Journal of Construction Engineering, Management & Innovation

Robert van Lith Alexus G. Entrop J.I.M. Halman

The thermal performance of conventional flat roof systems is in practice normally assessed by the heat transfer caused by conduction. The effects of radiation and convection are in such cases ignored as being insignificant. Holistic flat roof systems are designed to better utilize the impact of radiation and convection on improving the indoor climate. However, to determine the influence of radiation and convection, an integrated assessment should be used. In this article the effect of applying five different holistic flat roof systems is compared with a conventional roof system of an existing storage hall. With EnergyPlus the internal air temperature in the storage hall was simulated for a complete year using weather data of the moderate Dutch climate. The most efficient systems prove to be the systems that decrease the heat gain by solar radiation. These systems can decrease the number of overheating hours by up to 95%. Increasing the thermal resistance value of a roof could lead to adverse results. The study shows an integrated approach that could be implemented in policies and regulations for the thermal assessment of holistic flat roof systems.

https://doi.org/10.31462/jcemi.2018.01001017

Aynur Kazaz Serdar KOCAK Serdar ULUBEYLİ

During the last decades, especially in large scale construction projects, it is one of the widely applied strategies that the main contractors work with many subcontractors and overtake a large part of the works. This trend brings out the problem of selection of subcontractors. The classical approaches in the construction industry to select the subcontractor are the general practice reference, the lowest bid and the familiarity. This creates major risks for contractors since the construction sector involves time limited projects with a large variety of complex works. Putting the subcontractor selection on a scientific basis and minimizing the risks by choosing the most appropriate subcontractor among the bidders for a particular type of work, require for the construction industry to determine not only consistent and efficient but also uncomplicated and plain model. Instead of the widespread conventional application, this study represents a new alternative approach to the subcontractor selection with Additive Ratio Assessment Method, which is one of the multi-criteria decision making techniques. Additive Ratio Assessment Method is quite practical and convenient to use among the other multi-criteria decision making methods. This study aimed to demonstrate the utility of Additive Ratio Assessment Method on sub-contractor selection problems by exemplifying a real case application.

https://doi.org/10.31462/jcemi.2018.01018032

Serkan Yıldız Serkan KIVRAK Gökhan Arslan

Like in many other developing countries, urban renewal projects constitute a significant part of the activities of architecture, engineering and construction (AEC) industry in Turkey, and recently Turkey has started an urban renewal movement aiming renewal of 8 million dwellings. In this study, as a critical factor on the success and continuity of the urban renewal projects, the relation between built environment design and economic sustainability in urban renewal areas, was examined. In order to determine the importance of built environment design elements in terms of economic sustainability, a survey study was done with the participation of 323 people, who were mainly architects, civil engineers and urban planners and has previously worked in urban renewal projects. By applying factor analyses the design elements were grouped under six different factors, which were named as: Transportation and Accessibility, Built Environment Quality, Conservation of Resources, Supporting Social Life, Commercial and Economic Opportunities and Historical and Cultural Values. The importance weights of these factors were determined by AHP analyses conducted with the participation of a group of 60 people formed by academicians and practitioners. Conservation of Resources and Commercial and Economic Opportunities factors were found as the most important factors. It is evaluated that the results of the study will guide the urban renewal stakeholders in creating economically sustainable urban renewal areas.

https://doi.org/10.31462/jcemi.2018.01033042

Ümit Bahadır Xhensila Thomollari Vedat Toğan

A considerable amount of energy is consumed in buildings because of the economic developments and the increased population. By taking in consideration that 40% of total energy use is consumed in the building, the proper design of building’s envelope is crucial for reducing the negative effects of high energy consumption in the economy and environment of a country. This study aims to investigate the proper design alternatives on the reduction of energy consumption and life-cycle cost (LCC) of residential buildings for heating and cooling purposes. The study is carried out in two cities, Ankara and Antalya, which represents the cold and hot climate region. For this study, the same flat of 1+1 floor plan designed for a family of two in a reference residential building project is simulated with different location, in Ankara and Antalya. For these flats, the annual zone heating and total cooling energy consumptions and life cycle costs are calculated using DesignBuilder simulation program according to different window-wall ratios, glazing types and insulation thickness. Window assembly alternatives are composed of double glazing units with clear glass, low-e glass, blue tinted glass and reflective glass and PVC frame. While the investigated insulation thickness options are EPS 100 mm and EPS 50 mm. At the end of the study, energy and cost efficient design alternatives for cold and hot climate regions are proposed.

https://doi.org/10.31462/jcemi.2018.01043054

Sibel Maçka Kalfa

Building information models (BIM) have been used as common in the architecture, engineering, and construction (AEC) industry in recent years. Each country in the world has tried to adopted BIM systems because of their benefits. Owing to these systems, it could be provided time, labour and money savings and reduced errors in early design stage of a project. But, usage of BIM systems require deeply a knowledge, skill and expertise and unfortunately number of BIM experts have been not enough in many countries. BIM systems that serve as a bridge among many dicliplines such as architecture, civil engineering, mechanic engineering etc. study with softwares. Selection of confidential and accurate softwares have a great importance. To provide maximum efficiency from usage of BIM systems, firstly, it should be known that benefits, risks, challenges of these sytems and according to these, a roadmap is drawn. Then, usage aims and the status of BIM adoption in countries should be examined. In this context, in the light of above criterias, it is important that BIM systems that are a new project management approach for Turkey are discussed. In this paper, benefits, risks and challenges of BIM systems for the architecture, engineering and construction were discussed, situation in the world and Turkey were examined and applications constructed using BIM systems in Turkey were investigated.

https://doi.org/10.31462/jcemi.2018.01055066