Repetitive Construction Projects Research Articles

Optimizing the scheduling of crew deployments in repetitive construction projects under uncertainty

PurposeThis paper presents the development of a novel model for optimizing the scheduling of crew deployments in repetitive construction projects while considering uncertainty in crew production rates.Design/methodology/approachThe model computations are performed in two modules: (1) simulation module that integrates Monte Carlo simulation and a resource-driven scheduling technique to calculate the earliest crew deployment dates for all activities that fully comply with crew work continuity while considering uncertainty; and (2) optimization module that utilizes genetic algorithms to search for and identify optimal crew deployment plans that provide optimal trade-offs between project duration and crew deployment plan cost.FindingsA real-life example of street renovation is analyzed to illustrate the use of the model and demonstrate its capabilities in optimizing the stochastic scheduling of crew deployments in repetitive construction projects.Originality/valueThe original contribution of this research is creating a novel multiobjective stochastic scheduling optimization model for both serial and nonserial repetitive construction projects that is capable of identifying an optimal crew deployment plan that simultaneously minimizes project duration and crew deployment cost.

A Fixed Start Scheduling Approach for Repetitive Construction Projects

In the face of the high variability in the completion of construction projects, the following research is generated. In the literature we can find several proposals to program projects, however, the variability of the activities causes high variability in the completion date of the projects. We hope that the proposed method, by controlling the start of activities, will ensure the completion date of the projects, by fixing the start of every activity with a high level of probabilistic confidence for the planned project duration. The proposed fixed start method (FSM) was tested in two case studies by using discrete event simulation. Project completion duration results were compared with the critical path method (CPM) and the program evaluation and review technique (PERT). Project completion was evaluated in the case studies by the coefficient of variance (COV), mean, and variance. The new method decreased the scheduled duration variability while meeting project completion times.

New Approach to Improve General Contractor Crew’s Work Continuity in Repetitive Construction Projects

AbstractA significant number of construction projects involve repetitive processes. Planning them occurs to be a complex task. Network methods traditionally applied to construction scheduling prove...

Optimizing non-unit repetitive project resource and scheduling by evolutionary algorithms

Repetitive project scheduling is a frequently encountered and challenging task in project planning. Researchers have developed numerous methods for the scheduling and planning of repetitive construction projects. However, almost all current repetitive scheduling methods are based on identical production units or they neglect the priorities of activities. This work presents a new hybrid evolutionary approach, called the fuzzy clustering artificial bee colony approach (FABC), to optimize resource assignment and scheduling for non-unit repetitive projects (NRP). In FABC, the fuzzy c-means clustering technique applies several multi-parent crossover operators to utilize population information efficiently and to improve convergence efficiency. The scheduling subsystem considers the following: (1) the logical relationships among activities throughout the project; (2) the assignment of multiple resources; and (3) the priorities of activities in groups to calculate project duration. Two numerical case studies are analyzed to demonstrate the use of the FABC-NRP model and its ability to optimize the scheduling of non-unit repetitive construction projects. Experimental results indicate that the proposed method yields the shortest project duration on average and deviation of optimal solution among benchmark algorithms considered herein and those considered previously. The outcomes will help project managers to prepare better schedules of repetitive projects.

Generation, visualization, and evaluation schedule of repetitive construction projects using GIS

Surroundings is a major factor that affects scheduling of a repetitive construction project. But, both the past experience of planner and the commercially available tools are limited to take the effects of surroundings on the developed schedule into consideration. Therefore, geographic information systems (GIS) are used in the current study to consider the effects of surroundings on the schedule of a repetitive construction project. The interactive tool for project scheduling is developed in GIS environment by writing in-house scripts for both non-repetitive and repetitive units. 4D execution sequences along with its surroundings have been developed in GIS by linking schedule of a repetitive project with related 3D components. Hence, the effects of surroundings on the schedule of a repetitive construction project can be considered through using GIS in the current case study. Also, the 4D execution sequence along with its surroundings is used in checking the constructability of the developed schedule. Moreover, it helps in identifying logical errors, missing activities in the schedule, spatial feasibility, and constructability analysis. The developed interactive tool is used for the scheduling of Udaigiri boys hostel (UBH) building, as a case study, and helps the practitioners and planners in scheduling of their repetitive construction projects.

Quantifying the interruption impact of activity delays in non-serial repetitive construction projects

Available scheduling models for repetitive construction projects can be classified as serial or non-serial. Serial models assume that each repetitive activity is limited to have only one predecessor and one successor, while non-serial models enable repetitive activities to have multi predecessors and successors. Activity delays in serial and non-serial repetitive projects often cause work interruptions for successor activities and project delays. This paper presents the development of a novel scheduling model for both serial and non-serial repetitive construction projects to quantify the impact of any activity delay on interrupting the crew work continuity of its successors. An application example of a repetitive construction project from the literature is analyzed to illustrate the use of the model and its computations. This analysis illustrates the novel capabilities of the model in: (1) calculating a new float to identify the duration that each activity can be delayed without causing interruption in the crew work continuity of any of its successors; and (2) quantifying the impact of unexpected activity delay on interrupting the crew work continuity of its successors. These capabilities enable construction planners to analyze and minimize the impact of unexpected activity delays on interrupting the crew work continuity of all its successors.

Resource-Constrained Time-Cost Tradeoff for Repetitive Construction Projects

The time-cost tradeoff problem is to find optimal combinations of construction options with the objective of minimizing project time and cost. In order to search for such a set of optimal solutions, the total time and cost of projects needs to be calculated properly. In repetitive construction projects (RCPs), due to division of work into several units and involvement of many resources for activities completion, scheduling is unique and more complicated. Scheduling method in this paper besides addressing common constraints such as precedence relationships, required lead time and lag distance between activities, enables project managers to consider all resources and their shortages in scheduling. To raise the practicality of model, in addition to direct and indirect costs, resource idle cost is considered as a cost element in estimating total cost of project. The time variant multi-objective particle swarm optimization is applied to find non-dominated solutions on the basis of minimizing time and cost of project. An application example is presented at the end to illustrate the performance of the model. This research presents a resource-constrained time-cost tradeoff model to find the optimal set of crew combinations for project activities in RCPs, considering time and cost simultaneously.

MULTI-OBJECTIVE SYMBIOTIC ORGANISMS OPTIMIZATION FOR MAKING TIME-COST TRADEOFFS IN REPETITIVE PROJECT SCHEDULING PROBLEM

Time-cost problems that arise in repetitive construction projects are commonly encountered in project scheduling. Numerous time-cost trade-off approaches, such as mathematical, metaheuristic, and evolutionary methods, have been extensively studied in the construction community. Currently, the scheduling of a repetitive project is conducted using the traditional precedence diagramming method (PDM), which has two fundamental limitations: (1) progress is assumed to be linear from start to finish; and (2) activities in the schedule are connected each other only at the end points. This paper proposes a scheduling method that allows the use of continuous precedence relationships and piece-wise linear and nonlinear activity-time-production functions that are described by the use of singularity functions. This work further develops an adaptive multiple objective symbiotic organisms search (AMOSOS) algorithm that modifies benefit factors in the basic SOS to balance exploration and exploitation processes. Two case studies of its application are analyzed to validate the scheduling method, as well as to demonstrate the capabilities of AMOSOS in generating solutions that optimally trade-off minimizing project time with minimizing the cost of non-unit repetitive projects. The results thus obtained indicate that the proposed model is feasible and effective relative to the basic SOS algorithm and other state-of-the-art algorithms.

Scheduling of repetitive construction projects using geographic information systems: an integration of critical path method and line of balance

Critical path method (CPM) is the widely used technique for scheduling of non-repetitive construction projects, on the other hand, line of balance (LOB) is used for scheduling of repetitive construction projects. There may exist repetitive and non-repetitive parts together in a construction project. In the present study, to schedule repetitive and non-repetitive parts of a construction project together, CPM and LOB techniques have been integrated within the geographic information systems (GIS) environment. The scheduling tool has been developed in which activities of a repetitive part are scheduled using CPM and different repetitive parts are scheduled using LOB. A sample project scheduled using CPM technique takes 520 days, however, if the same project is scheduled using the developed tool takes 214 days. Further, construction planning is not done in isolation, that is, without considering surroundings of a construction project under consideration. The scheduling tool developed in GIS environment considers the effect of surroundings on the developed integrated schedule. A link has been established between the activities of the developed schedule and corresponding 3D components in GIS environment to develop 4D model of execution sequence of a construction project. This facilitates in checking logical errors, resource continuity, and incompleteness of the developed integrated schedule.

Planning repetitive construction projects considering technological constraints

AbstractRecently, there has been a growing number of construction projects that require more than one structure to be built - repetitive construction projects. These repetitive construction projects are characterized by a high degree of complexity both in terms of organisational and technological dependencies. A method is needed that will flexibly take into account the technological constraints that occur during the carrying out of repetitive construction projects. The article presents a method of priority scheduling that takes into account technological pauses that can prove useful in the planning of repetitive construction projects. The planner (usually a construction site manager) will be able to model the technological constraints occurring on the construction site in a more flexible way. The article also presents a calculation example in which the application of the developed model has been presented. The developed model proved to be effective in scheduling repetitive construction projects, taking into account technological constraints.

Delay Risk Assessment of Repetitive Construction Projects Using Line-of-Balance Scheduling and Monte Carlo Simulation

AbstractAlthough the line-of-balance (LOB) method is widely used for the scheduling of repetitive construction projects, there are only a limited number of studies that deal with the issue of how t...

Optimizing the Scheduling of Repetitive Construction to Minimize Interruption Cost

AbstractThis paper presents the development of a novel optimization model for the scheduling of repetitive construction projects. The model provides original and unique capabilities that enable pla...

Minimizing duration and crew work interruptions of repetitive construction projects

Abstract This paper presents the development of a novel scheduling model for minimizing the duration and crew work interruptions of repetitive construction projects. The main contributions of the developed model are its ability to (1) generate early and late start schedules that minimize the duration of repetitive construction projects while keeping the total work interruptions of their utilized crews to a minimum; (2) calculate novel types of crew work-continuity floats that consider the impact of delaying the early start of repetitive activities on crew work continuity; (3) develop a wide range of intermediate schedules between the early and late start schedules that maintain the least project duration and minimum total crew work interruptions; and (4) compare shortest duration schedules with and without interruptions to identify the best schedule that fits the specific project needs. The model performance was evaluated using an application example of a repetitive construction project.

Repetitive Project Modelling With Penalty and Incentive

Repetitive construction activities have the same activities which are performed repeatedly. Repetitive projects include: pipelines, highways, and multi-story buildings. Repetitive projects have been modelled widely using the traditional network techniques although, they have some disadvantages. Furthermore, different approached have been developed for repetitive activities including the graphical and analytical techniques. The objective of this research is to add new enhancements on an approach called Repetitive Project Model (RPM) which is related to the repetitive construction projects. The enhancements incorporating the incentives and penalties within the RPM. This model incorporates a network technique, a graphical technique, and an analytical technique. A numerical example was demonstrated in this research paper to aid on using the suggested model in the real-life application.

Opposition multiple objective symbiotic organisms search (OMOSOS) for time, cost, quality and work continuity tradeoff in repetitive projects

AbstractConstruction managers often face with projects containing multiple units wherein activities repeat from unit to unit. Therefore effective resource management is crucial in terms of project duration, cost and quality. Accordingly, researchers have developed several models to aid planners in developing practical and near-optimal schedules for repetitive projects. Despite their undeniable benefits, such models lack the ability of pure simultaneous optimization because existing methodologies optimize the schedule with respect to a single factor, to achieve minimum duration, total cost, resource work breaks or various combinations, respectively. This study introduces a novel approach called “opposition multiple objective symbiotic organisms search” (OMOSOS) for scheduling repetitive projects. The proposed algorithm used an opposition-based learning technique for population initialization and for generation jumping. Further, this study integrated a scheduling module (M1) to determine all project objectives including time, cost, quality and interruption. The proposed algorithm was implemented on two application examples in order to demonstrate its capabilities in optimizing the scheduling of repetitive construction projects. The results indicate that the OMOSOS approach is a powerful optimization technique and can assist project managers in selecting appropriate plan for project.Highlights This study presents an advanced multiple optimization algorithm OMOSOS. Opposition technique is utilized to spreading the initial population and generation jumping. OMOSOS is applied to solve time, cost, quality and work continuity tradeoff problem. The model performance is demonstrated in the experimental results.

Optimal crew routing for linear repetitive projects using graph theory

Abstract The line-of-balance (LOB) technique is considered as an effective tool for planning and scheduling linear repetitive construction projects. One of the main assumptions of the LOB technique is the uniformity and constancy of production rate for an activity. Moreover, some aspects of the LOB technique can be modified in order to suit the nature of construction projects. This paper proposes a hybrid approach for scheduling linear projects that optimizes resource allocation using the LOB scheduling technique. The paper presents an optimization model for resolving resource constraint dilemmas in linear scheduling projects. The proposed model utilizes a Matrix Laboratory (MATLAB) code using graph theory as a searching algorithm to automate the model formulation. The novelty of the model is that it supports decision makers in formulating the optimal crews routing among various activities and also considering the allocation of multitasking skilled crews. A case study for a repetitive 4-km sewage pipeline installation is used to test the capabilities of the proposed model. Results show that the model can feasibly reduce the number of crews employed in linear repetitive construction projects.

Template Design Packages for Repetitive Construction Projects

Template Design Packages for Repetitive Construction Projects

Construction flow index: a metric of production flow quality in construction

A new, process-oriented approach is needed in construction management. Lean construction emphasizes the concept of flow as a way to understand production in construction, yet there is still no accepted metric for measurement of flow quality. This has hampered research and practice. The proposed construction flow index (CFI) is a composite measure that reflects the quality of production flow in repetitive construction projects. It incorporates measures of work continuity for crews, processing continuity for locations, production rate variation, amounts of work in progress, interference and operation sequence logic. Expert knowledge was acquired to establish weights for the CFI parameters, and its use was tested in evaluating the planned and actual production flows for a number of projects. Project managers can use the CFI to evaluate the quality of their construction plans and to measure and communicate production flow quality status to trade crews, enabling management and improvement of production flow. The CFI is also a valuable tool for construction research. The CFI challenges traditional construction management by measuring flow, where standard practice only measures transformation (earned value). It challenges lean construction practice using the Last Planner System, suggesting that the percent plan complete measure of plan reliability is insufficient.

Optimized scheduling and buffering of repetitive construction projects under uncertainty

Purpose Construction projects are complex projects taking place in dynamic environments, which necessitates accounting for different uncertainties during the planning stage. There is a significant lack of management tools for repetitive projects accounting for uncertainties in the construction environment. The purpose of this paper is to present an algorithm for the optimized scheduling of repetitive construction projects under uncertainty. Design/methodology/approach Fuzzy set theory is utilized to model uncertainties associated with various input parameters. The developed algorithm has two main components: optimization component and buffering component. The optimization component presents a dynamic programming approach that processes fuzzy numbers. The buffering component converts the optimized fuzzy schedule into a deterministic schedule and inserts time buffers to protect the schedule against anticipated delays. Agreement Index (AI) is used to capture the user’s desired level of confidence in the produced schedule while sizing buffers. The algorithm is capable of optimizing for cost or time objectives. An example project drawn from literature is analysed to demonstrate the capabilities of the developed algorithm and to allow comparison of results to those previously generated. Findings Testing the algorithm revealed several findings. Fuzzy numbers can be utilized to capture uncertainty in various inputs without the need for historical data. The modified algorithm is capable of optimizing schedules, for different objectives, under uncertainty. Finally AI can be used to capture users’ desired confidence in the final schedule. Originality/value Project planners can utilize this algorithm to optimize repetitive projects schedules, while modelling uncertainty in different input parameters, without the need for relevant historical data.

Accelerating repetitive construction projects: with uncertainty and contractors’ judgment

Project acceleration is a common yet complicated task performed by contractors in construction projects. In repetitive projects, contractors often face having to accelerate their projects using too...