Critical Path Method Scheduling Research Articles

A Scheduling Model in Capturing Methane Gas from Methane Clathrates Deposits

The execution of any project type, especially engineering-based projects, is usually time-based, efficiency-driven, and cost-effective. These factors are the deterministic parameters that engineer successful project completion. The application of scheduling models remains the best technique for achieving these three factors to their best degrees. Therefore, this study was centered on the impact study of applying the scheduling model in harvesting methane gas from methane clathrates deposits. Various data on gas hydrate reserves in the Niger Delta region of Nigeria were collected from relevant literature, studied, and analyzed. Such data includes the pictorial representation and description of the gas hydrate site in the Niger Delta region of Africa and various shapes and sizes of gas hydrate perimeters in the studied region positions of the gas reserves. The normal faults are projected on a bathymetric map of the study area and the bathymetric map of the Pockmark (with the stippled black line indicating the sea floor projection of a prominent N-S trending fracture in 3-D seismic data). As a type of scheduling model, the critical path method (CPM) was applied to develop the project’s work sequence using the activity on node (AON) architectural technique and Primavera P6 software after carefully identifying the primary operations involved in the project and their respective sub-operations or work breakdown structure (WBS). The risks associated with each operation were meticulously identified, with their consequent impact and exposure matrix determined using probabilistic measures of 1-5 according to the degree of the risk. Mitigation strategies were recommended for all the identified risks. The cost benefits of the project were X-rayed using parameters such as net present value (NPV), project payback time, internal rate of return (IRR), and net cumulative cash flow. From the results obtained, the CPM schedule showed that the project execution would last approximately ten months. All the operations involved in the project execution plan were all critical, proving that each activity should be completed within the scheduled run period. Else, the entire project would be affected. Also, risks with a high exposure matrix of 25, 12, and 4 were mitigated to 5, 3, and 0 using the recommended strategies. In addition, the project yielded an NPV of $20,736,951.04for the run period of 22 years after the execution of the project, IRR of 14%, and a payback time of 8 years (adding 2023 – the year of project execution) provided the daily production rate is maintained within 60,000-65,000MSCF/day. If the daily production rate increases, the cash flow and payback time will decrease. Therefore, the application of CPM in extracting methane gas from gas hydrates positively affected the operation through the vivid insights provided in workflow pattern/methodology risks effects and cost benefits.

Comparison of different algorithms for time analysis for CPM schedule networks

Traditional Critical Path Method (CPM) and its different generalizations have become the prevailing technique in managing complex projects over recent decades. Among them, Precedence Diagramming Method (PDM), with its four precedence relationships, has become the most popular due to its increased flexibility in modeling complex project logic. Despite the four well-known precedence relationships, CPM/PDM still suffers from modeling shortcomings.Developments such as conditional logic, maximal relationships, point-to-point relationships, continuous relationships, and non-linear activities attempt to remedy these problems. However, these improvements require more complex and sometimes iterative time analysis.Monte Carlo (MC) simulation, which calculates the effects of risks on the project duration, also requires numerous repetitions of the deterministic time analysis. It is especially true if the network contains the developments mentioned above. In these cases, the time analysis speed is of great importance.The goal of this study is a) to implement different algorithms for time analysis that perform better than the traditional time analysis, b) to compare their speed on large-scale artificially created projects, c) to make suggestions regarding which algorithms are suitable in different cases d) to develop a database containing artificially created networks to serve as a basis for benchmarking for researchers and developers working in the field of project planning.Comparisons were based on networks with at least 1000 activities. Results show that, depending on the sample network's structure, different algorithms perform well. Therefore, different time analysis algorithms are necessary to implement into the scheduling tools, and they can decide which algorithms perform better.

Analysis of time acceleration using Critical Path Method (CPM) to increase motorcycle maintenance in authorized service station

Numerous studies have shown that maintenance requires proper scheduling by using preventive and corrective maintenance scheduling to maintain the state of the machine. The fact is the number of Honda motorcycle products has increased. This has resulted in a long motorcycle queue. Motorcycle queues cannot be prevented only by scheduling preventive and corrective maintenance, so scheduling of maintenance activities is necessity to speed up motorcycle maintenance time. This study uses the Critical Path Method (CPM) activity scheduling method with the help of the POM-QM program to increase the acceleration of maintenance time. Scheduling is made by calculating the logic of dependency and time of each maintenance activity. Activity scheduling is carried out on 7 types of maintenance, namely carburetor light service, carburetor and CVT light service, injection light service, injection and CVT light service, oil change, spare part replacement, oil and spare part replacement and final inspection of each type of maintenance. After that, the analysis of the scheduling results is done by comparing the results before and after the proposed improvement. Based on the results of research conducted it can be seen that the maintenance time at the authorized service station can be accelerated by using the CPM scheduling method. The efficiency of acceleration of maintenance time is 16.666% to 57.889%. The preparation of maintenance activities and processing of heavy service data is required if there is heavy service maintenance in the authorized service station.

CONSTRUCTION MANAGEMENT ANALYSIS OF CIDERES HOSPITAL

Reliable infrastructure requires effective and efficient management from the planning, structural, construction, operational and maintenance phases to the end of service life. Good management of civil infrastructure guarantees not only to save funds, but to use natural resources appropriately, thus ensuring ecological sustainability.Construction management is part of civil engineering science that focuses on managing construction projects to realize technical concepts and designs produced by other parts of civil engineering science. Construction management aims to build built physical facilities or infrastructure that is needed to support human life. Management of construction projects is becoming increasingly complex due to the many parties that interact in it and the increasingly high demands for quality of functions, comfort, security, aesthetics and sustainability. Therefore construction management is needed to ensure the efficiency and productivity of a construction project in meeting various expectations and requirements. This thesis analysis includes volume calculation, Needs of labor, materials and equipment, Bar chart, Cash flow, S Curve, method of CPM (Critical Path Method) is a method of identifying critical work paths or items. Forwards calculation, backwards calculation, free float and total float. Based on the calculation of cash flow to complete the construction of Cideres Hospital Kadipaten Dawuan Majalengka project until final stage more or less cost as much Rp. 9,034,000,000,00. These costs are divided into two parts, structure and architecture work ,for structures the cost as much Rp. 3,644,000,000,00 and for architecture the cost is Rp. 5,390,000,000,00. From the calculation of CPM scheduling analysis, the development of Cideres Hospitalproject takes time for 45 weeks Keyword: Project Management, Bar Chart, S Curve, Critical Path Method

ANALYSIS OF CONSTRUCTION MANAGEMENT CONSTRUCTION PROJECTS DEVELOPMENT OF FLATS OF TEGAL ALUR DKI JAKARTA

Location of the development project of Tegal Alur DKI Jakarta KSO.WIKA & CAKRA in the Lingkungan III Tegal Alur West Jakarta coordinates Y: 2500.000 X: 2500.000 (West Jakarta PUPR Office) Project management is an attempt to use limited resources efficiently, effectively and on time in completing a predetermined / planned project. There are 3 activities of the basic functions of project management namely planning, implementation and control. Of the three activities are controlled resources on a project that includes manpower, equipment, materials, money and methods. Analysis of Construction Management of Jakarta TegalAlur DKI Jakarta Project Development Project includes Analysis of Work Implementation Method, Volume Calculation and Budget Plan of Jakarta TegalAlur DKI Jakarta Development Project, Schedule Compilation at TegalAlur DKI Jakarta Flower Housing Project, Cash Flow Analysis On Development Project of TegalAlur DKI Jakarta Flats. This research methodology is composed of several main stages, namely Preparation of Survey and Identification of Field, Seeking primary data and secondary data in related institution and department needed to complete data needed in preparation of thesis, Conducting analysis of data obtained through identification problem and make formulation, Taking conclusions and suggestions from the results of research. With Budget Plan Cost and calculation of workload of Jakarta Flat Development Project TegalAlur DKI Jakarta resulted in Working Time Plan takes 231 days using CPM scheduling method with estimated cost of Rp. 36.690.228.549  Keywords         :Project Management, Bar Chart, Curva S, CPM (Critical Path Method)

Improving workflow and resource usage in construction schedules through location-based management system (LBMS)

Critical Path Method (CPM), a planning and controlling technique, is widely used in the construction industry. However, CPM is criticized for its lack of workflow and inability to schedule continuous resource usage. Location-Based Management System (LBMS) fill these gaps and has been implemented in many construction projects. We propose that LBMS will improve schedules and project performance, addressing CPM’s main shortcomings. This study is composed of three case studies. CPM schedules were analyzed and were improved using LBMS tools. The resulting schedules show improved workflows, crew balancing, resource usage and had fewer interruptions, without affecting project duration. Furthermore, LBMS schedules were optimized with only a few scheduling operations and fewer planning elements. The computational benefit of LBMS increases with the number of locations and tasks in a schedule. Project managers will benefit from a simpler scheduling process and better resource flow.

Scheduling of Empennage Structure Design Project of Indonesia’s Aircraft with Critical Path Method (CPM)

Production of the aircraft becomes very important to facilitate many passengers of aircraft in Indonesia in the future. The design of a very complex aircraft requires proper project management. This study aims to perform the best scheduling project of empennage structure design of Indonesia’s aircraft with limited resources. Critical Path Method (CPM) is used to schedule the project based on activity and resource. CPM scheduling results in completion time for activity data for 400 working days. CPM scheduling after assigning human resources results in a longer completion time for 1023.47 working days. CPM scheduling is carried out by reallocating of human resources to produce a shorter completion time, and it results in completion time for 955 working days.

APLIKASI METODA LINE OF BALANCE (LOB) DAN METODA CRITICAL PATH METHOD (CPM) DALAM PENJADWALAN KEGIATAN PEMBANGUNAN PERUMAHAN

Sutanto, in this paper explain that line of Balance is a variation of the linear scheduling method that allows the operating balance so that all activities can continue. In the various International leteratur usually shown as Line of Balance scheduling tool that is only suitable for the project - a project that is composed of repetitive activities, and is not suitable for non-repetitive projects. Network method is introduced towards the end of the 1950s by a team of engineers and mathematicians from Dupont company is working with the Rand Corporation, in an effort to develop a management control system. These systems are intended to plan and control a large number of which have a complex dependency relationship in the construction of engineering design problems and maintenance. Businesses - emphasized efforts to seek methods to minimize the costs, in conjunction with the completion of a period of activity. The system was then known as the critical path method (Critical Path Method/CPM). Research application method Line of Balance (LOB) and Critical Path Method (CPM) scheduling activities in residential construction and the impact on the field of technical constraints is one solution . Conclusions obtained from the results of the research, the use of residential construction projects activities scheduling with Line of Balance method combined with the Critical Path Method method would have added value. Keywords: Housing Development, Application lob and CPM scheduling method.

An Advanced Stochastic Time‐Cost Tradeoff Analysis Based on a CPM‐Guided Genetic Algorithm

AbstractThis article presents an advanced stochastic time‐cost tradeoff (ASTCT) method that performs time‐cost tradeoff analysis by identifying optimal set(s) of construction methods for activities, hence reducing the project completion time and cost simultaneously. ASTCT involves a stochastic time‐cost tradeoff analysis method based on a critical path method (CPM)‐guided genetic algorithm (GA). It makes use of CPM schedule data exported from a project management software, and alternative construction methods obtained from estimators (i.e., normal and accelerated durations and costs) for each activity. It simulates schedule networks, identifies an optimal set of GA parameters (i.e., population size, crossover rate, mutation rate, and stopping rule), implements several GA cycles, and computes near‐optimal solution(s) exhaustively. This study is of value to practitioners because ASTCT improves the computation time, reliability, and usability of existing GA‐based time‐cost tradeoff methods. The study is also of relevance to researchers because it facilitates experiments using different GA parameters expeditiously. Two test cases verify the usability and validity of the computational methods.

Application of Critical Path Method scheduling to research plan and management of graduate students' research project in engineering education

Application of Critical Path Method scheduling to research plan and management of graduate students' research project in engineering education

Integration of Building Information Modeling and Critical Path Method Schedules to Simulate the Impact of Temperature and Humidity at the Project Level

Steel construction activities are often undertaken in an environment with limited climate control. Both hot and cold temperatures can physically and psychologically affect construction workers, thus decreasing their productivity. Temperature and humidity are two factors that constantly exert forces on workers and influence their performance and efficiency. Previous studies have established a relationship between labor productivity and temperature and humidity. This research is built on the existing body of knowledge and develops a framework of integrating building information modeling (BIM) with a lower level critical path method (CPM) schedule to simulate the overall impact of temperature and humidity on a healthcare facility’s structural steel installation project in terms of total man hours required to build the project. This research effort utilized historical weather data of four cities across the U.S., with each city having workable seasons year-round and conducted a baseline assessment to test if various project starting dates and locations could significantly impact the project’s schedule performance. It was found that both varied project start dates and locations can significantly contribute to the difference in the man hours required to build the model project and that the project start date and location can have an interaction effect. This study contributes to the overall body of knowledge by providing a framework that can help practitioners better understand the overall impact of a productivity influencing factor at a project level, in order to facilitate better decision making.

Understanding the Occurrence of Two Total Floats in One Activity and Schedule Crashing Approaches for That Situation

Critical Path Method (CPM) Scheduling has proven to be an effective project management tool. However, teaching the topic has proven difficult to include all elements of CPM yet keep it simple enough for students to understand. In an effort to simplify the teaching of critical path method scheduling, the issue of two total floats in an activity does not get the attention necessary to address its occurrence. The objective of this paper is to present a mathematical method to show multiple total floats are possible for an activity. Also presented are suggestions for schedule crashing when multiple total floats are found. Two totals floats can be found if constraints (Lag or Lead) or non-Finish-to-Start (FS) relationships, or both are used in a network diagram. Situations are possible where an activity may have a start total float (STF) of zero but have a finish total float (FTF) greater than zero, or vice versa. Because the critical path generally follows the zero total float, these situations, where either the STF or the FTF is critical while the other is not, determines how the critical path activity must be controlled and crashed. This paper will present approaches of how to crash the schedule when a portion of the activity, either start or finish, is critical. Also presented will be methods to teach the subject matter with or without the use of scheduling software. Critical Path Method was revisited to see what the minimal conditions are needed to have activities with two total float. Generalized crashing methods were studied to see if the methods can be used when two total floats exist.

LOB and CPM Integrated Method for Scheduling Repetitive Projects

Repetitive projects require schedules that ensure the uninterrupted usage of resources from a unit to similar units in a repetitive activity while maintaining logical dependency constraints. The critical path method (CPM) is the most widely used and accepted planning and scheduling method for traditional (nonrepetitive) projects. However, CPM does not suit the planning and scheduling needs of repetitive projects. Consequently, resource-driven techniques, such as line of balance (LOB), have been used to schedule repetitive projects that ensure work continuity. LOB is primarily a graphical technique that lacks the analytical qualities of CPM scheduling. A need for an analytical technique fulfilling characteristics of repetitive projects has been reported in the literature. Few attempts have been made to combine the benefits of CPM and LOB techniques in planning and scheduling of repetitive projects. In this paper, an integrated CPM and LOB model has been developed to schedule repetitive projects in an easy nongraphical manner, considering both logic dependency and resource continuity constraints. Overlapping activities of a single typical unit are used to model duration and logical relationships of repetitive activities. The proposed model essentially consists of four steps. In the first step, basic LOB calculations are performed to ensure resource continuity. Activity duration along all repetitive units is calculated in the second step. In the third step, overlapping activities are used to model logical relationships between consecutive activities. Next, CPM time analysis is performed to specify activities’ timings and floats and project completion time. An example application is presented to illustrate implementation and features of the proposed model.

BDM 네트워크 공정 및 비용 진도율 통합관리 개념

국내 건설산업에 CPM(critical path method) 공정관리기법이 도입된 지 거의 40년 가까이 경과하고 있다. 그러나 국내건설현장의 대부분은 CPM 공정표를 작성하지 않거나, 발주처의 요구에 의해 수동적으로 작성한 후 운영 및 관리는 거의 하지 않고, 아직도 바차트(bar chart)기법에 의존하여 공정관리를 하고 있는 실정이다. 이러한 원인중 하나는 CPM 공정계획이 건설현장의 업무를 정확히 반영하지 못하고 있으며, 공사 진척현황을 시각적으로 명확하게 인식하기 어렵고, 작업들의 일정중심의 공정진도와 기성금액 중심의 비용진도를 효율적으로 통합 관리하지 못하기 때문이다. 본 논문은 새로운 CPM 공정관리기법인 BDM기법을 통해 공정계층체계 내에서 CPM 공정계획이 자동으로 요약되면서 동일한 CPM 형식을 유지하는 기능을 통해, CPM기법의 장점을 그대로 유지하면서도 일정중심의 공정진도율과 기성중심의 비용진도율을 통합 관리할 수 있는 새로운 진도율 관리 개념을 제안한다. 이러한 개념을 통해 국내 건설사업에 CPM 공정관리기법이 실질적으로 적용되고 활성화되어, 공사관리의 효율성이 향상되는 동시에 국내 건설사업관리의 발전에도 일조 할 수 있기를 기대한다. Almost 40 years have been passed since the CPM was introduced to the construction industry in Korea. However most of construction projects in Korea do not prepare the CPM schedule neither operate it after established manually, as well as still depend on the Bar-chart schedule only. One of these reasons is because the CPM schedule does not reflect the site works realistically, it makes so difficult to recognize the actual progress clearly in visual format, and it is impossible to integrate and manage the time and cost oriented work progresses effectively. This paper proposes new concept of progress management that is able to integrate and manage the time oriented schedule progress and earned value oriented cost progress while maintaining the merits of CPM although the CPM schedule summarized automatically within a schedule hierarchy by the BDM that is a new CPM technique. We expect that this concept could make the applications of CPM technique to the domestic construction industry popular and help the advancement of the construction management in Korea as well.

Building Chan Chan: A Project Management Perspective

AbstractThe labor investment in ancient monumental architecture is an important factor in hypotheses concerning a society’s size, organization, and social complexity. Most methods of quantifying labor expenditures are limited to simply designed structures with a minimal number of elements. Due to the lack of practical analytical methods, complex architecture is often described subjectively, offering little quantitative value, resulting in inferences that could be misleading or wrong. Using Ciudadela Rivero at the site of Chan Chan, Peru, as a case study, this research employed construction industry-standard planning, estimating, and scheduling tools to calculate the labor requirements and construction times under various building scenarios. Additionally, the application of Critical Path Method scheduling provides the means to model and compare numerous building scenarios by simulating the effects of various construction and labor organization strategies in their cultural context. The results for Ciudadela Rivero revealed a labor input of over two million labor hours, which could be accomplished by a modest labor force of as few as 250 workers over a six-year period. These data affect numerous archaeological hypotheses concerning scale of construction, organization of labor, and complexity of social organization.

Construction Project Scheduling with Time, Cost, and Material Restrictions Using Fuzzy Mathematical Models and Critical Path Method

This article evaluates the viability of using fuzzy mathematical models for determining construction schedules and for evaluating the contingencies created by schedule compression and delays due to unforeseen material shortages. Networks were analyzed using three methods: manual critical path method scheduling calculations, Primavera Project Management software (P5), and mathematical models using the Optimization Programming Language software. Fuzzy mathematical models that allow the multiobjective optimization of project schedules considering constraints such as time, cost, and unexpected materials shortages were used to verify commonly used methodologies for finding the minimum completion time for projects. The research also used a heuristic procedure for material allocation and sensitivity analysis to test five cases of material shortage, which increase the cost of construction and delay the completion time of projects. From the results obtained during the research investigation, it was determined that it is not just whether there is a shortage of a material but rather the way materials are allocated to different activities that affect project durations. It is important to give higher priority to activities that have minimum float values, instead of merely allocating materials to activities that are immediately ready to start.

Generating, Evaluating, and Visualizing Construction Schedule with Geographic Information Systems

Linking of the activities in a critical path method schedule with the corresponding elements of a three-dimensional (3D) model makes the project sequence easier to understand. Although some commercial tools allow the planner to build a 4D model and create graphical simulation of the construction process, it still lacks features like generation and manipulation of a 4D model within a single environment. This paper presents a geographic information systems (GIS) based methodology for scheduling as an alternative to the existing 4D computer aided design tools. A methodology to build a 3D model and link it with the construction schedule using several in-house scripts written in GIS environment is discussed. It allows the planner to understand the construction schedule quickly by linking the activities of the schedule with the corresponding 3D components as well as to visualize a buildable schedule on a computer screen. The proposed methodology utilizes the dynamic linkage between the activities in the schedule and corresponding 3D components, thus, making it possible to detect the incompleteness and logical errors in the schedule sequence. The ability of GIS to maintain spatial data (i.e., 3D components corresponding to each activity) in separate themes, which can be superimposed spatially, is utilized. The related nonspatial information (like schedule, material type and quantity, safety and quality control recommendations, etc.) are stored in the attribute tables of corresponding components, which can be extracted from the database maintained within the GIS itself.

Critical Path Scheduling under Resource Calendar Constraints

Resource calendars specify nonworking days of driving resources involved in construction projects. As part of the resource availability constraints in critical path method (CPM) scheduling, resource calendars may postpone activity start time, extend activity duration, and hence prolong the total project duration. Ultimately, resource calendars bring about changes to the critical path identification. Research has yet to address how to incorporate the effects of multiple resource calendars on the total float determination. In this research, the popular P3 software is used as a tool for investigating the current practice of CPM scheduling under resource limit and calendar constraints. We assess P3’s advanced resource scheduling functions (including resource leveling and resource calendars) and identify P3’s potential errors in total float determination. Further, we propose a new method based on the forward pass analysis alone for accurately evaluating activity total float subject to resource calendar constra...

Reconciliation of Owner and Contractor Views in Heavy Construction Projects

Delay and loss of productivity are the two main types of damage experienced by the contractor when the owner issues a change order. Courts have recognized critical path method schedule analysis as the preferred method of identifying and quantifying critical delays. As for the inefficiency damages, there is no direct way of measuring inefficiency due to its qualitative nature and the difficulty of linking the cause of the productivity loss to the damage. Most of the scholarly work published in this area was based on data supplied by the contractors; and that explains why there are discrepancies between what the contractor asks for and what the owner believes the contractor is entitled to. This study addresses the need for a statistical model to quantify the productivity loss from verifiable site data such as owner’s daily reports, change orders, drawings, and specifications, rather than rely solely on contractor surveys. A model is developed and validated to quantify the productivity loss in pipe work in roadway projects due to the change orders. The productivity loss study analyzed two sets of data that include: (1) variables that predict which of the two parties, the owner and the contractor, contributed to the productivity loss; and (2) variables that predict, from the legal viewpoint, productivity losses which only the owner is responsible for. The study showed the difference between what the contractor asked for and what he/she is actually entitled to. This model can be used by both the owner and the contractor to quantify the productivity loss due to change orders, and to offer an objective approach to reconcile their differences. This study concludes with an example to demonstrate the use of the model.

Subcontractor Schedule Control Method

Trade coordination and claims documentation is a challenge on any project, particularly for specialty subcontractors. The writers introduce a schedule control method initiated by the subcontractor, which facilitates coordination and communication between a subcontractor and other project participants as well as documentation to the prime contractor. A case study illustrates the preparation of a trade-specific critical path method (CPM) schedule, which is updated on a regular basis. The writers also address the interrelationship between the CPM schedule, internal reporting, schedule of values, and labor tracking. It is difficult to ensure that all subcontractor-produced documentation is complementary, but it is well worth the effort when it comes to supporting a claim. Monthly schedule updates and narratives communicate the conflicts, issues, and schedule constraints the subcontractor experiences or anticipates on a project, thereby providing contractually required notice to the prime contractor during the project. This increases the likelihood of resolving issues during the project, while simultaneously protecting a subcontractor's position if change order requests are denied or if back charges are levied prompting a subcontractor to enforce its rights, execute a claim, or proceed to litigation.