Empirical research comparing projects procured as public-private partnerships (PPPs) with other methods of procurement is important because Australian governments plan to spend $320 billion on infrastructure over the next decade and PPPs are perceived to be an appropriate form of delivery. Estimating cost and risks in Australian capital projects is often characterized by optimism bias—the tendency to be overly optimistic about planned actions—and is too often based on insufficient historical data on which to make decisions. Given this broad context it is important to begin to understand in detail how PPPs have performed against other forms of procurement. To achieve this, a detailed study has been undertaken to compare the project time and cost outcomes observed in the Australian PPP market with those projects delivered by governments via traditional procurement methods. Two sets or pools of projects were compared based on a detailed analysis of publicly available data for a sample of 21 PPP projects and 33 traditional projects. This selection was based on a consideration of previous studies, time and cost metrics, project size and the relative complexity of different project types. In comparing the two sets PPPs demonstrated superior cost efficiency over traditional procurement, which ranged from 30.8% when measured from project inception, to 11.4% when measured from contractual commitment to the final outcome. Between the signing of the final contract and project completion, PPPs were found to be completed 3.4% ahead of time on average, while traditional projects were completed 23.5% behind time. The overall conclusion is that PPPs provide superior performance in both the cost and time dimensions, and that the PPP advantage increases (in absolute terms) with the size and complexity of projects.PPPs, PFI, time and cost performance, procurement, infrastructure,

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Abstract. Engineering-Procurement-Construction (EPC) method has increasingly been applied in international markets. In this research, the causes of contractors' claims in international EPC projects are modeled and empirically tested with industry survey, structural equation modeling and case studies from the perspective of Chinese contractors. The established model outlines the causes of contractors' claims as: external risk (sociopolitical risks, economic risks, and natural hazards), clients' organizational behavior (untimely payment, change orders, and inefficient processing), and project definition in contract (unclear scope of works, and unclear technical specification). The structural equation modelling validates that these causes have direct influences on claim respectively. Besides, clients' organizational behavior acts as a partial mediation between external risk and claim, demonstrating that external risk can also exert influence on claim through affecting clients' organizational behavior. Seven case studies further confirmed and interpreted the substantive meaning of these relationships. This study establishes interdisciplinary linkages among knowledge areas of contracting, risk management, organizational behavior, and international EPC project delivery, which has important primary contributions in both theory and practice. Understanding how the fundamental factors interactively lead to claims can help contracting parties to develop effective claim strategies, proactively mitigate project risks, and ultimately improve EPC project performance.

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Summary Delamination is a serious form of deterioration in concrete bridge decks. Infrared thermography (IRT) is an advance non‐destructive testing method for concrete bridge deck delamination detection by capturing the absolute thermal contrast (ΔT) on the concrete surface caused by the disruption in heat flow due to subsurface defects. However, as the ambient environmental conditions (e.g. wind velocity and solar radiation) of a bridge could significantly affect the measurement outcomes of IRT, the optimal times for infrared data collection are still unclear. In this paper, a series of experimental and numerical studies were carried out to investigate the effects of the rate of heat flux and wind velocity on ΔT on the surface of bridge decks with the aim of identifying the optimal inspection times for different geometry characteristics of delamination (i.e. size and depth). The developed model is firstly validated by the experimental data and then a series of parametric studies were carried out. The result shows that the heat flux rate plays an important role in the development of ΔT on concrete surface, especially for a relatively shallow and small size delamination. However, the influence of heat flux rate gradually diminishes with the increase in size and depth of delamination. In addition, it demonstrates that there is a positive linear correlation between the total heat energy (external irradiation) and square of the delamination depth. The current research represents an important step towards the development of an effective and efficient way for defect detection using IRT.

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