Fire performance of innovative 3D printed concrete composite wall panels – A Numerical Study

The 3-Dimensional (3D) printing technology in the construction sector has seen an accelerating growth owing to its potential advantages. For this layer-based construction, a detailed investigation on fire performance is necessary. However, there are limited research studies for 3D Printed Concrete (3DPC) walls exposed to fire. Therefore, this paper investigates the fire performance of different types of 3D printed concrete walls using validated Finite Element Models (FEMs). Validated heat transfer FEMs were extended to investigate the fire performance of a range of 3DPC wall configurations (solid, cavity, and composite) under standard fire conditions. The results show that 3DPC non-load bearing cavity walls underperform when subjected to standard fire compared to solid 3DPC walls. The novel composite 3DPC walls with the use of Rockwool as cavity insulation offers superior fire resistance

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

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

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

Thermal Performance of LSF Wall Systems with Vacuum Insulation Panels

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

Fire performance analyses of modular wall panel designs with loadbearing SHS columns

Modular Building Systems (MBS) are still in the phase of developing its popularity in the industry, with emerging novel designs. Initially, MBS walls and floors had been highly influenced by the Light-gauge Steel Frame (LSF) designs made of Cold-Formed (CF) steel studs, either as loadbearing or non-loadbearing types which have been extensively researched all over the world. However, recently the MBS practice in the industry tends to incorporate Square Hollow Section (SHS) steel columns for their improved structural performance and convenience at the manufacturing stage despite of the limited research knowledge in terms of the Fire Resistance Level (FRL). Moreover, catastrophic failures and fatal accidents are common with steel-based structures in case of a fire. Hence, the fire performance of loadbearing modular walls with SHS columns have been identified as a critical research gap. Firstly, Finite Element Models (FEM) were developed for the original modular wall, a Light-weight Timber Frame (LTF) wall and some LSF walls. The FEM analyses results very well matched with the full-scale experimental results so that the FEM techniques were confidently used to study the effect of variables chosen based on material availability options, cost reduction and construction practice. Structural and Insulation FRLs have been evaluated for the chosen parametric walls, where the produced graphs of structural and insulation FRLs can be referred to determine the adequate thickness of column sheathing and the Insulation Ratio (IR) respectively. The choice of non-loadbearing stud type can be evaluated against other limitations related to energy, cost and construction practice

Effect of design variation in behaviour and performance of Endplate-Type intermodular connection

Intermodular connections play an important role in the constructability and performance of modular building structures. The wind-generated vertical uplift force and the lateral load on modular structures raise concerns about the tensile and shear capacity of the intermodular connection joints. This study focuses on investigating the change in load response behaviour, working mechanism and performance of endplate-type intermodular connections with varying design parameters. Initially, the paper presents the design criteria of endplate-type intermodular connections and their behaviour, with a detailed theoretical approach, to identify their performance and capacity under tensile and shear loads. Then, the capacity of the proposed connections in this study was evaluated based on both the presented theoretical design and numerical approaches. The design inspiration for the proposed connection was taken from literature using which the finite element models for 4 specimens were developed and validated. The validated connection models were then used to conduct parametric studies for 11 proposed models, focused on changes in base endplate thickness (8 mm, 10 mm and 12 mm) and steel grade (s275 and s355), bolt hole diameter (22 mm, 26 mm and 30 mm) and tolerance, bolt grade (8.8, 10.9 and 12.9) and applied preload (0, 50 kN, 90 kN and 110 kN) with and without additional plate over oversized bolt holes. The results obtained from both shear and tensile performance analysis indicate that the change in proposed design parameters has a greater impact on shear over tensile behaviour and capacity. Further, the conducted parametric studies helped in identifying the optimum design parameter combinations for enhanced connection performance which are also cost-effective and ideal for an onsite installation. Finally, the paper suggests recommendations for future research and essential advancement in the endplate-type intermodular connection design in enhancing performance and presents the practical limitations and challenges in using such techniques

Fire resistance of 3D printed concrete composite wall panels exposed to various fire scenarios

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