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The purpose of this study is to investigate the mutual interactions between the causes of design changes using Interpretive Structural Modeling (ISM) and to classify the causes using the “Matrice d’Impacts Croisés Multiplication Appliquée à un Classement” MICMAC technique. This study further identifies and proposes strategies to mitigate design change occurrence and map them onto the identified connections between the causes. To achieve these goals, critical causes of design changes were identified through a comprehensive literature review; 23 key causes were then refined according to the opinions of relevant experts involved in the Iranian building construction sector. Stakeholders associated with each cause and the management areas from which causes arise were also considered. The factors “Unfamiliarity with new construction methods”, “Design errors”, “Value engineering”, “Scope uncertainty”, “Change orders”, and “Constructability ignored in the design phase”, which are highly influenced by other factors, emerged at the highest level of the ISM diagram, and “Clients’ attitudes and experience” as the main root cause of design changes at the bottom of the diagram. The MICMAC technique results showed that consultant-related causes significantly influence other causes, and policy and client-related causes have a feedback effect on the whole system. The findings of this study provide a better insight into how various causes of design changes are connected to one another and can ultimately assist project managers of different parties, even in other countries, to choose influential strategies to mitigate design changes in building construction projects.
Shahab Shoar; Nicholas Chileshe. Exploring the Causes of Design Changes in Building Construction Projects: An Interpretive Structural Modeling Approach. Sustainability 2021, 13, 9578 .
AMA StyleShahab Shoar, Nicholas Chileshe. Exploring the Causes of Design Changes in Building Construction Projects: An Interpretive Structural Modeling Approach. Sustainability. 2021; 13 (17):9578.
Chicago/Turabian StyleShahab Shoar; Nicholas Chileshe. 2021. "Exploring the Causes of Design Changes in Building Construction Projects: An Interpretive Structural Modeling Approach." Sustainability 13, no. 17: 9578.
Purpose This paper aims to model different causal relations among factors interacting with labour productivity in order to recognize the most important factors influencing and influenced by it. Design/methodology/approach Top 60 factors affecting labour productivity were determined and grouped into 5 major groups by reviewing previous research and interviewing relevant experts. The interactions of factors were modelled using system dynamics (SD) approach. The resulting causal loop diagrams obtained from SD were then applied for identifying the most crucial factors influencing and influenced by labour productivity through the decision-making trial and evaluation laboratory (DEMATEL) method. The impact of factors on each other was finally determined based on the opinions of 63 experts selected from the Iranian construction industry. Findings The results indicated that factors such as fatigue, lack of labour motivation and lack of skill are the most influencing, and factors such as schedule delay and inflation in the cost of execution are the most influenced by labour productivity. In the end, a set of recommendations to improve construction labour productivity was also presented. Originality/value The main contribution of the study is proposing a novel method which is capable of providing insights into how causes and effects of construction labour productivity are interrelated. Furthermore, the proposed method makes this study distinct from previous research in the light of prioritizing factors and offering recommendations according to the interrelationships among factors.
Majid Parchami Jalal; Shahab Shoar. A hybrid framework to model factors affecting construction labour productivity. Journal of Financial Management of Property and Construction 2019, 24, 630 -654.
AMA StyleMajid Parchami Jalal, Shahab Shoar. A hybrid framework to model factors affecting construction labour productivity. Journal of Financial Management of Property and Construction. 2019; 24 (3):630-654.
Chicago/Turabian StyleMajid Parchami Jalal; Shahab Shoar. 2019. "A hybrid framework to model factors affecting construction labour productivity." Journal of Financial Management of Property and Construction 24, no. 3: 630-654.
Purpose The purpose of this paper is to present a fault tree (FT)-based approach for quantitative risk analysis in the construction industry that can take into account both objective and subjective uncertainties. Design/methodology/approach In this research, the identified basic events (BEs) are first categorized based on the availability of historical data into probabilistic and possibilistic. The probabilistic and possibilistic events are represented by probability distributions and fuzzy numbers, respectively. Hybrid uncertainty analysis is then performed through a combination of Monte Carlo simulation and fuzzy set theory. The probability of occurrence of the top event is finally calculated using the proposed FT-based hybrid uncertainty analysis method. Findings The efficiency of the proposed method is demonstrated by implementing in a real steel structure project. A quantitative risk assessment is performed for weld cracks, taking into account of both types of uncertainties. An importance analysis is finally performed to evaluate the contribution of each BE to the probability of occurrence of weld cracks and adopt appropriate response strategies. Research limitations/implications In this research, the impact of objective (aleatory) dependence between the occurrences of different BEs and subjective (epistemic) dependence between estimates of the epistemically uncertain probabilities of some BEs are not considered. Moreover, there exist limitations to the application of fuzzy set rules, which were used for aggregating experts’ opinions and ranking purposes of the BEs in the FT model. These limitations can be investigated through further research. Originality/value It is believed that the proposed hybrid uncertainty analysis method presents a robust and powerful tool for quantitative risk analysis, as both types of uncertainties are taken into account appropriately.
Shahab Shoar; Farnad Nasirzadeh; Hamid Reza Zarandi. Quantitative assessment of risks on construction projects using fault tree analysis with hybrid uncertainties. Construction Innovation 2019, 19, 48 -70.
AMA StyleShahab Shoar, Farnad Nasirzadeh, Hamid Reza Zarandi. Quantitative assessment of risks on construction projects using fault tree analysis with hybrid uncertainties. Construction Innovation. 2019; 19 (1):48-70.
Chicago/Turabian StyleShahab Shoar; Farnad Nasirzadeh; Hamid Reza Zarandi. 2019. "Quantitative assessment of risks on construction projects using fault tree analysis with hybrid uncertainties." Construction Innovation 19, no. 1: 48-70.
The aim of this research is to develop a systematic approach to identify and prioritize the most influencing factors on labor productivity in a construction project, with respect to their interrelations, and also investigate different scenarios which can affect it. In the first step, factors influencing construction labor productivity were identified through reviewing previous researches. Applying a group of experts, the most important factors were then determined using their relative importance index in the second step. In the third step, the interrelations among factors were determined through several sessions and interviewing those experts. Finally, the efficiency of the proposed methodology is proved by implementing in a real high rise building construction project. In this step, the selected factors from previous steps were used subsequently for analyzing their impact on labor productivity through fuzzy fault tree analysis. The probability of occurrence of events was determined according to the opinions of four members of the project management team who involved in that project. The most critical causes were also identified using importance analysis. It is believed that using the proposed methodology, appropriate response strategies could be adopted against the identified critical events to enhance the overall productivity of a construction project.
Shahab Shoar; Audrius Banaitis. APPLICATION OF FUZZY FAULT TREE ANALYSIS TO IDENTIFY FACTORS INFLUENCING CONSTRUCTION LABOR PRODUCTIVITY: A HIGH-RISE BUILDING CASE STUDY. JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 2019, 25, 41 -52.
AMA StyleShahab Shoar, Audrius Banaitis. APPLICATION OF FUZZY FAULT TREE ANALYSIS TO IDENTIFY FACTORS INFLUENCING CONSTRUCTION LABOR PRODUCTIVITY: A HIGH-RISE BUILDING CASE STUDY. JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT. 2019; 25 (1):41-52.
Chicago/Turabian StyleShahab Shoar; Audrius Banaitis. 2019. "APPLICATION OF FUZZY FAULT TREE ANALYSIS TO IDENTIFY FACTORS INFLUENCING CONSTRUCTION LABOR PRODUCTIVITY: A HIGH-RISE BUILDING CASE STUDY." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 25, no. 1: 41-52.
This paper presents a framework for solving risk response action selection problem by considering: (1) the impact of risk events on the project objectives, (2) the interactions between risk events and (3) management criteria and preferences. For these purposes, a framework is developed by combining an optimization-based model and a Multi Criteria Decision Making (MCDM) approach. First, in the optimization-based model, Ant Colony Optimization (ACO) is used to find the best combination of response actions which have more effects on time, cost and quality. Also, in this model, to overcome the imprecision situation resulting from lack of knowledge or insufficient data, risk parameters are determined using the fuzzy set theory. Moreover, the Design Structure Matrix (DSM) is used to capture the effect of interactions between risk events. Second, the Fuzzy Technique for Order Preference by Similarity to Ideal Solution (FTOPSIS) method is used to analyze the obtained solutions by ACO, based on the other management criteria. Finally, the efficiency of the proposed framework is examined by its implementation in a real building construction project. Discussions through the case study show that using the proposed framework decision makers can evaluate more aspects of response actions.
Shahab Shoar; Ahad Nazari. An Optimization Framework for Risk Response Actions Selection Using Hybrid ACO and FTOPSIS. Scientia Iranica 2018, 1 .
AMA StyleShahab Shoar, Ahad Nazari. An Optimization Framework for Risk Response Actions Selection Using Hybrid ACO and FTOPSIS. Scientia Iranica. 2018; ():1.
Chicago/Turabian StyleShahab Shoar; Ahad Nazari. 2018. "An Optimization Framework for Risk Response Actions Selection Using Hybrid ACO and FTOPSIS." Scientia Iranica , no. : 1.
Purpose The purpose of this paper is to develop a model for complex interconnected structure of various factors interacting with delay in order to identify the most important factors influencing and influenced by delay based on their interrelations. Design/methodology/approach Reviewing literature and interviewing with local experts selected from the Iranian construction industry, top 58 delay factors were identified and categorized into six major groups. The interrelations among these factors were, then, modeled using the system dynamics (SD) approach. The resulting causal loop diagrams obtained from SD were used subsequently for identifying the most significant factors influencing and influenced by delay through the Decision Making Trial and Evaluation Laboratory (DEMATEL) method. The impact of factors on each other was finally determined based on the opinions of 63 experts selected from the Iranian community of consultants, contractors, and clients. Findings According to the analysis, eight out of the 58 factors were identified as the most influencing factors on delay, and nine factors were found to be the most influenced factors by delay in the field of delay analysis. The study also concluded that factors related to labors are the most important and influential factors. In addition, factors related to client were the most influencing factors and external-related factors were the least important ones. At the end, some recommendations to reduce variation of delay in the construction projects are presented as well. Originality/value Considering the interconnected structure of the factors, the paper identifies the most important factors interacting with time delay in construction projects.
Majid Parchami Jalal; Shahab Shoar. A hybrid SD-DEMATEL approach to develop a delay model for construction projects. Engineering, Construction and Architectural Management 2017, 24, 629 -651.
AMA StyleMajid Parchami Jalal, Shahab Shoar. A hybrid SD-DEMATEL approach to develop a delay model for construction projects. Engineering, Construction and Architectural Management. 2017; 24 (4):629-651.
Chicago/Turabian StyleMajid Parchami Jalal; Shahab Shoar. 2017. "A hybrid SD-DEMATEL approach to develop a delay model for construction projects." Engineering, Construction and Architectural Management 24, no. 4: 629-651.
This paper presents a stochastic logic-based method for quantitative risk assessment using fault tree analysis (FTA) that can take into account both types of uncertainties including objective and subjective uncertainties. In the proposed method, each fault tree gate is translated to its corresponding stochastic logic template and then is implemented on a field programmable gate array (FPGA). Because the analysis does not utilize any transformation methods, the results of analysis are more accurate than those methods which are based on transformation from possibility to probability distributions or vice versa. Experimental results for a benchmark fault tree show that this method accelerates analysis time compared to conventional hybrid uncertainty analysis method and transformation methods. The efficiency of the proposed method is demonstrated by implementation in a real steel structure project. The quantitative risk assessment is performed for the incomplete penetration as one of the defects encountered in arc welding process, and its results are compared with transformation methods. The comparison results show the proposed hybrid uncertainty analysis method is also more accurate in comparison to the transformation-based approaches. Copyright © 2016 John Wiley & Sons, Ltd.
Shahab Shoar; Hamid R. Zarandi; Farnad Nasirzadeh; Elham Cheshmikhani. Fast Fault Tree Analysis for Hybrid Uncertainties Using Stochastic Logic Implemented on Field-Programmable Gate Arrays: An Application in Quantitative Assessment and mitigation of Welding Defects Risk. Quality and Reliability Engineering International 2016, 33, 1367 -1385.
AMA StyleShahab Shoar, Hamid R. Zarandi, Farnad Nasirzadeh, Elham Cheshmikhani. Fast Fault Tree Analysis for Hybrid Uncertainties Using Stochastic Logic Implemented on Field-Programmable Gate Arrays: An Application in Quantitative Assessment and mitigation of Welding Defects Risk. Quality and Reliability Engineering International. 2016; 33 (7):1367-1385.
Chicago/Turabian StyleShahab Shoar; Hamid R. Zarandi; Farnad Nasirzadeh; Elham Cheshmikhani. 2016. "Fast Fault Tree Analysis for Hybrid Uncertainties Using Stochastic Logic Implemented on Field-Programmable Gate Arrays: An Application in Quantitative Assessment and mitigation of Welding Defects Risk." Quality and Reliability Engineering International 33, no. 7: 1367-1385.