No abstract

Water distribution networks (WDNs) are undoubtedly a critical part of water utility assets, as they are responsible for water transmission (Atef et al., 2016;Berardi et al., 2014). It has been reported that, on average, 80% of water utility expenditures are spent on the management of WDNs (Poulakis et al., 2003). However, available evidence shows that the failure of WDNs is increasing at a fast rate, which negatively impacts individuals' social, economic, and health status (Steffelbauer et al., 2022;Yazdani & Jeffrey, 2012).In the USA and Canada, around 700 water pipes fail daily, thereby contributing to the loss of over 2 trillion gallons of clean water annually (Fan et al., 2022). In 2017, more than 2.2 billion m 3 of water was loss in China (Liao et al., 2021). The enormous financial commitment associated with the failure of water distribution networks cannot be overemphasized. According to the American Water Work Association (AWWA), the USA needs to invest around $1 trillion in replacing and repairing the deteriorating components of their WDNs (Fan et al., 2022). In Australia, the estimated cost of repairing and maintaining WDNs is about AUD 1.4 billion (Weeraddana et al., 2020). In South Korea, 52.5% of the water pipes will require rehabilitation by 2024, as indicated in a study by Seo et al. (2015). In the case of Colombia, a developing country, approximately 50% of water is lost due to water pipe failures (Giraldo-González & Rodríguez, 2020). From the aforementioned, the failure of WDNs, which mostly consist of water pipes, is a global issue that requires utmost attention. WDNs are founded underground; therefore, these infrastructures need to be designed to resist traffic, soil, internal, and overburden pressures, and other environment and operation related loads (Berardi et al., 2008). In essence, the reliability of WDNs must not be compromised during their service life; hence, catastrophic failure

The Repair, Maintenance, Minor Alteration, and Addition (RMAA) sector accounted for 50% of all fatalities in the Hong Kong construction industry in 2016. In spite of the different policies launched in recent years, the casualty rate has held constant, raising doubts over the effectiveness of current measures for improving safety performance in RMAA works. Against this backdrop, this study is aimed at identifying and evaluating the 1) effectiveness of prevailing policies; 2) potential difficulties in improving safety performance in Hong Kong; and 3) best ways to improve the safety performance of RMAA. Following an extensive literature review, 15 existing policies and 10 common difficulties are established. Based on the solicitation of experts having rich experience in the area of RMAA, the analytical hierarchy process (AHP) is employed to prioritize the identified policies and Likert-scale-based survey to establish the relative importance of the identified difficulties. The 'award of encouragement' is found to be the most effective policy category, whereas the 'lack of self-regulation of workers' appeared as the most significant hurdle.In order to further validate the results obtained from the study, a number of interviews using highly experienced professionals were conducted. It is recommended that strategies such as registration of RMAA workers, intensifying monitoring and enforcement, and provision of loan services for safety can overcome the difficulties. The hindsight provided from this study can pave the way for the concerned parties towards improving the occupational safety and health (OSH) of such projects by improving the effective policies concurrently with improving the status quo of critical hampering.

Many nations across the globe face the challenge of housing deficit. Modular integrated construction (MiC), which has the highest level of prefabrication among off-site construction manufacturing (OSM), has been adopted as a fast and reliable construction method to address the housing deficit. Previous studies have assessed the productivity of the prefabrication stage of MiC, while investigations into the productivity of the MiC installation process with the consideration of pragmatic factors, especially for high-rise buildings, are lacking in the literature. Therefore, this study contributes by (1) developing a discrete-event simulation (DES) model to assess the productivity of MiC installation while considering pragmatic factors (e.g., weather conditions, topography, work dimension, etc.) and management conditions (e.g., workers’ motivation, training, equipment maintenance, etc.); (2) developing a mathematical model to understand the relationship between productivity and various resources utilized in MiC installation. After verifying and validating the DES model, it was applied to a case study in Hong Kong. A sensitivity analysis using a full factorial experiment design was conducted to identify the parameters (e.g., number of trucks, tower cranes, different crews) that significantly affect a number of performance measures, such as the project duration, productivity, and total costs. Furthermore, the mathematical model shows high prediction accuracy, as the mean absolute percentage error is 8.93%. This study would help construction practitioners in their decision-making process, while planning a project by providing them with a model that can predict the productivity of the MiC installation process before and during the project implementation.

Green building development has increasingly gained momentum globally due to growing public concerns and government policies. A variety of rating systems have been developed to assess the sustainability of a construction project. In Hong Kong, BEAM Plus is the most preferred system among the practitioners, however, its implementation is slow due to industry and policy-level challenges. While scholarly works relating to the performance and assessment factors of rating schemes have been conducted, limited efforts have been made towards the investigation of the challenges to the implementation of BEAM Plus. This research, therefore, conducted a thorough investigation to identify the challenging factors, and potential policies to encourage the use of BEAM Plus among construction stakeholders. A comparison of BEAM Plus with leading green building assessment schemes is made and the current policies regarding the implementation of these schemes in Hong Kong and other countries are discussed. Questionnaire surveys and expert interviews were conducted to validate the challenges and potential policies. The collected data is studied using Analytical Hierarchy Process and the responses from the interviews are found to mostly aligned with the AHP results.It is found that 'high initial cost' is the most critical factor affecting the application of BEAM Plus whereas 'shortage of green building experts' is the least important concern. The study revealed that 'gross floor area concession' is the most attractive policy whereas the effectiveness of the 'assessment fee subsidy' is insignificant. It is also disclosed that significant changes are required in existing policies such as gross floor areas should be granted on the level of green achievements instead of only registering for the scheme.