Abstract: With the significant increase in the role of the public in the implementation of infrastructure PPP projects, this study constructs an evolutionary game model for the synergistic performance enhancement of infrastructure PPP projects with government incentives, social capital enhancement, and public participation, constructs a social capital benefit distribution model considering the target interval of performance enhancement, and through a simulation analysis explores the behavioral strategy choice and its influencing factors for the collaborative performance improvement of the three parties. The study shows that: the behavioral strategy choice of any party and its evolution path is closely related to the behavioral strategies of other game players, and their influence on each other’s initial strategies is different; the benefits such as credibility enhancement, rewards from higher authorities, and fines have positive effects on the government’s incentive behavior, while the government’s incentive costs have negative effects on the government’s incentive behavior. The benefit distribution of social capital is closely related to the parameters of the target range, reward factor, and penalty factor, and the benefit distribution of social capital decreases with the increase of the target range of performance. The benefit distribution of social capital is related to the parameters of target scope, reward factors, and penalty factors, and the benefit distribution of social capital gradually decreases as the scope of the performance target increases. The research results are conducive to enriching and improving project performance management theories, and providing reference for government to introduce relevant policies and design performance enhancement mechanisms for PPP projects.

Key words: tripartite evolutionary game, infrastructure, PPP project performance, collaborative improvement, benefit distribution