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Reducing the duration of construction works requires additional organizational measures, such as selecting construction methods that assure a shorter realization time, engaging additional resources, working overtime, or allowing construction works to be performed simultaneously in the same working units. The simultaneous work of crews may affect the quality of works and the efficiency of construction processes. This article presents a simulation model aimed at assessing the impact of the overlap period on the extension of the working time of the crews and the reduction of a repetitive project’s duration in random conditions. The purpose of simulation studies is to provide construction managers with guidelines when deciding on the dates of starting the sequential technological process lines realized by specialized working crews, for sustainable scheduling and organization of construction projects.
Sławomir Biruk; Łukasz Rzepecki. A Simulation Model of Construction Projects Executed in Random Conditions with the Overlapping Construction Works. Sustainability 2021, 13, 5795 .
AMA StyleSławomir Biruk, Łukasz Rzepecki. A Simulation Model of Construction Projects Executed in Random Conditions with the Overlapping Construction Works. Sustainability. 2021; 13 (11):5795.
Chicago/Turabian StyleSławomir Biruk; Łukasz Rzepecki. 2021. "A Simulation Model of Construction Projects Executed in Random Conditions with the Overlapping Construction Works." Sustainability 13, no. 11: 5795.
The problem of setting prices for construction works is significant for both the investor and contractor companies. The periodically occurring instabilities in the economy require investment process participants to perform detailed market analyses and assessments, as well as to monitor price forecasts in construction. It is only after such an assessment that it is possible within the framework of the initial assumptions for cost calculation to select the basis for setting prices and their levels. The identification and analysis of the risks related to uncontrolled price increases allow contractors to secure their businesses by developing bids that ensure maximum profit. In view of the above, this study proposes an approach based on the use of game theory against nature to identify the optimal variant of a bid estimate. The study considers price forecasts for construction products, which may reduce the negative impact in case the prices increase. The obtained results confirmed the effectiveness of the used decision-making support methods, indicating the optimal strategy to reduce financial losses in times of market instability. The proposed approach also allows for a balance (symmetry) between maximum profit and probability of winning the contract.
Łukasz Rzepecki; Piotr Jaśkowski. Application of Game Theory against Nature in Supporting Bid Pricing in Construction. Symmetry 2021, 13, 132 .
AMA StyleŁukasz Rzepecki, Piotr Jaśkowski. Application of Game Theory against Nature in Supporting Bid Pricing in Construction. Symmetry. 2021; 13 (1):132.
Chicago/Turabian StyleŁukasz Rzepecki; Piotr Jaśkowski. 2021. "Application of Game Theory against Nature in Supporting Bid Pricing in Construction." Symmetry 13, no. 1: 132.
During planning the execution of each construction project, the factors that may affect the effectiveness of its realization should be analyzed in detail. The costs of execution construction projects are significantly influenced by (apart from technical factors) decisions in the field of inventory management, among others, variability of environmental conditions, prices of construction products, the ability to acquire local suppliers, distance of transport, limited size of storage for construction products as well as the individual character of the project. In projects related to the buildings erection and other construction works, there are many logistical tasks in the area of supply in construction products, raw materials, equipment, as well as in the area of financial and information flow. Taking into account the large share of material costs, inventory management in the costs of projects realization and the high potential for their reduction, every enterprise operating in the construction industry should pay a great importance to the supply logistics sector. Determination of the size and delivery times of construction products, as well as the transport routes, storage and reloading locations are decision-making problems that are solved by management of both the enterprise and the construction projects. The paper presents a proposal for a methodology, which allows to determination and comparison of the inventory management costs in enterprise conducting parallel works on several construction sites. Mathematical models have been developed which simulate the functioning of supply logistics systems and allow, through their solution, to determination of the minimum logistics costs with optimal arrangements for the supply schedule (delivery volumes in subsequent periods of the project execution). This is the foundation for the selection of the optimal variant of a supply chain management. The practical application of the methodology proposed is illustrated using an example.
Lukasz Rzepecki. Optimization of inventory costs management in the construction enterprise. IOP Conference Series: Materials Science and Engineering 2019, 603, 032046 .
AMA StyleLukasz Rzepecki. Optimization of inventory costs management in the construction enterprise. IOP Conference Series: Materials Science and Engineering. 2019; 603 (3):032046.
Chicago/Turabian StyleLukasz Rzepecki. 2019. "Optimization of inventory costs management in the construction enterprise." IOP Conference Series: Materials Science and Engineering 603, no. 3: 032046.
Repetition of the same processes on different objects or units of a construction project and their concurrent execution makes it necessary to use the same limited resources at the same time. Managers prefer simple heuristic priority rules to scheduling construction activities, but there is not one the best for all projects. In addition that the experience from deterministic scheduling problems and priority-rule methods cannot always be directly transferred to stochastic environment. The paper presents the pure reactive simulation model for planning construction projects in random conditions, taking into account the availability of renewable resources. Conducting simulation tests allows for various priority rules to determine the distribution of construction project duration and evaluate the robustness of the schedule. The paper analyzes the effectiveness of the selected priority rules in a pipe line project. In the analyzed project, the Dynamic Minimum Slack rule ensures the lowest average duration of the project in random conditions and the highest quality robustness. The analysis of the simulation results can help the construction manager to choose the procedure ensuring the timely completion of the construction project in the stochastic environment.
Sławomir Biruk; Łukasz Rzepecki. Simulation model for resource-constrained construction project. Open Engineering 2019, 9, 211 -217.
AMA StyleSławomir Biruk, Łukasz Rzepecki. Simulation model for resource-constrained construction project. Open Engineering. 2019; 9 (1):211-217.
Chicago/Turabian StyleSławomir Biruk; Łukasz Rzepecki. 2019. "Simulation model for resource-constrained construction project." Open Engineering 9, no. 1: 211-217.
One of the main factors having a decisive impact on the completion date of a construction project and its total cost is the duration of individual processes. Projects such as the construction of multi-storey residential and public buildings, line facilities, highways, networks of external installations or pipelines are conducted with time-location methods of work organization. It is possible to notice the cyclical nature of building processes in projects, whose characteristic parameter is length or height. In such cases, works are entrusted to specialized organizational units (crews, teams) that conduct repeated operations on identical or similar sections, called units. With each repetition of the operations, workers acquire more and more practical experience which has a positive effect on their work efficiency and leads to a reduction in the time and cost of a construction project. The learning theory bring on a mathematical description of the interdependence between the repetitions number of the same task and work efficiency. Taking into account the learning effect allows for a more accurate estimation of the individual construction processes duration, which may provide an advantage at the stage of submitting bids in tenders. The aim of research is to prepare the implementation plan of repetitive construction processes conducted in a multi-storey residential building. The schedule will take into account the impact of the learning and forgetting effect for the duration of construction works and the interruptions in crews work on the example of finishing works. Due to the lack of commercial software for preparing construction schedules taking into account the learning and forgetting impact, a spreadsheet was developed in MS Excel to set the start and end dates and time buffers of construction processes.
Sławomir Biruk; Lukasz Rzepecki. Scheduling Repetitive Construction Processes Using the Learning-Forgetting Theory. IOP Conference Series: Materials Science and Engineering 2019, 471, 112039 .
AMA StyleSławomir Biruk, Lukasz Rzepecki. Scheduling Repetitive Construction Processes Using the Learning-Forgetting Theory. IOP Conference Series: Materials Science and Engineering. 2019; 471 (11):112039.
Chicago/Turabian StyleSławomir Biruk; Lukasz Rzepecki. 2019. "Scheduling Repetitive Construction Processes Using the Learning-Forgetting Theory." IOP Conference Series: Materials Science and Engineering 471, no. 11: 112039.
Linear projects such as highways, multi-storey buildings or pipelines are implemented by repeating the sequences of processes on units. Repetitive operations affect acquiring more and more experience, which shortens the duration of subsequent activities. On the other hand, the possible breaks in work make this effect disappear. Breaks at work are most often caused by the lack of crew work continuity. While delaying the subsequent sequences of processes properly, it is possible to reduce interruptions and limit the forgetting effect. A simulation method for scheduling linear construction projects has been developed, taking into account the learning and forgetting effect. It allows to increase the probability of the crew work continuity while meeting the project deadline with a specific probability. As a result, the estimation of the project duration is more accurate, which may provide an advantage at the stage of submitting offers in tenders for construction works.
Łukasz Rzepecki; Sławomir Biruk. Simulation Method for Scheduling Linear Construction Projects Using the Learning– Forgetting Effect. MATEC Web of Conferences 2018, 219, 04007 .
AMA StyleŁukasz Rzepecki, Sławomir Biruk. Simulation Method for Scheduling Linear Construction Projects Using the Learning– Forgetting Effect. MATEC Web of Conferences. 2018; 219 ():04007.
Chicago/Turabian StyleŁukasz Rzepecki; Sławomir Biruk. 2018. "Simulation Method for Scheduling Linear Construction Projects Using the Learning– Forgetting Effect." MATEC Web of Conferences 219, no. : 04007.
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.
Construction projects encompass repetitive works carried out on the same or similar object parts, called working units. Due to the cyclical nature of construction processes it is possible to use the learning-forgetting theory to construction projects scheduling. The article shows an example of using learning-forgetting theory in the planning of implementation multi-storey residential building in random conditions.
Sławomir Biruk; Łukasz Rzepecki. Wpływ zjawiska uczenia i zapominania na czas realizacji powtarzalnych procesów budowlanych realizowanych w warunkach losowych. Przegląd Naukowy Inżynieria i Kształtowanie Środowiska 2017, 26, 202 -209.
AMA StyleSławomir Biruk, Łukasz Rzepecki. Wpływ zjawiska uczenia i zapominania na czas realizacji powtarzalnych procesów budowlanych realizowanych w warunkach losowych. Przegląd Naukowy Inżynieria i Kształtowanie Środowiska. 2017; 26 (2):202-209.
Chicago/Turabian StyleSławomir Biruk; Łukasz Rzepecki. 2017. "Wpływ zjawiska uczenia i zapominania na czas realizacji powtarzalnych procesów budowlanych realizowanych w warunkach losowych." Przegląd Naukowy Inżynieria i Kształtowanie Środowiska 26, no. 2: 202-209.