, the utilization of built-up sections in modular construction with sustainability enhancement is addressed and illustrated in a conceptual diagram

Numerical Study of Fire and Energy Performance of Innovative Light-Weight 3D Printed Concrete Wall Configurations in Modular Building System

3D Printed Concrete (3DPC) technology is currently evolving with high demand amongst researches and the integration of modular building system (MBS) with this technology would provide a sustainable solution to modern construction challenges. The use of lightweight concrete in such innovative construction methods offers lightweight structures with better heat and sound insulation compared to normal weight concrete. It is worth noting that fire and energy performance has become central to building design. However, there are limited research studies on the combined thermal energy and fire performance of 3DPC walls. Therefore, this study investigates fire performance of 20 numbers of varying 3DPC wall configurations using validated finite element models under standard fire conditions. The fire performance analysis demonstrated that 3DPC non-load bearing cavity walls have substantial resistance under standard fire load and its performance can be further improved with Rockwool insulation. There is significant improvement in terms of fire performance when the thickness of the walls increases in a parallel row manner. Previous thermal energy investigation also showed a lower U-value for increased thickness of similar 3DPC walls. This research concludes with a proposal of using 3DPC wall with Rockwool insulation for amplified combined thermal energy and fire performance to be used in MBS

Energy Performance of 3D-Printed Concrete Walls: A Numerical Study

Three-dimensional-printed concrete (3DPC), which is also termed as digital fabrication of concrete, offers potential development towards a sustainable built environment. This novel technique clearly reveals its development towards construction application with various global achievements, including structures such as bridges, houses, office buildings, and emergency shelters. However, despite the enormous efforts of academia and industry in the recent past, the application of the 3DPC method is still challenging, as existing knowledge about its performance is limited. The construction industry and building sectors have a significant share of the total energy consumed globally, and building thermal efficiency has become one of the main driving forces within the industry. Hence, it is important to study the thermal energy performance of the structures developed using the innovative 3DPC technique. Thermal characterisation of walls is fundamental for the assessment of the energy performance, and thermal insulation plays an important role in performance enhancements. Therefore, in this study, different wall configurations were examined, and the conclusions were drawn based on their relative energy performance. The thermal performance of 32 different 3DPC wall configurations with and without cavity insulation were traced using validated finite element models by measuring the thermal transmittance value (U-value). Our study found that the considered 3DPC cavity walls had a low energy performance, as the U-values did not satisfy the standard regulations. Thus, their performance was improved with cavity insulation. The simulation resulted in a minimum thermal transmittance value of 0.34 W/m2.K. Additionally, a suitable equation was proposed to find the U-values of 100 mm-thick cavity wall panels with different configurations. Furthermore, this study highlights the importance of analytical and experimental solutions as an outline for further research

Integration of origami and deployable concept in volumetric modular units

Modular building systems (MBS) and Origami are two emerging methods used in current construction practice. Origami is directly associated with the principles of the ancient Japanese art of paper folding, characterised by high morphological possibilities and ultimately creates foldable structures with tuneable mechanical properties. However, there is a lack of knowledge on the structural behaviour of origami for architectural engineering applications. MBS is a volumetric prefabricated construction technique enhancing productivity in construction. In this paper, a modular unit is designed which employs origami techniques. The roof and floor panels of the modular units formed with steel joists were substituted with origami sandwich panels, while corner posts were substituted with origami columns. The origami-like foldable system demonstrated superior efficiency in constructability, being highly compact during transportation and requiring few operations for the in-situ installation. The structural performances of the developed and foldable modular units were assessed through finite element analysis. It was found that, without increasing the self-weight of the system, the design of origami-like modular units can be tuned for high structural performances and various structural sizes, which can impact the usability of space and the aesthetics of architecture. While this is a preliminary study and physical testing is needed, the positive results open the possibility of exploring highly deployable modular structures of novel shapes that can be employed during post-disaster and emergencies (Covid-19)