Onur Behzat Tokdemir | Istanbul Technical University (original) (raw)

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Papers by Onur Behzat Tokdemir

Arabian Journal for Science and Engineering , 2023

ipeline construction projects are necessary to provide gas and liquid energy transportation. Alth... more ipeline construction projects are necessary to provide gas and liquid energy transportation. Although various studies have investigated the contributing factors to accidents occurring in pipeline construction projects, there is a need for a predictive model for such incidents. The main purpose of this study is to provide an artificial intelligence-based model to predict the outcomes of occupational accidents. In this context, 1184 incident cases, including injury, near-miss, and asset-product damage, taken from a pipeline construction project constituted the primary dataset. Twelve prediction models are formed by changing the input domain according to the type of incident, time, and cause type attributes, leading to 12 distinct sub-datasets. Then, each dataset is tested with 11 different machine learning (ML) algorithms to derive an effective prescriptive model. The descriptive results show that low awareness of job hazards and improper vehicle operations were the most critical immediate causes, while failure in risk recognition and site supervision were the major root causes of pipeline construction accidents. Among the ML methods, the deep learning algorithm performed better than its counterparts in eight sub-datasets. Finally, a prescriptive model incorporating the ML application procedure is recommended for construction companies to reduce occupational accidents. Overall, the proposed model and findings are expected to contribute to preventing and reducing construction accidents in pipeline projects by adopting relevant strategies.

Sustainability

Buildings are responsible for almost half of the world’s energy consumption, and approximately 40... more Buildings are responsible for almost half of the world’s energy consumption, and approximately 40% of total building energy is consumed by the heating ventilation and air conditioning (HVAC) system. The inability of traditional HVAC controllers to respond to sudden changes in occupancy and environmental conditions makes them energy inefficient. Despite the oversimplified building thermal response models and inexact occupancy sensors of traditional building automation systems, investigations into a more efficient and effective sensor-free control mechanism have remained entirely inadequate. This study aims to develop an artificial intelligence (AI)-based occupant-centric HVAC control mechanism for cooling that continually improves its knowledge to increase energy efficiency in a multi-zone commercial building. The study is carried out using two-year occupancy and environmental conditions data of a shopping mall in Istanbul, Turkey. The research model consists of three steps: predicti...

Sustainability

Construction risk assessment (RA) based on expert knowledge and experience incorporates uncertain... more Construction risk assessment (RA) based on expert knowledge and experience incorporates uncertainties that reduce its accuracy and effectiveness in implementing countermeasures. To support the construction of RA procedures and enhance associated decision-making processes, machine learning (ML) approaches have recently been investigated in the literature. Most ML approaches have difficulty processing dependency information from real-life construction datasets. This study developed a novel RA model that incorporates a graph convolutional network (GCN) to account for dependency information between construction accidents. For this purpose, the construction accident dataset was restructured into an accident network, wherein the accidents were connected based on the shared project type. The GCN decodes the construction accident network information to predict each construction activity’s severity outcome, resulting in a prediction accuracy of 94%. Compared with the benchmark feedforward ne...

Buildings

Quality problems are crucial in construction projects since poor quality might lead to delays, lo... more Quality problems are crucial in construction projects since poor quality might lead to delays, low productivity, and cost overruns. In case preventive actions are absent, a lack of quality results in a chain of problems. As a solution, this study deals with non-conformities proactively by adopting an AI-based predictive model approach. The main objective of this study is to provide an automated solution structured on the data recording system for the adverse impacts of construction quality failures. For this purpose, we collected 2527 non-conformance reports from 59 diverse construction projects to develop a predictive model regarding the cost impact of the quality problems. The first of three stages forming the backbone of the study determines crucial attributes linked to quality problems through a literature survey and the Delphi method. Secondly, the Analytical Hierarchy Process (AHP) and a Genetic Algorithm (GA) were used to determine the attribute weights. In the final stage, w...

Buildings

Construction companies are under pressure to enhance their site safety condition, being constantl... more Construction companies are under pressure to enhance their site safety condition, being constantly challenged by rapid technological advancements, growing public concern, and fierce competition. To enhance construction site safety, literature investigated Machine Learning (ML) approaches as risk assessment (RA) tools. However, their deployment requires knowledge for selecting, training, testing, and employing the most appropriate ML predictor. While different ML approaches are recommended by literature, their practicality at construction sites is constrained by the availability, knowledge, and experience of data scientists familiar with the construction sector. This study develops an automated ML system that automatically trains and evaluates different ML to select the most accurate ML-based construction accident severity predictors for the use of construction professionals with limited data science knowledge. A real-life accident dataset is evaluated through automated ML approaches...

Journal of Construction Engineering and Management

As construction industry is one of the dominant contributors to the world’s total CO2 emissions a... more As construction industry is one of the dominant contributors to the world’s total CO2 emissions and it has huge negative impacts on the environment, sustainable construction has become a key aspiration in the field. Through utilizing resource efficiency and ecological design, sustainable construction is considered as the main concept to create and operate a healthy built environment. Although sustainability has been demonstrated as a timeless objective for continuous development in Turkey’s governmental policies, the number of qualified professionals in the field and the attributed significance to the notion of sustainability in the Turkish educational context is questionable. Accordingly, this paper concentrates on the Turkish architectural and civil engineering education - two disciplines that are expected to raise experts on the subject – within the scope of sustainable construction. Ten research universities, which are identified by Higher Education Institute (YÖK), are analyzed...

Smart and sustainable built environment, Sep 6, 2022

This research aims to identify and measure the correlations between Building Information Modellin... more This research aims to identify and measure the correlations between Building Information Modelling (BIM) and Lean Construction (LC) principles at the design and construction phases. Design/methodology/approach: The study investigates BIM-LC principles correlations using the Istanbul Grant Airport (IGA) as a case study. The Delphi technique, performed quantitatively, contributes to the identification and quantification of a set of correlations between 11 selected BIM uses and 13 LC principles, which are supported with practical examples from the case study. Findings: Together, the two research methods provide an evidence-based approach to understand the correlations between BIM and LC. The correlation analysis results in 46 correlations, and the correlations between the LC principles and BIM uses are intensified with the LC principles. Originality: BIM and LC practices represent approaches to improve performance in construction projects. While BIM has both information technology (IT) and process perspectives, the LC approach is mainly a process and product-oriented philosophy for project efficiency, effectiveness and the elimination of non-value-adding activities and waste. Many studies have investigated how the two approaches complement each other and concluded that their combined implementation in projects can improve efficiency and effectiveness. However, to date an analytical and granular investigation identifying and measuring correlations between BIM and LC based on empirical data is lacking. This paper fills that gap with an evidence-based analysis of the tightness of coupling and correlations between BIM uses and LC principles. Practical implications: A quantitative understanding BIM use and LC principles correlations and appreciation of their specific uses can guide the practical implementation of BIM and LC, especially in large and mega projects.

Engineering, Construction and Architectural Management

PurposeCost overruns remain a persistent problem in the construction industry. Although various c... more PurposeCost overruns remain a persistent problem in the construction industry. Although various cost management strategies have been implemented, innovative approaches are still required. Therefore, the authors attempted to introduce and test a new cost management strategy for the construction industry.Design/methodology/approachZero-based budgeting (ZBB) is one such method whose effectiveness has been proven in different industries over many years. Therefore, the authors initially developed two different frameworks related to the integration of ZBB into a multinational construction contractor and the application process of ZBB for a construction project in this study. Then, the effectiveness and feasibility of the proposed frameworks are tested via an actual field study in a mega construction project.FindingsThe results show savings of 0.81% of the total project budget and 4.74% of the focused cost items by following the ZBB framework compared to the traditionally estimated project...

Journal of Construction Engineering, Management & Innovation

Due to poor performances in construction projects, there is a necessity to apply novel project ma... more Due to poor performances in construction projects, there is a necessity to apply novel project management approaches instead of traditional ones. Recently, although new project management methods have emerged and applied in different industries, the construction industry has stayed behind in implementing these techniques. The agile Project Management (APM) approach is one of these methods, and it has been highly discussed recently. As developing countries considerably suffer from poor performance in construction projects, applying new project management methods has gained more importance in these territories. Even though different studies attempted to understand the applicability of the APM, it is also necessary to explore the potential benefits of the agile methods for the construction industry. For this purpose, we surveyed 140 construction experts for the prioritization of factors and received responses on the potential advantages of the APM regarding team and project performance in construction. The results achieved from the Iraq field study demonstrate that the APM could be feasible for the construction industry and could effectively bring solutions to the project performance issues. We also concluded that the adverse effects of poor project performance, such as quality defects, schedule variances, cost overruns, and low productivity, could be eliminated especially in the construction industry of developing countries, through APM approaches.

Değişken ve zorlu piyasa koşulları, gerçekleştirilen projelerde karşılaşılan operasyonel riskler ... more Değişken ve zorlu piyasa koşulları, gerçekleştirilen projelerde karşılaşılan operasyonel riskler ve organizasyon dâhilinde oluşan iletişim ve koordinasyon problemleri nedeniyle, günümüz iş dünyasında faaliyet gösteren birçok şirket söz konusu sorunları engellemek amacıyla çeşitli stratejiler benimsemektedir. Bu kapsamda, Proje Yönetim Ofisi (PMO) literatürde birçok yazar tarafından kurum içi ve dışı dinamiklere ilişkin risklerin kontrol edilebilmesi ve gerçekleştirilen projelere ilişkin gerekli yönetim stratejilerinin kurulabilmesi amacıyla önerilmiştir. Ancak, Proje Yönetim Ofislerinin inşaat sektöründe kurulumu ve uygulamalarına ilişkin yayımlanmış kısıtlı sayıda çalışma olduğu gibi, Proje Yönetim Ofisi hakkında açık ve etkin bir anlayış ise henüz pratikte önerilmemiştir. Bu çalışmanın amacı, inşaat, enerji ve yatırım sektörlerinde faaliyet gösteren ve yüksek iş hacmine sahip bir şirket bünyesinde, sürdürülebilir büyüme hedefleri doğrultusunda belirlenen stratejik planların uygula...

Metraj çıkarma ve maliyet hesabı inşaat projelerinde zahmetli bir süreçtir ve pek çok durumda kap... more Metraj çıkarma ve maliyet hesabı inşaat projelerinde zahmetli bir süreçtir ve pek çok durumda kapsamlı tecrübe gerektirir. Son yıllarda yapı bilgi modelleme (YBM) teknolojilerinin kullanımı ile birlikte bu süreçlerin otomatize edilmesine çalışılmakta ve ölçülebilir sonuçlar, YBM teknolojilerinin kullanımının önemli zaman kazanımları sağlayabildiğini göstermektedir. Bu çalışmada YBM tabanlı metraj çıkarma ve maliyet hesabı süreci tanımlanmış ve açıklanmıştır. Sözü edilen süreçlere özgü zorluklar anlatılmış ve sonuçlar sunulmuştur. Bu çalışmanın amacı Türk yüklenicilerin kullanabileceği, uygulanabilir YBM tabanlı metraj çıkarma ve maliyet hesabı sistemi oluşturmaktır

6th International Project and Construction Management Conference (e-IPCMC2020) Istanbul Technical University, (12-14 November 2020), Dec 2, 2020

Design codes provide methods to analyze and design structures according to different types of ris... more Design codes provide methods to analyze and design structures according to different types of risks the structure may suffer, and they differ from each other in several aspects, such as load combinations and earthquake loads evaluation. In this study, the cost of the building designed according to both Turkish and European codes are compared, and cost-effectiveness is measured. The objective of the study is to identify which code provides a more economically feasible design. In consideration of seismic risk, Turkey is regarded to be one of the most hazardous places in the world. Since the case structure is located in Istanbul, in a zone with a high PGA (0,4g), the comparison of the designs will result in more distinctive outcomes about the cost-effectiveness of the codes. After the design of the structure is completed according to both codes, respectively, the bill of quantities for each is calculated, and costs are estimated for the structure. The cost estimation showed that the Turkish Earthquake Code is more economical than the European one. As the world goes into a deeper economic recession, the cost of the design plays a paramount role in being sustainable as well as resilient

null, Dec 2, 2020

Lean construction is a new approach, adapted from lean thinking, focuses an increase in productiv... more Lean construction is a new approach, adapted from lean thinking, focuses an increase in productivity through control over the process to eliminate waste of project while maximizing the value offered by the project. The Last Planner System (LPS) is one of the production control and planning systems for project management in lean construction philosophy. It emphasizes reliable and optimized workflows by taking measures (Identification and resolving) for problems that may occur in advance collaboratively at the lowest level by breaking down tasks into more details, from the master schedule to the daily work plan. However, the application of daily look-ahead meetings is rather limited to both academically and practically in the construction industry. This paper aims to explore the efficacy of daily look-ahead meetings adaptation in the construction environment. Systematic literature review and expert interviews with senior and mid-level managers from the construction industry are carried out to evaluate the results of its implementation in construction projects. Although the literature perceives the positive impacts of daily look-ahead meetings on productivity and quality, practitioners emphasize the fundamental obstacles to adapt daily look-ahead meetings in practice. The paper concludes by revealing benefits and challenges and recommending several strategies to overcome the obstacles about productivity and quality in the construction industry

Journal of Construction Engineering and Management, 2022

Automation in Construction, 2021

Arabian Journal for Science and Engineering , 2023

Sustainability

Buildings

Journal of Construction Engineering and Management

Smart and sustainable built environment, Sep 6, 2022

Engineering, Construction and Architectural Management

Journal of Construction Engineering, Management & Innovation

6th International Project and Construction Management Conference (e-IPCMC2020) Istanbul Technical University, (12-14 November 2020), Dec 2, 2020

null, Dec 2, 2020

Journal of Construction Engineering and Management, 2022

Automation in Construction, 2021

The increase in world's population, rapidly social and economic developments and environmental ch... more The increase in world's population, rapidly social and economic developments and environmental changes are some of the most significant reasons that are leading to water crises. Governments have encouraged appropriate strategy for sustainable water management especially for building since buildings are responsible for 13{\%} of water consumption. Therefore, designing and constructing water efficient buildings gained importance recently. This paper aims to explore the latest methods for improving water sustainability in buildings and show the benefits via case study. Recent successful experiences indicate that green buildings can reduce water consumption up to 40 {\%} as proved in the case study.

Development of a lean and automated progress tracking system is one of the most challenging subje... more Development of a lean and automated progress tracking system is one of the most challenging subjects in the construction industry. Since the current methods depend on individual and manual inspections of the site, they may have various problems. For instance, results include a natural bias since field personnel makes interpretations depending on their educational and expertise level. From the practical point of view, manual data collection and their comparison with construction drawings and schedules are inefficient as it takes too much time. With the recent advancement of Unmanned Aerial Vehicles (UAVs) into the market and inclusion of lean project management principles, project management studies are inclined towards the digital and lean approaches. Within this perspective, the objective of this study is to reveal the use of UAVs as a lean project management tool. This paper indicates merely that UAVs have the potential for such a purpose. Keywords:

The results of the bibliometric analysis carried out in this paper show the publication status of... more The results of the bibliometric analysis carried out in this paper show the publication status of Lean Construction in a detailed manner. Different research individuals, groups, organizations, and countries that made the most significant contributions to the Lean Construction Journal and Lean Construction research were clearly mentioned in this paper. Also, tree-map of the authors' keywords and results of content analysis are the most valuable findings of this study because they show the research trends of the Lean Construction Journal. This review also helps people to understand the general view of the lean concept in the construction sector. As a bridge between the publications of the Lean Construction Journal, this review will be the basis of further researches and the progress of Lean Construction.

Record keeping systems are gaining more importance in addressing safety problems in megaprojects.... more Record keeping systems are gaining more importance in addressing safety problems in megaprojects. The information recorded is being converted into large data domains since it has become necessary to examine problems down to the last detail to deal with them properly. Due to a high number of attributes and the type of information, the data has a high level of heterogeneity. The aim of this paper is to propose an innovative safety assessment methodology to predict the possible scenarios and determine preventative actions. The study introduces predictive models based on factual information and shows how to deal with the safety data which has a significant level of heterogeneity. Latent Class Clustering Analysis (LCCA) was performed to reduce the heterogeneity and extract homogenous subgroups from the data. For predictive purposes, Artificial Neural Network (ANN) and Case-Based Reasoning (CBR) were employed to estimate the outcome of incidents in terms of severity. CBR gave promising results and exhibited better performance than ANN. CBR achieved results in 86{\%} of the test cases with 18{\%} error at most. Moreover, the overall prediction accuracy of fatal incidents was equal to 86.33{\%}. As a final step, the study presented preventative actions to eliminate safety failures. Ultimately, the proposed methodology can assist construction industry professionals in examining future safety problems by utilizing the collected large scale data. Furthermore, the study provides necessary preventative measures to be implemented before and during the construction stage.

Lean production concentrates on creating more value for customers by eliminating waste thoroughly... more Lean production concentrates on creating more value for customers by eliminating waste thoroughly with a holistic approach that affects all processes. The construction industry is now trying to apply the principles of lean production. However, the integration process is advancing still gradually.Manychallenges and constraints affect the adaptation of lean construction. Training and education are becoming a critical success factor in overcoming the barriers to applying lean principles. The objective of the study is to introduce a collective preparation process of lean construction course, which relied on a piece of factual knowledge about lean principles. The study intends to intensify the adaptation progress and extend lean education at universities, especially for the ones located in developing countries. The process began with defining the existing production problems of the construction industry by conducting semi-structured interviews with lean construction practitioners. Then, the current state of lean construction education was examined to structure the significant elements of the course. The current state of Turkey and the U.S. were investigated in terms of lean construction to determine the teaching methods, student constraints, and resources. The information collected via research and interviews formed the frame of the planned lecture. Next, the evaluation process was introduced for enhancement and strengthening the lean construction course. Three-step evaluation tasks were presented to determine whether the given course was sufficient for meeting the industry's needs or not. Ultimately, the proposed research aims to develop a unique process to offer Lean Construction courses through universities by generalizing the content of lean construction education.

Recently, the amount of energy consumed in buildings has increased daily due to technological dev... more Recently, the amount of energy consumed in buildings has increased daily due to technological developments and population growth. Significant portion of this energy is consumed in residential buildings. Reducing the energy consumption of residential buildings is crucial, considering the depletion of fossil-based energy resources and its effect on the economy of the countries. This study aims to investigate the effect of window alternatives on the reduction of energy consumption and life cycle cost (LCC) of residential buildings for heating and cooling. The study is carried out in the city of Trabzon, which represents the moderate-humid climate region. For this study, a residential flat that has 1+1 floor plan for a family of two, is used for simulation. For this flat, yearly heating and cooling energy consumptions and life cycle costs are calculated using DesignBuilder simulation program according to different window-wall ratios of window alternatives. Window assembly alternatives are composed of double glazing units with clear glass, low-e glass, blue tinted glass and reflective glass and PVC frame. As a conclusion, the most energy and cost efficient window alternatives for moderate-humid climate regions are recommended.

Building Information Modeling (BIM) has been an emerging concept in architecture, engineering and... more Building Information Modeling (BIM) has been an emerging concept in architecture, engineering and construction (AEC) industry with a vast amount of promising benefits to construction projects. Implementation of BIM, however, requires comprehensive research and strategic planning. Industry-wide and organizational implementation guidelines and standards have been published around the world either to encourage organizations to adopt BIM or to present the minimum requirements to be followed where BIM implementation is a statutory obligation. In contrast, governments or organizations in several countries such as Turkey have not mandated BIM implementation and provide no guidance. Organizations in these countries which plan to adopt BIM processes are forced to develop their own implementation plans. The purpose of this study is to provide guidance in BIM implementation for construction companies in countries where BIM implementation has not been mandated particularly during the construction phase of the building projects. 23 BIM standards and guidelines covering the BIM execution process have been reviewed. Topics that need to be addressed by BIM implementation plans have been identified and categorized under four headings. A case study of BIM implementation at a large construction company that focuses on conducting quantity takeoff and cost estimation is presented, and unique challenges of BIM implementation in Turkish AEC industry are discussed.

Despite significant productivity gains in most industries for the last four decades, the producti... more Despite significant productivity gains in most industries for the last four decades, the productivity of the construction industry has not been improved. Insufficiently skilled labor force, limited research and development expenditure, reluctance to invest technologically superior machinery are among a few of many reasons for industry's low productivity. Each of these creates waste during the life cycle of a construction project. Compatible with lean construction practices, automation and digitization offers promising solutions for elimination of these wastes and increase productivity in the sector. Hence, the objective of this study is to investigate the potential of different technologies from a lean construction perspective and develop an end-to-end construction model that adopts some of these tools. This paper concludes that although prefabrication, construction robots, advanced BIM, sensors, 3D printing, and modular construction are prominent technologies, they modernize only specific part of the construction value chain. Hence, the proposed model suggests vertical integration of processes which transforms construction repetitive and sequenced assembly of activities. Only if customers and contractors share the same mission and start to use these technologies simultaneously, the end-to-end construction model can help the industry improve productivity.

This paper focuses on creating a lean environment for the end user of the building. There are man... more This paper focuses on creating a lean environment for the end user of the building. There are many studies on lean thinking, yet there is a few about utilizing lean methods to optimize the space performance of the architectural design. Some architectural concepts and tools, which may be utilized to enhance the end user's experience, were developed during the history of architecture. The problem is that there is not a holistic ground to define their aims for providing valuable space. Since lean aims operational excellence and looking for possibilities for continuous improvement, it may offer a framework for the techniques of enhancing the end user's experience. The objective of this study is to demonstrate architectural concepts' parallelism with lean principles and what can be derived from lean principles in order to contribute to the end users' experience. This paper is conducted from a conceptual perspective. The correlation between the fundamentals of lean thinking and the well-established architectural concepts is examined via narrowed literature research.