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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.

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 characterization 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

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.

Lightweight Steel Frames (LSF) in building construction are becoming more popular due to their fast, clean, and flexible constructability. Typical LSF wall panels are made of cold-formed and thin-walled steel lipped channel studs with plasterboard linings. Due to the high thermal conductivity of steel, these LSF components must be well engineered and covered against unintended thermal bridges. Therefore, it is essential to investigate the heat transfer of the LSF wall of different configurations and reduce heat loss through walls by lowering the thermal transmittance, which would ultimately minimise the energy consumption in buildings. The effect of novel thermal insulation material, Vacuum Insulation Panels (VIP), their position on the LSF wall configuration, and Oriented Strand Board (OSB) and plasterboard’s effect on the thermal transmittance of LSF walls were investigated through numerical analysis. A total of 56 wall configurations and 112 finite element models were analysed and compared with the minimum U-value requirements of UK building regulations. Numerical model results exhibited that using plasterboards instead of OSB has no considerable effect on the U-value of the LSF walls. However, 77% (4 times) of U-value reduction was exhibited by introducing the 20 mm VIP. Moreover, the position of the VIP to the U-value of LSF was negligible. Based on the results, optimum LSF wall configurations were proposed by highlighting the construction methods. Additionally, this study, through literature, seeks to identify other areas in which additional research can be conducted to achieve the desired thermal efficiency of buildings using LSF wall systems.

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Purpose Fire safety of a building is becoming a prominent consideration due to the recent fire accidents and the consequences in terms of loss of life and property damage. ISO 834 standard fire test regulation and simulation cannot be applied to assess the fire performance of 3D printed concrete (3DPC) walls as the real fire time-temperature curves could be more severe, compared to standard fire curve, in terms of the maximum temperature and the time to reach that maximum temperature. Therefore, this paper aims to describe an investigation on the fire performance of 3DPC composite wall panels subjected to different fire scenarios. Design/methodology/approach The fire performance of 3DPC wall was traced through developing an appropriate heat transfer numerical model. The validity of the developed numerical model was confirmed by comparing the time-temperature profiles with available fire test results of 3DPC walls. A detailed parametric study of 140 numerical models were, subsequently, conducted covering different 3DPC wall configurations (i.e. solid, cavity and rockwool infilled cavity), five varying densities and consideration of four fire curves (i.e. standard, hydrocarbon fire, rapid and prolong). Findings 3DPC walls and Rockwool infilled cavity walls showed superior fire performance. Furthermore, the study indicates that the thermal responses of 3DPC walls exposed to rapid-fire is crucial compared to other fire scenarios. Research limitations/implications To investigate the thermal behaviour, ABAQUS allows performing uncoupled and coupled thermal analysis. Coupled analysis is typically used to investigate combined mechanical-thermal behaviour. Since, considered 3DPC wall configurations are non-load bearing, uncouple heat transfer analysis was performed. Time-temperature variations can be obtained to study the thermal response of 3DPC walls. Originality/value At present, there is limited study to analyse the behaviour of 3DPC composite wall panels in real fire scenarios. Hence, this paper presents an investigation on the fire performance of 3DPC composite wall panels subjected to different fire scenarios. This research is the first attempt to extensively study the fire performance of non-load bearing 3DPC walls.