Accelerating linear projects

Abstract

Scheduling linear repetitive construction projects, such as highways and pipelines, poses unique challenges due to maintaining crew work continuity. An efficient method is presented, developed to accelerate the delivery of this class of projects so as to meet a specified deadline with least associated cost. The method is simple and ensures crew work continuity. An iterative approach is employed, where, in each iteration, the project schedule is analysed and an activity is identified as the controlling activity. A controlling activity is an activity that if accelerated, would reduce project duration at least additional cost. Upon its identification, the method selects an expediting strategy that would reduce project duration, and the project is rescheduled. Several expediting strategies are considered, including working overtime, double shifts and weekends. The method is implemented in a prototype software that operates in a Windows� environment, providing a user-friendly graphical interface. It has an open architecture, enabling the user to actively participate in tailoring the generated schedule to suit the requirements of the project at hand. The proposed method accounts for incentives and liquidated damages to aid users in identifying the most cost-efficient schedule. A relational database model is implemented in Microsoft Access� to store typical crews and their associated productivity, as well as their availability dates. A project, drawn from the literature, is analysed to demonstrate the basic features of the proposed method and highlight its capabilities.Repetitive construction, acceleration, crew productivity, time-cost trade-off,

Challenges and opportunities for productivity improvement studies in linear, repetitive, and location-based scheduling

“…LS was presented as a tool to support scheduling, but also other managerial functions (Christian, 1961;Seppänen and Kankainen, 2004;Henrich and Koskela, 2005;Seppänen and Aalto, 2005;Seppänen and Kenley, 2005;Kenley and Seppänen, 2010), and the design of production systems (Kemmer et al, 2008). These studies support a link between LS and potential productivity improvements with continuous workflows and micro-managing activities (Kenley, 2004), minimizing cost of accelerating LS (Hassanein and Moselhi, 2005), incorporating learning in LS (Arditi et al, 2001), and considering variable production rates (Carr and Meyer, 1974;El-Sayegh, 1998) and batch sizes (Angelim and Heineck, 2010). Another group of studies supports LS based on considering site conditions (Duffy, 2009), realistic and project-specific production data (Peer, 1974;Arditi et al, 2002), and by developing algorithms to formalize LS (Al Sarraj, 1990).…”

“…The vast majority of studies developed LS algorithms theoretically, but did not implement them on real projects so that their effect on productivity could have been measured (e.g. Al Sarraj, 1990;El-Sayegh, 1998;Arditi et al, 2001;Hassanein and Moselhi, 2005;Duffy et al, 2011). This created the concern that synthesizing their results directly would be inadvisable, because they lacked a common basis for comparison.…”

Automated trade‐off between time and cost in planning repetitive construction projects

“…The need to recognize crew work continuity and the location of work in the scheduling limits the use of traditional network scheduling methods such as critical path method for scheduling construction projects that involve repetitive units (Adeli and Karim, 1997;ElRayes and Moselhi, 1998;Hassanein and Moselhi, 2005;Fan and Tserng, 2006;and Georgy, 2008). As such, several scheduling algorithms were developed to consider and support the modelling of crew work continuity during the planning and scheduling of repetitive construction projects including: line of balance, linear balance charts and linear scheduling method (El-Rayes and Moselhi, 1998;Harris and Ioannou, 1998;Fan and Tserng, 2006;Georgy, 2008).…”

Optimized Acceleration of Repetitive Construction Projects

“…Acceleration strategies that are extracted from literature and included in the scope of this research mostly depend on increasing the man hours assigned to the activity. This can be done by choosing one of the following strategies: (1) working overtime; (2) working double shifts; (3) working weekends and (4) employing more productive crews 8 .…”

“…The technique adopted in this research is a modified version of the technique proposed by Hassanein and Moselhi 8 . In their technique, identification of critical activities was set based on activities' least alignment with their successors.…”