The fourth revolution in the construction industry, known as Construction Industry 4.0, promotes more innovative, digitalised, integrated and automated construction processes ^[1][7]. There are six main steps to creating a framework for successfully implementing Construction Industry 4.0, as shown in Figure 1.

The first step is mapping. Mapping aims to outline the digital maturity within the construction industry and sets targets for the future direction. As a result, mapping focuses on digitalisation in construction, including building information modelling (BIM) BIM-based project management ^[2][3][8,9] automation ^[4][10], supply chain ^[5][11] and document management ^[6][12]. The second step is pilot projects. Pilot projects are designed as proof of concept and allow digital leaders to apply innovation and digitalisation in the construction industry. Therefore, this step aims to collaborate with digital leaders to validate the end-to-end concept of Construction Industry 4.0 ^[7][13]. The third step is building capability. This step aims to develop pilot projects by incorporating robot usage ^[8][14] and digital fabrication ^[4][10], such as 3D printing. This highlights additive manufacturing as a significant contributor to Construction Industry 4.0. The fourth step is data analytics. This step integrates managerial and stakeholder objectives and BIM data using machine learning and artificial intelligence ^[9][15]. The fifth step is the transformation of digital enterprises within the industry. This focuses on emerging technologies ^[10][16] and removing obstacles ^[11][17]. The sixth step is a sustainable system that promotes the importance of having a sustainable system that addresses supply chain continuity challenges. Therefore, this step focuses on setting new policies and regulations ^[9][15] and the use of sustainable technologies, including AM.

The first 3D printer was developed by Chuck Hull in 1984, as an AM technology with limited application. Due to technological advancements, 3D printing has become a popular technology with various applications in multiple industries, including construction ^[12][18].

The increased popularity of 3D printing in the construction industry led to the serial production of 3D printers in 2015. Moreover, the emergence of building information modelling (BIM) enhanced the capability of AM ^[13][19] by creating a holistic process of creating and managing information for a built asset ^[14][20]. This makes AM and BIM an integral part of Construction Industry 4.0.

The 3D printing technology relies on the fundamental principle of reducing the 3D volume into a sequence of 2D layers ^[15][21]. This process uses a BIM software, such as Autodesk Revit 2022 ^[16][22], to apply this principle using various additive technologies.

Stereolithography (SAL) is a standard additive technology to produce 2D layers, using a photochemical process. This process uses a high-powered laser that triggers a reaction in monomers and oligomers in resin. This reaction forms a polymer and hardens the resin to create 3D objects ^[17][23]. Selective laser sintering (SLS) is another additive technique that uses a powerful laser in joints, defined by the BIM software and hardens the powdered materials into solid 3D objects ^[18][1]. Fused filament fabrication (FFF) uses the extrusion technique to deposit building materials through a heated nozzle by establishing the object’s outline and filling the enclosed area ^[19][24]. One of the benefits of FFF is the flexibility of building materials. FFF can use a wide range of filaments, including wax, plastic, ceramic, and concrete ^[15][21]. Moreover, the nozzle size can be adjusted based on the objects and filaments ^[20][25]. Therefore, FFF has become a popular additive technique in construction and is widely used in construction 3D printers.

Three of the most used printing materials in construction are cementitious, polymer and metallic materials ^[19][24]. These materials are deposited into layers using the FFF technique. One of the printing material limitations is incompatibility with concrete reinforcement, which can be addressed using a fibre-reinforced concrete composite (FRC) ^[21][26]. FRC can improve the flexural strength of concrete to a value similar to reinforced concrete members ^[22][27].

The benefits of 3D printing can be categorised into two groups: constructability and sustainability ^[15][21].

AM can lead to faster construction than traditional methods ^[16][22]. For example, using 3D printing to create a wall reduced the construction time from 100 to 65 h ^[23][28]. Moreover, faster construction results in faster commissioning, leading to mass production.

Using 3D printing can dramatically reduce the cost throughout the project. Due to storing capability of 3D printing, the cost of storage and transporting materials can be reduced ^[24][2]. Moreover, since the 3D printer only requires one operator, labour costs can also be reduced. For example, the application of 3D printing resulted in a 60% lower labour cost in constructing the Dubai Future Foundation (DFF) ^[25][29].

Flexible design and freedom in construction have made 3D printing a promising technology among engineers and architects. As opposed to the traditional and expensive construction methods, AM can build the structure of various complex geometries ^[26][30]. This promotes freedom in structural design and can lead to innovative designs by architects ^[27][31].

The supply chain is considered a time-consuming, yet critical, part of every construction project that can be shortened using 3D printing. By printing on demand using raw materials, the lead time of materials will reduce dramatically ^[28][32]. In addition, due to automation, AM reduces human intervention, leading to a shorter and more efficient supply chain system ^[29][33].

One of the primary benefits of 3D printing in construction is its contribution to the Sustainable Development Goals (SDGs), as summarised in Table 1.

The adaption of 3D printing could contribute to no poverty (SDG 1), as it significantly reduces construction and labour costs leading to more affordable housing ^[30][34]. Moreover, unlike traditional construction methods, 3D printing is innovative, automated and sustainable ^[24][2], aligning with SDG 9 and SDG 11. Compared to the reductive manufacturing, additive manufacturing uses a closed-loop process, leading to significantly less waste during production, contributing to SDG 12 and SDG 13 ^[30][34].

AM in construction is considered sustainable and eco-friendly ^[16][22]. Moreover, construction 3D printers can use recyclable filaments, such as concrete mixed with recyclable materials. In addition, 3D printing builds by establishing the object’s outline and filling the enclosed area ^[19][24]. Therefore, construction waste is estimated to reduce by 30–60% ^[31][35].

Another sustainable benefit of 3D printing in construction is reduced framework. The frameworks used for concrete are mainly made from wood, resulting in using trees. Since 3D printing is on-site, the need for wooden form and environmental impact reduces significantly ^[28][32].

Three-dimensional printing can also result in a safer working site. Safety is a significant challenge in the construction industry. Since 3D printing is automated and requires minimal human intervention, it could reduce the work hazard and promote safer construction sites ^[28][32].

As a new technology, 3D printing has several drawbacks. These drawbacks can be grouped into five categories: challenges with materials, 3D printers, architecture, construction management and regulations ^[15][21].

Printability, buildability and open time are some of the challenges with the material. Printability is the process of pumping and printing materials, such as concrete ^[32][36].

For the sake of enhancing printability, materials should have the right consistency for the nozzle, limiting the use of reinforced bars, unlike traditional construction materials ^[21][26]. Obtaining this condition, materials should be workable and include the right mixture of content ^[33][37]. Moreover, deposited printing materials should be able to resist deformation subjected to different loadings. This phenomenon is known as buildability ^[32][36]. Consistency between buildability and printability is one of the significant factors during construction.

Some of the 3D printer-related challenges are scalability and directional dependency. Traditionally, 3D printers were able to create objects strictly smaller than the chamber volume of the 3D printer. This situation can be challenging for large-scale construction projects ^[34][38]. In addition, additive manufacturing uses a filament which could impact material load-bearing capacity and strength properties ^[35][39]. This setting is due to the directional dependency used in layered manufacturing.

Another challenge of 3D printing is related to architecture and structural integrity. Most BIM software excludes building services such as electrical and plumbing. Therefore, an additional reductive effort is needed to account for services. This can affect the structural integrity of the building and could lead to structural defects ^[26][30].

Using 3D printing can also challenge construction management. Since additive manufacturing is a new technology in construction, it could be challenging to provide accurate cost estimation and scheduling ^[15][21]. Moreover, 3D printing requires a complex installation and controlled environment, making it a challenging technology.

One of the substantial challenges of 3D printing is the need for design codes and regulations. A clear legitimate framework is required to affect the adaption of 3D printing in construction. Moreover, developing reliable numerical design methods can lead to overcoming liability issues for construction companies ^[31][35].

The effort to use 3D printing as a sustainable construction method is growing. According to the Construction Industry 4.0 framework, the successful implementation of 3D printing requires global awareness and regulations ^[9][15]. Given the benefits of AM and its alignment with SDGs, it can be expected to see more countries setting regulations across the use of 3D printing in construction.

In addition, due to advancements in technology, the adaption of AM could lead to more innovative construction methods. An example of this would be the use of cable frames to address the scalability challenges and introduce new alternative materials instead of steel-reinforced concrete, such as fibre-reinforced concrete composites (FRCs) ^[21][26].

The Finite Element Method (FEM) is a standard method for numerically analysing structures. Since FEM uses the discretisation of the structure into small elements, it is deemed an accurate and reliable method for structural analysis ^[36][6].

FEM can also be used to assess the accuracy of 3D-printed buildings. This helps analyse the performance of a proposed 3D-printed structure prior to its construction. In one study, it was observed that FEM could give an accurate quantitative estimation of unconfined uniaxial compression tests (UUCT) and direct shear tests (DST) of a 3D-printed building ^[37][40]. Since the numerical and experimental results were consistent, FEM could be a viable method for analysing 3D-printed structures.

FEM is a reliable numerical method of analysis due to discretisation. Using discretisation, the structure is subdivided into smaller elements connected with nodes. Each element is called a finite element, which has the same behaviour as the whole structure and is analysed using a discrete system of equations. It is then integrated through the whole system to approximate its behaviour ^[38][41].

One of the constraints of FEM is associated with the meshing process. Meshing is the process of discretising the structure into smaller defined elements. This process controls the accuracy of the analysis and is based on engineering judgement. Generally, finer meshing results in more accurate results; however, it also increases the computational time and cost ^[38][41]. Reasonable effort was made in preparation for this rpapesearchr to minimise the inaccuracy caused by meshing.