Stochastic scheduling optimization of repetitive construction projects to minimize project duration and cost

2021 ◽  
pp. 1-10
Author(s):  
Abbas Hassan ◽  
Khaled El-Rayes ◽  
Mohamed Attalla
Keyword(s):  
Construction Projects ◽  
Stochastic Scheduling ◽  
Scheduling Optimization ◽  
Project Duration

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

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abbas Hassan ◽  
Khaled El-Rayes ◽  
Mohamed Attalla
Keyword(s):  
Construction Projects ◽  
Design Methodology ◽  
Real Life ◽  
Stochastic Scheduling ◽  
Content Type ◽  
Project Duration ◽  
Trade Offs ◽  
Original Contribution ◽  
Novel Model ◽  
Scheduling Technique

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.

scholarly journals Scheduling Optimization of Prefabricated Construction Projects by Genetic Algorithm

2021 ◽  
Vol 11 (12) ◽  
pp. 5531
Author(s):  
Linlin Xie ◽  
Yajiao Chen ◽  
Ruidong Chang
Keyword(s):  
Project Scheduling ◽  
Construction Projects ◽  
Resource Constraints ◽  
Construction Project ◽  
Engineering Application ◽  
Project Schedule ◽  
Scheduling Optimization ◽  
Implementation Method ◽  
Traditional Construction ◽  
Construction Project Scheduling

Prefabricated buildings are the direction of the future development of the construction industry and have received widespread attention. The effective execution of prefabricated construction project scheduling should consider resource constraints and the supply arrangement of prefabricated components. However, the traditional construction resource-constrained project scheduling implementation method cannot simultaneously consider the characteristics of the linkage between component production and on-site assembly construction. It cannot also fully adapt to the scheduling implementation method of the prefabricated construction projects. It is difficult to work out a reasonable project schedule and resource allocation table. In order to determine the relevant schedule parameters that can reflect the actual construction situation of the prefabricated building and meet the scheduling requirements of the prefabricated project, this study proposes a prefabricated construction project scheduling model that considers project resource constraints and prefabricated component supply constraints. Additionally, it improves the design of traditional genetic algorithms (GAs). Research results of the experimental calculation and engineering application show that the proposed project scheduling optimization model and GA are effective and practical, which can help project managers in effectively formulating prefabricated construction project scheduling plans, reasonably allocating resources, reducing completion time, and improving project performance.

scholarly journals A Novel Method of Developing Construction Projects Schedule under Rework Scenarios

2019 ◽  
Vol 11 (20) ◽  
pp. 5710
Author(s):  
Guofeng Ma ◽  
Shan Jiang ◽  
Tiancheng Zhu ◽  
Jianyao Jia
Keyword(s):  
Construction Projects ◽  
Development Project ◽  
Real Estate Development ◽  
Design Structure Matrix ◽  
Project Duration ◽  
Project Completion ◽  
Design Structure ◽  
Novel Method ◽  
The Impact ◽  
Critical Chain

Construction projects have faced serious schedule delays caused by rework risks. However, it appears that traditional methods are of limited value in developing applicable project schedules. This study presents an analysis on construction projects schedule development under rework scenarios by a novel method named the improved critical chain design structure matrix (CCDSM). Research data are collected from a real estate development project in China. As a result, predictions of project completion duration and probability have been made. A reliable schedule considering information interactions has been developed and visualized. Rework impact areas of activities have been examined to quantitatively record the impact on project duration. To meet different demands, the method generates two more schedules setting different rework buffers. Furthermore, these activities have the potential of causing rework and have been quantified based on the calculation of two criticalities, providing an identification of rework-intensive works that should be payed close importance to, which have not be realized by previous methods. The results proved the feasibility and effectiveness of this method in developing a schedule for construction projects disturbed by rework, helping practitioners adopt measures to avoid rework-caused schedule delays and achieve sustainable development of such projects.

scholarly journals Forecasting the Project Duration Average and Standard Deviation from Deterministic Schedule Information

2020 ◽  
Vol 10 (2) ◽  
pp. 654 ◽  
Author(s):  
Pablo Ballesteros-Pérez ◽  
Alberto Cerezo-Narváez ◽  
Manuel Otero-Mateo ◽  
Andrés Pastor-Fernández ◽  
Jingxiao Zhang ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Network Analysis ◽  
Construction Projects ◽  
Project Evaluation ◽  
Alternative Methods ◽  
Stochastic Network ◽  
Project Duration ◽  
Deterministic Scheduling ◽  
Mathematical Expressions ◽  
Additional Calculation

Most construction managers use deterministic scheduling techniques to plan construction projects and estimate their duration. However, deterministic techniques are known to underestimate the project duration. Alternative methods, such as Stochastic Network Analysis, have rarely been adopted in practical contexts as they are commonly computer-intensive, require extensive historical information, have limited contextual/local validity and/or require skills most practitioners have not been trained for. In this paper, we propose some mathematical expressions to approximate the average and the standard deviation of a project duration from basic deterministic schedule information. The expressions’ performance is successfully tested in a 4100-network dataset with varied activity durations and activity durations variability. Calculations are quite straightforward and can be implemented manually. Furthermore, unlike the Project Evaluation and Review Technique (PERT), they allow drawing inferences about the probability of project duration in the presence of several critical and subcritical paths with minimal additional calculation.

scholarly journals A Multiobjective Robust Scheduling Optimization Mode for Multienergy Hybrid System Integrated by Wind Power, Solar Photovoltaic Power, and Pumped Storage Power

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Lihui Zhang ◽  
He Xin ◽  
Jing Wu ◽  
Liwei Ju ◽  
Zhongfu Tan
Keyword(s):  
Wind Power ◽  
Hybrid System ◽  
Supply And Demand ◽  
Stochastic Theory ◽  
Stochastic Scheduling ◽  
Economic Benefits ◽  
Load Curve ◽  
Scheduling Optimization ◽  
Pumped Storage ◽  
Photovoltaic Generators

Wind power plant (WPP), photovoltaic generators (PV), cell-gas turbine (CGT), and pumped storage power station (PHSP) are integrated into multienergy hybrid system (MEHS). Firstly, this paper presents MEHS structure and constructs a scheduling model with the objective functions of maximum economic benefit and minimum power output fluctuation. Secondly, in order to relieve the uncertainty influence of WPP and PV on system, robust stochastic theory is introduced to describe uncertainty and propose a multiobjective stochastic scheduling optimization mode by transforming constraint conditions with uncertain variables. Finally, a 9.6 MW WPP, a 6.5 MW PV, three CGT units, and an upper reservoir with 10 MW·h equivalent capacity are chosen as simulation system. The results show MEHS system can achieve the best operation result by using the multienergy hybrid generation characteristic. PHSP could shave peak and fill valley of load curve by optimizing pumping storage and inflowing generating behaviors based on the load supply and demand status and the available power of WPP and PV. Robust coefficients can relieve the uncertainty of WPP and PV and provide flexible scheduling decision tools for decision-makers with different risk attitudes by setting different robust coefficients, which could maximize economic benefits and minimize operation risks at the same time.

Modeling of the harmonization method for executing a multi-unit construction project

2019 ◽  
Vol 9 (1) ◽  
pp. 282-291 ◽  
Author(s):  
Michał Tomczak
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Construction Project ◽  
Optimization Method ◽  
Linear Processes ◽  
Project Duration ◽  
Construction Enterprises ◽  
Non Linear ◽  
Implementation Time ◽  
Selection Of

AbstractOne of the key problems in managing the realization of a construction project is the selection of appropriate working crews and coordinating their activities in a way that ensures the highest degree of implementation of defined goals (minimizing the project duration and/or reducing downtime and related costs). Most of the existing methods of work harmonization used in construction industry allow obtaining the desired results only in relation to the organization of the processes realization in repetitive linear projects. In case of realization of non-linear construction objects or construction units, it is usually necessary to choose between the reduction of the project implementation time and maintaining the continuity of crews work on the units. It was found that there is a lack in the literature of developed method enabling harmonization of crews’ work, while minimizing the downtime at work and the duration of the entire project taking into account additional constraints, e.g. the need to not exceed the deadlines for the realization of the project stages.The article presents the concept of a multi-criteria optimization method of harmonizing the execution of non-linear processes of a multi-unit construction project in deterministic conditions. It will enable the reduction of realization time and downtimes in work, taking into account the preferences of the decision maker regarding the relevance of the optimization criteria. A mathematical model for optimizing the selection of crews and order of completion of units in multi-unit construction projects was also developed. In order to present the possibility of usage of the developed concept, an example of the optimal selection of crews and their work schedule was solved and presented. The proposed method may allow for better use of the existing production potential of construction enterprises and ensure synchronization of the crews employed during the work, especially in the case of difficulties in acquiring qualified staff in construction industry.

Modelling of tri-parameter bidding integrating cost, time and risk: a stochastic approach

2017 ◽  
Vol 22 (2) ◽  
pp. 117-134 ◽  
Author(s):  
Mohamad Rabie ◽  
Sameh El-Sayegh
Keyword(s):  
Stochastic Scheduling ◽  
Stochastic Approach ◽  
Time Parameter ◽  
Content Type ◽  
Project Duration ◽  
Baseline Schedule ◽  
Schedule Flexibility ◽  
Risk Parameter ◽  
Proposed Model ◽  
Schedule Risk

Purpose This paper aims to propose a new tri-parameter bidding model integrating cost, time and risk. The key value of the model is that it remains within the framework of the competitive bidding system while controlling the risk resulting from float loss. Design/methodology/approach The model utilizes stochastic scheduling to quantify the float loss impact at the project level. Prospective bidders are evaluated based on their total combined bid (TCB) including cost, time and risk. The risk parameter is calculated as the relative risk between the bidder’s schedule and the client’s baseline schedule. Findings The results confirmed that choosing the contractor based on the lowest price and time reduces the available float and increases the schedule risks. The probability of completing the project on time dropped from 46 per cent for the baseline schedule to 19 per cent for the bidder with the most compressed schedule. The selected bidder, using the proposed model, has the lowest TCB of cost, time and risk. Results show that adding the risk parameter in the evaluation changed the ranking of the bidders. Research limitations/implications The model does not discuss all project risks that the contractor retains. It focuses on schedule risks that result from shortening project duration. The model focuses on solving the problem with price plus time bidding method by addressing the schedule risk issue. Other criteria, such as sustainability, are not considered. Practical implications The proposed model encourages contractors to pay more attention to the time parameter and the schedule risks resulting from aggressive reduction in project duration. Originality/value Problems arose, in the current complex construction industry, as owners rely solely on price as the award criterion. Recently, the bi-parameter bidding system, A + B, introduced the time parameter to the awarding criteria. However, reducing the project duration by compressing the schedule consumes the float of non-critical activities, which reduces the schedule flexibility of a project. The proposed model allows clients to evaluate potential bidders objectively. Rather than evaluating the bidders based on price, in the conventional low bid system, or based on price and time, as in the A + B system, the bidders are evaluated based on three parameters: price, time and risk.

scholarly journals Scheduling Linear Construction Projects with Constraints on Resource Availability

2017 ◽  
Vol 63 (1) ◽  
pp. 3-15 ◽  
Author(s):  
S. Biruk ◽  
P. Jaśkowski
Keyword(s):  
Construction Projects ◽  
Construction Project ◽  
Production Capacity ◽  
Limited Resource ◽  
Renewable Resource ◽  
Project Planning ◽  
Mixed Integer ◽  
Fixed Costs ◽  
Project Duration ◽  
Construction Companies

AbstractProduction rates for various activities and overall construction project duration are significantly influenced by crew formation. Crews are composed of available renewable resources. Construction companies tend to reduce the number of permanent employees, which reduces fixed costs, but at the same time limits production capacity. Therefore, construction project planning must be carried out by means of scheduling methods which allow for resource constrains. Authors create a mathematical model for optimized scheduling of linear construction projects with consideration of resources and work continuity constraints. Proposed approach enables user to select optimal crew formation under limited resource supply. This minimizes project duration and improves renewable resource utilization in construction linear projects. This paper presents mixed integer linear programming to model this problem and uses a case study to illustrate it.

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