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MICHAŁ TOMCZAK is assistant professor at Lublin University of Technology, Faculty of Civil Engineering and Architecture, Department of Construction Methods and Management, Poland. He received the Ph.D. Eng. degree in civil engineering from Lublin University of Technology. Author of over 25 scientific publications. His research interests include the organization and modelling of construction processes, construction projects scheduling, metaheuristic algorithms, supply chain management.
In the literature on the scheduling of construction projects it is difficult to find a justification for adopting the criteria for evaluating work schedules based explicitly on the preferences of those who develop them. This article tries to fill this gap and provide information on the preferences of construction site managers for sustainable scheduling and organization of construction projects. The publication focuses on the views and needs of construction site engineering staff regarding methods of work organization, the need to reduce downtimes in the work of crews, the deadline for project realization and the selection of crews for tasks. This information was obtained on the basis of surveys conducted among managerial staff of various levels (74 people). The authors hope that the information provided in this publication will allow the creation of more reliable tools to support construction managers better adapted to their preferences and needs, and therefore more likely to be applied in practice.
Michał Tomczak; Piotr Jaśkowski. Preferences of Construction Managers Regarding the Quality and Optimization Criteria of Project Schedules. Sustainability 2021, 13, 544 .
AMA StyleMichał Tomczak, Piotr Jaśkowski. Preferences of Construction Managers Regarding the Quality and Optimization Criteria of Project Schedules. Sustainability. 2021; 13 (2):544.
Chicago/Turabian StyleMichał Tomczak; Piotr Jaśkowski. 2021. "Preferences of Construction Managers Regarding the Quality and Optimization Criteria of Project Schedules." Sustainability 13, no. 2: 544.
A variety of schedule compression techniques are used to get delayed construction projects “back on tracks”. This paper presents a new optimization approach to schedule crashing by relocating some of the workers from non-critical to critical processes (changing composition of crews using the initial pool of workers) and employing additional resources. The authors describe their idea in the form of a mixed-integer linear problem. A numerical example illustrates the merits of the proposed approach. The method may become a practical support in construction scheduling decisions.
Michal Tomczak; Piotr Jaskowski. Crashing Construction Project Schedules by Relocating Resources. IEEE Access 2020, 8, 224522 -224531.
AMA StyleMichal Tomczak, Piotr Jaskowski. Crashing Construction Project Schedules by Relocating Resources. IEEE Access. 2020; 8 (99):224522-224531.
Chicago/Turabian StyleMichal Tomczak; Piotr Jaskowski. 2020. "Crashing Construction Project Schedules by Relocating Resources." IEEE Access 8, no. 99: 224522-224531.
A significant number of construction projects involve repetitive processes. Planning them occurs to be a complex task. Network methods traditionally applied to construction scheduling prove inefficient in the case of repetitive construction projects (RCPs) due to the increased number of relationships among processes, locations (units), and resources. Frequently, the aim of scheduling RCPs is making the full use of the resources’ capacity, thereby ensuring continuity of the crews’ work. To achieve this, the planner typically allows discontinuity of some secondary processes to shift resources to the key processes, allowing optional modes of process delivery and introducing soft precedence relations between processes. This paper presents a new way of increasing the continuity of work of a general contractor’s crews in RCPs by employing subcontractors’ crews. A deterministic mathematical model of the mixed-integer linear problem of a repetitive (nonlinear) project was formulated to find a schedule that minimizes the downtime of the general contractor’s crews under constraints of a maximum acceptable total project duration and a maximum acceptable cost of the works commissioned to subcontractors; the model accounts for the limited availability of crews. Application of the model is illustrated by an example.
Michał Tomczak; Piotr Jaśkowski. New Approach to Improve General Contractor Crew’s Work Continuity in Repetitive Construction Projects. Journal of Construction Engineering and Management 2020, 146, 04020043 .
AMA StyleMichał Tomczak, Piotr Jaśkowski. New Approach to Improve General Contractor Crew’s Work Continuity in Repetitive Construction Projects. Journal of Construction Engineering and Management. 2020; 146 (5):04020043.
Chicago/Turabian StyleMichał Tomczak; Piotr Jaśkowski. 2020. "New Approach to Improve General Contractor Crew’s Work Continuity in Repetitive Construction Projects." Journal of Construction Engineering and Management 146, no. 5: 04020043.
In carrying out construction projects, enterprises strive to obtain the highest degree of harmonization of the work of the resources involved. It is manifested in ensuring continuous and regular production with a full usage of their executive potential. The purpose of harmonization is to eliminate unjustified interruptions in the work of resources. When planning the realization of non-repetitive construction projects, one should use methods of scheduling that allow the analysis of the project model not only as a function of time. It is also important to take into account the effectiveness of using your own resources and limitations in their availability. The article analyzes the problem of harmonizing the work of crews of the general contractor, performing non-rhythmic, non-cyclical and inhomogeneous processes under the assumption of deterministic operating conditions. An important issue from the point of view of reducing the costs of crews’ employment is the continuity of their work. A mathematical model was developed concerning the problem of minimization of downtime in the work of the general contractor crews with a directively fixed time and limit of the project realization cost, taking into account the limitations in the availability of crews and the possibility to outsource works to subcontractors. The possibility of subcontracting works does not allow for a clear indication in the project model sequences of processes carried out by crews and the usage of previously developed scheduling methods. The method of solving the model (in a linear form with continuous and binary variables) is presented in the example. Additionally, the proposed method allows analyzing the impact of the amount of downtime at work on the duration of the project and the impact of the work outsourced to subcontractors on the continuity of the general contractor’s work.
Michał Tomczak; Piotr Jaśkowski. The method of scheduling construction projects increasing the use of resources of the general contractor. The proceedings of the 13th international conference "Modern Building Materials, Structures and Techniques" (MBMST 2019) 2019, 1 .
AMA StyleMichał Tomczak, Piotr Jaśkowski. The method of scheduling construction projects increasing the use of resources of the general contractor. The proceedings of the 13th international conference "Modern Building Materials, Structures and Techniques" (MBMST 2019). 2019; ():1.
Chicago/Turabian StyleMichał Tomczak; Piotr Jaśkowski. 2019. "The method of scheduling construction projects increasing the use of resources of the general contractor." The proceedings of the 13th international conference "Modern Building Materials, Structures and Techniques" (MBMST 2019) , no. : 1.
One 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.
Michał Tomczak. Modeling of the harmonization method for executing a multi-unit construction project. Open Engineering 2019, 9, 282 -291.
AMA StyleMichał Tomczak. Modeling of the harmonization method for executing a multi-unit construction project. Open Engineering. 2019; 9 (1):282-291.
Chicago/Turabian StyleMichał Tomczak. 2019. "Modeling of the harmonization method for executing a multi-unit construction project." Open Engineering 9, no. 1: 282-291.
The continuous growth of competition on the construction market results in the fact that construction companies are forced to keep searching for solutions facilitating the building process and construction logistics. In the recent decades, one of the most fascinating ideas which enable a real improvement in the aspect of a company's competitiveness on the market is supply chain management. It has undergone a transformation from fragmented actions to integrated operations intending to optimize the flow of physical resources and information. The first step towards the application of the modern logistics tools is the selection and evaluation of entities involved in a cooperation within the supply chain framework. The selection of reliable partners to supply a construction site or a building company may reduce the operational costs, minimize inventory and improve timeliness as well as the quality of offered services. Any mistakes made in the process of supplier selection may lead to issues such as supply delays, difficulties in keeping contract deadlines and even complete failure of a project or bankruptcy of a construction company. An 18th century criterion for the selection of the most preferable candidate developed by Nicolas de Condorcet is commonly accepted owing to its fair rules of choice (anyone who defeats most of their competitors in a direct confrontation wins). Due to its democratic approach, most criteria decide as to the selection of the winner. Should the choice of a winner or establishing a Condorcet ranking from the perspective of the social choice theory prove impossible, the selected candidate ought to be as much similar to a winner in the Condorcet sense as possible. The theory was developed in order to facilitate the selection of the most suitable candidate in the election, however it may also find application in the selection of a supply chain elements evaluated with the use of multiple criteria. There are a number of decision-making methods which fulfil the Condorcet criterion. They vary in their computational complexity and may provide different final order. The intention of this paper is to review the methods which may offer support while selecting the most preferable supplier of construction products.
Michal Tomczak; Sławomir Biruk; Piotr Jaskowski. Selection of Construction Products Suppliers According to the Condorcet Criterion. IOP Conference Series: Materials Science and Engineering 2019, 471, 112068 .
AMA StyleMichal Tomczak, Sławomir Biruk, Piotr Jaskowski. Selection of Construction Products Suppliers According to the Condorcet Criterion. IOP Conference Series: Materials Science and Engineering. 2019; 471 (11):112068.
Chicago/Turabian StyleMichal Tomczak; Sławomir Biruk; Piotr Jaskowski. 2019. "Selection of Construction Products Suppliers According to the Condorcet Criterion." IOP Conference Series: Materials Science and Engineering 471, no. 11: 112068.
The problem of multi-family building maintenance is complex and comprises numerous issues, one of which is the process of planning expenditures for residential building renovation. This task is important from the manager’s point of view as their responsibility is to maintain a building in a non-deteriorated condition. To fulfil this task, the authors of this paper suggest utilising a decision-making model aimed at defining renovation activities making it possible to retain the maintenance standard (as regards newly commissioned residential buildings) or improve it (as regards existing buildings). The suggested model is based on a multi-criteria building assessment including seven requirements. The calculations conducted using the suggested model enable us to define the costs and scope of renovation taken to ensure the assumed building condition or, by assuming various rates paid to the renovation reserve, to define the period in which the above-mentioned goals may be achieved.
Robert Bucoń; Michał Tomczak. DECISION-MAKING MODEL SUPPORTING THE PROCESS OF PLANNING EXPENDITURES FOR RESIDENTIAL BUILDING RENOVATION. Technological and Economic Development of Economy 2018, 24, 1200 -1214.
AMA StyleRobert Bucoń, Michał Tomczak. DECISION-MAKING MODEL SUPPORTING THE PROCESS OF PLANNING EXPENDITURES FOR RESIDENTIAL BUILDING RENOVATION. Technological and Economic Development of Economy. 2018; 24 (3):1200-1214.
Chicago/Turabian StyleRobert Bucoń; Michał Tomczak. 2018. "DECISION-MAKING MODEL SUPPORTING THE PROCESS OF PLANNING EXPENDITURES FOR RESIDENTIAL BUILDING RENOVATION." Technological and Economic Development of Economy 24, no. 3: 1200-1214.
The selection of a general contractor for construction works is one of the most important decisions made throughout the entire construction project. It may be decisive in the success or failure of the project (e.g. delays in the commissioning of works, exceeding the budget, low quality of works). The article presents a method for supporting group decision-making in the contractor qualification process. The proposed method is a development of Mikhailov's approach to Fuzzy Analytic Hierarchy Process. It consists in the aggregation of the decision makers' judgments using type-2 fuzzy sets, allowing for inaccuracy of the decision-maker’s assessment. The use of an unbiased estimator of standard deviation for determining compromise evaluation enables the small size of the expert group and deviations in their evaluations to be taken into consideration. The quality of the solution obtained through this method was compared with the results obtained by means of Mikhailov’s Fuzzy Preference Programming and Enea & Piazza Method. The use of the proposed method generated better results for this example of preparing a ranking of contractors than the two other methods discussed. The method presented herein may also be proposed for solving decision-making problems in other spheres.
Michał Tomczak; Piotr Jaśkowski. Application of Type-2 Interval Fuzzy Sets to Contractor Qualification Process. KSCE Journal of Civil Engineering 2018, 22, 2702 -2713.
AMA StyleMichał Tomczak, Piotr Jaśkowski. Application of Type-2 Interval Fuzzy Sets to Contractor Qualification Process. KSCE Journal of Civil Engineering. 2018; 22 (8):2702-2713.
Chicago/Turabian StyleMichał Tomczak; Piotr Jaśkowski. 2018. "Application of Type-2 Interval Fuzzy Sets to Contractor Qualification Process." KSCE Journal of Civil Engineering 22, no. 8: 2702-2713.
One of the most important factors which have an effect on the cost and time of the building process is the organization of physical resources and the information flow structure. Depending on how effective this system is, a building project may end with a success or a failure. Because of many conditions of the construction executing and different needs of the contractors, there are different Supply Chain Management (SCM) systems connected with supplying construction projects: single-stage, multi-stage or combined. The article presents a comparative analysis of construction SCM systems based on a modified fuzzy AHP. The modification of this method is based on the use of interval type-2 fuzzy sets to aggregate evaluation according to the idea proposed by Mikhailov. The use of such a model of group preferences of decision-makers, makes it possible to take into consideration both the linguistic imprecision of an evaluation and the small number of experts. The weight values of specific criteria and the final scale vector of considered variants are obtained during the analysis. This may give a recommendation to general contractors in construction projects about which evaluation criteria and supply systems are preferred.
Michał Tomczak; Łukasz Rzepecki. Evaluation of Supply Chain Management Systems Used in Civil Engineering. IOP Conference Series: Materials Science and Engineering 2017, 245, 72005 .
AMA StyleMichał Tomczak, Łukasz Rzepecki. Evaluation of Supply Chain Management Systems Used in Civil Engineering. IOP Conference Series: Materials Science and Engineering. 2017; 245 ():72005.
Chicago/Turabian StyleMichał Tomczak; Łukasz Rzepecki. 2017. "Evaluation of Supply Chain Management Systems Used in Civil Engineering." IOP Conference Series: Materials Science and Engineering 245, no. : 72005.
During executing of construction projects enterprises seek for high level of coordinating engaged resources. This seeking evinces in providing continuity and levelling production. It enables making of entire production capability. This paper analyses scheduling work of general contractor crews, which carry out unrhytmic, noncyclic and inhomogeneous processes in deterministic conditions. The mathematical model of work gaps for general contractor crews in construction project scheduling is formulated. This model also counts crews availability limits, cost and time constraints and possibility of tasks outsourcing for subcontractors.
Piotr Jaśkowski; Michał Tomczak. Problem minimalizacji przestojów w pracy brygad generalnego wykonawcy w harmonogramowaniu przedsięwzięć budowlanych. Przegląd Naukowy Inżynieria i Kształtowanie Środowiska 2017, 26, 193 -201.
AMA StylePiotr Jaśkowski, Michał Tomczak. Problem minimalizacji przestojów w pracy brygad generalnego wykonawcy w harmonogramowaniu przedsięwzięć budowlanych. Przegląd Naukowy Inżynieria i Kształtowanie Środowiska. 2017; 26 (2):193-201.
Chicago/Turabian StylePiotr Jaśkowski; Michał Tomczak. 2017. "Problem minimalizacji przestojów w pracy brygad generalnego wykonawcy w harmonogramowaniu przedsięwzięć budowlanych." Przegląd Naukowy Inżynieria i Kształtowanie Środowiska 26, no. 2: 193-201.
Maintenance of multi-family buildings is a difficult and complex task, which requires a proper (multi-criteria) assessment of a building’s condition as well as determining and planning maintenance costs. It requires from a building administrator to be well experienced and have skills in making decisions, which include a proper investment of limited funds allocated for maintenance. This task is usually preceded by the analysis of cost-effectiveness and validity to perform certain repairs. Taking into account the above the authors proposed a model supporting an administrator in making decisions while determining a scope of building renovation. The system algorithm proposed comprises a few stages including: building condition and its proposed repair evaluation and the choice of renovation variant. It is based on tools such as multicriteria methods to support decisions and linear programming. Calculations conducted using the suggested model allow an administrator to obtain key information for appropriate maintenance of a building, i.e. to determine a renovation variant and its cost as well as a monthly renovation contribution (at assumed number of years) to achieve assumed condition of a building.
Robert Bucoń; Michał Tomczak. SUPPORTING BUILDING ADMINISTRATOR’S DECISIONS IN DETERMINING MAINTENANCE COSTS OF RESIDENTIAL BUILDINGS. Engineering Structures and Technologies 2016, 8, 15 -22.
AMA StyleRobert Bucoń, Michał Tomczak. SUPPORTING BUILDING ADMINISTRATOR’S DECISIONS IN DETERMINING MAINTENANCE COSTS OF RESIDENTIAL BUILDINGS. Engineering Structures and Technologies. 2016; 8 (1):15-22.
Chicago/Turabian StyleRobert Bucoń; Michał Tomczak. 2016. "SUPPORTING BUILDING ADMINISTRATOR’S DECISIONS IN DETERMINING MAINTENANCE COSTS OF RESIDENTIAL BUILDINGS." Engineering Structures and Technologies 8, no. 1: 15-22.
Michał Tomczak; Robert Bucoń. CONSTRUCTABILITY AND PLANT UTILISATION: THE CASE OF FACADE SCAFFOLDING SYSTEM SELECTION. Proceedings of the 24th International Academic Conference, Barcelona 2016, 1 .
AMA StyleMichał Tomczak, Robert Bucoń. CONSTRUCTABILITY AND PLANT UTILISATION: THE CASE OF FACADE SCAFFOLDING SYSTEM SELECTION. Proceedings of the 24th International Academic Conference, Barcelona. 2016; ():1.
Chicago/Turabian StyleMichał Tomczak; Robert Bucoń. 2016. "CONSTRUCTABILITY AND PLANT UTILISATION: THE CASE OF FACADE SCAFFOLDING SYSTEM SELECTION." Proceedings of the 24th International Academic Conference, Barcelona , no. : 1.
Robert Bucoń; Michał Tomczak. MULTICRITERIA OPTIMIZATION OF BUILDING RENOVATION. Proceedings of the 24th International Academic Conference, Barcelona 2016, 1 .
AMA StyleRobert Bucoń, Michał Tomczak. MULTICRITERIA OPTIMIZATION OF BUILDING RENOVATION. Proceedings of the 24th International Academic Conference, Barcelona. 2016; ():1.
Chicago/Turabian StyleRobert Bucoń; Michał Tomczak. 2016. "MULTICRITERIA OPTIMIZATION OF BUILDING RENOVATION." Proceedings of the 24th International Academic Conference, Barcelona , no. : 1.
Paper identifies obstacles limiting functioning and development of small and medium construction enterprises. It also includes a description of cluster supply chain (CSC) idea as a suggested solution to some of the problems resulting from the small scale of company activities. One of more important issues of every distribution centre, i.e. portions of deliveries smaller than truck capacity for particular consumers, is also discussed. This problem was formulated for the first time in dairy industry, therefore, it was called milk runs. Moreover, the authors of this paper presented the outcome analysis of survey carried out among construction engineers and managers. This study aimed at determining organizational principles for logistic centre working with CSC framework. The mathematical model depicting milk runs deliveries with overtime consideration, done for many construction sites within a distribution centre is presented hereunder. This model may be potentially used to optimize distribution centres working within cluster supply chain framework.
Michał Tomczak; Robert Bucoń. Milk runs model with overtime: application to cluster supply chain. Budownictwo i Architektura 2015, 14, 139 -147.
AMA StyleMichał Tomczak, Robert Bucoń. Milk runs model with overtime: application to cluster supply chain. Budownictwo i Architektura. 2015; 14 (4):139-147.
Chicago/Turabian StyleMichał Tomczak; Robert Bucoń. 2015. "Milk runs model with overtime: application to cluster supply chain." Budownictwo i Architektura 14, no. 4: 139-147.
Concrete batching plants are typically equipped with modern automated high-capacity systems and provide high quality products. The plants often dispose of fleets of concrete transport trucks. However, the plants rarely use decision support tools to plan transport routes and schedule production of the mix. The decisions in this respect base on experience of the staff. The paper investigates into the problems of integrated production scheduling and vehicle routing. A concept of mathematical model for vehicle routing optimization was proposed. If implemented, it is expected to improve plant operations so that more orders can be completed and the plant potential can be utilized more efficiently to the customer’s satisfaction, offering the plant competitive advantage in this demanding business.
Sławomir Biruk; Michał Tomczak. Transport optimization for ready-mix concrete distribution. Budownictwo i Architektura 2014, 13, 335 -342.
AMA StyleSławomir Biruk, Michał Tomczak. Transport optimization for ready-mix concrete distribution. Budownictwo i Architektura. 2014; 13 (4):335-342.
Chicago/Turabian StyleSławomir Biruk; Michał Tomczak. 2014. "Transport optimization for ready-mix concrete distribution." Budownictwo i Architektura 13, no. 4: 335-342.