Theoretical model of trust-based relationships in building information modelling supply chain for construction projects

The structure of relationships among project participants has a significant impact on trust development, while the number of participants involved in the relationship increases the complexity of trust. Hence, it becomes inappropriate to generalise the existing dimension and components of trustbased relationships to trust-based relationships among the building information modelling (BIM) supply chain members because of the multiple structures of relationship and the numerous interpersonal and inter-organisations that participate on BIM-based construction projects. This article investigates the nature of trust-based relationships among the BIM supply chain members and establishes whether the requirements of the BIM process influence trust-based relationships among the BIM supply chain members. A five-stage PRISMA was adopted for systematic reviews and metaanalysis. The systematic review enabled the development of a theoretical model of trustbased relationships in BIM supply chain which was subjected to meta-analysis for validation. Acta Structilia 2019: 26(2) 108 The findings revealed that trust-based relationships among the BIM supply chain members entail trusting and trustworthy behaviours, positive expectations, and positive reputations, under which twenty-seven components were identified and classified appropriately. The article concludes that the nature of trustbased relationships among the BIM supply chain members, as influenced by the requirements of the BIM process, can be explained as trusting and trustworthy behaviours, positive expectations, and positive reputations. The article advances the understanding of trust-based relationships among the BIM supply chain members and recommends a first-hand investigation into the nature of trust-based relationships among the BIM supply chain members in future studies.

The structure of relationships among project participants has a significant impact on trust development, while the number of participants involved in the relationship increases the complexity of trust. Hence, it becomes inappropriate to generalise the existing dimension and components of trustbased relationships to trust-based relationships among the building information modelling (BIM) supply chain members because of the multiple structures of relationship and the numerous interpersonal and inter-organisations that participate on BIM-based construction projects. This article investigates the nature of trust-based relationships among the BIM supply chain members and establishes whether the requirements of the BIM process influence trust-based relationships among the BIM supply chain members. A five-stage PRISMA was adopted for systematic reviews and metaanalysis. The systematic review enabled the development of a theoretical model of trustbased relationships in BIM supply chain which was subjected to meta-analysis for validation.
The findings revealed that trust-based relationships among the BIM supply chain members entail trusting and trustworthy behaviours, positive expectations, and positive reputations, under which twenty-seven components were identified and classified appropriately. The article concludes that the nature of trustbased relationships among the BIM supply chain members, as influenced by the requirements of the BIM process, can be explained as trusting and trustworthy behaviours, positive expectations, and positive reputations. The article advances the understanding of trust-based relationships among the BIM supply chain members and recommends a first-hand investigation into the nature of trust-based relationships among the BIM supply chain members in future studies.

Introduction
Trust as a concept is complex and dynamic, because it is difficult to create and slow to develop (Woolthuis, Hillebrand & Nooteboom, 2005: 821). Buvik andRolfsen (2015: 1485) as well as Bakker (2010: 467) subscribe to the complexity of trust by indicating that it requires time, the experience of other parties' trustworthiness, and prior collaboration to build. Similarly, Diallo and Thuillier (2005: 238) describe trust as a psychological state that brings about constructive interaction without fear of selfish intentions or hidden motives from partners. Despite its complexity, trust is fundamental to successful interactions and dispositions among the construction project supply chain (McKnight & Chervancy, 2000). Swan, Wood, McDermott and Cooper (2002) confirm that trust is essential for achieving flexibility, ensuring a smooth flow of information, and ensuring effective collaboration in construction project supply chain. Nooteboom (1996: 987) claims that trust is an interaction that indicates a positive perception of an intention to behave in a trustworthy manner. Simons and Peterson (2000: 108) establish that trust has a positive impact on conflicts, costs, and team effectiveness. Complementary to this, Erdem and Ozen (2003: 133) maintain that trust causes the development and protection of the team spirit by providing cooperation and solidarity among team members. Trust-building requires time. However, owing to its importance to the success of construction project delivery, construction project supply chains (CPSCs) are allowed to develop a 'temporary trust' (trust-based relationship) because of the temporary nature of construction projects (Diallo & Thuillier, 2005: 240;Chow, Cheung & Chan, 2012: 931). Bachmann and Inkpen (2011: 286) posit that a trust-based relationship (TBR) is an interactive process on which trusting behaviour develops. Although TBR is permissible for CPSC, its development is influenced by the characteristics of construction projects and the nature of relationships in construction projects. Construction projects are temporary, unique, limited by time, and characterised by a high number of participants. All these characteristics have an impact on trust development (Simons & Peterson, 2000: 110). The nature of relationships in construction projects is such that the participating members have to work with new, old, unfamiliar, and heterogeneous members. The effect of this type of relationship on trust development is significant, because there may be no history of interactions, dispositions, and priorities among the members which are imperative to trust development (Buvik & Rolfsen, 2015: 1487. The nature of relationships in, and the characteristics of construction projects generate hierarchical and non-collaborative interactions among the project participants. This has given rise to opportunities such as excessive change orders and decentralised decisions for the pursuance of self-interest by the project participants (Kadefors, 2004: 176). The solution to this problem, according to Khalfan, McDermott and Cooper (2004: 2), is an integrated CPSC wherein the supply chain is centrally coordinated; relationships in the chain are maintained during and beyond a specific project; the chain is directed towards sharing of information and transfer of knowledge; there is optimised integration, collaboration, and sharing of risks.
An integrated CPSC typifies a Building Information Modelling Supply Chain (BIM-SC), because it significantly correlates with informationsharing, network communication, and knowledge transfer, all of which are the hallmark of BIM-based construction projects and BIM-SC (Taylor & Bernstein, 2009: 71;Papadonikolaki, Vrijhoef & Wamelink, 2016: 486;Talavera, 2013;Chu & Fang, 2006: 225). This implies that a BIM-SC automatically forms in BIM-based construction projects and that its members are expected to avoid the exploitation of opportunities for the pursuance of self-interests. In so doing, members of the BIM-SC are obligated to undertake TBR for decision-making, information model development and exchange, communication, and collaboration. This will enable members of the BIM-SC to understand their respective responsibilities in the BIM process as well as each other's needs and concerns, thereby guaranteeing a successful construction project delivery (Talavera, 2013).
The dimensions of TBR such as goodwill and attitude, as provided by these existing models of TBR, denigrate the interactive process of TBR and contradict the complexity and requirements of trust development in a supply chain. Apart from the contradictions in these existing models of TBR, they are inadequate for explaining TBR in BIM-SC for three major reasons. First, a BIM supply chain is network-related in that it consists of multiple interpersonal and interorganisational relationships such as client-contractor, contractorconsultant, contractor-supplier, BIM manager-project manager, and BIM manager-BIM coordinator. Secondly, the BIM process comes with certain expectations such as, for example, integration, cooperation, coordination, interoperability, and collaboration that alter the nature of supply chain relationships. Thirdly, in BIM-SC, representatives of the participating organisations have a personal and organisational trustworthy reputation to protect (Lau & Rowlinson, 2011: 640). Thus, it becomes clear that the concept and dimensions of TBR vary, based on the structure of relationships and the number of parties involved in the relationship. The structure of relationships has a significant impact on trust development, while the number of parties involved in the relationship increases the complexity of trust (Simons & Peterson, 2000: 111). With BIM-SC exhibiting multiple structures of relationship and multiple interpersonal and inter-organisational participants, it becomes inappropriate to generalise the existing dimension and components of TBR to BIM-SC (Wong, Cheung, Yiu & Pang, 2008: 823;Costa, 2003: 615).
This article aims to understand the nature of TBR in BIM-SC and establish whether the requirements of the BIM process influence TBR. In this article, the term BIM supply chain (BIM-SC) refers to short-or long-term networks of multidisciplinary BIM-based project participants such as clients, subcontractors, main contractors, suppliers, and BIM consultants (Getuli, Ventura, Capone & Ciribini, 2016: 545;Papadonikolaki et al., 2016: 480;Papadonikolaki & Wamelink, 2017: 652;Robson, Boyd, and Thurairajah, 2014;Nawi, Haron, Hamid, Kamar & Baharuddin, 2014: 7;Wu, Mao & Li, 2017: 43). Members of the BIM-SC denotes BIM-based project participants as represented by persons or organisations. TBR refers to direct and intense interaction and dispositions that are based upon positive expectations of the behaviour and intentions of another over time.

Theoretical framework
Trust as a concept is multifaceted in nature. Therefore, to effectively capture the complexity or multifaceted nature of TBRs in BIM-SC, this article draws from theoretical perspectives in Behavioural Decision Theory, Social Exchange Theory (SET), and BIM-enabled collaboration theory. The theory of Behavioural Decision-making in construction projects postulates on the actuality of project decisions such as trust, commitment, and risk management, as well as the influence of these decisions on project participants (Stingl & Geraldi, 2017: 126;Morton & Fasolo, 2009: 270;Lloyd-Walker, Mills & Walker, 2014: 233). The SET, on the other hand, explains the relational exchange and mutual dependence among a network of actors, by postulating that social exchange occurs when the exchange partners have resources of value to exchange with each other and they must conduct an analysis of the exchange afterwards (Zeng, Huang & Dou, 2009: 7;Cropanzaro & Mitchell, 2005: 879;Chinowsky, Diekmann & Galotti, 2008: 808).
BIM application on construction projects requires the initiation and sustenance of collaboration among the BIM-SC right from the early phases of construction projects through information-sharing and exchange, knowledge-sharing and transfer, communication, and collaborative procurement (Manu et al., 2015(Manu et al., : 1499. This indicates that the BIM process is more about cooperation and collaboration, and that trust is an important ingredient for the continuous nurturing of collaborative processes (Vangen & Huxham, 2003: 11). These insights are summarised in the following five major principles that are significant to understanding TBR in BIM-SC: • Trust is a behavioural decision to be made by members of the BIM-SC.
• Trust is a resource of exchange among members of the BIM-SC.
• Trust is an element of collaboration in the BIM process.
• Successful collaboration among members of the BIM-SC depends on TBR.
• Relationships among members of the BIM-SC manifest as collaboration through information-sharing and exchange, knowledge-sharing and transfer, communication, and collaborative procurement.
This was done so as to make available a theoretical grounding that will guide the formulation of the model of TBR in BIM-SC. Construction projects require heterogeneous relationships (Buvik & Rolfsen, 2015: 1488, while BIM-SC entails multidisciplinary collaboration (Manu et al., 2015). This understanding differentiates the relationships in construction projects from the other types of relationships and supports the complexity of TBR in BIM-SC. Figure 2 explains the nature of relationships in BIM-SC and shows that TBR in BIM-SC can manifest in a variety of ways (see Figure 2):

Theoretical model
• 'Interpersonal relationships': a relationship involving or occurring between two or more people. For example, client and main contractor, client and subcontractor, BIM manager and BIM coordinator, BIM manager and project manager, client and BIM consultant, and client and BIM manager.
• 'Organisational relationships': a relationship between a person or organisations other than the one s/he represents or works for.
• 'Intra-organisational relationships': a relationship between multiple individuals across two or more organisations.

Theoretical background 2.3.1 Trusting and trustworthy behaviours
Behaviour is a pattern of reactions over time or a manifestation of intentions through actions. In relation to trust, behaviour could manifest as trustworthy behaviour (actions that demonstrate trustworthiness), trusting behaviour (action that demonstrates how a truster relies on a trustee), or as both (Lazzeri, 2014;Vidotto, Massidda, Noventa & Vicentini, 2012: 581). Behavioural problems in interpersonal and/or inter-organisational relationships usually manifest as injurious behaviour, duplicitous behaviour, inconsistent behaviour, haughty behaviour, or opportunistic behaviour (Talavera, 2013). According to Jagtap and Kamble (2015: 23), opportunistic behaviour emanates from the lack of trust among the supply chain members, with features such as motive to maximise one's self-interest, failure to interact, and misuse of information.
Likewise, Jaffar, Tharim and Shuib (2011: 197) identify behavioural problems among construction project supply chain members as including reluctance to check the clarity of information, professional stereotypes, and poor communication. Ensuring the absence of behavioural problems in relation to the collaborative requirements of BIM-SC means that certain cooperative behaviours such as reliability, promise fulfilment, and fairness are expected of members of the BIM-SC (Mayer et al., 1995: 7, 15). Talavera (2013) claims that collaborative requirements of BIM-SC, as manifested in cooperative behaviours, are founded on trusting and trustworthy behaviours, because they refer to the absence of behavioural problems in that they prevent members of the BIM-SC from pursuing personal or professional interests and misusing shared information. A study by Zhang, Lu and Rowlinson (2013) reports a case study of BIM-based projects, where members of the BIM-SC, who exhibited behavioural problems, are swiftly replaced with new members because of the need to sustain cooperative behaviours among members of the BIM-SC. The study further links the absence of power conflicts and hierarchical behaviours to trusting and trustworthy behaviour among members of the BIM-SC.
Conclusively, trust develops over time and, in construction projects, the long-time relationship is not feasible, owing to the temporary nature of construction projects. Hence, trust and trustworthy behaviour become essential to trust development among members of the BIM-SC, because such behaviours accelerate trust development. With regard to the link between trust and trustworthy behaviours, a case can be made that trusting behaviour is the same as trustworthy behaviour, because trusting behaviour promotes trustworthy behaviour and trustworthy behaviour nurtures trusting behaviour (Barr, 2003: 621). Tanis and Postones (2005: 418) agree with this claim, explaining that, in a group, team or supply chain, members engage in trusting behaviour, because they expect their behaviours to be reciprocated by other members.

Positive expectations
Positive expectations are positive noteworthy contributions towards the success of construction projects by members of a BIM-SC (Nalewaik & Mills, 2015: 6;Nalewaik, 2011), because they help members anticipate the needs, concerns, and interests of one another. Traditionally, the components of positive expectations from project supply chain include discretion, reliability, competence, integrity, concern, benevolence, consistency, foresight, intuition, empathy, commitment, self-awareness, responsiveness, and value congruence (Chow et al., 2012: 929;Das & Teng, 2001: 261;Mishra, 1996: 261;Costa & Anderson, 2011: 131). However, in construction projects, together with the collaborative requirements of BIM, greater responsibilities are placed on members of the BIM-SC. These responsibilities represent positive expectations from members of the BIM-SC and cut across roles, competencies, ethics, skills, and contractual relationships (Husain, Razali & Eni, 2018: 411).
The positive expectations that enable TBR among members of the BIM-SC are risk-sharing, cross-functional cooperation, the competence of personnel and organisation, problem-solving ability, openness in sharing information, lack of confrontation and adversarial relationship, work and social interaction, conflict resolution, and absence of competing interests (Mikapagaro & Germin, 2018: 138). For example, in a case study of BIM-SC reported by Zhang et al. (2013), openness in sharing information was a major positive expectation from members of the BIM-SC, as every member of the BIM-SC is expected to update and upload each revision of discipline-specific information models to the integrated BIM database rather than delivering it to the BIM manager.

Positive reputation
Because of the short-term and multiple nature of relationships in BIM-SC as well as the requirements of the collaborative interaction of the BIM process, positive reputation becomes an essential part of TBR in BIM-SC, because it helps predict trustworthy behaviours and positive expectations of members of the BIM-SC (Cicmil & Marshall, 2005: 529). Trustworthy behaviour and positive expectations reveal a trustworthy attribute on the part of members of the BIM-S, but it is only a consistent occurrence. These attributes lead to a positive reputation (Aqueveque & Ravasi, 2006). Without prior ties and prior collaboration, abundant time to study the trustee's attributes and experience of the trustee's trustworthiness, a truster will have to engage in TBR with the trustee, based on his forecast of the trustee's positive reputation (a set of consistent positive attributes) (Vidotto et al., 2012: 583). This is a typical arrangement for accelerated trust development among members of the BIM-SC. However, any negative attributes from any member of the BIM-SC are detrimental to trust development (Kadefors, 2004: 177). Notwithstanding the need for accelerated trust development among members of the BIM-SC, one-off positive attributes such as honesty and mutual commitment are required to initiate the process of trust development at the early stages of the construction projects. This must be followed up with a consistent exhibition of some unique positive and trustworthy attributes such as integrity.
As pointed out by Jiang, Lu and Le (2016: 428), integrity is a function of circumstances and opportunities. If it does not happen consistently, the individual or organisation in question cannot be said to possess integrity. A positive reputation is, therefore, defined as a set of consistent positive attributes of an entity (organisation or individual). An example of studies providing support for positive reputation as a dimension of TBR in BIM-SC is the study by Jamal and Bakar (2017), in which positive reputation is associated with efficiency and a high level of professionalism. Similarly, Naismith, Price, Dainty, Bryman, Greasley and Soetanto (2005: 16) report that a reputation for consistent positive attributes is a necessity for the occurrence of integration and collaboration on construction projects. Naismith et al. (2005: 20) further identify positive reputation such as honesty, integrity, commitment, and confidence in other members, as significant factors in TBR.
In summary, there is no TBR without positive reputation. As positive expectations and trusting and trustworthy behaviour ensure the initiation and development of TBR in BIM-SC, positive reputation maintains the TBR at the later stages of construction projects or possibly on subsequent construction projects. The BIM-SC is expected to collaborate through all the stages of a construction project and, if possible, on subsequent construction projects. Therefore, a positive reputation is an important ingredient of TBR in BIM-SC.

Research methods
This study adopts the 5-stage Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method proposed by Shamseer, Moher, Clarke, Ghersi, Liberati, Petticrew, Shekelle & Stewart (2015). A systematic review attempts to collate all relevant evidence that fits pre-specified eligibility criteria, in order to answer a specific research question (Shamseer et al., 2015: 3). PRISMA outline a structured guide (protocol) that researchers agree to follow, in order to manage identification, screening, eligibility, and inclusion of articles that formed the body of research studies included in their investigation (Shamseer et al., 2015: 3). For this article, the 5-stage process includes defining the criteria for collecting articles from the data set (Scopus, Engineering Village, Ebesco, Google Scholar, and Web of Science); searching for articles in the data set; identifying dimensions from the articles; categorising the dimensions with variables (components), and conducting a meta-analysis. The criteria for collecting articles from the data set stipulate that the articles must be peer-reviewed, within the fields of trust and trust-based relationships in construction supply chain and BIM-SC, written in the English language, and not have been published prior to 1997.

Data-collection method
The actual searching for articles in the data set was done using keywords such as BIM-enabled trust, trust-based relationships in construction supply chain/BIM supply chain, relationships among project participants in BIM, effects of BIM process on stakeholders' relationships, and BIM requirements and trust development. In total, 1,984 articles were collected at this stage. These articles were screened for eligibility by checking the relevance and content of their titles and abstracts. The searching and screening stages together with their respective number of articles are illustrated in Figure 3. Data from these articles were extracted onto structured fill-in forms with headings showing the formal data such as the purpose of the study, the method of data collection, a summary of the study's aim, the country where the study took place, and the method of analysis.

Data analysis and interpretation
The selected articles were analysed to identify the dimensions and components of TBRs in BIM-SC. The analysis was done using ATLAS. ti 8 Qualitative Research Tool following the procedures outlined by Smit (2002: 69-70). The coding process for the analysis was carried out by assigning categories and concepts to the various segments of information that relate to the research objectives. The analysis was interpreted and summarised using qualitative data set synthesis process. According to Major and Savin-Baden (2010: 130), data set synthesis brings original insights and mechanism to understand a phenomenon through a collective body of research. The synthesis process includes categorising the identified concepts into major themes (dimensions and components) and reaching consensus on the major themes, in order to assure credibility. The analysis was summarised graphically using a descriptive figure (see Figure 1). The analysis yielded three dimensions (positive reputation, positive expectations, and trusting and trustworthy behaviours) and twenty-seven components as the dimensions of TBRs in BIM-SC. Positive reputation has 5 components; positive expectations have sixteen components, and trusting and trustworthy behaviours have 6 components.
The validities of the components were determined using metaanalysis (effect size and percentage of mention of the components). Meta-analysis uses statistical techniques to combine and summarise the results of multiple studies/articles and report the findings in terms of effect sizes (Hunter & Schmidt, 2000: 278-280;Rosenthal, 1995:184).
For this article, the statistical analysis was done by determining the number of studies mentioning the components, the sample means, the frequency of mentioning the components, the population mean, the percentage of mention, and the effect size. The frequency and number of studies mentioning the components were identified from the outputs of the ATLAS.TI 8. A cloud-based statistical analysis tool (online calculator) from Select Statistics was used to calculate the sample means and the population mean (SelectStatistics, n.d.: online). The sample means were determined using the total number of articles and the number of studies mentioning the components. The percentage mention of each component was based on the total number of studies mentioning the components and the frequency whereby these studies mentioned the components. The effect size was estimated using a cloud-based practical metaanalysis software (online calculator) from Campbell Collaboration (Wilson, n.d.: online). Only components with an effect size of 0.2 and above were considered relevant.

Results
Tables 1-3 present the meta-analysis estimates for the components of TBR among members of the BIM-SC and show overwhelming evidences for the components as valid elements of TBRs among members of the BIM-SC. Specifically, Table 1

D = Cohen's d effect size, F = frequency of mention in the database, N = Number of studies mentioning the components, χ = Sample mean
Although the results suggest that positive reputation is mainly characterised by the 'mutual exchange of ideas' and 'exploiting each other's strength', according to the strength of the effect size and percentage of mention, it also suggests that all the components characterise positive reputation, because they have an acceptable effect size and more than 10% of mention by the studies in the meta-analysis.

5.
Discussion of findings

Influence of BIM process requirements on TBR
Based on the theoretical model and meta-analysis estimates, this study identified 3 elements that determine TBR among members of the BIM-SC. These elements are 'positive reputation', 'positive expectations', and 'trusting and trustworthy behaviours' (see Figure 4). These elements were analysed to achieve a general understanding of their components, and the influence of BIM process requirements on these elements was established. Traditionally, opportunism and non-cooperative relationships characterise the construction project supply chain. However, the application of BIM in construction projects fundamentally changes the nature of relationships among members of the BIM-SC through the BIM process requirements such as informationsharing, network communication, and knowledge transfer (Chu & Fang, 2006;Papadonikolaki et al., 2016;Talavera, 2013). Based on these collaborative requirements of the BIM process, the nature of relationships among members of the BIM-SC requires trust. The findings of this study explain that trust development or trust-based relationship among members of the BIM-SC depends on the 'positive reputation', 'positive expectations', and 'trusting and trustworthy behaviours'. Tai et al. (2016) list information-sharing, communication, interaction history, relation-specific investments, competence, reputation, integrity, and opportunistic behaviours as the factors affecting TBR in construction projects. These factors disagree with the complexity and requirements of trust development in a BIM-SC.
The dimensions or elements of TBR in BIM-SC that agree with the complexity and requirements of trust development in a BIM-SC, as identified and validated in this study, are broadly consistent with the findings by Jaffar et al. (2011: 196), Singh, Gu and Wang (2011: 137), Porwal and Hewage (2013: 208), Hooper and Ekholm (2011), Fazli, Fathi, Enferadi, Fazli and Fathi (2014: 1119, Bryde, Broquetas, and Volm (2013: 975), Gilligan and Kunz (2007: 39), Ilozor and Kelly (2012: 28), Kuiper and Dominik (2013: 8), Miettinen and Paavola (2014:87), Chen and Luo (2014: 67), and Khalfan et al. (2004: 2). Jaffar et al. (2011) identify trusting and trustworthy behaviours such as racism, tribalism, and professional stereotypes as factors of conflict in construction project delivery. Khalfan et al. (2004) identify integrity and display of confidence as a way of building a positive reputation among the integrated construction project supply chain. However, the dimensions of TBR in BIM-SC, as identified in this study, do not agree with the model of first-based relationships proposed by Wong et al. (2008). Wong et al. (2008) identify communication, organisation policy, knowledge, thoughtfulness, emotional investments, and contracts as the dimensions of TBR in construction projects, information sharing, communication, interaction history, relation-specific investments, competence, reputation, integrity, and opportunistic behaviours.

5.2
The nature of TBR in BIM-SC

Positive reputation and its association with TBR among members of the BIM-SC
Reputation is required by members of the BIM-SC in order to form opinions about each other and decide on how to relate and interact with each other (see Table 1 and Figure 5). A positive reputation will lead to trust development. This study found that a positive reputation can be created and maintained in BIM-SC through consistent integrity, display of confidence for each other, persistence of relationship, honesty, mutual commitment, and mutual rewards and benefits. This component provides an explanation for the role of positive reputation in TBR among members of the BIM-SC, because maintaining a positive reputation is fundamental to being transparent, responsive, and trustworthy. This indicates that consistent integrity is essential to the survival of TBR in BIM-SC. Integrity and consistent integrity refer to uncompromising truthfulness, accuracy, and adherence to ethical and contractual principles.
BIM is a process involving a fair amount of relationships. Trust development in these relationships will not be smooth without consistent adherence to BIM principles and requirements. This means that, without consistent integrity, there is no foundation on which to build TBR, because consistent integrity makes a person or an organisation trustworthy and dependable. The persistence of relationships among members of the BIM-SC after a particular project is also a way to develop trust through positive reputation, because positive reputation leads to better relationships in the BIM-SC network. Thus, this relationship could persist after the current project in the form of referrals and recommendations. The study by Dossick and Neff (2013) confirms that the display of confidence for each other by members of the BIM-SC is associated with a trust-based relationship. Dossick and Neff (2013) indicate that the display of confidence for each other by members of the BIM-SC allows the quick defection of problems in the BIM process. The display of confidence for each other by members of the BIM-SC is an indication of a positive reputation, because it reveals a lack of fear and insecurities about the responsiveness and trustworthiness of each other. Display of confidence for each other by members of the BIM-SC is an essential ingredient for TBR, because they are expected to respect time, principles, and deadlines, so as to inspire confidence in each other.
Straightforward and mutual commitment, as a component of a positive reputation, indicate a mutual dependence that motivates members of the BIM-SC to trust each other, thereby promoting a TBR. They guarantee that members of the BIM-SC will do their best for the success of the projects and the BIM process. This finding is consistent with that of Hooper and Ekholm (2011) who found that mutual commitment among members of the BIM-SC is important to a collaborative process in BIM. Similarly, Mathews, Love, Mewburn, Stobaus and Ramanayaka (2018: 209) report that BIM application on projects creates a BIM-SC where a network relationship is formed from hierarchical relationships that lead to mutual rewards and benefits. Mutual rewards and benefits find a place in TBR among members of the BIM-SC, because, when all the members are interested in contributing value to the BIM process and expecting advantages that correspond to their respective value, the trust will effortlessly develop among them.

Positive expectations and their association with TBR among members of the BIM-SC
This study describes positive expectations as a dimension of TBR in BIM-SC, because positive expectations entail the behavioural forces that expect positive contributions from member of the BIM-SC towards the success of the project and the BIM process, while maintaining positive attributes that will attract positive contributions (see Table 2 and Figure 6). Positive expectation is anticipation and exhibition of positive contributions from all the members of the BIM-SC. Some of the ways in which to achieve positive expectations are the absence of confrontation and adversarial relationships, absence of competing interests, work and social interactions, conflict resolution, shared interests and project expectations, risk sharing, problem-solving ability, and openness in sharing information. Confrontations and adversarial relationships occur when people or organisations on the BIM-SC are opposing each other. This will create oppositional relationships that are devoid of trust and will affect project performance. However, a lack of confrontation and adversarial relationships will ensure TBR. This finding accords with the findings by Glick and Guggemos (2009) and Olatunji (2015: 308), indicating that members of the BIM-SC are expected to have a spirit of cooperation that will eliminate the functional and traditional adversarial relations among them. Closely related to confrontation and adversarial relationships is competing interests. Competing interests occur when multiple interests are involved in a relationship. The existence of competing interests usually generates a conflict of interests and professional judgement that will interfere with project interests. Therefore, the absence of competing interests will support the realisation of one of the main BIM objectives, namely collaboration. This qualifies the absence of competing interests as a component of TBR in BIM-SC. Love, Edwards, Han and Goh (2011: 179) confirm that the absence of competing interests among members of the BIM-SC is important, in order to achieve collaboration in the BIM process, and this will be achieved when members of the BIM-SC share common interests and problems through regular interaction. In addition, certain accidental, regulated, repeated, and regular social and work interactions must occur between members of the BIM-SC. Such interactions allow members to make positive contributions to the project at hand through their actions and reactions. Liu, Van Nederveen and Hertogh (2017: 678) confirm that there is a need for frequent social and work interactions in BIM-enabled collaboration among members of the BIM-SC, in order to stimulate the trust effects of BIM application on projects. In the BIM process, when a dispute arises, as it must, all members of the BIM-SC are expected to make efforts to facilitate the peaceful ending of the dispute or conflict. Doing so signifies not only professional growth, but also the existence of TBR. Studies by Azhar (2011: 19), Ashcraft (2008: 9), as well as Sacks, Koskela, Dave and Owen (2010: 973) provide support for this argument.
BIM is required to foster a common understanding of project expectations among member of the BIM-SC. Therefore, when the understanding of the project expectations is common to all members of the BIM-SC, it reflects a certain positive expectation that will lead to TBR. In support of this argument, Dossick and Neff (2008) explain that shared interests and project expectations can influence collaboration and eliminate conflicting obligations among members of the BIM-SC. In the BIM process, the probability and impact of risks are expected to be reduced through the appropriate distribution of the risk. Failure to do this will frustrate trust development. This suggests that risk sharing among members of the BIM-SC is a way of avoiding obstacles to information-sharing and exchange among members of the BIM-SC (Gilligan & Kunz, 2007: 40;Wong & Fan, 2013: 141;Aranda-Mena, Crawford, Chevez & Froese, 2009: 424). The personnel or organisations on the BIM-SC must be able to demonstrate a set of BIM-related skills, knowledge, and capability. This constitutes a positive expectation, because the competence of organisation and personnel positively stimulates the productivity level and the quality of work that influences project performance (Aranda-Mena et al., 2009: 426).
Another reason is that the level of BIM competency of organisations determines the realisation of the benefits of the BIM application such as collaboration (Alaghbandrad & Forgues, 2013). More importantly, competence is a major expectation among members of the BIM-SC, because it enables them to have confidence in the information models and reviews shared by the other members (Liu et al., 2017: 688). Another important component of positive expectations as a dimension of TBR in BIM-SC, as identified in this study, is the problem-solving ability of members of the BIM-SC. Problemsolving abilities such as active listening, analytical skills, and teambuilding skills are highly useful and inevitable in TBR. Problem-solving abilities enable members of the BIM-SC to share with each other their own views on the conflict issues and the likely resolution tactics (Aranda-Mena et al., 2009: 428). This study also identifies openness in sharing information as an element of positive expectations among members of the BIM-SC. The explanation for this is that concealment and restriction of access to information is catastrophic to trust development in BIM-SC.
Openness in sharing information stimulates TBR in BIM-SC, because it allows members of the BIM-SC to better understand expectations and predict actions (Won & Lee, 2010: 144;Won, Lee, Dossick & Messner, 2013: 414;Love et al., 2011:181;Lu & Issa, 2005: 63). This study also found that members of the BIM-SC must have the right to pass across their opinions and perspectives. This creates a sense of belonging and provides feedbacks that are imperative to trust development. The freedom to state opinions and perspectives is a clear demonstration of commitment to each other and it nurtures trust among members of the BIM-SC (Liu et al., 2017: 691). It is encouraging to compare the findings of this study with those of Grilo and Jardim-Goncalves (2010: 525), which indicate that mutual exchange of ideas secures the commitment of members of the BIM-SC to a mutually agreed solution, thereby fostering trust. This confirms that members of the BIM-SC must be able to come up with a suggestion as to a possible course of action towards the success of the BIM process and projects.

Trusting and trustworthy behaviours and their association with TBR among members of the BIM-SC
Trusting and trustworthy behaviours deal with the promotion of trust development by eliminating behavioural problems such as racism, tribalism, silo mentalities, and defensive behaviours (see Table 3 and Figure 7). Members of the BIM-SC are expected to never exhibit behaviours that stem from strong loyalty to a tribe or social group or race. Racist and tribalistic behaviour will promote prejudices, discrimination, and antagonism that will frustrate TBR. Therefore, the absence of sociocultural issues such as racism and tribalism are important to trust development in BIM-SC (Davies & Harty, 2013: 18;Carvalho, Braganca & Mateus, 2019: 177;Kuiper & Duffield, 2018). This study found the silo mentalities among members of the BIM-SC to be a strong component of trusting and trustworthy behaviours which is a dimension of TBR in BIM-SC. Nothing damages TBR as a silo mentality on the part of members of the BIM-SC, because it creates hierarchy and division in the BIM-SC that will reduce the efficiency of members of the BIM-SC. A silo mentality is a reluctance to collaborate with the other members of the BIM-SC through non-sharing of resources such as data, information, ideas, and knowledge. Emotional interaction was also identified as a feature of trusting and trustworthy behaviours. Emotional interaction supersedes social and work interactions in that it serves as behavioural responses to the actions and reactions of other members. Emotional interactions convey the internal state of the individuals in the BIM-SC.
Information is of central importance in the BIM process. The misuse of information is associated with the use and distribution of information models that usually manifest as copyright abuse and license abuse (Rosenberg, 2007;Azhar, 2011: 248;Azhar, Khalfan & Maqsood, 2012: 23;Arensman & Ozbek, 2012: 150). The findings of this study agree with these observations. This study also finds the absence of defensive behaviour as a valid component of trusting and trustworthy behaviour. Defensive behaviour is a form of response to perceived or anticipated threats that may not exist. With such behaviour occurring in the BIM-SC, members will be struggling to dominate, deceive, or impress. Defensive behaviour is distrustful and only the absence of defensive behaviour can ensure trust development in BIM-SC.

Conclusions
Opportunism and non-cooperative relationships are the hallmarks of the traditional construction project supply chain. However, the application of BIM in construction projects fundamentally changes the nature of relationships among members of the BIM-SC. Based on the collaborative requirements of the BIM process, the nature of the relationships among members of the BIM-SC requires trust. This study attempts to understand the nature of trust-based relationships in BIM-SC, in order to establish whether the requirements of the BIM process influence TBR.
In this study, a model of TBR in BIM-SC is developed to provide practical insight into the nature of TBR in BIM-SC. The nature of a concept can be understood by investigating its factors, aspects, dimensions, elements, characteristics, or components. To achieve the objective of this study, dimensions and components of TBR in BIM-SC were investigated and then identified using relevant theoretical perspectives, while the related components were identified using meta-synthesis. The relevance of the components was determined using meta-analysis estimates. This study developed a model of TBR in BIM-SC, which categorised TBR in BIM-SC into a positive reputation, positive expectation, and trusting and trustworthy behaviours. In terms of a positive reputation, TBR relates to 'consistent integrity'; 'display of confidence for each other'; 'persistence of relationship after projects'; 'honesty and mutual commitment', and 'mutual rewards and benefits'. Positive expectation consists of 'lack of confrontation and adversarial relationship'; 'absence of competing interests'; 'social interaction'; 'work interaction'; 'conflict resolution'; 'shared interests and project expectations'; 'risk sharing'; 'cross-functional cooperation'; 'competence of personnel and organisation'; 'problem-solving ability'; 'openness in sharing information'; 'compensating for each other's weaknesses'; 'Eeploiting each other's strengths'; 'freedom to state opinions and perspectives'; 'mutual exchange of ideas', and 'support for innovation and learning'. While trusting and trustworthy behaviours entails 'absence of racism'; 'absence of tribalism'; 'absence of silo mentalities/professional stereotypes'; 'emotional interaction'; 'nonmisuse of information', and 'absence of defensive behaviours'.
The findings of this article have provided an opportunity to advance the understanding of TBR among members of the BIM-SC, have furnished information on the influence of the requirements of the BIM process on trust development among members of the BIM-SC, and have given insight for a case study of TBR among members of the BIM-SC. However, it is beyond the scope of this article to empirically validate the dimensions and components of TBR among members of the BIM-SC. Hence, a future article is required to undertake this.