4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication
Abstract
O objetivo desta investigação é encorajar uma maior produtividade na indústria AEC, representando e promovendo uma análise comparativa de abordagens de construção muito diferentes: construção tradicional versus pré-fabricação total rumo à industrialização. A construção de um edifício cujo projeto foi realizado em BIM, totalmente orientado para a industrialização, apresenta-se como uma oportunidade para realizar uma análise 4D abrangente que compara soluções tradicionais e industrializadas (abordagens de construção no local e fora do local). A investigação concentra-se na análise deste caco de estudo prático, baseado em BIM e está centrada na avaliação dos impactos no planeamento das várias fases de construção, e na exposição dos impactos detalhados da solução industrializada quando comparada com uma solução tradicional. A construção do edifício em estudo começou em 2022. A sustentabilidade e a circularidade estão implícitas. O estudo de caso sugerido é um hotel em Guimarães que ultimamente tem recebido a atenção dos meios de comunicação devido à sua inovadora metodologia de pré-fabricação. Os módulos pré-fabricados são utilizados para a construção do edifício. Esta abordagem será avaliada e comparada com as alternativas tradicionais existentes. Considerando isto, foi desenvolvido um quadro teórico propondo um quadro baseado numa análise comparativa BIM 4D para ambas as abordagens de construção: construção tradicional e pré-fabricação total. Quantificando as vantagens da utilização da pré-fabricação em relação à construção convencional, utilizando a grande extensão da tecnologia de modelação de informação de construção (BIM), e os benefícios potenciais da utilização de um motor de programação inteligente para a análise comparativa 4D.
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Universidade do Minho Escola de Engenharia Abdelrahman Zarea 4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication September 2022 UMinho | 2022 Abdelrahman Zarea 4D comparitive analysis of construction approaches twords industrialization: traditional vers total prefabrication Co-funded by the Erasmus+ Programme of the European Union The European Master in Building Information Modelling is a joint initiative of:
Universidade do Minho Escola de Engenharia Abdelrahman Zarea 4D comparative analysis of construction approaches towards industrialization: t raditional versus total prefabrication Master Dissertation European Master in Building Information Modelling Work conducted under supervision of: Isabel Valente Miguel Pires (Tutor in Company) September, 2022
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 2 AUTHORSHIP RIGHTS AND CONDITIONS OF USE OF THE WORK BY THIRD PARTIES This is an academic work that can be used by third parties, as long as internationally accepted rules and good practices are respected, particularly in what concerts to author rights and related matters. Therefore, the present work may be used according to the terms of the license shown below. If the user needs permission to make use if this work in conditions that are not part of the licensing mentioned below, he/she should contact the author through the RepositóriUM platform of the University of Minho. License granted to the users of this work Attribution CC BY https://creativecommons.org/licenses/by/4.0/
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 3 ACKNOWLEDGEMENTS First of all, I would like to start by expressing how happy I am to have gained real-world experience in Building Information Modelling. I'm grateful that the BIM A+ consortium allowed me to enrol in that European master`s program at BIM. Thank you, Professor Isabel Valente, for her kind help, good guidance, and the support that she gave to me to develop this work. It wouldn't be as satisfying without her instructions as it is right now. Thanks to the CASAIS group, especially Engineer Miguel Pires, for proposing this argument and providing a case study that helped me a lot to develop my work to the aim of the research. In addition, I should also thank Isabel Godinho for her significant assistance with the suggested case study Thanks to my beloved parents, their existence, and their daily support. I am fortunate to have my sisters and brother in my life, especially for the way you inspire me to keep working.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 4 STATEMENT OF INTEGRITY I hereby declare having conducted this academic work with integrity. I confirm that I have not used plagiarism or any form of undue use of information or falsification of results along the process leading to its elaboration. I further declare that I have fully acknowledged the Code of Ethical Conduct of the University of Minho.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 5 RESUMO O objetivo desta investigação é encorajar uma maior produtividade na indústria AEC, representando e promovendo uma análise comparativa de abordagens de construção muito diferentes: construção tradicional versus pré-fabricação total rumo à industrialização. A construção de um edifício cujo projeto foi realizado em BIM, totalmente orientado para a industrialização, apresenta-se como uma oportunidade para realizar uma análise 4D abrangente que compara soluções tradicionais e industrializadas (abordagens de construção no local e fora do local). A investigação concentra-se na análise deste caco de estudo prático, baseado em BIM e está centrada na avaliação dos impactos no planeamento das várias fases de construção, e na exposição dos impactos detalhados da solução industrializada quando comparada com uma solução tradicional. A construção do edifício em estudo começou em 2022. A sustentabilidade e a circularidade estão implícitas. O estudo de caso sugerido é um hotel em Guimarães que ultimamente tem recebido a atenção dos meios de comunicação devido à sua inovadora metodologia de pré-fabricação. Os módulos pré-fabricados são utilizados para a construção do edifício. Esta abordagem será avaliada e comparada com as alternativas tradicionais existentes. Considerando isto, foi desenvolvido um quadro teórico propondo um quadro baseado numa análise comparativa BIM 4D para ambas as abordagens de construção: construção tradicional e pré-fabricação total. Quantificando as vantagens da utilização da pré-fabricação em relação à construção convencional, utilizando a grande extensão da tecnologia de modelação de informação de construção (BIM), e os benefícios potenciais da utilização de um motor de programação inteligente para a análise comparativa 4D. Palavras chave: (Análise 4D; BIM; programação inteligente; estudo de caso prático; pré-fabricação; Construção fora do local)
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 6 ABSTRACT The purpose of this research is to encourage higher productivity in the AEC industry by promoting a comparative analysis between very different construction approaches: traditional construction versus total prefabrication towards industrialization. The construction of a building whose project was carried out in BIM, totally oriented towards industrialization, presents itself as an opportunity for a comprehensive 4D analysis that compares traditional and industrialized solutions (onsite and offsite construction approaches) in terms of time and needed resources. The research concentrates on proposing a BIM-based framework to quantify the 4D analysis of this practical case study. It is focused on assessing the impacts on the planning of the execution stage, both off-site and on-site, and on exposing the detailed impacts of the industrialized solution when compared to a traditional one. The effective construction of the building in the study began in 2022. Sustainability and circularity are implied. The suggested case study is a hotel in Guimarães that has lately received media attention due to its innovative pre-fabrication methodology. Prefabricated modules are used to construct the building. This approach will be evaluated and compared to existing traditional alternatives. Considering this, a theoretical framework was developed by proposing a framework based on a 4D BIM comparative analysis for both approaches of construction: traditional construction and total prefabrication. Quantifying the advantages of using prefabrication over conventional construction, By using the large extent of building information modelling (BIM) technology, and the potential benefits of using an intelligent schedule engine for the 4D comparative analysis. Keywords: (4D Analysis; BIM; intelligent scheduling; practical Case study; prefabrication; Offsite construction)
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 7 TABLE OF CONTENTS 1. INTRODUCTION ............................................................................................................. 15 1.1. SCOPE AND MOTIVATION ...............................................................................................16 1.2. RESEARCH OBJECTIVES ..................................................................................................16 1.3. STRUCTURE OF THE RESEARCH ....................................................................................16 2. LITERATURE REVIEW .................................................................................................. 17 2.1. THE DEFINITION OF OFFSITE CONSTRUCTION ..........................................................18 2.2. TYPES OF OFFSITE CONSTRUCTION .............................................................................19 2.2.1. Volumetric Construction ................................................................................................19 2.2.2. Panelized Construction. ..................................................................................................21 2.2.3. Hybrid Construction .......................................................................................................21 2.2.4. Sub-Assemblies and Component Systems. ....................................................................22 2.3. THE KEY BENEFITS OF OFFSITE CONSTRUCTION .....................................................22 2.4. THE KEY CHALLENGES TO OFFSITE CONSTRUCTION .............................................26 2.5. THE OFFSITE PROCESS .....................................................................................................28 2.6. THE EFFECT OF THE OFFSITE CONSTRUCTION ON SCHEDULE .............................30 2.7. BIM IN OFFSITE CONSTRUCTION ...................................................................................32 2.7.1. BIM ................................................................................................................................32 2.7.2. BIM project life cycle ....................................................................................................33 2.7.3. Level of information need ..............................................................................................35 2.7.4. BIM 4D schedule ...........................................................................................................36 3. FRAMEWORK ................................................................................................................. 39 3.1. INTRODUCTION ..................................................................................................................39 3.2. MACRO WORKFLOW CONCEPT ......................................................................................40 3.3. ELEMENTS USED IN TRADITIONAL CONSTRUCTION ...............................................41 3.3.1. Traditional construction elements ..................................................................................41 3.3.2. The way of construction and needed resources ..............................................................42 3.3.4. Advantages of using reinforced concrete .......................................................................44 3.3.5. Disadvantages of using reinforcement concrete .............................................................44 3.4. CREE SYSTEM USED IN PREFABRICATION .................................................................44 3.4.1. The way of construction in CREE system ......................................................................47 3.4.3. Advantages of using CREE system ................................................................................48 3.4.4. Disadvantages of using CREE system ...........................................................................48 3.5. PROPOSED 4D FRAMEWORK ...........................................................................................49 3.5.1. 3D BIM model ...............................................................................................................50 3.5.1.1. Create the 3D model ...................................................................................................50 3.5.1.2. Review the 3D model .................................................................................................50 3.5.1.3. 3D modelling for 4D analysis ....................................................................................50 3.5.2. Model checking and IFC ................................................................................................51 3.5.3. 4D BIM model ...............................................................................................................52 3.5.3.1. Custom breakdown structure ......................................................................................52
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 8 3.5.3.2. Custom selection sets (CSS) ...................................................................................... 53 3.5.3.3. Intelligent scheduling ................................................................................................ 54 3.5.3.4. Assigning resources ................................................................................................... 58 3.5.4. 4D comparative analysis ................................................................................................ 58 4. CASE STUDY .................................................................................................................. 59 4.1. CASE STUDY OVERVIEW ................................................................................................ 59 4.2. THE SCOPE OF WORK ....................................................................................................... 60 4.3. TRADITIONAL WAY CASE STUDY ................................................................................ 61 4.3.1. 3D BIM MODEL........................................................................................................... 61 4.3.2. Model checking and IFC ............................................................................................... 62 4.3.3. 4D BIM model ............................................................................................................... 63 4.3.3.1. Custom Breakdown Structure CBS ........................................................................... 65 4.3.3.2. CSS, QTO, and Cost Classification ........................................................................... 67 4.3.3.3. Intelligent scheduling ................................................................................................ 69 4.3.3.4. Assigning resources and what if scenario .................................................................. 76 4.3.3.5. 4D Simulation ............................................................................................................ 78 4.4. CREE SYSTEM – CASE STUDY ........................................................................................ 79 4.4.1. 3D BIM Model .............................................................................................................. 79 4.4.2. Model checking and IFC ............................................................................................... 80 4.4.3. 4D Model ....................................................................................................................... 81 4.4.3.1. Custom Breakdown Structure .................................................................................... 81 4.4.3.2. CREE Custom selection sets - CREE CSS ................................................................ 83 4.4.3.3. Creating Rules with logic relationships ..................................................................... 84 4.4.3.4. Assigning resources and what if scenarios ................................................................ 86 4.4.3.5. 4D Simulation ............................................................................................................ 88 4.5. 4D COMPARATIVE ANALYSIS ........................................................................................ 89 4.5.1. Time ............................................................................................................................... 89 4.5.2. Resources ....................................................................................................................... 90 5. CONCLUSION ................................................................................................................ 93 5.1. THEORETICAL AND PRACTICAL CONCLUSION ........................................................ 93 5.2. FURTHER RESEARCH AND RECOMMENDATIONS .................................................... 94 REFERENCES......................................................................................................................... 95 LIST OF ACRONYMS AND ABBREVIATIONS................................................................. 99
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 15 1. INTRODUCTION The growth of prefabrication in the construction industry is a significant and recent trend in construction. Modular buildings are produced and manufactured offsite, in factories, as an alternative to traditional buildings. The site is prepared for assembly process after the modular buildings have been transported. “A lot of developers like the idea, but because they haven’t done it before, there are a lot of unknowns and a hesitancy to jumpstart a new project, but as people are getting more comfortable and the industry is maturing, more and more developers are getting comfortable with the idea," said Josh Kimmel (vice president at Chicago-based Project Management Advisors Inc.). According to Kimmel, there is a lack of awareness among people or stakeholders about prefabrication and the advantages of using the offsite construction rather than total onsite, despite the fact that many developers like the prefabrication idea of saving time and money and producing less waste. This study focuses on the time effect of using total prefabrication in construction, instead of using traditional systems built onsite and tries to quantify the benefits of using offsite construction, especially considering time and resources. Building information modelling (BIM) is the technology that has been developed for dealing with engineering processes, material quantities and quality, costs, and time (Kim et al., 2010). A 4D BIM connects the 3D model to the schedule, simulating the construction process. It helps a wide variety of users to execute the construction in the right direction by anticipating the time and the resources that will be needed. 4D BIM analysis will be useful for modular construction by helping the user to visualize the construction information and resources as a process with a micro time frame. Therefore, the work focuses on how much time is saved in comparison to the traditional construction, and a framework is developed to enable the 4D analysis on a case study that is being built in Guimarães, using the total prefabrication CREE system. The construction scheduling is usually carried out manually. Integrating wide BIM applications and 4D visualisation can be done automatically. By connecting the logical relationships of the construction tasks to the BIM objects in visual representation results in an automatically generated schedule with minimal human interaction. A software can offer this integration using an intelligent schedule engine. Furthermore, a framework is generated to quantify the time saved in the case of using total prefabrication instead of the traditional method, by creating a 4D model using the intelligent schedule engine. It will be precisely shown in the case study how this new method of construction saves time. This research is organized as follows: first, the definition of offsite construction is briefly explained, followed by the identification of key benefits and challenges of the offsite construction. Then, types of offsite construction, the difference between offsite and onsite construction processes, and their effect on time are described. 4D BIM, as the technology that integrates that type of construction into the whole process, allows us to quantify the benefits of using offsite construction. Furthermore, a comparative analysis is conducted, with the proposed framework, on a case study of a hotel in Guimarães that is being built using total prefabrication. and This study concludes with a 4D quantitative analysis of both construction methods.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 16 1.1. Scope and motivation The present work has been carried out by combining theory and practice in a real case study of a building project constructed in total prefabrication way. A deep understanding in several areas is required: the offsite construction, the offsite construction process, the benefits of using offsite construction, the use of BIM to carry out building projects, using the 4D modelling to reach the research aim and quantify the benefits of using the total prefabrication instead of the basic traditional construction throughout the suggested case study. 1.2. Research Objectives The specific objectives of this research are: - To have knowledge on offsite construction and on the different types of offsite construction systems; - To identify the potential benefits and challenges of using off-site construction; - To clarify the technology of BIM and the effect of using 4D simulation on offsite construction; - To establish a framework to enable a 4D comparative analysis between a traditional way of construction and the CREE total prefabrication system; - To develop a 4D BIM-based analysis on the suggested case study; - To quantify the benefits of using total prefabrication compared to the traditional way of construction in terms of time and use of resources. 1.3. Structure of the research This research is divided into five main chapters: ▪ Chapter 1 provides the background of the project and introduces the scope of the research, states the problem, defines the research goal, objectives and the general purpose of the study. ▪ Chapter 2 focuses on the review of literature related to the main topics discussed in this research: offsite construction, building information modelling and 4D BIM schedule. ▪ Chapter 3 develops a theoretical framework by proposing a concept 4D BIM comparative analysis for both approaches of construction; traditional and total prefabrication. ▪ Chapter 4 develops a 4D BIM comparative analysis applied on the suggested case study, exposes the findings, and discusses the results obtained from the case study, including the traditional 4D model, and the total prefabricated 4D model. ▪ Chapter 5 summarizes the important findings and conclusions of the study that contribute to the body of knowledge and suggests future developments. The limitations of the study are discussed. Finally, suggests further works to enhance this research and the best practices for the prefabrication construction industry sector projects.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 17 2. LITERATURE REVIEW This literature review discusses several aspects of off-site construction. This chapter provides a detailed explanation of each of the four types of off-site construction. Offsite construction has several advantages that will be mentioned, along with the primary challenges it faces. Traditional and off-site construction vary in their methods and procedures, and this has an impact on how long a project takes to finish. The other objective of the literature review is to gain more knowledge about the 4D BIM in construction and to understand the procedures and level of information required to assess the advantages of using prefabrication off-site building. “Building in controlled environments makes even more sense in a world that requires close management of the movement and interaction of workforces. Such a rationale further strengthens the case for offsite construction, beyond the existing quality and speed benefits. In fact, we expect to see contractors gradually push fabrication offsite and manufacturers expand their range of prefabricated subassemblies.” (Biörck et al., 2020) We are in an era where industrialization and construction industry have a vital role in our lives nowadays. The industry needs to change to modular industry during the life cycle of the project, planning, design, and execution to make the maximum use of the reduced capital cost and project time, and many other benefits that are brought to a project using this type of construction. With the increased industrial focus on enhanced safety, lower energy consumption, and creating a circular economy with less waste, improved safety, and higher quality, capital projects must rely on a combination of modularization, standardization, lean, and unique efforts. However, the AEC has a little understanding of what needs to be done to execute modularization successfully. As a result, companies fail to realize the impact of saving cost and time by implementing modularization incorrectly and late on a project. The construction industry institute (CII) indicates that there will be an annual growth rate of 9.6% in the offsite construction market as shown in Figure 1 – An annual growth rate in the offsite construction market (CII - Planning for the Future with Modularization and Offsite Construction) The usage of off-site construction is estimated to rise significantly as society and the construction industry fight to handle important issues such as the availability of affordable housing, a skilled labor shortage, material use and sustainability, job site safety, and industry productivity. Therefore, off-site construction will play a significant role in the future of the construction sector.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 18 Figure 1 – An annual growth rate in the offsite construction market (CII - Planning for the Future with Modularization and Offsite Construction) 2.1. The definition of offsite construction Construction is moving in a new direction, requiring manufacturing equipment that makes the process easier to control, more precise, and safer. One option is to modify the materials used for construction to facilitate handling, transfers, and installation of components with reduced weight. (Advancing the competitiveness and efficiency of the U.S. construction industry, 2009) Off-site construction is a method of construction that comprises the planning stage, design, fabrication, transportation, and assembly of prefabricated building components on-site at a rapid rate and with a high level of finish. This level of accuracy is better than on-site construction. (What is Offsite Construction? - The Constructor, n.d.) Offsite construction uses a variety of materials and systems, as well as innovative manufacturing and fabrication techniques and current assembling techniques. There are various types of offsite construction. Modular, panelized, and modularized parts are used as structural elements, enclosure and service elements, or interior partition systems in the output of an offsite construction. Off-site construction can be optimized by integrating these systems with the supply chain, as well as conducting thorough extensive research, design, testing, and prototypes. The following are some reasons why off-site building can be the best option: 1The project must be completed within a certain amount of time. 2The site is suffering serious weather, which is causing the project to be delayed.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 19 3The structure of the building has a number of repeating parts, as does the construction process. 4Space limitations in the site. 5Theft and damage are causing problems and putting people in danger. 6Due to the extreme heat, cold, and heights, there are safety considerations. 2.2. Types of offsite construction There are different forms of offsite construction: volumetric construction, panelized construction, hybrid construction, and sub-assemblies and component systems. 2.2.1. Volumetric Construction Volumetric modules are available in a variety of configurations, such as basic structural shells or with interior and external finishes and services. The modules can be made up of a timber or concrete frame, light gauge steel, or composite materials, as shown in Figure 2. Figure 2 - Volumetric Construction. (Taylor, 2010) There are two-part types in volumetric construction: a. Modular Construction Factory-made pre-engineered building components are delivered to the construction site. After that, the modules are put together as huge volumetric components or significant pieces to form the building, as shown in Figure 3.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 20 Figure 3 - Modular construction. (Modular Construction, Advantages and Challenges | Real Projectives) b. Pod Construction Non-structural elements combined with a load-bearing structure are called pods. They are mostly used in the construction of hotels and other hospitality services. A timber frame, concrete frame, steel frame, or load-bearing framework can be used to create the enclosure. Three-dimensional features are used in the building's superstructure in this form of building. These prefabricated modules can be connected to create a complete setting. A light steel framework holds them all together. All the final building services are pre-installed on site, leaving only the final connection to complete. The construction of hotel bathrooms, accommodation buildings, and kitchen units are good examples. Figure 4 shows installing a module bathroom using this type of offsite construction. Figure 4 - Pod Construction. (Projetos Inovadores e Sustentáveis - Blufab)
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 21 2.2.2. Panelized Construction. These are flat panel modules that are utilized to make a complete structural shell as walls, floors, or roof panes. These panel modules are created in the factory and brought to the job site to be assembled as a three-dimensional structure or to fit into an existing structure. Factory-built structural floors and roofs are referred to as "cassettes." These "cassettes" can be both load-bearing and non-load-bearing structures. Timber, insulated panels, light gauge steel, concrete, or non-structural in-fill walls can be used to construct these structural panel modules. These panel units can be used in any sort of structure. Windows, timber frames, insulation, and windows are examples of building components manufactured using panelized methods. Open panels, closed panels, concrete panels, insulated panels, composite panels, and infill panels can all be used in panelized construction. Figure 5 shows an example of panelized construction as type of offsite construction. Figure 5: Panelized construction. (Panelized Modular Building Systems Market research & forecast during 2020-2025) 2.2.3. Hybrid Construction In order to create a single building, hybrid construction uses both volumetric, and panelised technologies. As a result, this structure is also known as semi-volumetric. Building facilities that are totally constructed or prefabricated in the factory are hybrid systems. These units have a finished look. Once the hybrid systems have been finished, they are brought to the job site. For example, highly serviced spaces such as toilets and kitchens are initially built as volumetric units, while the remainder of the house is built using panels, as shown in Figure 6.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 22 Figure 6: Hybrid construction. (Taylor, 2010) 2.2.4. Sub-Assemblies and Component Systems. The sub-assembly system is the procedure through which building components are first created offsite before being permanently placed on the job site. Building components, materials, equipment, and prefabricated parts are here included. Small building components such as roof trusses, flooring pipes, staircases, precast concrete beams, and columns are manufactured in this type of construction. Prefabricated foundations, floor cassettes, and roof cassettes make up the sub-assembly system. Figure 7 shows an example of panelized construction as type of offsite construction. Figure 7: Component system construction. (Component Building Systems, Inc) 2.3. The key benefits of offsite construction Prefabrication and modular construction offer numerous advantages and positive effects on the project itself, the environment, and the overall society, as will be further explored. Despite the benefits in time and money when compared to traditional onsite construction, the construction industry has only recently focused its interest on offsite construction, since it creates less environmental impact and is more secure. The following are the primary advantages of offsite construction:
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 23 a. Efficiency. As presented in Table 1, less than 5% of building in the UK uses offsite techniques, compared to roughly 9% in Germany, 12 to 15% in Japan, and 20% in Sweden. Offsite building, which includes manufacture and assembly, can provide greater efficiency in fitting more correctly and quickly on site than the traditional method. Table 1 – offsite construction in numerous high-income countries. (Steinhardt and Manley, 2016) Country UK Germany Japan Sweden Percentage 5% 9% 12-15% 20% b. Less manpower. The prefabrication of construction components in a factory can be significantly more automated than the traditional onsite brick-by-brick method. The factory-built kitchen and bathroom pods allow the rooms with the most complex mechanical and engineering components to be prefabricated and transported to the job site without the need to coordinate workers with various skills. Without offsite construction, it is common to have different sub-contractors to build kitchens, small rooms and bathrooms on-site. According to the Construction Leadership Council's 2016 Farmer Review (The Farmer Review of the UK Construction Labour Model Modernise or Die Time to decide the industry’s future, 2016), for every worker hired into the construction business, four workers leave. Because about one-third of construction workers are over 50 and will retire in the next 15 years, the shortage of competent labour is projected to worsen. In the next years, the sector will have to work with even fewer personnel, therefore automation offers a way to fill the void left by retiring humans. Figure 8 shows the age profile of the UK construction industry reflects poor recruitment of younger people. Figure 8 – The age profile of the UK construction industry reflects poor recruitment of younger people (The Farmer Review of the UK Construction Labour Model Modernise or Die Time to decide the industry’s future, 2016) 11% 21% 38% 26% 4% 0% 10% 20% 30% 40% Age 16 to 24 Age 25 to 34 Age 35 to 49 Age 50 to 64 Age 65 and over 2011 Census Estimate - Residents aged 16 and over in construction employment 2011 Census Estimate - Residents aged 16 and over in construction employment
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 24 Japan has a larger shortage of construction skills than the UK, which is made worse by an aging population with a high retirement age and inadequate recruitment into the industry. (Lessons from Japan: A comparative study of the market drivers for prefabrication in Japanese and UK private housing development, n.d.). The construction sector needs to either adopt less labour-intensive methods like offsite construction or increase recruitment by a factor of more than five. c. Reduced costs of building services Modular buildings or such centralized systems may be replaced by more localized systems in modern buildings. For example, rather than centralized plants, demand-controlled ventilation systems in each flat are used, and modern buildings' greater insulation allows central heating systems to be replaced with electric convection and infrared heaters in each room. Such localized systems require people with specialized expertise, and each one requires a unique set of materials, which are logistically lot easier - and thus less expensive - to manage in a factory than onsite. By incorporating building services into volumetric units, they can be planned with a small number of electrical and plumbing connections that can be easily plugged in after the structure is put together. d. Less time spent on site While much of the construction is moved from the construction site to the factory, a developer spends less time on the construction site. The amount of time saved varies on the type of project and how much work is done offsite, but according to the Buildoffsite report (An Offsite Guide for the Building and Engineering Services Sector, 2015), it can range from 25% for large buildings like office complexes and supermarkets to 60% for smaller projects like schools. Aside from the cost savings from not having to hire generators and cranes, anyone who has ever had to perform an environmental impact assessment would appreciate the ability to minimize local disruption. Some planning officials hold the notion that no construction site should ever be noisy or dusty. While offsite construction will not satisfy a planning authority, it can reduce the length of onsite time that must be approved. e. Improved safety and working conditions Despite the fact that the construction industry's safety record has improved substantially over the previous three decades, the Health and Safety Executive (Construction statistics in Great Britain, 2021, 2021) notes that the construction industry still has a fatal injury rate of 2,310 per 100,000 workers each year that is more than two times that of the manufacturing industry which has a rate of 1,080 per 100,000 workers.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 31 Figure 15 - The process of construction approaches over the time (Double Time Your Build: Podium + Modular - Base4)
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 32 2.7. BIM in offsite construction 2.7.1. BIM Building information modelling, as defined by (Borrmann et al., 2018), is a detailed digital representation of a facility that contains a high level of information. This three-dimensional model has geometric information and non-physical information, such as spaces and zones. The term Building Information Modelling (BIM) refers to both the process of developing the digital model as well as the process of keeping and exchanging it over the project life cycle. In addition, building information modelling is defined by UK`s national building specification (NBS) as the process for creating and managing the information and data represented in a model throughout the project life cycle. “As part of this process, a coordinated digital description of every aspect of the built asset is developed, using a set of appropriate technology. It is likely that this digital description includes a combination of information-rich 3D models and associated structured data such as product, execution, and handover information”. (About NBS | NBS, n.d.) The BIM process and associated data structures are defined in ISO 19650 and 12006 series of standards. These are the standards that define building information modelling information structure and process, at an international level. According to Eastman (Eastman, 2008), a lot of information is lost throughout the project life cycle, in conventional process projects. Using digital information workflows increases the project's overall time commitment. Figure 16, by (Eastman, 2008), shows the difference between digital and conventional workflow of information. Figure 16 – Loss of information caused by disruptions in the digital information flow (Eastman, 2008) Furthermore, BIM in offsite construction can help manufacturing in many different ways. BIM allows accuracy and precision in specifying material requirements, which can reduce over-ordering and reduce construction site waste, which is the main aim of using prefabricated construction. By providing the geometrical and non-geometrical information from the 3D model, BIM can help the contractor and fabricators. It can also accurately represent the geometry, properties, and information needs of each
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 33 individual element that forms the building or the volume. By exchanging the information within BIM models, the possibility for more interfacing and communication between designers, manufacturers, suppliers, and users could happen. (Ezcan, Isikdag and Goulding, 2013) Ezcan argued that the most helpful and advantage in using BIM, is bridging the offsite manufacturing implementations gaps, avoiding long lead times, high costs and modification issues. As well as by using BIM, it is able to provide an improved design, more collaboration, and exchange the information need precisely. Offsite manufactured projects will be more efficient if BIM is used to represent the all offsite construction elements. 2.7.2. BIM project life cycle These are all the different stages of the building process where it is possible to use BIM information, from conceptual design, through construction, to operation and back in the form of renovations and maintenance. The BIM information model goes through various stages that follow the project's life cycle, starting with the planning stage and moving through the design, construction, and operation phases. According to the BIM's lifecycle, the level of information it contains should be acceptable. For instance, until the asset has advanced to the "Build" stage, it is probably not acceptable to represent construction logistics like cranes and hoists. The model begins with the idea, during the design phase, and all team members, from all disciplines, work together to produce the precise coordinated drawings. Following the stages of analysis and documentation, fabrication begins. In this scenario, the factory may begin the production process. After that, the 4D/5D stage of construction involves factoring in time and integrating the BIM model with task planning that originates from the project management team. In this step, the building simulation and assembly process are specified. Figure 17 – BIM project life cycle.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 34 According to MacLeamy`s curve, the BIM based planning process is almost the same as the conventional one with some shifting on time which is earlier in BIM-based, and the maximum planning effort is almost the same. In case of the integrated approach, the team’s decreasing ability to affect project variables such as cost, schedule, and functional capability as the project progresses, however the traditional process shows how the cost of making changes increases as the project progresses. Therefore, BIM shifts planning effort and design decisions to an earlier phase. This makes it possible to influence the design, performance, and costs of the resulting facility before design changes start to become costly to implement. Figure 18 illustrates the relationship between design effort/cost (Y-axis) and the traditional phases of design and construction (X-axis). Figure 18 - The “MacLeamy Curve” - difference between BIM-based planning process and the conventional planning process.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 35 2.7.3. Level of information need The level of information need is the framework which defines the level of information that will be exchanged. There should be several concepts used to describe the level of information: geometrical information, alphanumerical information, and documentation. It is a combination of geometrical information, alphanumerical information and/or documentation as shown in Figure 19. In terms of the need to demonstrate such as a 4D BIM model, the level of information need, such as the geometrical information needs to be defined before beginning. Since, the representation of the detail of the building needs to be defined in which stage it needs to be planning stage, early design stage, and detail design stage as shown in Figure 20. Therefore, in accordance with the 4D BIM modelling process the detail of the building needs to be in detailed design phase which can help the planner to find the elements of the model that represent an activity or more according to the schedule. Figure 19 – Relation diagram for the level of information need. (BSI Standards Publication Building Information Modelling-Level of Information Need, 2020) Figure 20 – Three different representation for the detail of the building. (BSI Standards Publication Building Information Modelling-Level of Information Need, 2020) Moreover, an accurate and complete 3D model is needed in order to demonstrate 4D modelling. The primary requirement is a data checklist that is accurate and comprehensive. Modellers has to check and review the 3D model and make the needed adjustment according to the purpose of 4D modelling. That will lead the 4D modeller to get a proper 4D model.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 36 2.7.4. BIM 4D schedule Building information modelling is a dynamic process of information exchange that takes place during the life cycle of the project. According to the project requirements and the stage of this project, specific parameters are added in BIM regarding time, costs, sustainability, and facility management. BIM dimensions 3D, 4D, and 5D are defined as follows: ▪ 3D dimension: It represents the three geographical dimensions (x,y,z) of a building. The 3D geometry helps the stakeholders to navigate the building in three-dimensional view before starting the real project. In terms of 3D BIM, it means developing the 3D model and sharing the information using the same common data environment (CDE). ▪ 4D dimension: It is a 3D model adding to it a new dimension which is time. It helps outlining the duration of the project. This dimension is related to the scope of this research and further benefits from using a 4D model will be discussed, as shown in Figure 21. ▪ 5D dimension: 5D BIM is used when the budget and cost estimation are required before starting the project. It enables project owners to analyze the costs that will occur over time throughout the project activities. Figure 21 – BIM uses (DIFFERENT DIMENSIONS, DIFFERENT USES, 2020) 4D includes time in the analysis and the planning of the construction site by establishing the relationship between the site tasks and the building elements. The time schedule of the building helps to identify how long the project will take to complete and how it will change over time. 4D BIM tools organize onsite tasks by showing the effect of modification made over the whole life cycle of the project, and it is possible to predict early site clashes before starting the project. There are a lot of benefits to using the 4D in construction projects, at the preconstruction stage such as: ▪ Improving the site works, planning, and scheduling efficiency. ▪ Coordination among engineers, contractors, and sub-contractors on site works. ▪ Helping in early clashes among site tasks.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 37 ▪ Better planning for the following milestones in each stage of construction. ▪ Increasing the productivity and safety of site works regarding the time schedule. ▪ Before beginning the job on site, visualize the tasks and their logical relationships. The process of manufacturing is dynamic and needs to be fully coordinated with all operations, that takes place in terms of time. The decision of using BIM based on the 4D simulation to optimize the manufacturing output. 4D simulation for the prefabricated output represents the time schedule, quantity, and quality of the output. (Chou, 2011) Concerning the 4D simulation, using the critical path method is a useful and widely used technique, that makes it easier to describe, examine and update the process of construction (Arashpour et al., 2016) . There is clearly explanation for using the simulation for the short-term management and long-term management. Short-term management can detect the clashes that occur over time, resolve them quickly and precisely by knowing the task procedures and assigning certain resources relative to the building quantities and getting the suitable module for the short process. Long-term process provides parametric information to achieve the output related to the module manufacturing schedule, material quantity and quality. (Nasereddin, Mullens and Cope, 2007) The BIM 4D developed model is based on a BIM model with high level of detail, detailed time schedule information and with detailed activities, to be easily mapped. A site environment with factory BIM models and equipment sets can be created using various module manufacturing activities in a brief amount of time, enabling both shortand long-term simulations. (Lee and Kim, 2017) However, a 2020 assessment on the effects of prefabrication and modular construction is available. Dodge data and analytics shows the impact of modular construction on schedule performance. Schedule Performance on Figure 22 which describe the percentage of schedule performance improvement that respondents report experiencing over the past three years before 2020 from modular construction. ■ Almost all (88%) of general contractors and construction managers’ report positive impact with 60% better than 5% schedule gains. ■ Nearly two thirds (65%) of design firms agree on its positive impact, with 20% reporting the highest level (over 10% improvement). ■ While over one third (36%) of trade contractors report improvement in schedule performance, they are less enthusiastic overall than design firms or general contractors and construction managers.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 38 Figure 22 – impact of prefabrication on project schedule performance (percentage reporting each of three levels of improvements) (Bibeau et al., 2020) Successful prefabrication requires a comprehensive coordination between the systems and disciplines therefore using BIM enhances the accuracy, detect the clashes, improve the coordination and saving time and cost. The Dodge data and analytics shows the impact of using BIM in prefabrication on schedule with the companies which do not use BIM, companies that use BIM on less than 50% of projects, and Companies that use BIM on 50% or more of projects over the last three years from 2020 as shown in Table 4. Table 4 - Percentages Reporting Improved Schedule Performance from Prefabrication (by Level of BIM Usage) (Bibeau et al., 2020) Companies that do not use BIM Companies that use BIM on less than 50% of projects Companies that use BIM on 50% or more of projects Percentage reporting improved schedule performance 46% 46% 59% Percentage reporting improved Cost performance 21% 44% 46% 32 28 18 13 20 18 20 40 65 88 36 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Architect/ Engineers General Contractor/ Construction management Trades Decreased by 5% or Less Decreased 6-10% Decreased by more than 10% Just strong impact
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 39 3. FRAMEWORK 3.1. Introduction This chapter's goal is to establish the workflow and procedure for completing the research endeavour, which is a 4D comparison of prefabrication and conventional methods for constructing the same building. Since there are more advantages on adopting prefabrication, the goal is to quantify those advantages in terms of time. This work provides a macro workflow for both the prefabrication and the traditional way of construction, in order to generate a 4D model for each of them and define a 4D analysis for the two approaches. A comparison and an overview of traditional and prefabricated elements are intended. Moreover, there is another micro workflow for this study. This workflow acts as a framework used for the proposed case study to demonstrate a quantitative 4D BIM comparative analysis between these two methods of construction. The first one is for traditional construction and the second is for prefabricated construction using the CREE system. Furthermore, a case study of a building is used to apply this framework, considering both the conventional and the prefabricated approaches. The CREE system, which will be illustrated in the next part, is used to construct this building in a prefabricated way. Then, after creating a 4D simulation for each approach, the 4D comparative analysis is established. The literature review has already shown how to create a 4D simulation. In the case study application, presented in chapter four, the different resource assignments will be defined. So, the workflow for this chapter is defined as shown in Figure 23, and it is organized as the following steps: ▪ Defining the structural elements that are used for traditional construction; ▪ Defining the prefabricated elements that are used in the CREE system; ▪ Proposing a Framework to generate a 4D model based on two different 3D models; ▪ Defining the case study that will be used to apply the 4D framework; ▪ Defining the 4D analysis for traditional construction and for total prefabrication. Figure 23 – Research workflow.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 40 3.2. Macro workflow concept The aim is to create a workflow that is used to make a 4D analysis for both construction systems applied to the same project, in order to quantify their benefits, as well as optimize the data and information workflow to generate the 4D model. From the database, the company developed a 3D model that has all the data and information needed. It is important to decide on the level of information needed to facilitate the 4D process. The first step is to establish the Work Breakdown Structure (WBS) for the model elements, in both models. The company should establish this WBS for the elements levels in their database, so that they can reuse it in each new project. The level of information need is defined in detail in the micro workflow that help the user in the 4D modelling. Moreover, to start the 4D BIM process, the user needs the exported IFC file from the 3D model. Regarding creating the 4D model, the user needs a WBS for elements to make the links between the elements and the tasks easier. Therefore, a user defined property sets could be considered while exporting the IFC file. The macro workflow to generate a 4D analysis is shown in Figure 24. Figure 24 – The Macro proposed Workflow.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 47 Figure 34 – Steel girder at CREE system. (Sustainable building systems | timber hybrid office buildings - CREE Buildings) 3.4.1. The way of construction in CREE system To begin the erection operation, all CREE components are carried to the location. starting the assembly process while holding the components with a crane tower and a portable crane. A trained team is in place to supervise the procedure and link the various parts. The following Figure 35 shows how the CREE system was assembled on-site. Figure 35 – How the CREE system was assembled on-site. (Sustainable building systems | timber hybrid office buildings - CREE Buildings,) 3.4.2. Resources needed by CREE Less resources are required in this case than in the traditional construction. The needed resources for assembly process on-site for CREE elements are as following: ▪ Trained crew ▪ Portable crane ▪ Tower crane
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 48 3.4.3. Advantages of using CREE system There are certain advantages to using CREE construction instead of the conventional way of construction: ▪ 400-500 m2 of airand water-tight floor area each day; ▪ Greater productivity per worker and therefore fewer workers needed; ▪ Prefabrication can increase workplace safety; ▪ Less dependent on site conditions; ▪ No unforeseen costs following construction. 3.4.4. Disadvantages of using CREE system There are some of disadvantages to using CREE prefabricated elements that should be mentioned and considered in this comparative analysis between the traditional and CREE structure. ▪ Transportation: The distance between the factory and the construction site is a factor that must be taken into account, as the higher the distance, the higher the cost of transportation. ▪ Handling: Prefabricated elements need to be handled with proper care and precaution. Prefabricated components are typically huge and heavy. The CREE components are often handled by portable or tower cranes. ▪ Modification: Prefabricated constructions have the disadvantage that it is challenging to change the structure. For instance, removing a structural wall will affect the building's overall stability. ▪ The Sensitive Connection: To ensure that connections between several structural parts behave as planned, supervision and good installation are required. In addition to this, bad connections might cause insulation failure and water leaks.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 49 3.5. Proposed 4D framework Figure 36 describes the proposed workflow which is explained in detail in the following sections. Figure 36 – Proposed 4D comparative Analysis.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 50 3.5.1. 3D BIM model This research was developed with Autodesk Revit as the 3D modeling software and BEXEL Manager as the 4D modelling software. 3.5.1.1. Create the 3D model The modeling stage can start once all the necessary data has been gathered. By reviewing the 3D model and the schedule created by the project management team, the modeler or any team member working on this stage should double-check all the information acquired to create a detailed model that respects the level of information and details needed for the purpose of creating the 4D model. 3.5.1.2. Review the 3D model The model should be reviewed and updated. Since the 4D modeler will be in charge of monitoring and coordinating the 3D modeler and making the updates to the 4D model, it is essential to add the missing information to the 3D model to facilitate the 4D process. Updates and modifications should be made as often as necessary. The review should make sure that: ▪ the modeling is simple to understand; ▪ the modeling can be utilized to create a 4D model afterwards ; ▪ the level of detail is correct; ▪ the level of information needed is provided; ▪ the model comprises all the necessary components of the project schedule. 3.5.1.3. 3D modelling for 4D analysis It is important to have a 3D model layering scheme that supports the 4D modelling activities. This research addresses the traditional model, which is based on reinforced elements such as slabs, beams, and columns, and on the exterior envelop that is composed of masonry works and exterior windows. All building elements should be assigned to the created WBS level parameters in Revit. This WBS will make it easier for the 4D modeler to generate the 4D model by assigning the building components to the schedule. The WBS levels created in the 3D model in Revit file is shown in Figure 37. Therefore, it is easy as for a 4D software such as BEXEL Manager, with a specialized way to automatically link the elements with the activities to support the accuracy of the 4D model. This can be implemented through the following process: 1. Specifying the layering standards in the 3D model; 2. Include additional building elements and activities that support visualization; 3. Allocate WBS levels to the building elements, according to the level of the actual planning.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 51 Figure 37 – WBS levels with element at Autodesk Revit. 3.5.2. Model checking and IFC The Industry Foundation Classes (IFC) is an open framework for the exchange of building data models used in building design and construction across various software. It is utilized to exchange information within different disciplines along the project life stages (design, construction, maintenance, and operation.) The IFC file will be exported from the 3D model team in order to start the process of the 4D BIM integration model. Before an IFC is published, the quality and accuracy of the IFC export must be verified. This is known as model checking. Afterward, the model can be checked in an IFC viewer (e.g., BIMCollab, BIMvision). Sometimes a setting is left unchecked, or the export is done from the wrong view (2D view rather than 3D views), which results in an incomplete IFC export. Moreover, when everything has been exported, a quick check needs to be done, for instance, by making a few cuts and checking the geometry of the model in the IFC viewer and by navigating inside and outside of the model. Sometimes, specific objects may be wrongly exported to IFC. The best option in this situation is to erase the object and model it once more in the modeling software. Then you can make a new export. To make sure that the level of information need is ready to be provided in the IFC file, it is possible to define it as an export user defined property set. Export user defined property sets is an additional method for exporting chosen parameters by specifying the export parameters in a text file. Everything between < > is replaced and defined by the user according to the specific parameters needs, as shown in Figure 38. Figure 38 – The text file has the replaced parameters by the user. (Revit IFC Manual 2.0)
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 52 3.5.3. 4D BIM model Using BEXEL Manager as a software to generate the 4D BIM model. The first step is to import the IFC exported file from Revit. There are many features to do in BEXEL Manager before demonstrating the 4D model. The process in BEXEL Manager is starting with creating a custom breakdown structure (CBS) according to the created WBS in REVIT. These CBS will help the user to have a BIM model according to the selected attributes - in this manner it will be the WBS properties – which will help the user in the 4D BIM process and to know how many elements of the BIM model have within these selected attributes. Furthermore, creating the custom selection sets (CSS) is the next step . The CSS is a user defined selection for group of elements which will help the user to select certain elements for the purpose of generating the 4D model. The process in BEXEL is sequential and it might be dependent on other factors. For instance, it is better to start generating the CBS first and create the CSS based on a selected CBS based on the creation wizard feature in BEXEL. To generate a 4D integrated model in BEXEL Manager, it should start with creating cost classification and cost version using the auto-assign process before creating the automated schedule by defining the zone editor levels (spatial distribution), methodology levels (order of the work execution), and creating a template based on the zone and methodology levels which will be explained later in the case study, as shown in Figure 39. Figure 39 – The 4D BIM workflow in BEXEL. (‘BEXEL_Manager_Handbook-ENG’, 2020) 3.5.3.1. Custom breakdown structure After the IFC model is inserted into BEXEL Manager, the first thing to do is to make a custom break down structure for the elements, depending on the criteria needed to start the 4D modelling process. This created breakdown could be used for reviewing the elements if they are under the certain defined attributes as well as it used for creating a smart custom selection sets CSS) which will be explained in the next part. The CBS displays the breakdown structure which is just created for two rules. The first one is the building levels and the second one is the categories as shown in Figure 40. The total model
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 53 elements are given as 3497 elements that are divided into defined attributes. Each group can be disabled and made invisible in the viewport within the created breakdown. Figure 40 – An example of created Custom Breakdown Structure in BEXEL Manager. 3.5.3.2. Custom selection sets (CSS) Creating smart custom selection sets is a smart and important tool in BEXEL Manager which is used in every single stage of the 4D BIM process. Beside creating the selection sets manually, there are smart selection sets that are created with predefined rules based on which elements are included in the selection sets. For instance, the Figure 41 describes the CSS for one building only which is selected by a rule defined with a building name. The CSS has several uses such as when constructing a 4D BIM model. When linking the schedule to the BIM model, the selection sets can be assigned to a single task or to a group of tasks in the schedule. In addition, the user can create CSS from previously created CBS. It could happen by with using smart feature creation wizard in BEXEL Manager as shown in Figure 42. Total number of elements
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 54 Figure 41 – Example of created Custom Selection Set based on rule in BEXEL Manager. Figure 42 – Example of creating Custom Selection set based on created Custom Breakdown Structure in BEXEL Manager. 3.5.3.3. Intelligent scheduling Planners and schedulers usually start the scheduling process in traditional way by creating schedules containing several tasks down to the level of each individual work task. After that start with linking and
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 55 creating the sequential logical relationships among those tasks as well as allocating the resources individually, and manually for each task. However, BEXEL Manager`s scheduling engine uses advanced scheduling algorithms that were created to make it possible to create fully automated schedules and reduce the painful process of doing that manually like any other solutions to create a 4D schedule where the user needs to create it manually or semi-automated. Intelligent scheduling engine enables the creation schedule based on construction methodology (the defining order of works execution) in the way the planners think about the execution process. Therefore, methodologies in BEXEL Manager gives the planer that way of thinking to represent the way of construction in methodologies levels as well as create relationships and dependencies between theses activity groups, which act as methodologies in BEXEL Manager. The intelligent scheduling workflow for any project is shown in Figure 43. Figure 43 – Intelligent Scheduling workflow in BEXEL Manager. (‘BEXEL_Manager_HandbookENG’, 2020) ▪ Creating Zones The spatial distribution of construction processes has to be properly scheduled on every project. Most of construction projects have different buildings in the same project, building storeys, and construction phases. All of them are considered as construction zones in this process. Therefore, the first zone level created should be the different buildings. Therefore, the zones (spatial project distribution) could be defined as a horizontal for the defined building and vertical for the building storeys as shown in the Figure 44.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 56 Figure 44 – An example for Zones Spatial project Organization provided by BEXEL. (Education and Webinars - BEXEL Manager, 2020) ▪ Creating the Methodology The advanced way of creating the intelligent scheduling depends mainly on the created methodologies (the defining order of works execution) which represents the sequence in which are performed. The sequence of construction works and the relationships between various types of work can be defined by the user using methodologies. For instance, user specifies that the foundation works are performed after the excavation is completed. And the superstructure is completed after foundation completion. So, it is basically common construction logic that every scheduler uses. Creating methodology is based on a certain classification which can be used for different similar projects. There are probably two main level of methodologies. At level one of methodology, the user can define the work packages and the relationships between them using logical sequential relationships. The user can enter one or more work packages at the second level of methodology and define the individual works and the relationships between each individual work that belongs to that work package. For instance, structural work has been starting with column, beams, and slab. For the second level of methodology, user is able to define and enter every individual work in each group according to the construction logic sequence. For instance, in column work package, the work starts with the following sequence: assembly of formwork, rebars, pouring concrete and dismantling the formwork. Another example of the first and second methodologies provided by BEXEL is shown in Figure 45 and Figure 46.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 63 names as displayed in Revit are on the left side and the property set names that need to be inserted by the user as displayed in the IFC property set, are on the right side. Between them, is the data type, which is Text in this case, as shown in Figure 52. The IFC is exported with the chosen parameters by specifying the export parameters in a text file as a user-defined property set, as is shown in Figure 53Figure 52. Figure 52 – The text file used for the user defined property set for the traditional model, in Autodesk Revit. Figure 53 – The IFC export using the user defined property sets text file. 4.3.3. 4D BIM model BEXEL Manager is an IFC-certified BIM software solution for construction project management that combines the most important 3D/4D/5D BIM uses into a single software interface and allows the user to optimise digital workflows. Therefore, this case study is set in BEXEL in order to get the advantages of using this software and take the best possible decisions regarding the obtained 4D analysis from applying the framework on both ways of construction, the traditional construction and the CREE system as prefabrication construction. Firstly, import the IFC file of the traditional model to start the 4D modelling process. It starts with making CBS based on the defined WBS property sets defined in the Revit file. Secondly, the user can
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 64 create some custom selection sets in a smart way. These CSS will assist the modeller in creating automated schedules for defining the spatial distribution zones, by using the intelligent scheduling, which generates sequential tasks linked to the BIM elements. Figure 54, shows a selection for the hotel building, that will help the modeller in creating spatial distribution and the sequence of work, at the intelligent scheduling phase. It is created from a defined query by using the property of LEVEL02_BUILDING to be equal Hotel. Figure 54 – Selection set created for the hotel building. Meanwhile, the user should check the level of information needed in BEXEL Manager, as an IFC viewer. The user can click on any element in the model, such as, for example, the structural wall shown in Figure 55, and verify that the Pset_WBS is imported, readable, and attached to that element. Figure 55
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 65 Figure 55 – The level of information need displayed in BEXEL Manager. 4.3.3.1. Custom Breakdown Structure CBS The first significant step in BEXEL Manager is to create a Custom Breakdown Structure (CBS). The CBS should be sorted from level one to level four, starting with the B&B project and moving down to the categories and families’ levels. By going to the custom breakdowns in the interface, a new CBS is created, select the building, and start to put defined property rules starting with the property name LEVEL01, LEVEL03, LEVEL04, and then add another defined rule that has a shortcut “family” as shown in Figure 57. LEVEL 02 will be used to define the spatial distribution through the creation of zones at the intelligent scheduling stage in order to create the sequence of work between the two buildings. However, using BEXEL Manager has the advantage of adding any new properties under any group of property sets if the modeller needs any additional properties that are missing for the model. That could happen as shown in Figure 56. Figure 56 – Adding new properties to element in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 66 Figure 57 – The way of creating a custom breakdown structure with adding rules, in BEXEL Manager. The purpose of creating a CBS is to categorize and sort the elements according to the created WBS levels. For instance, it is possible to select all structural building elements, such as slabs, columns, and beams. As well as the user can select elements that are sorted and created from the CBS by the defined properties, such as selecting all slabs or columns, as shown in Figure 58. The same is true for architectural elements like exterior walls and windows. The created CBS is shown in Figure 59 with colour coding for each discipline. Figure 58 – Selecting the structural slabs only or columns from the created CBS.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 67 Figure 59 – The color coding for the created custom breakdown structure, in BEXEL Manager. 4.3.3.2. CSS, QTO, and Cost Classification The purpose is to create an automated schedule by using the intelligent scheduling engine provided by BEXEL. Before starting the process of intelligent scheduling, some smart custom selection sets, the quantity taking off (QTO) and cost classification should be defined. ▪ To create CSS From the building explorer, a selection set is created for the hotel building and for the housing building. The creation wizard is used to establish a new CSS from custom breakdown, and selecting the created CBS, as shown in Figure 60. ▪ To create the QTO From the QTO editor, a new QTO is established, based on the previously created CSS, and adding the quantity units in accordance with the quantification's units for elements like volume, area, and count, as shown in Figure 61. ▪ To create the Cost Classification From the cost classification editor, a new cost classification is established based on the previously created QTO, and making checks on the cost of items that are linked to the model elements, since they are created from the QTO, which is already linked with the BIM model. The cost classification created from the QTO is shown in Figure 62.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 68 Figure 60 – Creating custom selection sets from created custom breakdown structure, in BEXEL Manager. Figure 61 – Creating quantity taking off based on the created custom selection sets, in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 69 Figure 62 – Creating new cost classification from quantity takeoff, in BEXEL Manager. 4.3.3.3. Intelligent scheduling As explained before, in section 3.5.3.3, the intelligent schedule engine needs to create the spatial zones, methodology levels, and the template before running the new schedule. The scope of work will be limited to the structural works of the two 4-storey buildings, hotel and housing, and the respective exterior envelop. ▪ Creating zones By specifying spatial zones and relationships between the elements, the vertical spatial distribution is for the building stories and the horizontal spatial distribution is for the building construction sequence. The distribution and the sequence of work will consider these created zones. Through the zone editor in BEXEL manager software, new zones are created based on the building's stories and the relationship specified between each one, beginning with the ground level and moving through the first floor, second floor, third floor, fourth floor, and roof floor. as shown in Figure 63. According to the predefined construction sequence, a second zone needs to be created. A smart selection set must be made before this stage for the two buildings, hotel and housing. It is created from a defined query regarding the properties that the elements have. With the property of LEVEL02 BUILDING, the two CCS from that query will be defined, one for the hotel and the other for the housing. The next step in the zone editor is to establish a new zone for the phases, choose these selection sets, and specify the relationship between them, as shown in Figure 64.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 70 Figure 63 – The zones created for the Building Stories, in BEXEL Manager. Figure 64 – The zones created for the construction sequence, in BEXEL Manager. ▪ Creating the methodology Regarding the case study, there are three levels of organizing the construction elements for creating the order of execution. Level one divides the set of works between structural and architectural. The architectural works come after the structural ones, as shown in Figure 65. The second level is defined by grouping structural activities and assigning logical relationships among them, based on the logical sequence of construction. For instance, in the case study, the structural group of work consists of the execution of reinforced concrete slabs, beams, columns, shear walls, stairs, and the user needs to add logical relationships between them, as shown in Figure 66. Level three of the methodology is the relationship between the individual works inside the group works, such as shown in Figure 67, which describes level three for each group work in the level two. Furthermore, the user must define the relationships between cost items and elements. The intelligent engine considers the relationships between tasks to create a certain schedule. If there are any gaps between two tasks, they must be defined as well, or the intelligent schedule will ignore them. For instance, to execute the concrete columns on site, it is necessary to wait seven days after casting for curing the slab. Therefore, the user needs to put in a five-day lag considering the work calendar with two days off per week. The relationships between structural works with time lag is highlighted, as shown in Figure 66.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 71 Figure 65 – Level one of the methodology, in BEXEL Manager. Figure 66 – Level two of methodology for group works, in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 72 Figure 67 - Level three for each group work defined in level two, in BEXEL Manager. ▪ Creating the template This is the final step before running the schedule. From the schedule toolbar, the user can create the template. From new, by selecting the created zones and methodologies, the template can be created. Figure 68 shows how the created zones are inserted into the template. Meanwhile, Figure 69 shows how the created methodologies are selected in the template.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 79 4.4. CREE system – Case Study The B&B will be constructed with CREE technology. This system includes prefabricated light frame façade panels, steel girders and columns, and hybrid floor slabs. The CREE floor panels used have 8.1 or 6.3 meters of length. These slabs stand on the metal girder on one end, and on the wall panel on the opposite end. To prevent any down stands, the girder is flush with the floor system. All the structural elements are prefabricated in the factory and transported to the site before the assembly process begins. This system allows a quick construction. 4.4.1. 3D BIM Model The CREE 3D model was previously developed by CASAIS company. The scope of analysis in the development of the case study is restricted to the CREE elements, and the outer envelope of the building. The typical CREE model is created using Autodesk Revit by using the CREE system elements such as panel slabs, wooden beams, columns, steel girders and façade panels. The 3D model is used to develop the 4D model afterwards. Therefore, deciding the level of information need is vital to start the process of 4D modelling. Assigning the WBS for the elements is the first step after creating the 3D model, in the same manner as was done before with the traditional model. In the case of CREE, four levels of WBS were created. Level one is the project name, in case there are different projects; second level is the building, if there are more than one building; the third level is the building floors, such as the second floor; and the fourth level is the CREE element ID. For instance, by selecting one of the façade panels, CREE01_PROJECT is B&B, CREE02_BUILDING is the hotel, CREE03_LEVEL is Piso 4, and CREE04_ELEMENT is D23 as shown in Figure 78. Figure 78 – The level of information need to the façade panel, in Autodesk Revit. The way to add the level of information need is as same as was presented for the traditional model. Figure 79 shows the procedure to create the four levels of WBS.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 80 Figure 79 - The workflow for adding the WBS parameters to the elements, in Autodesk Revit. 4.4.2. Model checking and IFC The same process that happened to the traditional BIM model is now applied to the CREE BIM model to review and check if all elements have been assigned to the created WBS levels. Then, exporting the IFC file with defined export settings and user-defined property sets needs the text files as was also explained before and is shown in Figure 80, to ensure that the added parameters are provided as a Pset_WBS in BEXEL Manager, which will allow to start the 4D modelling process. Figure 80 – Text file used for the user defined property in the CREE BIM model, developed in Autodesk Revit.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 81 4.4.3. 4D Model To start the phase of 4D modelling in BEXEL manager, it is necessary to have the IFC file for the CREE model ready and exported in the same way as done for the traditional model. The workflow for the CREE model is generally the same as the one defined for the traditional BIM model. Checking the IFC file that provides the added WBS levels to the elements is important to start the 4D modelling process for creating the CBS for the elements according to those levels. For instance, one of the façade panels has a different categories of elements, such as, the vertical panel that acting as exterior wall, the Glulam columns that transmit the bearing loads as mentioned before, and windows. The level of information need is displayed as user defined properties in Pset_WBS. It has four levels of WBS for elements. The first level is for project, the second level is for the building, the third level is for floor level; and the fourth level is for a determined element, as shown in Figure 81. Figure 81 – The Pset_WBS has the created information need, in BEXEL Manager. 4.4.3.1. Custom Breakdown Structure The custom breakdown structure for the CREE system is a bit different than the one defined for the traditional model. The CBS is created and sorted according to the defined WBS properties for CREE. The purpose of the CREE CBS is to reach the lowest level for elements that are used in the CREE system, which could be a vertical panel supported by columns or a horizontal panel supported with four beams. To create a CBS for CREE, it is necessary to open the custom breakdown interface, create a new CBS, select the building, put defined property rules starting with the property name CREE01_PROJECT, CREE02_BUILDING, CREE03_LEVEL, and at the end, CREE04_ELEMENT. Therefore, the CREE CBS will be sorted according to the properties defined , and afterwards the user can reach the lowest level of elements easily. Figure 82 shows the way of creating the CREE CBS.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 82 The user may choose any element from the resulting list after the CREE CBS has been created, as shown in Figure 83. After that, it is easier for the modeller to choose any CREE CBS level or element with just one click. In order to use it in the 4D process, a CSS can also be produced from these specific options. Figure 82 – The workflow to create the CREE CBS, in BEXEL Manager. Figure 83 – The created CREE CBS, in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 83 4.4.3.2. CREE Custom selection sets - CREE CSS The process used in the traditional construction system to create smart selection sets is also used for the CREE model. The purpose of creating CSS is to help the user demonstrate the schedule with the logical relationships between the selected sets. The CREE CSS is created as shown in Figure 84 by using the creation wizard available in BEXEL manager, from Custom Breakdown, selecting the created CREE CBS and pressing all elements. Therefore, at the interface of selection sets, CREE CSS is displayed, and the user can keep selection with any of the created CSS lists. For instance, the first CREE floor of the hotel could be kept in selection by clicking on it in the selection sets interface as shown in Figure 85. In addition, it is easier for the user to select a specific CREE element, such as the vertical panel, or horizontal panel that will be constructed onsite as shown in Figure 86. Figure 84 – Creating a CSS obtained from the previous CBS, in BEXEL Manager. Figure 85 – Selection set for the first floor of the Hotel Building, in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 84 Figure 86 – Selecting vertical or horizontal CREE elements, in BEXEL Manager. 4.4.3.3. Creating Rules with logic relationships The way of creating the schedule for CREE is a bit different than what was done in the traditional model with a semi-intelligent engine process. The 4D modeller in this case is able to automatically create a schedule already linked with elements based on predefined selection sets with defined easy logic relationships between them, since the majority of CREE elements are in a sequential finish-to-start relationships. To create the schedule using the developed CSS, by following these steps, as shown in Figure 87 and Figure 88, respectively: ▪ Go to the schedule editor and create a new schedule; ▪ From the logic schedule interface, select new task; ▪ From the dynamic creation rules, select the parent tasks; ▪ Repeat this process till it reaches the children`s tasks; ▪ Set the relationships between parents and children`s tasks. Following these steps, the Gantt Chart is built with elements that are already linked as shown in Figure 89, and the LOB is shown in Figure 90. The 4D modeller can update the schedule and begin the simulation, so that the schedule can check the logical sequence of the constructed elements.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 85 Figure 87 – Creating a schedule based on rules and selection sets, in BEXEL Manager. Figure 88 - Creating a schedule based on rules and selection sets, in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 86 Figure 89 – The Gantt chart for the CREE model, in BEXEL Manager. Figure 90 – Line of Balance for the CREE model, in BEXEL Manager. 4.4.3.4. Assigning resources and what if scenarios The aim is to use the same resources to construct the hotel building and the housing building. The housing building follows the hotel building in all activities. The needed resources in this case are just one portable crane and one tower crane to load the elements to their location, as shown in Figure 91. There is a trained crew of six people for the assembly process, who are there to connect the elements together with the assistance of the cranes.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 87 In BEXEL manager, the user defines the resources needed in the current project and assigns them to each cost item that is created in the cost editor. This creation can be done in two ways: the first one is obtained with the creation wizard based on the QTO created from the selection sets, and the second one is collected from the created CBS, which has selections for each element. Since the CREE system is a sequential process, it uses the same crew and equipment resources along the assembly process. Figure 91 – Using a portable crane and a tower crane with the trained crew in the assembly process. In BEXEL Manager, the user should follow these steps to define resource, it is described in Figure 92: ▪ Define the needed resources; ▪ Select the needed resources from the cost editor window; ▪ Assign the resources needed to complete the task, using the created cost items editor. This process needs to be applied to all cost items. If the task needs the same resources, the user can select all the tasks that need the same resources and assign the resources at once. If not, the user needs to assign the resources to each cost item.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 88 Figure 92 - Workflow to define the needed resources in CREE system, in BEXEL Manager. 4.4.3.5. 4D Simulation In this step, the user can check and review the sequence for creating the 4D CREE BIM model. The animation represents the created schedule-based model that is based on creation rules and selection sets, as shown in Figure 93. Figure 93 - 4D simulation for the CREE BIM model, in BEXEL Manager.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 95 REFERENCES About NBS | NBS (no date). Available at: https://www.thenbs.com/about-nbs (Accessed: 4 July 2022). Advancing the competitiveness and efficiency of the U.S. construction industry (2009) Advancing the Competitiveness and Efficiency of the U.S. Construction Industry. National Academies Press. Available at: https://doi.org/10.17226/12717. An Offsite Guide for the Building and Engineering Services Sector (2015). Arashpour, M. et al. (2016) ‘Analysis of interacting uncertainties in on-site and off-site activities: Implications for hybrid construction’, International Journal of Project Management, 34(7), pp. 1393– 1402. Available at: https://doi.org/10.1016/j.ijproman.2016.02.004. ‘BEXEL_Manager_Handbook-ENG’ (2020). Bibeau, N.G. et al. (2020) Prefabrication and Modular Construction 2020 SmartMarket Report Chief Executive Officer Senior Vice President Custom Solutions Prefabrication and Modular Construction 2020 SmartMarket Report Executive Editor SmartMarket Report. Available at: www.construction.com/. Biörck, J. et al. (2020) Engineering, Construction and Building Materials Practice. Borrmann, A. et al. (2018) ‘Building information modeling: Why? What? How?’, in Building Information Modeling: Technology Foundations and Industry Practice. Springer International Publishing, pp. 1–24. Available at: https://doi.org/10.1007/978-3-319-92862-3_1. BSI Standards Publication Building Information Modelling-Level of Information Need (2020). Cassino, K.E. et al. (2011) McGraw-Hill Construction Prefabrication and Modularization: Increasing Productivity in the Construction Industry SmartMarket Report Executive Editor SmartMarket Report. Available at: www.construction.com. Chou, J.S. (2011) ‘Cost simulation in an item-based project involving construction engineering and management’, International Journal of Project Management, 29(6), pp. 706–717. Available at: https://doi.org/10.1016/j.ijproman.2010.07.010. CII - Planning for the Future with Modularization and Offsite Construction (no date). Available at: https://www.construction-institute.org/blog/2021/september-2021/planning-for-the-future-withmodularization-and-of (Accessed: 28 June 2022). ¿Cómo se hace una Construcción Modular? | © Neoblock Modular (no date). Available at: https://neoblockmodular.com/como-se-hace-una-construccion-modular/ (Accessed: 30 June 2022). Component Building Systems, Inc. (no date). Available at: http://www.componentbuildingsystems.com/ (Accessed: 11 August 2022).
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 96 Concrete Floor Slab Construction Process - The Constructor (no date). Available at: https://theconstructor.org/concrete/concrete-floor-slab-construction/25628/ (Accessed: 6 August 2022). Concrete Pump (no date). Available at: https://arthanugraha.co.id/multiLang/lang/English/ConcretePump (Accessed: 6 August 2022). Construction statistics in Great Britain, 2021 (2021). DIFFERENT DIMENSIONS, DIFFERENT USES (2020). Double Time Your Build: Podium + Modular - Base4 (no date). Available at: https://www.base4.com/get-more-with-modular-over-podium/ (Accessed: 7 July 2022). Eastman, C., T.P., S.R.& L.K. (2008) BIM handbook: A guide to building information modeling for owners, managers, designers, engineers and contractors. John Wiley & Sons. Education and Webinars - BEXEL Manager (no date). Available at: https://bexelmanager.com/education-and-webinars/ (Accessed: 10 August 2022). Ezcan, V., Isikdag, U. and Goulding, J.S. (2013) BIM and Off-Site Manufacturing: Recent Research and Opportunities. Goodier, C.I. and Gibb, A.G.F. (2005) Barriers and Opportunities for Offsite in the UK. Kim, C. et al. (2010) ‘CASE STUDIES Applicability of 4D CAD in Civil Engineering Construction: Case Study of a Cable-Stayed Bridge Project’. Available at: https://doi.org/10.1061/ASCECP.19435487.0000074. Lee, J. and Kim, J. (2017) ‘BIM-Based 4d simulation to improve module manufacturing productivity for sustainable building projects’, Sustainability (Switzerland), 9(3). Available at: https://doi.org/10.3390/su9030426. Lessons from Japan: A comparative study of the market drivers for prefabrication in Japanese and UK private housing development (2000). Major Parts of Reinforced Concrete Buildings | Framed Structures Components - CivilDigital - (no date). Available at: https://civildigital.com/major-parts-reinforced-concrete-buildings-framedstructures/ (Accessed: 6 August 2022). Modular Construction, Advantages and Challenges | Real Projectives (no date). Available at: https://www.realprojectives.com/the-advantages-and-challenges-of-modular-construction/ (Accessed: 29 June 2022). Nasereddin, M., Mullens, M.A. and Cope, D. (2007) ‘Automated simulator development: A strategy for modeling modular housing production’, Automation in Construction, 16(2), pp. 212–223. Available at: https://doi.org/10.1016/j.autcon.2006.04.003.
4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 97 Panelized Modular Building Systems Market research & forecast during 2020-2025 (no date). Available at: https://www.whatech.com/og/markets-research/construction/639208-panelized-modular-buildingsystems-market-research-forecast-during-2020-2025 (Accessed: 11 August 2022). Projetos Inovadores e Sustentáveis - Blufab (no date). Available at: https://blufab.pt/ (Accessed: 11 August 2022). Revit IFC Manual 2.0 (2021). Available at: https://www.buildingsmart.org/compliance/software-certifi. Smith, R.E. (2014) An Authoritative Source of Innovative Solutions for the Built Environment Report of the Results of the 2014 Off-Site Construction Industry Survey 2014 OFF-SITE CONSTRUCTION INDUSTRY SURVEY RESULTS Off-Site Construction Council. Available at: www.nibs.org. Steinhardt, D.A. and Manley, K. (2016) ‘Adoption of prefabricated housing-the role of country context’, Sustainable Cities and Society, 22, pp. 126–135. Available at: https://doi.org/10.1016/j.scs.2016.02.008. Sustainable building systems | timber hybrid office buildings - CREE Buildings (no date). Available at: https://www.creebuildings.com/system (Accessed: 7 August 2022). TATUN, C.B., V.J.D., & W.J.M. (1986) ‘Constructability improvement using prefabrication, preassembly, and modularization’, Stanford, California, The Construction Industry Institute. Stanford University. [Preprint]. Taylor, M.D. (2010) ‘A definition and valuation of the UK offsite construction sector’, Construction Management and Economics, 28(8), pp. 885–896. Available at: https://doi.org/10.1080/01446193.2010.480976. The Farmer Review of the UK Construction Labour Model Modernise or Die Time to decide the industry’s future (2016). Available at: www.cast-consultancy.com. What is Offsite Construction? - The Constructor (no date). Available at: https://theconstructor.org/building/offsite-construction-features-methods/38319/# (Accessed: 28 June 2022).
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4D comparative analysis of construction approaches towards industrialization: traditional versus total prefabrication Erasmus Mundus Joint Master Degree Programme – ERASMUS+ European Master in Building Information Modelling BIM A+ 99 LIST OF ACRONYMS AND ABBREVIATIONS BIM INC Building Information Modelling Incorporated 4D 3D + Time Dimension 5D 4D + Cost Dimension AEC Architectural, Engineering and Construction CII Construction Industry Institute NIBS National Institute of Building Sciences IFC International Foundation Class WBS Work Breakdown Structure CBS Custom Breakdown Structure CSS Custom Selection Sets QTO Quantity Take-Off LOB Line Of Balance