The flexible contract is an important mechanism for owners to govern contractors in construction projects. Given the limited explanatory power of the justice mechanism and the important role of relational factors, this study explored the role of ongoing trust and justice perception in the relationship between contractual flexibility and the contractor’s cooperative behavior and aimed to further reveal the potential influence paths through an empirical analysis. We found the following: (1) apart from justice perception, ongoing trust is another crucial mediation factor in the relationship. (2) Together with the former, ongoing trust plays significantly multiple mediation effects and constitutes the main indirect influence paths, among which the parallel one is strongest and the chain one comes third. (3) Moreover, both factors are more likely to be impacted by contract executing flexibility, compared with contract content flexibility. These findings enrich relational mechanism research and provide some guidance for the owner to build contractual flexibility to govern contractors’ behavior.

The present study is developed based on conservation of resources theory (COR) to explore the underlying mechanism and boundary condition for the relationship between helping behavior and innovative behavior. To avoid the shortages of cross-sectional data, the present study collected two-wave and multi-source data. By collecting from 193 full-time Chinese workers and 68 supervisors at two separate time points, this study developed and examined a moderated mediation model using Mplus 7.0. The results show that helping behavior increases innovative behavior through enhancing positive affect, and psychological meaningfulness moderates the indirect relationship between helping behavior and innovative behavior through positive affect. In the condition of high psychological meaningfulness, helping behavior has a stronger indirect impact on innovative behavior through enhancing positive affect. This study enriches the literature on the outcomes of helping behavior. Moreover, this study provides several managerial implications to amplify the positive impact of helping behavior on innovative behavior. This study develops several strategies to enhance psychological meaningfulness and promote the benefits of helping behavior.