Hybrid Approach To Minimize Construction Project Delays
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Decisions taken at the project planning level can affect project scheduling within a construction supply chain (CSC). After all, project scheduling requires vital resources and collaboration among project stakeholders. If these decisions are not the best possible, they can have negative effects such as delays, budget overrun, and project performance issues. These effects are considered waste in lean construction (LC). The concept of LC is still limited regarding its application to CSC. This study aims to develop a decision-making model (LC tool) to minimize project delays using mathematical model techniques. By using the proposed LC tool, results show that delays in ongoing projects can be minimized, as validated in a case company. Finally, decision-makers can use this technique to manage concurrent projects and suppliers who provide essential resources to these projects. KEYWORDS: Lean Construction (LC), Construction Supply Chain (CSC), Optimization, Offsite Construction, Scheduling
Assigning Resources and Managing Schedules
A construction consulting firm based in Montréal, Canada, delivers construction projects (modular or traditional) for Canadian customers based in Montréal. We named the company XYZ to protect their privacy. XYZ also provides optimal foundation and structural repair solutions. Their problem was allocating resources to different projects and managing different project schedules. They were looking for efficient solutions to improve project scheduling and resource allocation across multiple projects. Initially, they had no process mapping, and many processes needed to be eliminated as they added no value to their work.
Figure 1: Future Construction System Integration including Logistics
Proposed Optimized Business Process
The company’s business process is analyzed and improved in the first step to obtain the required data needed to generate schedules. Figure 2 shows the information flow process proposed by XYZ for schedule management. There are two departments: administration and technical, and three people involved in generating and managing project schedules. The company manager is from the administration department, and the project manager and team leader are from the technical department. The information flow system is integrated, and information, whether input or output of the process, is shared by these three people through an IT system called the scheduling system in the figure.
The information generated in these processes includes the number of scheduled projects to be optimized, the type of resources required for the project, supplier information, duration of project activities, costs of resources by suppliers, precedence of activities related to each other, and project completion date. These inputs are shown with green borders in the figure below. This input information will be stored in an integrated system that will allow them to manage and view it.
The “XOR” gate used in the team leader pool shows the decision to make regarding resources. If the company has enough resources for the project, it will proceed without suppliers. If company resources are insufficient, the team leader considers the cost and time associated with getting resources from suppliers. Then, after receiving the project input information from the team leader, the project manager assigns relative importance weights to these projects based on priority. These weights will be critical as the model in the second step will optimize the project schedules based on these weights.
Figure 2: Proposed XYZ Information Flow Process for Managing Project Schedules
Reducing Project Completion Time
The completion time and tardiness (delay) for each project are shown in Figure 3. The model can minimize the delay of these projects with respect to their due dates. Project 1 delay is minimized to 2 weeks, Project 2 delay to one week, and Project 3 delay to 2.7 weeks. This figure shows the improvement in project schedules by implementing this model, comparing before and after conditions.
Figure 3: Comparison of Projects Completion Times Before and After Model Implementation (in weeks)
This research provides a methodology for minimizing the delay (lean) of multiple construction projects managed simultaneously for the company. The methodology consists in two steps. The first step involves streamlining the organization’s information processes, which generate the input needed to manage and create schedules. Once this input is generated, it is fed into the mathematical mixed integer linear programming model in the second step to obtain optimal project schedules and minimize project delays.
Thus, this research brings a novel lean methodology that utilizes qualitative (BPR) and quantitative (optimization) methods to minimize construction project delays and generate optimal schedules. This will help the project-delivering company manage its resources, project tasks and suppliers in real time.
