Introduction

In order to address the needs previously recognized, the following research objectives were identified:

 Identify the value that can be delivered to the owner and the construction team, at the end of the design stage of a facility

 Identify the BIM uses that can create and deliver that value during the design stage  Identify BIM tools and related activities that reduce the waste of resources in

producing the design

 Develop an approach for an integrated, BIM-based design process

These objectives were attained by using the Axiomatic Design (AD) method (Suh 1990) which consisted of the following major steps:

 Develop the hierarchical decomposition and check for axiom 1 compliance  Conduct a case study of the design process in a Design-Build (DB) company  Develop a proposal for an integrated, BIM-based design process

 Validate the proposal through simulation and axiom 2 compliance

 Perform a comparative analysis between a Design-Build (DB) process and the proposed an integrated, BIM-based design process

AD is a design methodology first developed in the field of mechanical engineering by Suh in the 70’s and formalized in the 90’s with the objective to establish a scientific basis for design. AD consists of three important elements: the structure or domains, the zigzagging decomposition and, most important, the two axioms: the independence axiom and the information axiom. The independence axiom, or axiom one, seeks to maintain the design adjustable and controllable using the design matrix. The second, the information axiom, helps in selecting the best design solution by calculating the information content (IC). It has been accepted that all good designs are consistent with these two axioms (Suh 1990,

Brown 2011a, Brown 2011b). The AD method is explained in more detail in Appendix A.

AD was selected as the methodology of this research because it provides a systematic process to clearly understand and define the requirements for the problem to be solved throughout the zigzagging decomposition. The zigzagging decomposition allows breaking the problem down into parts that are easier to understand and conceive, and to select a design solution for each of those parts, creating a one-to-one relationship between what is to be achieved and how to achieve it. The second advantage of using the AD method is the use of the design matrix, which provides a systematic method to optimize the design. Finally, the AD method provide a means to objectively select the best design solution and to compare it against benchmark designs (Towner 2013).

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On the other hand, during the application of AD some challenges were encountered. Among the most important are that the application of the AD method is more common in the areas of product design, decision making and manufacturing systems, with a little application in the design of process design. In the civil engineering area, most of the applications focus on specifics areas of architectural and structural design, like modular design and structural performance. Other areas of civil engineering include transportation and water treatment (Thompson 2013a). But regardless of the area of application, most of the studies that include AD approach focus primarily on the use of the independence axiom, leaving axiom two out of consideration and with little reference to its application (Kulak et al. 2010).

Figure 3-1 Steps of the axiomatic design decomposition and axiom one compliance

Figure 3-1 and 3-2 show in more detail the methodology followed in this research. Figure 3-1 illustrates the steps for the development of the AD decomposition and axiom one compliance, explained in more detail later in Chapter 4. These steps have the main

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objective to identify the BIM uses and other tools and applications that could satisfy the achievement of the functional requirements2 _{(FRs) in the design domain (DPs). Figure 3-}

2 illustrates the steps followed to develop the proposed integrated, BIM-based design process, which are contained in the first horizontal block, and the steps followed to perform the calculation of axiom two of the DB process and the proposed integrated, BIM- based design process, which are contained in the second and third horizontal blocks.

Figure 3-2 Steps followed to develop the proposed integrated, BIM-based design process and axiom two

2 _{Functional Requirement: a minimum set of independent requirements that completely characterizes the functional}

needs of the product (or software, organizations, systems, etc.) in the functional domain. By definition, each FR is independent of every other one at the time the FRs are established – Taken from Nam Suh, 1998

Develop a proposal for an

integrated, BIM-based

design process

Validate the proposal through simulation and axiom 2 compliance

Comparative analysis of the design processes

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In the vertical direction, once the AD decomposition has been completed (Figure 3-1), the mapping and simulation of the resulted BIM processes starts using the BIM Project Execution Planning Guide (CIC 2010) as a reference (shown with the letter “A” in Figure 3-2 and presented in Chapter 6 of this document). Simultaneous to this process, the mapping and simulation of the Design-Build (DB) process is performed by documenting the actual design process of a DB Company in Worcester, MA (shown with the letter “B” in Figure 3-2 and presented in Chapter 5 of this document). The process of comparison of both design processes (the DB and the integrated, BIM-based process) is shown with the letter “C” in Figure 3-2. For this process, first, the metrics to measure the fulfilment of each FR are determined. The results of the processes simulations may feed the calculation of the information content since some metrics are time-based; The steps for the process simulation steps are discussed in chapter 5 and 6. Also, they are used to compare the performance and execution times of both processes in the comparative analysis box shown in Figure 3-2. The information content is calculated for both processes and explained in Chapter 7.