Management of schedule risks of prefabrication housing production in Hong Kong

Abstract

As a solution to a series of dilemmas and constraints witnessed in the construction industry in Hong Kong, prefabrication housing production (PHP) is envisaged to gain momentum owing to its potential benefits such as environment-friendly, better quality, cleaner and safer working environment. Potential benefits may not be fully exploited if its inherent weaknesses of fragmentation, discontinuity, and poor interoperability not being mitigated, which nurtures a variety of risks that impose significant adverse influence on the schedule performance of prefabrication housing production. This is further exacerbated by the fact that the whole prefabrication manufacture sector in Hong Kong has been moved to offshore areas in the pearl river delta (PRD) region for a reason of lower material and labor cost. As a result, delay frequently occurs in PHP project despite the promise of the government to meet the high housing demand. To help address schedule delay problems encountered in the construction of prefabrication housing, many studies have investigated risk-related issues in the management of PHP. However, none of these studies developed an effective tool for managing schedule risks of PHP by envisaging the key characteristics of schedule risks and prefabrication housing production. Most of previous research regarding to the management of prefabrication construction tends to consider risks from static and isolated perspectives, despite that these risks are coherently interrelated with each other and their influence varies throughout the whole PHP process. This study applies social network analysis approach to analyze and identify critical schedule risks with consideration of various stakeholders involved in major production processes of PHP from a network perspective, then a hybrid dynamic model is developed to evaluate and simulate the impact of identified schedule risks on the schedule performance of PHP in view of underlying interrelationships and interactions, employing the hybrid system dynamics (SD) and discrete event simulation (DES) method. The resulting hybrid model is validated through a serial of model structure tests and model behavior tests, with the use of data collected from a PHP project in Hong Kong. Based on the simulation results, corresponding managerial and technical solutions are proposed for dealing with critical schedule risks and enhancing the schedule performance of PHP project. This study contributes to current knowledge of the management of prefabrication construction by having developed an effective model that offers an in-depth understanding of how schedule performance of PHP are dynamically influenced by interrelationships and interactions underlying various schedule risk variables. Through depicting interrelationships underlying various identified schedule variables, the processes and interrelationships of the activities of prefabrication housing production can be better understood by the involved stakeholders to gain insight on the complicated mechanism inherent in the PHP system. The developed model not only has the benefits of ease of modifying model structure to reflect real schedule situation of PHP project, performing various risk analyses and communicating with simulation results, but also is of value of providing an experiment platform for identifying and determining managerial and technical solutions proposed to minimize and mitigate the influence of corresponding schedule risks prior to implementation.