Project Scheduling

Traditional construction scheduling approaches have proved not to have the capacity to produce and make it easily and timely available the information needed for a latter effective and efficient construction control and execution reflected in a high Percentage of Planned Activities Completed. nD poses barriers and opportunities associated to big transformations which for example could lead to relegate traditional construction scheduling approaches like the CPM in which the critical path has become a bottleneck, a constraint of a project. The big change of working with a nD construction schedule can lead to lose less time on the critical path itself but exploiting this constraint and subordinating everything else to it. Most problems that impact the critical path do not occur on the critical path itself, then subordination is not a nicety, it is a must (Goldratt, 1997). Another big change is that using nD Modeling it is possible to alter the order in which the different level of detail schedules are developed for a construction project. Using nD and CAVT it is possible to develop first the more detailed schedule and then obtaining the master schedule grouping activities in this more detailed schedule. The master schedule can then be adjusted to project requirements and the detailed schedule reviewed in an iteratively process. This opposes to the way scheduling is carried out today in which the detailed schedule follows the master schedule development effort and rarely one goes back to review the master schedule deeply, but makes the maximum effort to adjust the detailed schedule to the master schedule. And finally a very important change is that Visualization, Planning, Analysis and Communication capabilities embedded in a new nD construction scheduling development process can improve the traditional scheduling process to the extent that this schedule could finally be used as a real production control mechanism that could lead to tackle problems proactively and re-schedule the project as necessary.

This paper presents time and cost planning in construction projects using building information modeling (BIM) approach. The BIM technique can be incorporated into the time and cost planning process through several steps. At the beginning, a 3D model of the construction object is developed using an adequate modeling application. After that, the 3D model is imported into suitable BIM construction management software. Thereupon, the project costs are estimated on the basis of quantities of required resources, consumptions, production rates and unit costs. The project activities are then defined and linked to the construction elements of the 3D model as well as updated with allocated resources and costs. The activities with established durations are mutually connected together into a project network plan by taking into account relevant precedence relationships. The project duration is automatically determined from the generated network plan. Finally, the BIM model of the construction object is completed by upgrading the 3D model with defined scheduling and cost data. An application example is presented in the paper to demonstrate the advantages of BIM implementation in architecture, engineering and construction industry.

This paper describes the methodology and results obtained after productivity improvement work conducted on two consecutive building construction jobs.  The first one was used to evaluate production rates and productivity, current construction methods, potentials and lacks of construction equipment, current construction planning methodology, and existing tools to asses productivity.  These are briefly discussed in this paper. The second job was preplanned based on the experience and detailed documentation obtained in the first one. Work was conducted in order to “design” construction methods in detail, develop a detailed production planning based on the construction methods developed, select crew components and select their specific tasks, and design communication and control tools. Although the second job’s schedule and budget were originally calculated using standard methods (i.e. historical production rates), new schedule and budget were calculated based on the preplanning effort. Construction performance was measured against these values.

T he project scheduling problem involves the scheduling of project activities subject to precedence and/or resource constraints. Of obvious practical importance, it has been the subject of intensive research since the late fifties. A wide variety of commercialized project management software packages have been put to practical use. Despite all these efforts, numerous reports reveal that many projects escalate in time and budget and that many project scheduling procedures have not yet found their way to practical use. The objective of this paper is to confront project scheduling theory with project scheduling practice. We provide a generic hierarchical project planning and control framework that serves to position the various project planning procedures and discuss important research opportunities, the exploration of which may help to close the theory-practice gap.

Opportunities offered by the explosion of Information Technology (IT) tools are not being adequately used to solve productivity, schedule, cost and quality problems faced by the design and construction of industrial projects.
The Computer Advanced Visualization Tools (CAVT) concept defined as “the collection of all the necessary tools, which allow for the visual representation of the ends and the means of AEC/EPC needed to accomplish an AEC/EPC design and construction project” was developed and its impact in the design process of industrial projects was described as an answer to the stated problem.
The research was carried out using the observation-participation method in which the industry became a laboratory that offered the opportunity to have access to events and groups that are not commonly accessible to scientific research.
The design process was studied considering the state of the art about production principles applied to the construction industry through the Lean Construction approach. This allowed the ability to model, analyze, understand and describe the design process, providing and adequate framework to study the impact of CAVT which is presented mainly considering activities that add value to the design process.
The research led to discover change patterns and trends in the design process of industrial projects that can lead to obtain benefits in terms of cost and schedule reduction, and productivity, quality and safety increase in construction industry projects.

Goldratt's Critical Chain (1997) and the resulting project scheduling practices known as Critical Chain Project Management (CCPM) have been popular in our business schools but a subject of disagreement among our scholars. We survey the academic literature about the pros and cons of CCPM to examine claims in the book. We then present a sequence of numerical practice problems that are designed to clarify a student's understanding of the reading and highlight complications that Goldratt ignored. We conclude with two counterexamples that demonstrate ideas in the book that are not necessarily true in practice. Throughout the article are a number of open questions about CCPM that we as an academic community have not yet answered.

The Program Evaluation and Review Technique (PERT) has become a classic Project Management tool for estimating project duration when the activities have uncertain durations. However, despite its simplicity and widespread adoption, the original PERT, in neglecting the merge event bias, significantly underestimated the duration average and overestimated the duration variance of real-life projects. To avoid these and other shortcomings, many authors have worked over the last 60 years at producing interesting alternative PERT extensions. This paper proposes joining the most relevant of those to create a new reformulated PERT, named M-PERT.
M-PERT is quite accurate when estimating real project duration, while also allowing for a number of interesting network modelling features the original PERT lacked: probabilistic alternative paths, activity self-loops, minima of activity sets and correlation between activities. However, unlike similar scheduling methods, M-PERT allows manual calculation through a recursive merging procedure that downsizes the network until the last standing activity represents the whole (or remaining) project duration. Hence, M-PERT constitutes an attractive tool for teaching scheduling basics to engineering students in a more intuitive way, with or without the assistance of computer-based simulations or software. One full case study will also be proposed and future research paths suggested.

I n recent decades, the project-scheduling practice known as critical chain project management (CCPM) has been successful in industrial applications, yet remains a subject of disagreement among scholars and is only sporadically taught in business schools. The purpose of this paper is to assess what aspects of CCPM are appro-priate in operations courses, whether dedicated project management classes or broader introductory operations management classes. To answer this, we survey academic literature on traditional project management problems that gave rise to CCPM to understand if these issues are real. We also examine whether the CCPM methodology should, according to scholars, correct these problems, and survey project success stories attributed to CCPM. We conclude that CCPM is an appropriate project management methodology for student consideration on the basis of motivating critical thinking—especially about behavioral issues—rather than on formal scientific proof of its merit. In s...

Fuzzy logic has been proposed as an alternate ap-proach for quantifying uncertainty relating to project activity du-ration. The fuzzy logic approach may be suitable in the situations where past data are either unavailable or not relevant, the definition of the activity itself is somewhat unclear, or the notion of the activ-ity's completion is vague. The purpose of this paper is to present a new methodology for fuzzy critical path analysis that is consistent with the extension principle of fuzzy logic. It is the direct general-ization of critical path analysis to the fuzzy domains, and resolves some of the problems expressed in the fuzzy critical path literature, especially in computing the fuzzy backward pass of the project network and fuzzy activity criticality. Here the uncertainty is rep-resented by three possible time estimates in a way that is similar to the well-known program evaluation and review technique (PERT) approach. Another important advantage of the proposed appro...

The purpose of this paper is to present modern ways to manage time, resources and progress in a large-scale project. Over the last ten years, new project management techniques and tools have appeared such as concurrent engineering, Continuous Acquisition Lifecycle Support (CALS) and Engineering Data Management System (EDMS). The world downturn of the early 90s influenced project management: increasing constraints on time and budget and more external direction on spending that, for example, requires sophisticated sub-contracting practises. However, the evolution of the software and hardware market makes project control tools cheaper and easier to use. All project groups want to have their scope of work considered as complete projects and to control them themselves. This has several consequences on project staff behaviour concerning project control, and has to be taken into account in every planning process designed today. The system described will be at the heart of the planning and ...

Most of the construction projects are exposed to time and cost overruns due to various factors and this is a major problem. As a solution to this, the Earned Value Management (EVM) method is considered. EVM is a powerful and well-known method used in monitoring and controlling the project. EVM gives an early indication that either project is delayed or not and the project is either over budget or under budget at any particular day by tracking it. Thus, it helps to improve the management control system of a construction project, to detect and control the problems in potential risk areas and to suggest the importance and purpose of monitoring the construction work. This paper explains the main parameters of the EVM system involved in the calculation of time and cost for construction projects. In this study, the Primavera P6 software is used to deals with the project monitoring process of a seven-storeyed (G+6) faculty building whose construction is in progress at Istanbul, Turkey. A comparison between the planned progress of construction activities and actual progress is performed and the analysis results are interpreted. This case study justifies the benefits of using EVM for project cash flow analysis and forecasting.

This paper proposes an improved critical chain method with fuzzy approach to schedule projects under uncertainty. Utilizing fuzzy numbers can be wise because of the natural uncertainty in estimation of required work to accomplish the project tasks. To minimize the project duration as an objective taking into account resource limitations and other constrains, a Resource Constraint Project Scheduling Problem model (RCPSP) is adopted. The outputs of this model determine the project schedule. Then, regarding to CCPM concepts, a new buffer sizing method is introduced. As a result, a project buffer is added to the end of the project schedule and will be used if necessary. The methodology can be used as a control procedure.

ABSTRACT Resource management ensures that a project is completed on time and at cost, and that its quality is as previously defined; nevertheless, resources are scarce and their use in the activities of the project leads to conflicts in the schedule. Resource leveling problems consider how to make the resource consumption as efficient as possible. This paper presents an Adaptive Genetic Algorithm for the Resource Leveling Problem, and its novelty lies in using the Weibull distribution to establish an estimation of the global optimum as a termination condition. The extension of the project deadline with a penalty is allowed, avoiding the increase in the project criticality. The algorithm is tested with the Project Scheduling Problem Library PSPLIB. The proposed algorithm is implemented using VBA for Excel 2010 to provide a flexible and powerful decision support system that enables practitioners to choose between different feasible solutions to a problem in realistic environments.

This paper surveys single-project, single-objective, deterministic project scheduling problems in which activities can be processed using a finite or infinite (and uncountable) number of modes concerning resources of various categories and types. The survey is based on a unified framework of a project scheduling model including resources, activities, objectives, and schedules. Most important models and solution approaches across the class