Cost overrun and schedule delay are pervasive in large public infrastructure projects in Canada and there is an ongoing debate over the root causes of these delivery risks and how best to mitigate them. Since public-private partnerships (P3s) have been long touted as an effective mitigating measure, this study aimed to provide comparative empirical evidence to explore this claim. By collecting cost and schedule data at three key milestones (decision to build, contract awarding and substantial completion) from 39 traditional projects and 27 P3 projects across Canada between 2004 and 2016, the study develops an innovative longitudinal profiling approach to inform the debate about the causes of cost overruns in large public projects. Statistical analyses of the collected data unambiguously demonstrate that P3s outperform non-P3 traditional delivery models during the construction stage in both cost overrun and schedule delay. However, substantial budget underestimation is found in the strategic decision-making process of both models of project delivery. Results from the study also provide solid objective grounds for the development of advanced value-for-money assessment methodology.

Public–private partnerships (PPPs) have long been touted as an innovative project delivery method that encourages technological innovation and chases delivery efficiency. However, literature based on European PPP practices seems to provide conflicting evidence. To help better understand and further improve this prevailing delivery method, this study collected and analysed empirical evidence of engineering innovations that have been successfully used in existing PPP projects in Canada. Drawing on literature review and an intensive interview programme involving 19 interviewees from 15 successful PPP projects, the study answered the what, who, when, why and how questions about innovation in PPPs. The study concluded that the PPP delivery system does provide unique innovation opportunities and scope that traditional delivery models cannot support. Performance-based output specifications, vertical integration and communication are the three key areas for improvements to enhance innovation in PPPs further.

Thousands of coastal reinforced concrete structures using HRB400 bars have served for over three decades in China. Their reinforcement simultaneously endures chloride corrosion and seismic action, yet studies on performance degradation remain limited. This paper investigates the low-cycle fatigue (LCF) behavior of HRB400 bars under various strain amplitudes, systematically analyzing corrosion morphology, cyclic stress–strain response, fatigue life, and underlying mechanisms. Corrosion is induced by an adjusted accelerated method that replicates field conditions. Observations reveal that corrosion pits act as primary crack initiation sites. Crack paths and fracture surfaces progressively follow the local pit geometry as strain and corrosion grow. The detrimental effect of corrosion on LCF life is more pronounced for smaller bars. At a γ of around 8%, 20 mm bars lose 60.7% of the half cycles to failure at ε = ±1.5%, but only 37.5% at ε = ±5.0%. Predictive corrosion-inclusive strain amplitude (ε_a)–fatigue life models are proposed, yielding R² = 0.952 (16 mm) and 0.928 (20 mm). A unified LCF predictive model, calibrated on a database of 310 corroded/uncorroded bar tests, is established. The final model comprehensively considers the characteristics of rebars, seismic action, and corrosion damage, improving the conventional relationship between LCF life and seismic loading. This work contributes to the understanding of the fatigue behavior of HRB400 bars and provides support for time-dependent seismic reliability analysis of aging reinforced concrete structures in corrosive environments.