The main purpose of this study is to investigate the advantages of digital fabrication pertaining to construction project management, in particular, in terms of different project management factors, using case studies of irregular-shaped buildings in which digital fabrication has versatile applications. This study collected secondary data corresponding to 27 construction projects of irregular-shaped buildings that implemented digital fabrication. Success criteria were developed based on the Project Management Body of Knowledge (PMBOK) to assess the benefits of implementing digital fabrication for management of the considered construction projects of irregular-shaped buildings. Content analysis was performed to investigate the degree of satisfaction for the success criteria of each project. With this approach, it is possible to see which success criterion appears more times as a positive factor and which ones appear as challenges or problems. Among the positive benefits of digital fabrication on construction project management, quality increase and control appeared in the highest number of projects (17 out of 27 projects) at the highest frequency (26 instances). However, among the negative benefits that were mentioned as challenging or causing difficulties of digital fabrication on construction project management, cost reduction and control appeared in the highest number of projects (14 out of 27 projects) at the highest frequency (21 instances). But it does not mean that the use of digital fabrication was overall negative.
The construction industry is responsible for up to 40% of energy consumption and greenhouse gas emission worldwide [
Despite this, interest in irregular-shaped buildings with considerably complicated structures compared to typical buildings is continuously growing [
It is common to introduce digital fabrication with new materials and manufacturing methods in such irregular-shaped buildings to construct the complicated structures [
The number of studies analyzing the effects of digital fabrication on sustainability is gradually increasing [
The manufacturing paradigm started from a very slow process of manual crafting. Mass production became possible through the industrial revolution in the early 20th century, and the manufacturing system has greatly evolved economically through endless technology development. Lean manufacturing allowed the mass production of standardized products with high quality [
In supporting this trend, additive manufacturing (AM) processes such as rapid prototyping and stereolithography play an important role in reducing the time and cost of development required for assessing designs using prototypes [
Such changes in the production paradigm in the construction industry can be seen through the gradual increase in the number of large-scale irregular-shaped buildings with very complex structures. Irregular-shaped buildings face limitations, in which conventional construction materials and production methods cannot be applied effectively owing to the structural constraints. Moreover, construction projects are fundamentally involved with one-off teams based on a disjointed production system. Because the product size is large compared to that in the manufacturing industry, customization in advance is difficult. Consequently, digital fabrication is gradually being introduced to overcome the fundamental problems of a conventional production system. However, studies that analyze the effects of digital fabrication on actual construction projects are rare. In particular, a performance indicator for construction project management, which can be used by construction firms trying out the new manufacturing paradigm of digital fabrication, is not yet available. Therefore, this study aims at suggesting key performance indicators (KPIs) for assessing the benefits of digital fabrication for construction projects and verifying them through case studies.
Recent studies have emphasized the benefits that AM brings regarding sustainability [
A new manufacturing method that clearly distinguishes itself from conventional production methods in the construction industry is digital fabrication, which is based on various digital technologies [
However, questions still prevail concerning the positive benefits for sustainability in the manufacturing sector wherein digital fabrication is applied. Traditionally, the performance of a production system in the manufacturing stage was evaluated by monitoring four main factors: cost, time, quality, and flexibility. However, additional elements that are an integral part of sustainability such as energy and resource efficiency must be considered, as shown in Figure
Manufacturing decision-making attributes in the 1990s and at the present time [
Digital fabrication is a technology that is crucial for the construction industry for constructing irregular-shaped buildings, but it cannot be regarded as the only system that is required for constructing buildings. Currently, real-life projects have a basis in conventional manufacturing and only apply digital fabrication to limited building segments. Lean construction refers to applying the concept and principles of the Toyota Production System (TPS) to construction fields and focuses on waste reduction, increase in customer value, and continuous improvement [
Sustainability is the latest main interest in many industries [
However, studies evaluating the sustainability aspects of particular technologies of AM and DDM are very limited in terms of their findings [
Understanding the potential benefits of digital fabrication through projects is a challenge that must be addressed. By implementing new manufacturing technologies such as digital fabrication, changes occur in the roles of key parties (e.g., clients, architects, contractors, subcontractors, and suppliers) in a construction project, contract relations, and reengineered collaborative processes [
In order to investigate the type of benefits of digital fabrication on construction project management, secondary data for irregular-shaped buildings in which digital fabrication was employed were collected. Empirical studies on tasks related to construction project management often use self-reported data [
Twenty-seven study cases on irregular-shaped buildings that mentioned positive and negative benefits of adapting digital fabrication were selected for further analyses. In order to evaluate the project advantages of digital fabrication in terms of the management of construction projects, case projects were selected considering the characteristics of the project. In other words, we selected a project to investigate the characteristics (e.g., an area of irregular-shaped segments, a number of unit materials, a size of unit material, a production method, and segments with irregular shapes) of digital fabrication. On the other hand, we excluded projects where the project size was small, or digital fabrication was applied only to some sections and did not bring significant benefits to construction projects.
Evaluation criteria were established to analyze data on the types of benefits introduced due to digital fabrication, or if any benefits were introduced at all. This analysis was performed by deriving a “success criteria” that met the goals for time, cost, and quality of construction projects and was related to process management aspects including effective scope management and communications. These success criteria reflected the idea of multidimensional success of construction projects by including not only the projects themselves but also project management [
The success criteria were classified according to the Project Management Body of Knowledge (PMBOK) knowledge areas of the Project Management Institute (PMI) in order to establish the evaluation standards for the positive and negative benefits of digital fabrication for construction projects [
Success criteria based on PMBOK knowledge area.
PMBOK knowledge area | Definition (after PMI, 2013) | Criterion | Positive consideration |
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Integration management | Unification, consolidation, articulation, and integrative actions | Integration | Improvement |
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Scope management | Defining and controlling what is and is not included in the project | Scope | Clarification |
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Time management | Manage the timely completion of the project | Time | Reduction or control |
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Cost management | Planning, estimating, budgeting, financing, funding, managing, and controlling costs | Cost | Reduction or control |
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Quality management | Quality planning, quality assurance, and quality control | Quality | Increase or control |
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Human resource management | Organize, manage, and lead the project team | Organization | Improvement |
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Communication management | Timely and appropriate planning, collection, creation, distribution, storage, retrieval, management, control, monitoring, and the ultimate disposition of project information | Communication | Improvement |
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Risk management | Increase the likelihood and impact of positive events and decrease the likelihood and impact of negative events in the project | Risk | Negative risk reduction |
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Procurement management | Purchase or acquire the products, services, or results needed from outside the project team | Procurement | Help |
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Stakeholder management | Develop appropriate management strategies for effectively engaging stakeholders in project decisions and execution | Stakeholder | Satisfaction |
It is very difficult to objectively evaluate the impact of digital fabrication on construction projects. However, researchers have difficulty in securing the expert pool by applying digital fabrication to the irregular-shaped buildings, and even if they have a pool of experts, interviews and expert interviews are limited. In this regard, Bryde et al. analyzed the project benefits of BIM on construction projects through content analysis of secondary data [
A content analysis process suggested by Harris was carried out to confirm the positive and negative benefits of digital fabrication for construction projects using secondary data for each irregular-shaped building. The unit of analysis adopted was the “phrase,” which may vary from a single word to a whole sentence [
The projects were then organized using the added score for each of them (positive benefits minus negative benefits). This is not an attempt to find which case demonstrates the most beneficial use of digital fabrication but to organize the data in a way that highlights were there are more positive than negative benefits. Hence, the numbers on the score column should not be seen as an indicator of how successful or unsuccessful those case study projects were, but simply how many success criteria were mentioned positively or negatively [
Table
Details of cases.
PJT no. | PJT name (city/country) | Total area (m2) | Irregular-shaped segments (m2) | Irregular-shaped segment material | Number of members | Fabrication method | Interior/exterior | Member size | Work type | Construction Period | Software |
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P1 | GT tower (Seoul/Korea) | 54,583 | 19,000 | AL. BAR glass | 22,000 EA |
CNC machine | Exterior | 1,400/1,450 mm × 4,500/6,000/7,000 mm |
Curtain wall | 12 months |
CATIA |
P2 | Tri bowl (Incheon/Korea) | 2,893 | 3,012 | AL. panel | 2,308 EA | CNC machine | Exterior | 1,600 mm × 800 mm | Exterior finish | 8 months |
CATIA, Rhino |
P3 | DDP (Seoul/Korea) | 83,024 | 33,228 | AL. panel | 45,133 EA | CNC machine and MDSF | Exterior | 1,600 mm × 1,200 mm | Exterior finish | 14 months |
CATIA, Rhino, TEKLA |
P4 | Ecorium (Seocheon/Korea) | 33,091 | 9,628 | Glass | 32,093 EA | CNC machine | Exterior | 540 mm × 540 mm | Steel curtain wall | 24 months |
CATIA |
P5 | Theme Pavilion of Yeosu EXPO (Yeosu/Korea) | 7,414 | GFRP | 98 EA | CNC machine and MDSF | Exterior | Exterior finish | 20 months |
CATIA | ||
P6 | Lotte World tower Podium (Seoul/Korea) | 328,351 | 8,181 | NT panel |
17,934 EA |
CNC machine | Interior | 1000 mm × 200 mm | Interior finish | 10 months |
CATIA |
P7 | The Arc (Daegu/Korea) | 5,963 | 1,991 | ETFE | 336 EA | CNC machine | Exterior | 3,000 mm × 2,500 mm | Steel exterior finish | 5 months |
CATIA |
P8 | KEB HANA Bank (Seoul/Korea) | 16,287 | 3450 | UHPC | 256 EA | CNC machine and mold | Exterior | 2,000 mm × 4,200/4,400/6,200 mm | Exterior finish | 12 months |
CATIA |
P9 | Korea National Maritime Museum (Busan/Korea) | 25,803 | CNC machine | Exterior | Curtain wall | TEKLA | |||||
P10 | BEAT360 (Seoul/Korea) | 1,880 | Al. panel |
7,553 EA; 8,800 EA | CNC machine | Interior/exterior | Interior/exterior finish | ||||
P11 | Denver Art Museum (Denver/USA) | 13,564 | 16,538 | Titanium panel | 9,000 EA | CNC machine | Exterior | 2,100 mm × 800 mm | Exterior finish | 39 months | CATIA, TEKLA |
P12 | Water Cube (Beijing/China) | 90,000 | 52,000 | ETFE | 4,000 EA | CNC machine and pressure | Exterior | Diameter-7,500 mm Circle | Steel exterior finish | 50 months | Rhino, 3D MAX, Microstation |
P13 | Bird’s Nest (Beijing/China) | 260,000 | 38,500 |
ETFE |
884 EA |
CNC machine and pressure | Exterior | Steel exterior finish | 46 months | TEKLA | |
P14 | Basra Sports City (Basra/Iraq) | 65,000 | GFRP | 560 EA | Mold | Exterior | Length: 300,000 mm | Exterior finish | 53 months | CATIA, TEKLA | |
P15 | Louis Vuitton Foundation (Paris/France) | 11,000 | 13,500 |
Concrete |
19,000 EA |
CNC machine and MSV | Exterior | 3,000 mm × 1,500 mm |
Exterior finish | 74 months | CATIA |
P16 | Louisiana State Museum and Sports Hall of fame (Natchitoches/USA) | 28,000 | 1,380 | Cast Stone panel | 1,150 EA | CNC machine | Interior/exterior | 2,000 mm × 500 mm | Interior/exterior finish | Navisworks | |
P17 | Hangzhou Sports Park Stadium (Hangzhou/China) | 400,000 | 15,000 | AL. Panel | 55 EA | CNC machine | Exterior | Height: 12 m–18 m | Exterior finish | 84 months | Grasshopper |
P18 | Perot Museum of Nature and Science (Dallas/USA) | 180,000 | 9,300 | Concrete steel | 700 EA |
CNC machine and mold | Exterior | 9,200 mm × 2,400 mm | Exterior finish | 31 months | REVIT |
P19 | Phoenix Biomedical Campus: Health Sciences Education Building (Phoenix/USA) | 24,898 | 8,910 | Copper panel | 6,000 EA | Press brake-punch-and-die machine | Exterior | 3,300 mm × 300/450/760 mm | Exterior finish | 27 months | REVIT |
P20 | Zlote Tarasy (Warszawa/Poland) | 205,000 | 10,240 | Glass |
4,788 EA |
CNC machine | Exterior | 2.14㎡ per panel | Exterior finish | 52 months | |
P21 | Weltstadthaus (Cologne/Germany) | 14,400 | 4,900 | Glass | 6,800 EA | CNC machine | Exterior | 0.72㎡ per a panel | Exterior finish | 72 months | |
P22 | BMW Welt (Munich/Germany) | 16,500 | 8,000 | Glass | 4,500 EA | CNC machine | Interior/exterior | 2.22㎡ per a module | Interior/exterior finish | 56 months | Nemetschek Allplan |
P23 | Museo Soumaya (Mexico City/Mexico) | 16,000 | Steel | 16,000 EA | CNC machine | Exterior | 630 mm hexagon | Exterior finish | 38 months | CATIA | |
P24 | O-14 tower (Dubai/UAE) | 28,000 | Concrete | CNC machine and mold | Exterior | Exterior finish | 48 months | Rhino, SAP2000 | |||
P25 | Qatar National Museum (Doha/Qatar) | 47,000 | 120,000 | GFRC | 75,000 EA | Mold | Exterior | 400 m × 250 m per disc | Exterior finish | 72 months | CATIA |
P26 | University of technology Sydney (Sydney/Australia) | 16,030 | 5,594 | Customized brick | 320,000 EA | Mold | Exterior | Brick: 76 mm × 110 mm × 230 mm | Exterior finish | 24 months | REVIT |
P27 | Benz Museum (Stuttgart/Germany) | 16,500 | 6,171 |
Glass |
1,800 EA |
Mold | Exterior | Exterior finish | 36 months |
A CNC machine was used to produce AL. panels, AL. bars, wood panels, titanium panels, and molds, and the members were directly manufactured through cutting, welding, and milling. Materials such as concrete panels, UHPC, and customized bricks were produced into members using an irregular-shaped formwork manufactured with a CNC machine. For a unique material such as ETFE, members are produced using pressure. AL. panels were produced using conventional materials with the latest machine multipoint stretching forming (MDSF) machine depending on the design. High-end software such as CATIA, which can minimize the error range in the production, was found to be used frequently for digital fabrication to ensure the quality of the irregular-shaped segments.
Table
Positive and negative benefits of using digital fabrication on selected cases.
Project | Integ. | Scope | Time | Cost | Qual. | Org. | Com. | Risk | Soft. | Mat. | Score | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
+ | − | + | − | + | − | + | − | + | − | + | − | + | − | + | − | + | − | + | − | ||
P1 | −1 | 1 | −1 | 1 | 0 | ||||||||||||||||
P2 | 1 | 1 | 1 | 1 | 4 | ||||||||||||||||
P3 | 1 | −2 | 2 | 1 | 1 | 2 | 5 | ||||||||||||||
P4 | 1 | 1 | |||||||||||||||||||
P5 | 1 | 1 | 1 | 3 | |||||||||||||||||
P6 | 2 | 1 | −2 | 2 | 1 | 1 | −1 | 1 | 1 | 6 | |||||||||||
P7 | 1 | 1 | −2 | 1 | 1 | 2 | 4 | ||||||||||||||
P8 | 2 | 1 | −1 | 2 | 1 | 1 | 6 | ||||||||||||||
P9 | −1 | 1 | 1 | 1 | |||||||||||||||||
P10 | 1 | 1 | |||||||||||||||||||
P11 | 1 | 1 | −2 | 1 | −1 | 2 | 2 | ||||||||||||||
P12 | 2 | −1 | 1 | 1 | 1 | 4 | |||||||||||||||
P13 | 1 | −2 | 2 | 1 | 2 | 4 | |||||||||||||||
P14 | −2 | 2 | 1 | 1 | |||||||||||||||||
P15 | 1 | 2 | 2 | 2 | 7 | ||||||||||||||||
P16 | 1 | 1 | 1 | 1 | 1 | 5 | |||||||||||||||
P17 | −1 | −1 | 1 | −1 | |||||||||||||||||
P18 | 1 | 1 | 1 | 1 | 4 | ||||||||||||||||
P19 | 1 | 1 | |||||||||||||||||||
P20 | −1 | −1 | |||||||||||||||||||
P21 | 1 | −1 | −1 | −1 | |||||||||||||||||
P22 | 1 | −2 | 2 | 2 | 3 | ||||||||||||||||
P23 | 1 | −1 | 1 | 1 | 2 | ||||||||||||||||
P24 | 1 | 1 | −1 | 1 | 2 | ||||||||||||||||
P25 | −2 | 1 | 1 | 1 | 1 | ||||||||||||||||
P26 | 2 | −1 | 1 | 3 | 2 | −1 | 2 | 8 | |||||||||||||
P27 | 2 | 2 | |||||||||||||||||||
Total | 17 | 0 | 4 | 0 | 7 | −6 | 1 | −21 | 26 | 0 | 5 | −1 | 3 | 0 | 7 | −3 | 20 | −1 | 16 | 0 | 74 |
Average | 0.63 | 0.00 | 0.15 | 0.00 | 0.26 | −0.22 | 0.04 | −0.78 | 0.96 | 0.00 | 0.19 | −0.04 | 0.11 | 0.00 | 0.26 | −0.11 | 0.74 | −0.04 | 0.59 | 0.00 | 2.74 |
The focus of evaluation was not on how effectively each case study used digital fabrication but on highlighting the positive benefits over the negative benefits. Therefore, the values in the score column in Table
Each success criterion was defined with the frequency of occurrence for positive and negative benefits (Table
Success criteria ranking of using digital fabrication.
Success criterion | Positive benefit | Negative benefit | ||||
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Total instances | Total number of projects | % of total projects | Total instances | Total number of projects | % of total projects | |
Quality increase or control | 26 | 17 | 62.96 | 0 | 0 | 0.00 |
Software issues | 20 | 16 | 59.26 | 1 | 1 | 3.70 |
Integration improvement | 17 | 13 | 48.15 | 0 | 0 | 0.00 |
Material improvement | 16 | 13 | 48.15 | 0 | 0 | 0.00 |
Negative risk reduction | 7 | 5 | 18.52 | 3 | 3 | 11.11 |
Time reduction or control | 7 | 7 | 25.93 | 6 | 5 | 18.52 |
Organization improvement | 5 | 4 | 14.81 | 1 | 1 | 3.70 |
Scope clarification | 4 | 4 | 14.81 | 0 | 0 | 0.00 |
Communication improvement | 3 | 3 | 11.11 | 0 | 0 | 0.00 |
Cost reduction or control | 1 | 1 | 3.70 | 21 | 14 | 51.85 |
There were a total of 26 instances of positive benefits in terms of quality increase or control from applying digital fabrication in 17 (63%) projects; the negative benefits were not observed. Digital fabrication can evaluate constructability starting from the design stage to allow optimum design, as well as use latest equipment such as a CNC machine, MDSF, and MSV that allow precise production and minimize error down to the millimeter range to achieve the quality required for construction projects. Case study P25 (National Museum of Qatar) included quality standards for irregular-shaped segments in the request for proposal (RFP) [
Positive benefits in terms of software issues from implementing digital fabrication were mentioned in 20 instances in 16 (59%) projects; a negative benefit was observed in one instance owing to the lack of experience in high-end software programming. Digital fabrication executes design, manufacture, and construction based on 3D models. Thus, software was used to generate 3D models in all studied projects. Most projects found positive benefits from using high-end software such as CATIA and TEKLA because it minimized error ranges in the manufacturing of irregular-shaped segments. In addition, a positive benefit of being able to swiftly and continuously provide necessary manufacturing information to the manufacturers by obtaining tens of thousands of 2D manufacturing blueprints from 3D models in a short period of time was observed [
Positive benefits in terms of integration improvement from applying digital fabrication were seen in 17 instances in 13 (48%) projects; negative benefits were not indicated. The integration process of increasing productivity by optimizing different and individually designed members from simultaneously considering design, manufacture, and construction is crucial for irregular-shaped buildings. Decisions on member size and production unit that consider materials and production methods were made by optimizing the design of irregular-shaped buildings. The design optimization results for irregular-shaped segments for case study P8 (KEB Hana Bank, Samsung-dong, Seoul) are shown in Figure
Design optimization for exterior cladding. (a) Original design with 12 types of formwork and (b) optimized design with 8 types of formwork.
Positive benefits in terms of material improvement from applying digital fabrication were seen in 16 instances in 13 (48%) projects; negative benefits were not observed. Unlike conventional regular-shaped buildings constructed with traditional materials, latest materials such as UHPC, ETFE, and GRCP were applied to irregular-shaped buildings with digital fabrication, which allowed various and complex exterior envelopes. The members for irregular-shaped buildings were produced using manufacturing equipment such as a CNC machine, MDSF, MSV, and pressure using 2D manufacturing blueprints obtained through 3D models. This helps overcome the limitations of conventional construction materials. Moreover, AL. panels or copper panels that have been constantly used in the construction industry can be manufactured into three-dimensional panels depending on the design using manufacturing equipment such as press brake punches and dies tools. The irregular-shaped formwork was manufactured at a factory using a CNC machine for exposed concrete or concrete panel materials for complex shapes, and then, members were produced by placing and curing the material. In irregular-shaped buildings, the positive benefits related to quality, software issues, and integration from applying digital fabrication is inevitably associated with new material, new design, and production method.
Positive benefits in terms of negative risk reduction from applying digital fabrication were seen in 7 instances in 5 (19%) projects; negative benefits were seen in 3 instances in 3 (11%) projects. Applying digital fabrication allows reducing risk that can arise during design, manufacture, and construction stages using 3D models to generate simulations and mock-ups. However, since irregular-shaped buildings are not considered as standard construction projects, discrepancies between initial plans and execution are inevitable, which becomes a potential risk. Currently, performance data or analysis data on the case studies of irregular-shaped buildings are not readily available, which makes it difficult to proactively avoid potential risks compared to typical construction projects [
Positive benefits in terms of time reduction or control from applying digital fabrication were seen in 7 instances in 7 (26%) projects; negative benefits were seen in 6 instances in 5 (19%) projects. Applying digital fabrication not only requires managing on-site construction but also additional off-site construction (e.g., fabrication factory). Moreover, managing new manufacturers introduced to the project because of the new manufacturing methods and consequential new supply chains becomes necessary. Such occurrences in the studied projects were either dealt with by going through trial and error in the early stages of a project before slowly learning to manage this as the project progressed or showed benefits that depended on management skills obtained from experience and skills gained throughout the project. When such management skills are put to use, great benefits, incomparable to that from the conventional production method can be achieved in the time reduction or control aspects. If not, a great amount of time may be consumed.
Positive benefits in terms of organization improvement from applying digital fabrication were seen in 5 instances in 4 (15%) projects. Negative benefits were seen in 1 instance in 1 (3%) project. The application of digital fabrication is very similar to the concept of lean construction. New labor, material or resources, and equipment can be allocated in the right location with JIT (just-in-time) and increase productivity. Construction involving digital fabrication requires prefabrication in a factory and transporting to a site before installation takes place. This process is different from that of a conventional construction production method, which may result in negative benefits in terms of improving and integrating processes due to inexperience in digital fabrication.
Positive benefits in terms of scope clarification from applying digital fabrication were seen in 4 instances in 4 (15%) projects; negative benefits were not observed. Digital fabrication requires defining the segments of the building, in which this production method is being applied to beforehand. Furthermore, the scope of work for design, manufacture, and construction firms responsible for digital fabrication and the scope of work and allocated tasks between initial production firms and new suppliers must be clearly defined.
Positive benefits in terms of communication improvement from applying digital fabrication were seen in 3 instances in 3 (11%) projects; negative benefits were not observed. Design, manufacture, and construction processes were established based on 3D models for irregular-shaped segments that required digital fabrication. Moreover, construction project participants carried out communication, collaboration, and arbitration using 3D models, which increased the accuracy of the design. The positive benefits from obtaining tens of thousands 2D manufacturing blueprints from 3D models were already dealt above with software issues, which seemed to have caused the low number of instances of positive benefits for communication improvement. All blueprints produced during a construction project serve as the most primary method of communication. Therefore, the study results cannot solely stand as a premise for digital fabrication with meager positive benefits for communication improvement.
Positive benefits in terms of cost reduction or control from applying digital fabrication were seen in 1 instance in 1 (4%) project; however, negative benefits were expressed in 21 instances in 14 (52%) projects. This was due to the burden of additional costs inevitably encountered when new technology is introduced in a construction project. New labor, software, and equipment are certainly required when digital fabrication is applied. Using the conventional construction method for irregular-shaped buildings can result in simultaneous loss in time, cost, and quality, which are important qualities in construction project management. On the contrary, construction project management that considers positive benefits of using digital fabrication not only allows attaining a certain quality for irregular-shaped segments but also allows reduction in time and cost.
This study collected secondary data from the AIA BIM TAP Awards, the Korean BIM journals, and the Korean BIM award, various publications from conferences, websites of corresponding projects, reports, and data from actual project progress reports from professional construction firms. However, challenges persisted in discovering in-depth data for every project, and it was difficult to compile secondary data owing to discrepancies in the amount and quality of data attainable for each project. Further, while it was relatively easy to obtain data on generally well-known irregular-shaped buildings and projects that had now been completed for years, it was impossible to obtain these data for the latest irregular-shaped buildings. Nonetheless, professional construction firms with direct experience in implementing digital fabrication were sought out to supplement the incomplete data in order to improve the quality of secondary data.
In order to evaluate the benefits of applying digital fabrication for construction projects, the knowledge areas of the PMBOK were used. The success criteria on procurement management and stakeholder management were omitted because they were difficult to evaluate using the collected secondary data. It was difficult to find such terms in the secondary data because digital fabrication was still not universally implemented in the construction industry. Instead, software issues and material improvement were added as criteria to evaluate the benefits of digital fabrication for construction project management.
Content analysis was performed to investigate the degree of satisfaction for the success criteria of each project. With this approach, it is possible to see which success criterion appears more times as a positive factor and which ones appear as challenges or problems. In the previous research, Bryde analyzed the impact of BIM on construction projects through the similar research method, while this study analyzed the impact of digital fabrication on construction projects. BIM supports construction as a virtual model and process, but digital fabrication is directly linked to the design, fabrication, and construction of the irregular-shaped buildings. Therefore, the analyzed results are more reliable. Among the positive benefits of digital fabrication on construction project management, quality increase and control appeared in the highest number of projects (17 out of 27 projects) at the highest frequency (26 instances). However, among the negative benefits that were mentioned as challenging or causing difficulties of digital fabrication on construction project management, cost reduction and control appeared in the highest number of projects (14 out of 27 projects) at the highest frequency (21 instances). But it does not mean that the use of digital fabrication was overall negative.
The purpose of evaluation in this study was not to find the project that used digital fabrication in the most effective way, but to find success criteria that should be considered and managed relatively more when managing projects wherein digital fabrication is applied to irregular-shaped buildings. The average score for 27 projects in the score column in Table
Scores on positive and negative benefits of using digital fabrication.
Among these, interviews with professionals revealed that compared to other projects, projects P15 (Louis Vuitton Foundation, Paris) and P26 (University of Technology, Sydney), each with a score of 7 and 8, were examples that could be referred to as the standard application of digital fabrication or quality achievement for applying digital fabrication in the future.
Production methods employed by the construction industry are not as diverse as the currently employed manufacturing methods. However, investigating various case studies on irregular-shaped buildings showed that applying digital fabrication had significant positive benefits for construction project management. The limitation of this study is that we analyzed the advantages of digital fabrication by using highly generalized PMBOK. Future research will need to develop performance indicators that reflect the characteristics of digital fabrication technology. In particular, quantitative cost factors need to be considered.
The data generated or analyzed during the study are available from the corresponding author by request.
The authors declare that there are no conflicts of interest regarding the publication of this paper.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2018R1A2B6007333).