Decision Factors of Stakeholder Integration in Connected Construction for Circular Economics

Abstract

The implementation of construction circular economics (CCE) will encourage higher green economic growth. The circular approach will be part of connected construction and is an approach that integrates processes and products from design to construction execution and then to the management of buildings, properties, and assets. Decision making for CCE involves many stakeholders who are involved in the entire connection process. In such situations, integration and negotiating support are needed. The aim of this study is to find the theoretical basis of decisions that allow stakeholders to share different preferences when selecting CCE options for the circular economic prototype of building systems. As a result, five dominant factors are obtained: the sustainability of the building system, energy efficiency, capture value creation, a high-level three-party consortia, risk allocation, and transfer. Each stakeholder has their own preferences, and these will determine the different priority of the alternatives to be selected. Finally, the priority of alternative choices is determined based on the connected construction process. A comparison of what is desirable for all stakeholders is the basis of choice before negotiations are carried out. Furthermore, negotiation automation can be achieved because in this paper, the satisficing algorithm is applied to the decision model and stakeholder integration. Optimal payoff and the best-fitting option based on coalition are important and interesting avenues for future research.

1. Introduction

Indonesia adopted the concept of a circular economy into its vision and development strategy, with particular emphasis on five industrial sectors, including construction. The follow-up to this adoption was the preparation of a National Action Plan (NAP) and making the circular economy one of the development priorities of the 2020–2024 National Medium-Term Development Plan (RPJMN). It is predicted that a circular approach can generate meaningful economic, environmental, and social benefits by 2030. This has the potential to generate additional Indonesian GDP as well as to reduce waste and create 4.4 million new jobs by 2030 [1].

The design of new building features has increased awareness of sustainability but has also increased invariability in assuming a certain level of technical sustainability due to concentrating more on economic and social sustainability [2]. Decisions should be made by involving key stakeholders in connected construction. The cooperation between them was studied from a variety of spatial scales and functional levels. The development process should use multidisciplinary expertise as a decision characteristic when building a circular economy since the diversity of stakeholder preferences will be the basis for the best decision-making processes. This can be achieved if there is a good multi-stakeholder relationship from the design stage of construction to operation. Integration is carried out to ensure the achievement of project development objectives. Because each stakeholder involved has direct involvement (through meetings) or indirect involvement (through automation) at each stage, the integration of stakeholders is carried out through knowledge sharing, collaboration, and communication processes [3].

However, there are challenges and obstacles related to the process that occur, including the involvement of inexperienced designers and problems related to the system for the exchange of data and object information from different stakeholders at different stages. Often, the stakeholders involved lack knowledge and skills, whereas experience is fundamental in the decision-making process to suggest feasible solutions. The problem of interoperability is then another obstacle to the exchange and integration of data because the use of different systems can cause the loss of data or important information related to objects.

The idea of incorporating multi-person decisions into the design process and the phases of connected construction in a circular economy provides a new approach to addressing distributed problems across multiple stakeholders [4]. The benefit is that it provides a decentralized approach to the problem of fragmentation [5] in a circular economy at each phase of connected construction. Therefore, the purpose of this study is to present a model approach that produces findings and potential innovations through decision support and business models for a circular economy of connected construction.

2. Theoretical Background

The circular economy of construction is in an early developmental phase [6,7]. Many researchers have presented previous research studies. A summary of the current research that has been conducted in this field is presented in

Table 1. Scope of circular economics in construction.

No	Definition and Scope	Source
1	The use of the practice, in all stages of the building life cycle, to keep materials in a closed system for as long as possible and to reduce the use of new natural resources in construction projects.	[8]
2	Contrary to the usual consumption of natural resources or “a circular approach of keeping resources in productive use in the economy for as long as possible”.	[9]
3	Buildings that are designed, planned, constructed, operated, maintained, and deconstructed in a manner consistent with the circular principles of the economy.	[10]
4	Regenerative closed systems can be achieved through design, maintenance, repair, or reuse.	[11]
5	A life cycle approach that optimizes a building that is useful for life, integrates the end-of-life phases in the design, and uses a new proprietary model in which materials are only temporarily stored in buildings that act as deposit materials.	[12]

.

This approach gives importance to multi-stakeholder decisions involving mutual satisfaction and addresses the key characteristics of life cycle and uncertainty reviews. Behavioral sciences, economics, and engineering apply this rational choice [12]. There is another concept that is known as satisficing [13].

Multi-person decision environments use the concept of group and negotiation to distribute roles. Cooperative decisions are the results that each coalition of stakeholders can achieve and determine the total utility the coalition can share. An integration between many parties is a coalition when each stakeholder obtains more benefits than another member without joining the coalition [14]. Stakeholders can choose to work together and to integrate with one another by forming a coalition. Decisions are made by all stakeholders at each stage of connected construction.

From the circular economics-based concept of connected construction, there are a total of seven concepts used as variables in this study. These variables then become criteria in the decision model. The seven variables are divided into two groups. The first group represents the considerable variables, and the second group represents the desirable variables. The concepts underlying these variables are explained below.

2.1. Capital Expenditure (Capex)

Capex is the first considerable variable. Capex is the costs incurred by an organization or company when they plan to acquire or to maintain assets that are already owned in order to provide long-term benefits [15]. It is also used as a performance parameter of the assets by combining calculations for LCC analysis [16] and the expenses of maintaining assets, including the cost of work for significant repairs [17]. In this sense, capital expenditure is used to improve product quality and to improve production performance to provide satisfaction to customers and to optimize revenue [18]. According to Majanga [17], to remain the best in the market, the organization or company needs to increase its capital expenditure, especially in the development of innovation through research and development. Regarding infrastructure development, capital expenditure is used for restoration or to make new technological breakthroughs to ensure asset performance to the end users to provide value to the community [19]. On the other hand, capital expenditure can increase company performance [20]. Even if the capital expenditure investment is developed with green principles, it will be more valuable for the community and the environment [21].

2.2. Life Cycle Cost (LCC)

The second considerable variable is LCC. LCC is a methodology that uses economic analysis to calculate costs throughout the life cycle of the product or assets in the long term [22]. LCC represents the total costs associated with project development, from the design to the disposal of a building. Life cycle cost is used to increase the life cycle budget at each stage of a project’s life cycle. On this basis, the LCC method functions as a plan for the life of the building and the assets being built [22]. The role of LCC is very important to discuss at the beginning of building design and is commonly used in industrial construction. The characteristics of the calculation to conduct LCC analysis is the use of capital expenditure (capex) and operating expenditure (opex) [22]. To facilitate the implementation of the LCC, the LCC calculation needs to be integrated with building management to make it easier for practitioners using LCC methodology. Comparative analysis studies of green and conventional buildings were also carried out using the LCC methodology [23].

Capex and LCC become two considerable variables as a consequence of the desirable variables that will be obtained from a circular and connected building system. In the decision model, these two variables are the opposite criteria to the desirable criteria for forming a satisfaction-based decision model. The following discussion is about five concepts for decibel variables.

2.3. Sustainability of Building System (SBS)

SBS is the first desirable variable and is obtained from alternative options that are available later on in the construction process, namely a sustainable building representing changeability in the circular economy of construction and that can be accepted by all stakeholders at all of the stages of connected construction. Buildings consist of many systems and important components that play a role in the functions of building performance. As interest in sustainable buildings increases, the main goals of recent building systems have undergone many developments and are varied. Wong and Li [24] define sustainable building systems as smart buildings because these building systems are designed to be interconnected and integrated so that they are comfortable for residents, safe, have low operating costs, are easy to maintain, etc. The economic aspects must be integrated into sustainable buildings to maintain social well-being and to increase the quality of the environment and vice versa [25]. It is difficult to define sustainable building systems; therefore, assessment tools to build objective criteria for sustainability have been offered, such as having framework to assess building sustainability [26]. One of the assessment or rating systems for sustainable criteria was BREEAM, which recognizes eight key categories: site, energy, water, indoor environmental quality (IEQ), materials, waste and pollution, management, and other [27]. The primary goal is to focus on the design and operation of the building to ensure the maintenance of health and comfort while harnessing green technology.

2.4. Energy Efficiency (EE)

It is hoped that the building system selected can provide energy efficiency during the design, construction, and operational stages while also having the ability to become circular. Classical energy efficiency refers to the ratio between the output of the process and the energy input, and this concept is often applied in various fields [28]. In the construction industry, energy efficiency has been highlighted as an important factor for achieving sustainable buildings [29]. There are differences of opinion about the meaning of energy efficiency among researchers, such as in the research by Shove [30], who stated that energy efficiency is minimizing the amount of energy and carbon emissions resulting from building operations, including the energy use and carbon emissions from household appliances, the use of heating and cooling technology, and industrial processes. Li and Tao [28] observed energy efficiency as a measure of the ratio between useful output and energy input. The researchers Harputlugil and de Wilde [31] said that energy efficiency refers to the behavior of occupants related to saving energy in buildings. Developers will often face the choice of making decisions on designs that are conceptualized on sustainability criteria such as a healthy environment, the comfort of residents, and energy efficiency. The basic principle of energy efficiency is to use as little energy as possible during building operation without neglecting the comfort and health of occupants.

2.5. Capture Value Creation (CVC)

This is the third variable acting as a criterion in the decision model and refers to having a background in achieving circular and connected building system choices that produce the best value at all stages of the project and for all existing stakeholders. Basically, value is defined as the achievement of a project according to various criteria and whether or not the project can support the needs and satisfy all of the stakeholders involved. Value is the basis of an organization’s work processes [32]. It can be seen as use value and exchange value. Use value is everything that is subjectively based on the user’s perceptions of the advantages offered by a product. User perception refers to the belief that a product is able to meet needs, desires, and expectations and that it is able to provide a unique experience [33]. The success of a product or service can be based on capturing value and the value created for users. According to this, organizations can create and capture value together [34]. There are three things involved in the value creation process: coordination, consultation, and compromise. Next, the process of capturing value depends on (1) anticipation before and during collaboration; (2) assessment, which keeps all of the actors in the organization motivated; and (3) the application of values, with the aim of improving processes, knowledge, and stakeholder positions simultaneously [34].

2.6. High-Level Three-Party Consortia (HLC)

Connected construction integrates products and stakeholders during the design, construction, and operational stages of a project. At all of these stages, it is expected that all of the stakeholders form a consortium in order to select and overcome the consequences of choosing a circular and connected building system. The collaboration model that forms a network that connects various partners such as organizations or individuals with various types of expertise to complement each other and gain experience and skills is called a consortium. In principle, the network has limited members and is bound by a contract to carry out certain tasks under the cooperation plan [35]. According to the study in [36], the consortium relies on active participation between partners, and the function is to facilitate collaboration and knowledge transfer for project success. The formation of a consortium as a cooperation partner can be adjusted based on objectives. For example, a short-term consortium is formed to complete a particular project, and cooperation will end when the project is completed; alternatively, a long-term consortium may be formed [36]. This is called a sustainability relationship [37].

Achieving a high-level consortium requires a strategy to integrate individuals or organizations as partners in a project. Engebø et al. [38] investigated how to build relationships between stakeholders through trust during the design phase of a construction project. In this case, the initial project meetings, team composition, shared interests, management support, and the use of concurrent engineering can build trust [39]. Research [37] shows that communication, trust, and mutual respect are driving factors in improving the working relationships between stakeholders. In addition to improving working relationships, stakeholder integration can be achieved through attitudes and commitments so that it benefits all parties and supports sustainable relationships.

2.7. Risk Allocation and Transfer (RAT)

Uncertainty characterizes decisions in connected construction. Uncertainty is constituted by different stages, different stakeholders, the circular processes of different building system products, demand identification, analysis, and the allocation and transfer of risks from existing uncertainties. Risk is an event that can be harmful and generally occurs within a certain period. It should be further stated that in order to achieve value for money, it is necessary to allocate and transfer risk. The allocation and transfer of risk are defined as efforts to share and transfer responsibility related to the risks that may occur in a project with all of the parties involved [40]. The allocated risk must be right on target in the sense that the risk is handled by parties who are believed to be able to manage the risk effectively [41].

Good risk management can build trust in a relationship [40] as well as improve performance and sustainable relationships between parties [42]. According to Shrestha et al. [42], in carrying out efficient risk allocation and transfer, three parameters are needed, namely (1) control, in which the party bearing the risk has the ability to minimize the severity of the possible occurrence of risk; (2) information, which refers to parties having information about risks to assist in conducting risk evaluations at the assessment stage; and (3) incentives that encourage related parties to manage risks effectively. Project characteristics influence risk allocation, so it is important to allocate the risk among project stakeholders and to clearly define the contract to achieve decision-making solutions in every stage of the project life cycle [43].

3. Methods

This paper implemented the following methodologies: focus group discussions (FGDs), statistical generalization, and analytical hierarchy processes (AHP). FGDs were used to explore important factors in stakeholder integration as the basis for building decision-making systems for use in connected construction. FGDs were carried out by all of the stakeholders in a large-scale high-rise residential project. The stakeholders were the design management (DM) group, which comprised four people; the project management (PM) group, which comprised six people; and the property/facility management (FM) group, which comprised two people. The PM group is represented by an in-house PM from the developer company. The design management team includes architectural consultants, and the property management team includes the relevant residential management company. FGDs were carried out during the project stage of the testing and commissioning process as well as during the soft opening at the beginning of the handover from construction to operation. Contractors were not involved in the FGDs because the construction process was controlled by the project management team.

AHP was used to obtain the priority weight of each factor based on each stakeholder as well as the aggregation value of all stakeholders. AHP provides a clear rationale by subtracting complex decisions for a series of comparisons and then synthesizing the results. The group also successfully implemented AHP [13]. The analytical hierarchy (AHP) process will allow for more complex hierarchies of AHP, and these may appear at the sub-criterion, sub-alternative, and even stakeholder levels.

The factors analyzed were the considerable factors (two factors) and the desirable factors (five factors). Four steps were included in the stages: The first step is to fill in pairwise comparisons for each stakeholder. The second step is to normalize the pairwise comparisons to obtain the same priority scale. The third step is to determine the priority weight of each factor obtained from the average value of the normalization results. The fourth step is to compare the results of each stakeholder and to analyze them in the form of aggregations and differences in priorities. The stages of the AHP process are presented as part of the decision hierarchy.

The process of the method is shown in Figure 1. There is a two-stage method applied in this paper, including the stage of empirical studies and stage of the decision process. A questionnaire-based FGD was used to obtain empirical confirmation on the basis of the decision criteria. At the stage of the decision process, steps include the determination of the decision hierarchy, criterion analysis, alternative evaluation, and determining the best fit for the connected construction process. The empirical respondents were from the three main stakeholders involved in connected construction: the design management, project management, and property management teams. The figure of the respondents is presented in

Table 2. Information of respondents.

Stakeholders	Number	Percentage
Design Management	38	22%
Project Management	87	49%
Property Management	51	29%
Total	176	100%

.

4. Factors Empirical Study

4.1. Relationship Analysis

Relationship analysis was implemented to predict the relationship between the important factors of stakeholder integration with the connected construction system using regression analysis. The influence of each stakeholder on all of the other stakeholders is presented in Table 2, and the influence of the factors as a whole is presented in

Table 3. Results of relationship analysis.

Model		B	t	p-Value	VIF
Design Management	(Constant)	2.001	1.099	0.280
	SBS (X1)	0.466	1.836	0.076	1.038
	EE (X2)	0.203	0.794	0.433	1.423
	CVC (X3)	0.010	0.038	0.970	1.641
	HLC (X4)	0.276	0.972	0.338	1.184
	RAT (X5)	0.802	3.563	0.002	1.446
Project Management	(Constant)	0.919	3.155	0.002
	SBS (X1)	0.137	2.988	0.003	1.071
	EE (X2)	0.267	3.954	0.000	1.035
	CVC (X3)	0.231	6.570	0.000	1.092
	HLC (X4)	0.186	4.652	0.000	1.118
	RAT (X5)	0.196	4.573	0.000	1.046
Property Management	(Constant)	0.790	3.821	0.000
	SBS (X1)	0.193	6.705	0.000	1.100
	EE (X2)	0.220	6.579	0.000	1.594
	CVC (X3)	0.187	6.236	0.000	1.297
	HLC (X4)	0.190	4.407	0.000	1.176
	RAT (X5)	0.199	5.930	0.000	1.382
All Stakeholders	(Constant)	0.485	1.319	0.189
	SBS (X1)	0.211	4.497	0.000	1.908
	EE (X2)	0.254	5.949	0.000	1.837
	CVC (X3)	0.177	3.519	0.001	1.370
	HLC (X4)	0.144	2.259	0.025	1.350
	RAT (X5)	0.324	6.016	0.000	1.208
Dependent Variable: (Y)

. Here, X1 is sustainability of the building system (SBS), X2 is energy efficiency (EE), X3 is capture value creation (CVC), X4 is high-level three-party consortia (HLC), and X5 is risk allocation and transfer (RAT). X1–X5 will become the desired criteria (d1–d5) in the decision model (Figure 2).

To find out whether there is a correlation between the independent variables in the model being tested, a multicollinearity test was conducted. In the relationship model, multicollinearity can be identified by calculating the value of the variance inflation factor (VIF). VIF is a parameter of the effect of the independent variable on the standard error coefficient of the model. The VIF value determined was VIF < 10 [44]. The results of the analysis found that there is no indication of multicollinearity for each stakeholder and for all stakeholders. The presence of multicollinearity symptoms can reduce the ability of the variables to make predictions and can make it difficult to identify the influence of independent variables.

Next, to determine the effect of each independent variable on the dependent variable, we partially looked at the t value at a significance level of α < 0.005. Based on the table, it is known that for design management stakeholders, only risk allocation transfer (RAT) has a partial influence on the connected construction system, with a value of t = 3.563 (sig. 0.002). Meanwhile, project management and property management stakeholders recorded a significant influence in a positive direction as well as for all stakeholders. The following are the equations obtained based on the results of the analysis:

Design management:

Y = 2.001 + 0.466X₁ + 0.203X₂ + 0.010X₃ + 0.276X₄ + 0.802X₅

(1)

Project management:

Y = 0.919 + 0.137X₁ + 0.267X₂ + 0.231X₃ + 0.186X₄ + 0.196X₅

(2)

Property management:

Y = 0.790 + 0.193X₁ + 0.220X₂ + 0.187X₃ + 0.190X₄ + 0.199X₅

(3)

All stakeholders:

Y = 0.485+ 0.211X₁ + 0.254X₂ + 0.177X₃ + 0.144X₄ + 0.324X₅

(4)

Table 4. Contribution of all factors and predicted relationship.

No.	Model	Adjusted R-Square	F	p-Value
1	Design Management	0.303	4.215	0.005
2	Project Management	0.572	30.702	0.000
3	Property Management	0.799	54.171	0.000
4	All Stakeholders	0.324	21.820	0.000

shows the influence of the independent variables on the dependent variables simultaneously as well as the contribution value of all variables to each stakeholder and all stakeholders.

Based on Table 4, the value of F was used to see the influence of the variables simultaneously, with the significance level of α < 0.005, while the value of the adjusted R² was used to determine the contribution of the independent variable in predicting the dependent variable. Based on the results of the analysis, it can be seen that the design management stakeholders obtained a value of F = 4.215 (sig. 0.000 < 0.005). Project management obtained a result of F = 30.701 (sig. 0.000 < 0.005), and property management had a simultaneous influence of F = 54.171 (sig. 0.000 < 0.005) for all variables. In general, for all stakeholders, all of the variables have a simultaneous influence, with a value of F = 21.820 and significance of 0.000 < 0.005.

Furthermore, based on the adjusted R² value, the contributions of the variables in making predictions for the design management stakeholders are 30.3%, 57.2% for project management stakeholders, and 79.9% for stakeholder property management; for all stakeholders, the ability for the variables to make predictions is 32.4%.

4.2. Integration and Decision Model

This research begins with the formulation of a decision model. The model is based on a satisfaction algorithm that allows decisions to be accepted by all stakeholders at every stage of connected construction. Next, we had to determine the factors used as decision criteria. These factors were determined according to the concepts of CCE, connected construction, and multi-person decision making through FGDs.

4.2.1. The Decision Model

There are five levels in the proposed decision hierarchy (Figure 1). The first level is the goal of obtaining the best option for the building system in connected construction, that is, the best building system that can be accepted by all stakeholders at every stage of connected construction. Unlike the common AHP, this hierarchy is structured to allow the best choice to be made at a level of acceptance that is satisfactory to each stakeholder.

The second level is the two main criteria for forming a satisficing option, namely the considerable criteria and desirable criteria. The considerable criteria must be considered and sacrificed to obtain the result, and the desirable criteria are expected to be obtained. The third level is a sub-criterion of the considerable criteria in the form of costs incurred, which include capital expenditure and life cycle costs. The desirable sub-criteria is derived from the concept of a circular economy and the interests of stakeholders in the choice of building system. The fourth level is an alternative building system, and the last level is the stage in connected construction.

4.2.2. Considerable and Desirable Criteria

Considerable (Pc) and desirable (Pd) are the main criteria for decision models that follow the concept of satisficing game theory. To be able to carry out coalitions and negotiations between stakeholders, the considerations are divided into two categories, namely what is expected and something that can be sacrificed. The stakeholder will pay off the other for each consideration. The final result will be considered through a comparison of values. This satisficing model allows stakeholders to make joint decisions using their respective payoffs.

4.2.3. Factors for Decision Criteria and Stakeholders’ Priority

Sub-criteria for considerable variables include capital expenditure (capex) and LCC. Capex is the overall initial costs and includes the cost of financing capital. LCC covers all costs throughout the duration of the project cycle, from design to operation. Meanwhile, there are five desirable sub-criteria, namely the sustainability of the building system [18], energy efficiency [19], capture value creation [20], high-level three-party consortia [21], and risk allocation transfer [22].

Based on the pairwise comparison for each stakeholder, their preferences can be seen in Figure 2. The numbers of each matrix cell are obtained by dividing each matrix cell during the pairwise comparisons by the total number of columns in the paired comparison field. There are different priorities for each stakeholder. In Figure 3, it can be seen that each stakeholder has different priorities. Property management teams prefer energy efficiency, while project management teams tend to choose a high-level three-party partnership. Meanwhile, design management teams indicated that value creation was a priority. These different priorities can be understood because of different interests and different performance measures. In the figure, it can also be seen that with the average size, the high-level consortium factor of the three parties becomes the optimal priority for the three stakeholders. There is one factor that was not chosen by anyone as a priority, namely the sustainability of the building system. The results of the weighting for project management and property management stakeholders can be seen in the comparison of the priority factors according to each stakeholder.

4.2.4. Building System Alternatives and the Priorities

The three alternatives proposed in the decision model including stakeholder integration are based on how the building system is generated. The first is from the internal system, the second is from the external system, and the third is the combination of such systems. External systems refer to the involvement of external systems that carry out the functions of the building system, for example, systems and technologies that are separate from the building design, including the systems connecting buildings. Combining systems means using both systems by considering optimization and the trade-offs between the two systems. Examples of building systems that can be explained through the use of these alternatives are building energy, mechanical and electrical energy, roofing, and others.

Table 5. Satisficing option process for design management.

	Considerable (Pc)				Desirable (Pd)						Normalization
	c1	c2	Cost	Loss	d1	d2	d3	d4	d5	∑	(Pc)	(Pd)
Design Management
Internal System	0.152	0.286	0.438	0.157	0.034	0.046	0.164	0.007	0.019	0.270	0.200	0.270
External System	0.086	0.071	0.157	0.438	0.058	0.020	0.051	0.047	0.005	0.181	0.557	0.181
Process Combination	0.262	0.143	0.405	0.191	0.194	0.103	0.216	0.023	0.012	0.549	0.243	0.549
Project Management
Internal System	0.261	0.082	0.342	0.315	0.008	0.020	0.063	0.039	0.136	0.265	0.324	0.265
External System	0.148	0.020	0.168	0.490	0.013	0.009	0.020	0.265	0.037	0.344	0.503	0.344
Process Combination	0.449	0.041	0.490	0.168	0.044	0.045	0.083	0.133	0.086	0.391	0.173	0.391
Property Management
Internal System	0.051	0.476	0.527	0.148	0.026	0.142	0.051	0.004	0.042	0.265	0.144	0.265
External System	0.029	0.119	0.148	0.527	0.044	0.063	0.016	0.027	0.011	0.161	0.515	0.161
Process Combination	0.087	0.238	0.325	0.349	0.148	0.318	0.068	0.013	0.027	0.574	0.341	0.574

present the satisficing process to obtain the value of each alternative for each stakeholder. Figure 4 clearly shows the Value = desirable (Pd)/considerable (Pc) for the alternatives.

The design management teams chose process combination as the best alternative. The exploration of designs for both building energy systems can be expanded with creativity. The project management teams decided that external systems were the best choice. This decision was based on capex preferences. Based on the highest property value impact on the combination of the building’s internal energy system and process combination, the property management team selected process combination as the best alternative. Although it is the same as design management, there are differences in the underlying criteria.

In this process, each stakeholder assigns a priority value to each alternative using a satisficing algorithm, where each alternative is assessed based on a comparison of the two axes (x and y) between what is considered (cost) and what is expected to be obtained. To make this comparison, the measurement scales of the two must be equated. In AHP analysis, low costs have a high value, so loss is measured first. This is different from what is expected to be obtained in situations in which high yields have high values as well. Finally, each x and y axis is normalized and compared with the desirable with considerable variables to obtain alternative values as the basis of priority.

4.2.5. Stakeholder Integration and Connected Construction

Every construction stakeholder can benefit from connected workflows, teams, data, and technology throughout the life cycle of a construction project to enhance collaboration. Connected construction stages include planning and design, construction, and operation. The planning and design stage includes initiation in the form of ideas, the refinement of ideas through a simple market test, and investment decisions and feasibility, schematic design, architectural design, and design development. During the construction stage, the project is implemented according to the design to a real product, including negotiations and formal commitments at the procurement stage. The preliminary stage is a transitional stage that takes place from the completion of construction to the operational stage. This is a critical stage, during which the project is completed and moves on to operational activities. This includes the transition process, commissioning, and testing as well as the introduction of market behavior input through the soft opening and grand opening processes. At the operational and maintenance stages, business activities are conducted to ensure returns on capital.

There are at least three stakeholders with very different and alternating interests at each stage of connected construction. Performance preferences and acceptance are different. For example, project management and property management have opposite preferences for cost. Project management is dependent on initial costs (capital expenditure), while property management is dependent on life cycle costs, especially those related to operations and maintenance.

Figure 5 presents how the key stakeholders at each construction stage are connected and integrated. Property management can be present from the design stage and the construction stage. In high-rise residential properties, this condition is very beneficial because there are still end users who have very different characteristics, and it is only possible that knowledge about them is held by experienced property management teams. There are different stages that allow all three stakeholders to meet during the construction stage. However, it is not easy to integrate all stakeholders because of the different contractual relationships between stakeholders.

The consequences of the different preferences of each stakeholder cause the choice of alternative priorities to also be different. They also affect the priority of alternative choices during different stages of the connected construction process. There are five connected construction processes that are considered, namely the design process only, the construction process only, the operational process only, the joint design and construction process (for example design build), and the joint design, construction, and operational process (for example, design-build-operate).

Table 6. The value of each alternative and each stakeholder based on connected construction process.

	Design Management		Project Management		Property Management
	Pc	Pd	Pc	Pd	Pc	Pd
Internal System
Design	0.023	0.014	0.018	0.014	0.027	0.014
Construction	0.039	0.024	0.031	0.024	0.047	0.024
Design and Construction	0.039	0.024	0.031	0.024	0.047	0.024
Operation	0.267	0.165	0.209	0.162	0.322	0.162
Design, Construction, Operation	0.069	0.042	0.054	0.042	0.083	0.042
External System
Design	0.069	0.079	0.073	0.150	0.065	0.070
Construction	0.029	0.033	0.031	0.063	0.027	0.030
Design and Construction	0.007	0.008	0.008	0.016	0.007	0.008
Operation	0.009	0.010	0.009	0.019	0.008	0.009
Design, Construction, Operation	0.044	0.050	0.046	0.095	0.041	0.044
Process Combination
Design	0.028	0.037	0.033	0.027	0.022	0.039
Construction	0.103	0.140	0.125	0.100	0.083	0.146
Design and Construction	0.209	0.284	0.253	0.202	0.168	0.296
Operation	0.027	0.036	0.032	0.026	0.022	0.038
Design, Construction, Operation	0.038	0.052	0.046	0.037	0.031	0.054

presents how the priority value of each alternative is determined based on the considerable (Pc) and desirable (Pd) values. For each connected construction process based on the circular economy, there are different alternative priorities according to each stakeholder. The illustration of the value is presented in Figure 6. It can be seen that for the internal system alternatives, overall, the value of Pc is quite a bit higher than the values of Pd. Alternatives two and three have the same tendency, with Pd being higher than Pc, but for the external system alternative, both x and y almost coincide with one another. The third alternative is the combination process representing the best fit for the entire construction process and that can be accepted by all stakeholders.

The results of this model are different from those of existing general decision models. This model has two alternative hierarchies with different domains; they are not sub-alternative. The two alternatives are first: the development of the product and the connected construction for product development. In general decision models, there is usually only one alternative hierarchy or two hierarchies but in the form of alternatives and sub-alternatives.

5. Discussion

5.1. Design Management

Fundamentally, the circular economy in construction is about the practices used across all stages of the project life cycle to optimize the life of a building and to reduce the use of new natural resources [8]. In this context, the circular economy should be introduced from the early stages of the project, especially in the design phase. This is because the design phase is the stage of the project life cycle that determines the outcomes of decisions the most, including how to design building products with the best value [33]. Design management chooses capture value creation as a priority in a circular and connected building system. These results confirm research results by [32] that a designer has four goals when creating and capturing value: reputation, development, pleasure at work, and money [3]. Reputation is concerned with building a positive image through improving project quality. This is because clients generally choose a design company based on their reputation in the field and their expertise. Therefore, the delivery of high-quality projects is an important goal of design management to build reputation. Next is development, which is intended to increase competitive advantage through the use of design technology tools for innovation. The third is the pleasure of work, which is where the work produced can be appreciated and when the people involved in a project have fun. The last is money. This refers to a business perspective in which the purpose of work is to generate income and make a profit. In short, compared to other stakeholders, design management has the opportunity to capture and create the highest-value product during the project life cycle.

The second factor is the sustainability of the building system, and energy efficiency received a moderate rating according to management design. This can be related to stakeholders of design management being the main controller promoting the circular economy into its design objectives. However, the designer generally executes the design based on the performance requirements identified as wishes or expectations originating from the project owner. In other words, the project owner plays an important role in determining the requirements of design [12]. According to Charef et al. [5], this is can be an obstacle in implementing circular economy construction during building, especially if the results of building products change ownership. It is different if the project owner plans to occupy the building, as it is possible to ensure that the building achieves optimal performance and reduces its long-term operational costs [36]. Furthermore, property management considers both as important factors because they are related to the role of property management as a stakeholder who is responsible for the operational performance and maintenance of the building [36].

The next factor that receives the lowest priority for design management stakeholders and that is the highest-priority factor for project management is high-level three-party consortia. Consortium factors relate to factors that support multi-stakeholder collaboration to achieve integration at all stages of the project from design to deconstruction. The stakeholders involved have a common understanding of how to achieve sustainability goals. The collaboration support factor is knowledge sharing, trust [38], commitment [39], clarity of project objectives, communication, contractual agreements, etc. [35]. Furthermore, consortium factors can also build sustainable multi-stakeholder relationships [37]. However, the consortium factor obtained conflicting scores from stakeholders in design management and property management. This result is confirmed by research conducted in [36], which indicates that currently, awareness of the involvement of multiple stakeholders from the early stages of the project is still very low, specifically regarding the involvement of property management. This is related to the increase in project costs charged by the project owner if property management is involved from the onset of the design process. Another thing also highlighted is the almost non-existent ongoing relationship between the designer with property management. Only a few designers maintain ongoing relationships in order to evaluate the results of their design innovations after the building is operational. Therefore, design management considers the consortium factor to be a less important factor.

Risk allocation and transfer is the factor with the lowest score based on the results of the management design stakeholders; however, it became the second-highest priority factor for project management stakeholders. This result is in line with the research by Zou and Zhang [41], which stated that in the project phase, most of the risks tend to come from contractors and sub-contractors, which means that this occurs in the construction phase. In the construction phase, design errors have generally been corrected. For example, the risk associated with inaccurate budget estimates is no longer a price error set in the design process but rather is set to cost control during the construction phase. Therefore, project management stakeholders allocate and transfer risks based on the contracts entered into with project owners [40], with the aim to reduce conflicts during the project implementation phase. Property management places risk allocation as the priority with the lowest score because it is related to the handover of project work to end users, representing the completion of the construction project.

5.2. Project Management

Based on the weighting of stakeholder priorities, project management stakeholders choose high-level three-party consortia as the highest priority, followed by stakeholder design management. The role of project management stakeholders will be greater in the planning and design phase and during the construction phase. Project management determines the goals and expectations of the end users through collaboration with stakeholders in the planning phase by maximizing the value-creation process. The project will be carried out based on cost considerations such as LCC and capital cost, and the development of assets with a circular concept will add value to the environment and end users [21]. This once again depends on establishing stakeholder value equality and is based the results of collaboration between project consortium participants [32].

To achieve the execution of the plan, commitment and collaboration strategies are needed through a high-level consortium comprising the three parties during the transition between project design and project execution [39]. The success of the commitment will be determined by the presence of a high degree of trust. In the planning phase, stakeholders require a high sense of trust due to a new project team being formed through delegation from each consortium. This fosters a sense of trust and requires a space and time during the process [38].

This finding is in line with the research by Faris et al. [35], in which project management stakeholders were shown to enhance the collaborative process from the planning to the execution phase to achieve a project performance that meets expectations. The decision-making process will be supported by project vision, relationship definition, communication, systematic processes, and contractual agreements [35]. Then, the stakeholders will proceed with the risk allocation criteria, becoming involved with the commitments in a project life cycle, and risk allocation will become an aspect that will support the consortium agreed upon by the participants. The decisions made will be based on risk allocation criteria to achieve long-term performance management of the construction project.

The factors related to the energy efficiency and sustainability of a building system are the last priority in the decision-making processes of project management stakeholders. Project management tends to have a profit-maximizing vision and tends to carry out designs that have been designed by design management stakeholders. The achievement of the criteria for energy efficiency and sustainability of the building system requires a long amount of time so that the role of project management is minimal. Additionally, attributes to reduce energy are dominated by building materials, technology utilization [29], and user habits [31]. Thus, the decision will return to the design process.

5.3. Property Management

Property management is a professional field that plays an important role and that has an import responsibility in managing building operations. This is based on property management choosing energy efficiency as the first priority and the sustainability of the building system as the second priority. Buildings are places where people spend a great deal of time, so the use of energy in buildings aims to provide a healthy and comfortable environment for the end user. In this regard, the research of [6] showed that buildings account for about 60% of global energy use, resulting in the appearance of a strong awareness regarding saving energy [31]. One of the strategies to increase the life cycle of buildings and to provide a comfortable environment for occupants (including thermal comfort, reduction of energy costs, and minimizing environmental impact) is through energy efficiency [6]. On the other hand, the use of sustainable building systems can also encourage a circular economy through the reuse of building elements after the demolition period so as to provide benefits from an economic and environmental perspective [11].

Meanwhile, risk allocation transfer and capture value creation received moderate ratings from the property management team. Property management takes on roles related to risk allocation that may occur during the operational phase, for example, the occurrence of operational cost overruns, disruptions during the operational phase, lack of quality of building services, and the maintenance levels that are not as planned. Property management will seek to build a relationship through trust to manage this risk as best as possible because it relates to maintaining a long-term reputation. The capture value creation is used by property management to achieve service quality that can provide satisfaction to project owners or their clients [3].

The last rating is high-level three-party consortia. As mentioned in Section 5.1, property management places this factor as the last priority because after the building is operational, design management and property management stakeholders are generally no longer involved, so long-term relationships with property management stakeholders are rare. Usually, the sustainability of the relationship only occurs as an evaluation material for design management and project management stakeholders in order for them to make improvements during their next project [36].

6. Conclusions

Circular economics can be applied to multiple stakeholders by applying the concept of connected construction. Decisions involve various stakeholders at different stages. Integration is a complex problem because it is not only a multidisciplinary problem but also the problem of multiple shareholders who have similar goals among themselves. Often, these stakeholders are not legally bound, so there has to be a coalition between them. This includes accommodating negotiations to obtain a total optimal payoff that does not result in a deadlock. Verification in the form of empirical decision making and modeling the automation of its negotiations act as recommendations for further research. The stakeholder integration factors presented in this paper are expected to provide information on both theory and practice to serve as the basis for joint decision making that enables further research on automation systems. A system with an agent coordinator function that performs integration through negotiation and or a decision-support system (NSS/DSS) would be beneficial.