Modified critical chain scheduling for construction projects

Planning is an important management function and its effective execution is crucial to ensure the success of any project. This second edition of Thomas Uher’s and Adam Zantis' textbook maintains its focus on operational rather than strategic aspects of programming and scheduling of projects, providing the reader with the practical planning skills needed to be successful. Unlike most other textbooks that largely focus on the critical path method, Programming and Scheduling Techniques includes a comprehensive review of a range of practices used around the world. Topics covered in this thoroughly revised edition include: deterministic scheduling techniques including the bar chart, the critical path method, the critical chain method, the multiple activity chart and the line of balance a comparison of the critical path and critical chain scheduling techniques options for computer-based scheduling stochastic scheduling techniques including the critical path method based on Monte Carlo simulation and the Program Evaluation and Review Technique (PERT) risk in scheduling work study. By covering a broad range of scheduling techniques this book is suitable for those planning projects in any industry, particularly in interdisciplinary or international contexts. Written for students studying undergraduate and postgraduate architecture, building, construction/project management, quantity surveying, property development and civil engineering programs.

Construction project scheduling is one of the most critical factors for project success measurement. Critical Path Method (CPM) is commonly used in the construction industry for project scheduling. CPM is a deterministic method that ignores uncertainties in activities through the network, which determines the duration of the projects. Program Evaluation and Review Technique (PERT) is a probabilistic method based on the assumption that the duration of a single activity can be described by a probability density function. PERT takes into account the uncertainties during the construction process to plan, schedule and control complex projects with many uncertainties. The work reported in this paper describes the PERT work process to carry out the construction schedule risk assessment and illustrates the model through case studies. The utilization in the estimate the construction liquidated damage with the uncertainties is performed, which also can be used in the insurance company to calculate the insurance premium.

This research examines the application of the Critical Path Method (CPM), Program Evaluation and Review Technique (PERT), and Earned Value Management (EVM) in estimating the time and cost of infrastructure projects, specifically in the construction of culverts. The study integrates Monte Carlo simulations to assess risks and uncertainties associated with project time and cost. By utilizing these methods, the study aims to provide accurate estimations and optimize project management strategies to mitigate delays and cost overruns. The findings demonstrate that integrating CPM and PERT can significantly enhance project planning, scheduling, and cost control, reducing time discrepancies and improving cost efficiency. Furthermore, Monte Carlo simulations offer probabilistic insights into the project's performance, while EVM provides a real-time monitoring tool for evaluating project execution. This research contributes to the improvement of infrastructure project management by offering a systematic approach to handle uncertainties and ensure more reliable project outcomes.

Within the early stages of construction project planning, resources restrictions are often neglected. Usually this leads to cost and schedule overruns. Moreover, the adoption of resources restricted project planning may lead to a complex optimization problem. Thus engineers should focus on resources-based project planning for more schedule efficiency. Nevertheless, the integration with traditional methods as the PERT (program evaluation and review technique) or the CPM (critical path method), can improve schedule reliability significantly in project failures due to insufficient resource allocation. Potential applications of resource-restricted project scheduling for construction project planning are revealed with some suggestions on the integration of this approach into traditional planning methods are made. For overlapping both, traditional planning methods as well as resource-based planning models, knowledge transferred from production planning to project planning by applying a hierarchical approach. Analyses of multi planning problems in construction projects are undertaken and the roles of the generalized resource-restricted project scheduling model and selected extensions within construction project planning are discussed

An air-conditioning and mechanical ventilation (ACMV) construction project involved many interrelated construction activities with varying durations and multiple dependencies. This paper focuses on the development of a best possible project planning and scheduling technique that can help the project manager to manage and complete the ACMV project in optimal time. The program evaluation and review technique (PERT) is used in this research. The PERT technique helps to determine the probabilities of various stages of the project by specified deadlines and identify the activities on the critical path that have high potential for causing delays in the project completion time. The completion times of 72, 76, 79, and 80 weeks were taken for the PERT analysis. Deadline of 72 weeks is the contractual period of the ACMV project as specified in the contract. Completion time of 76 weeks is the critical path of the project as analyzed by the PERT technique. The deadline of 79 weeks is the proposed completion time for the ACMV project whereas 80 weeks are the actual completion date of the project. The PERT analysis revealed that the project completion time of 72 weeks, which is as stated in the contractual completion time, yielded the probability of completion of 2.67% only. This analysis shows that the contractual period is impossible to be achieved and it is an unrealistic time setting. Further negotiation is required including changing or extending of the contractual completion time. The other completion times are able to be achieved but the company may need to face the high penalty costs due to the delays in completion time.

This study examines the comparison of PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method) in time management for construction projects through a case study of a 21-story high-rise building project in Yogyakarta. The research is motivated by the need for effective time management in construction projects to avoid delays that may escalate costs and disrupt project execution. The objectives are to determine the estimated duration for completing the building’s structural work, compare the differences between the initial schedule and the results of PERT and CPM analyses. The study employs a case study approach, with primary data collected through direct interviews with project stakeholders regarding activity durations and predecessors, as well as secondary data from project documentation, including schedules and structural drawings. Data analysis involves applying PERT calculations using three-time estimates (optimistic, most likely, and pessimistic) and identifying critical paths through CPM. Data processing and network diagram visualization are conducted using a project management software to comprehensively map critical and non-critical project activities. Results indicate that the CPM method predicts a project duration of 419 days, 237 days shorter than the initial schedule, while the PERT method estimates 580 days, 76 days shorter than the original timeline, with an 82.98% probability of timely completion.

Project delays are a major threat in project management that can result in increased costs and decreased operational efficiency. Therefore, an appropriate planning method is needed to optimize the schedule and reduce the risk of delays. This study aims to analyze the critical path and determine the optimal time in the H₂S Analyzer Upgrade project using the Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT). CPM is used to identify critical activities, namely contracts (A), field surveys (B), specifications (C), H₂S Analyzer (F), tubing & tubing connections (G), sample conditioning systems (H), accessories (I), electrical & instrument cables (J), bulk materials (K), and spare parts for one year of operation (L). The results of the analysis show that the CPM method estimates the project duration of 235 days. Meanwhile, the PERT method provides an estimate of completion in the range of 221 to 251 days, with a probability of project success being completed in 221 days of 0.14%, and in 251 days of 99.86%. The implementation of this method improves the accuracy of project scheduling and supports efficiency in resource management. The results of this study recommend combining CPM and PERT with other optimization techniques, such as crashing, to improve project time and cost efficiency. Keywords: CPM, Critical Path, PERT, Project Management, Time Optimization

The efficacy of managing a construction project mainly depends on proper planning and scheduling. Mass housing projects are highly repetitive in nature, as the methods used for construction are often repetitive or cyclic. Resources are therefore being deployed repeatedly for the similar or identical tasks in these projects. In order to eradicate delays in mobilizing resources, an efficient resource schedule is required. Traditional scheduling tools like Critical Path Method (CPM), Programme Evaluation and Review Technique (PERT) are less effective in scheduling repetitive construction projects, as they consider availability of resources are unlimited. The main challenge in preparing construction schedule for repetitive projects is synchronizing the precedence logic and the allocation of resources as per requirements for all the activities. Consequently, activity scheduling and resource planning are prepared in parallel and this will facilitate in eliminating delays and idle resources across the projects thereby, controls the chain-reaction management (ripple effects). Nevertheless, almost all the repetitive scheduling methods developed so far have been giving focus on continuous repetitive projects, whereas in the present study, the emphasis is on discrete (non-linear) repetitive projects. This paper presents a model that uses genetic algorithms to optimally assign resources to repetitive activities, which aimed to minimize the total project cost & duration, idle cost & time and to maximize resource utilization. In the present study, an attempt is made to generate a resource-driven construction schedule automatically, with which resources can optimally be allocated to the activities. This schedule can be very useful in improving productivity and saving construction time and cost and also in decision-making. In addition, a case study is delineated to check the efficiency and effectiveness of the resource-driven construction schedule which is automated.

Based on the problems and causes of the system analysis software project schedule, the idea of introducing critical chain technology into the software project schedule is proposed. This paper expounds the basic concept of the critical chain schedule of the software project, describes its core idea in detail, and constructs the critical chain schedule model of the software project. Then the objectives and construction principles of the software project critical chain schedule model are analyzed, and the implementation process is explained. Finally, the feasibility of the software project critical chain schedule is verified by examples.

Residential construction projects can have many risks and uncertainties that can affect their completion time. To ensure a residential construction project is completed on time, accurate duration estimates are required for each activity. The deterministic duration Critical Path Method (CPM) is extensively used in construction project scheduling. However, this method may not always yield a realistic schedule as it uses only one duration estimation for each activity. As an alternative, this study uses the Program Evaluation and Review Technique (PERT) which utilizes three duration estimates, and the Monte Carlo Simulation (MCS) which simulates the duration 5000 times. A house construction project with 24 activities was analyzed using CPM which yielded 63 days completion time. The project was then analyzed using PERT and MCS. PERT and MCS calculations found that to complete the project with a 95% level of confidence the project needed 70 and 79 days, respectively. The findings of this study indicate that PERT and MCS can assist project managers in creating a more realistic project schedule by considering the risks and uncertainties inherent in a construction project.

With the rise of the Internet and the booming development of information technology, more and more IT projects have been launched on the information infrastructure. However, due to the large uncertainty and specificity of IT projects, the project delays are very serious. Both the Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT) can no longer meet the management requirements. This paper has improved the Critical Chain Project Management (CCPM) to strengthen the progress and quality management of IT projects. According to the characteristics of IT projects, an improved Critical Chain Project Management (NS-CCPM) had been proposed, and which was based on social network and software maturity models. Then the application of NS-CCPM has been specifically elaborated in three aspects: critical chain identification, buffer design, and buffer dynamic management. Finally, a case was shown, which used the Monte Carlo simulation method to verify the availability of NS-CCPM.

Critical Chain Project Management (CCPM) is created on techniques and procedures taken from the Theory of Constraints (TOC). CCPM was presented in late 90s (1997) in a book named Critical Chain from several studies by Standish Group and others for customary project management methods, only half of the projects normally finish on time, projects generally take twice the duration originally planned, twice of the original planned cost, around 70% of projects fall short of their planned scope, and round about 30% of the projects are shut down in midway. CCPM can be used to avoid these customary statistics. Usually, CCPM case studies report greater than 95% on-time and on-budget completion when CCPM is applied in the approved manner. Initially, the CCPM guidelines and prescriptions and discovers its differences with customary project scheduling methods like Program Evaluation and Review Technique (PERT) and Critical Path Method (CPM). Then the Critical Chain Project Management solution has been outlined, which covers all the proposed steps—the elements of the Critical Chain Project Management solution. Thereafter, the methodology used for data collection and analysis has been explained. Further, it explains the application of CCPM in a Transmission Line Project undertaken by Larsen and Toubro Power Transmission and Distribution. Further, the results of the analysis and discussions about the same have been written.

The project scheduling establish the time sequence of various activities which has a certain time limit, this means that the project must be completed before or exactly at the specified time. The delay effect and result in delays to the completion of the overall project. The purpose of study is to analyze the scheduling of the project to find out how long a project can be completed, determine the critical path as well as optimize the time of execution of the project. Research methods used for the project implementation analysis of Clubhouse building construction using critical path method (CPM) and program evaluation and review technique (PERT). Results of the discussion and calculations obtained that the completion of the project still in accordance with the schedule that has been determained, with the critical path method (CPM) is 321 days, and the program evaluation and review technique (PERT), time most quickly resolved is 312 days (value of Z= 0,22%), the slowest time is 339 days (value of Z= 99,87%) and the most probable time is 325 days (value of Z= 49,20%). Be aware of the activities which constitute the critical path is the activities: A, B1, B2, B3, B4, C1, C2, C3, C4, C6, C5, C7, C8, D, and obtained the optimization of project completion time with the CPM method is 48 days, PERT method, time most quickly is 57 days,the slowest time is 30 days, and the most possible time is 44 days.

ProcessModel simulation allows the activity times of a project to be represented by a variety of distributions and further the resulting project time may also be represented by a variety of distributions. This is a significant improvement over the traditional methods of CPM and PERT. Program Evaluation and Review Technique (PERT) takes the CPM network and adds distributions to represent the activity times of the project. CPM assumes the activity times to be constant, which is not likely in the real world. PERT assumes the activity times of the project to be distributed as Beta distributions and the resulting project time to be a Normal distribution. This is better than assuming them to be constant, but these assumptions are needlessly restrictive. This paper demonstrates how simulation with ProcessModel can remove these needless restrictions.

This study aims to examine the application of the Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT) in optimizing project time management. The research method used is a literature study by analyzing various scientific references related to CPM and PERT. The results show that CPM is effective in identifying the critical path of a project that directly impacts project duration, while PERT excels in managing project time uncertainty through a probabilistic approach. The analysis indicates that combining both methods can enhance the accuracy of project time planning, minimize delay risks, and ensure optimal resource utilization. The conclusion of this study is that CPM and PERT have their respective advantages in project time management, and their simultaneous application can be an effective strategy for achieving project objectives more efficiently. Therefore, project managers are advised to understand the project characteristics and select the appropriate method to optimize project time management.