Journal of Construction Engineering, Management & Innovation
On state DOT projects, practitioners want to know why a project was or was not completed on time, and why a project was or was not on budget. To answer these questions effectively, practitioners must have a framework that allows them to compare projects by type, and look for performance patterns. The lack of a standardized method to classify state DOT projects may make it difficult for practitioners to identify trends, and patterns, and to use such information to inform and enhance practice. A standard classification of state DOT projects does not exist. Hence, the objective of this research is to develop a classification framework for state DOT projects based on several differentiating dimensions of state DOT projects. Following a qualitative synthesis research method, a framework that captured the key state DOT project differentiating dimensions was developed. The output of this research includes a classification framework for aggregating different types of state DOT projects. The significant contribution to the body of knowledge on classifying state DOT projects is that basic state DOT project performance analytics can be enhanced within and across the state DOTs by using the project classification framework developed from this research.
All kinds of energy are one of the basic requirements in life to sustain it. Therefore, the majority of research and applications have been mostly focused on self-sufficient energy or zero-energy buildings in developed countries. Most of these countries encounter energy demand suffer from carbon dioxide emissions from existing buildings. Energy-efficient applications must be also spread across developing and undeveloped countries especially in the Mesopotamia region due to the hot climate. Hence, the efficiency of a common practice, implementation of photovoltaic panels (PVs), in Iraq is investigated in this study. PVs were designed and empirically implemented in an existing conventional primary school building in Baghdad, Iraq as a case study for the Mesopotamia region. The sustainability and energy analysis of a school building was conducted in diverse scenarios to explore the potential of energy-saving and payback period of the PVs. The slope and number of PV panels located on the school building are the parameters of the current study. Results showed that PV panels with a 30 inclination angle reduced the energy cost of the building by 50%. The payback for the implementation of PVs can be obtained approximately in 8 years. Consequently, the PVs have major potential in energy efficiency and can be implemented in governmental buildings such as public school buildings in the Mesopotamia region. Besides, society and private institutions may become aware of the importance of sustainable energy with this study.
Despite a large number of studies on cash flow management in construction literature, a very limited number of attempts exist focusing on strategies employed by contractors to increase the amount of cash in their hands in the early phases of the project and to improve their cash balance. Based on this gap, this study aims to identify and evaluate cash flow management practices of contractors in Turkey. In this context, a web-based questionnaire survey was conducted with construction company owners and managers involved in the decision process of cash flow management practices. Data obtained from a total of 96 participants show that construction companies commonly hold working capital equivalent to 10% to 20% of the contract sum in their hands at the beginning of the construction. Construction companies frequently recourse to cash flow management strategies to decrease external financing requirements and prevent possible cash shortages during construction. While trade credits followed by overbilling are the most preferred approaches, unbalanced bidding techniques are employed to a limited extent. Furthermore, a clear distinction has been identified between the strategies adopted by companies of different ages and sizes. Trade credits are the first option only for small and young companies and are most widely used by them. Also, the adoption of overbilling techniques increases as company size and age grows. Similarly, unbalanced bidding practices increase with years of experience in the industry. Construction productivity, quality of work, and completion risks come to the fore as common concerns with delaying payments to suppliers and subcontractors. Also, unbalanced bidding practices are assumed very risky, and accurate estimations are of critical importance at this point.
Gürkan Emre Gürcanlı
İbrahim Mert Uzun
Restoration and renovation of historic buildings aim to preserve and sustain those buildings with their original state. This fact is important to conserve historical values for a society as well as for sustainable city planning. Restoration projects have their own occupational health and safety risks and differs from ordinary construction projects. Additionally, implementation of safety measures according to the current regulations are very difficult due to geometrical structure, type of material used and preservation consideration for the structural and architectural elements of the historic buildings. Since the risks as well as mitigation and abatement techniques differ from conventional buildings, restoration projects require paying attention to establish safety and health plan and risk management system to implement safety and health measures. In this paper, different health and safety risks of the restoration projects are discussed. Different safety and health practices are deal with ordinary structures, risk assessment are made according to specific risks, findings are revealed in some certain restoration projects in Turkey and a new approach for health and safety management in restoration projects is introduced.
Yusuf Oğulcan Doğan
Climate change will alter the inflows into the dam in the future; thus, the balance between water supply and water availability will directly impact the water levels and indirectly affects dam safety. Therefore, estimating the future inflows and reservoir water content can help the operators. In this study, a machine learning Wavelet-MultiLayer Perceptron (W-MLP) method is applied to estimate monthly future projections (2016-2100) of the inflows into the reservoir. The methodology is tested for one of the Ankara’s main water supply reservoirs, which distributes annual 142 hm3 water. The EURO-CORDEX database is used to obtain Regional Climate Model (RCM) simulations of RCA4 (12.5 km) from two different Global Circulation Models (GCMs), MPI-ESM-LR and IPSL-CM5A-MR, under two Representative Concentration Pathways (RCPs) (RCP 4.5 and RCP 8.5) scenarios. The monthly W-MLP models are independently trained and tested for each data set (observed data and GCM outputs). The GCM scenario results indicate a shift in monthly hydrographs for both RCPs projections with a reduction in inflows which will directly change the operation of the reservoir. The daily HEC ResSim model mimics future water content and releases. According to the results, the annual reduction expected in the future inflows scenarios varies between -3 % to -13% under the RCPs, and the effects on annual reservoir water content are much higher (between -21 % and -37 %). These findings can be used in different risk assessment metrics (reliability, resilience, and vulnerability) to estimate the future effects of dam safety.