This study aims to explore the influence of role stress (role ambiguity and role conflict) on job burnout and job performance in construction project managers in the Chinese construction industry. Based on the JD-R (Job Demands Resources) model, this study introduces career calling as the moderating variable, in order to develop a theoretical model. The theoretical model is then tested with structural equation modeling. This work uses data from 191 owners, contractors, subcontractors, and supervisors in the Chinese construction industry. The results indicate that: (i) role ambiguity has a negative and significant effect on job burnout and job performance; (ii) role conflict has a negative effect on job burnout, but has a non-significant influence on job performance; (iii) job burnout has a negative impact on job performance; (iv) career calling negatively moderates the relationship between role ambiguity and job burnout, and positively moderates the relationship between role conflict and job performance. Furthermore, the results also show that career calling can positively moderate the effect of role conflict on job burnout. This study expands the existing body of knowledge by reasonably controlling role stress and appropriately introducing career calling. In addition, the study provides some suggestions relevant to construction project management.

Purpose The purpose of this paper is to investigate the relationships between structure characteristics of project network, types of conflicts and project success. Design/methodology/approach Network density and centrality were used to reflect the structure characteristics of project network. This study collected 254 valid responses from construction professionals (including project managers, department managers and project engineers) via a questionnaire survey and analyzed the data using structural equation modeling and bootstrapping techniques. Findings The results showed that network centrality of project stakeholders negatively affected project success, whereas the effect of network density on project success was non-significant. The network density was positively related to task conflict, whereas negatively related to process and relationship conflict. Network centrality was positively related to relationship conflict and had negative effects on task and process conflict. Project conflicts served as the mediator, weakening the relationship between network structure characteristics and project success. Research limitations/implications This study provides direction for project managers and other stakeholders (e.g. owners, contractors and subcontractors) to appropriately establish social ties and manage conflicts to achieve project success. However, the potential influence of conflict transformation on project success, the dynamic nature of project networks and the network diagram were not addressed in the context of diverse culture. The future research should cover different stakeholders in order to get an integrative understanding of project networks and collect data from different cultural and industrial characteristics, extending and verifying the results. Originality/value The outcomes of the study provide evidence in regard to social network ties governance, which is comprised by the important or representative stakeholders, being a part of the effective strategy in improving project success. This study also contributes to the knowledge of conflict management in the project context, revealing the positive and negative of project conflicts and enriching the current understandings of the underlying mechanism of the project network characteristics on project success.

To promote the natural regeneration of secondary forests under gap disturbance is one of important approaches for realizing their restoration and sustainable management. However, soil seed bank, one of regeneration strategies, is poorly understood in gaps of secondary forests. Objectives of the study were to evaluate the effects of sizes of experimentally created gaps on seed distribution in soil, and of seed banks on vegetation recovery at early formation stage of gaps in temperate secondary forests, Northeast China. It was found that with increasing gap size, species richness in the seed bank significantly increased (r=0.691, P<0.05, n=10), but correspondence in species-composition of seed reservoir between gaps and canopies adjacent to gaps decreased (r=−0.83, P<0.01, n=10). Gap size and soil depth and their two-way interactions had significant differences on the distribution of seed bank density (F=4.101, P<0.05; F=34.483, P<0.01; F= 5.232, P<0.01, respectively). The Sokal and Sneath similarity indices in species-composition between extant and potential (seed bank) vegetation were generally low, ranging from 0.06 (interior of large gaps) to 0.24 (canopies adjacent to large gaps). From the view of seed bank to restore temperate secondary forests, establishment of medium-sized artificial gaps (i.e., gap size with 500-150 m 2 ) could be more feasible for seed invasion. To conclude, the regeneration potential out of soil seed banks is limited, and the restoration of gaps at early formation stage may be mostly dependent on other reproductive strategies (e.g., vegetative propagation of species).

PurposeThis study aims to investigate the relationships between the different strengths of ties (strong ties and weak ties), types of trust and project performance in megaprojects.Design/methodology/approachA questionnaire survey was conducted with various experts and professionals involved in megaprojects, and 350 valid responses were received. Data was analyzed by means of structural equation modeling.FindingsThe results show that both strong ties and weak ties have positive impacts on trust in megaprojects, but weak ties have a more significant positive effect than do strong ties. Unexpectedly, the introduction of interorganizational trust significantly weakens the effect of the strength of ties on project performance. The indirect influence of the strength of ties on performance has different paths. Weak ties have an indirect effect via calculative trust and relational trust. However, in a strong ties network, inferior stakeholders lack the information necessary to complete a megaproject, and they believe that calculative trust will not promote project performance until the megaproject is successfully delivered. Thus, the effect of calculative trust on project performance is not significant.Research limitations/implicationsThese findings provide evidence in regard to strength of ties governance being a part of the effective strategy in improving megaprojects’ performance. It also demonstrates the mediating function of trust and advances the current understandings of the underlying mechanism of the strength of ties on project performance, thus providing implications for researchers and practitioners. However, this study has some limitations. For example, the strength of ties and trust between organizations are a dynamic process in megaprojects. This study does not conduct in-depth analysis of the evolution mechanism and investigate the different levels of trust at different stages of the megaproject. Future research can be guided by these directions.Originality/valueThe main contribution of this study is fourfold. First, this study enriches the literature on strength of ties by accentuating the roles of trust in megaproject context. Second, this study contributes to the theoretical development of a conceptual model for explaining the interrelationships among strength of ties, types of trust and project performance. Third, this study responds to the call “which dimension (i.e. strong ties or weak ties) is more influential” by exploring the direct and indirect effects of strength of ties on project performance. Finally, this study breaks through the limitation of traditional cognition that megaproject management can be met by relying on rigid contracts. In other words, trust can supplement the weakness of rigid contract by forming contract flexibility with different strength of ties. Meanwhile, the specific strategies to establish and maintain trust are given, such as building information model (BIM) collaboration platform and reputation management mechanism.