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Open access

Yonas Mitik Degu and Derbew Alebel

Abstract

Gyrocopter or gyroplane is a type of rotorcraft that uses an unpowered main rotor in free autorotation to develop lift. Gyrocopter rotor blades have smaller cord length and longer span compared to helicopters blades. National Advisory Committee for Aeronautics (NACA) 8-H-12 gyrocopter rotor blade profile, unsymmetrical airfoil sections were used for this research. An attempt has been made in this work to investigate the effect of ribs and spar elements in response to applied load. Three possible modeling alternatives were studied to predict the actual induced stress and deformation of the blade: Model I is by considering the blade shell part only, Model II is blade shell with 25 numbers of ribs and without the spar element and Model III is blade shell with 25 numbers of ribs and with spar element. The rotor blade was sized based on single seat open frame and high-wind-start gyrocopter. Structural static analysis has been carried out to evaluate the strength of composite rotor blade using ANSYS Workbench 15. The results show that among these three proposed models; Model III had registered minimum Von Mises stress and deformation. Also the result reveals that by considering ribs and spar element during analysis of gyrocopter blade is crucial because, it will help to know the actual induced stress and deformation. The predicted value of induced stress and deformation is closer to the actual values will help the designer not to overdesign the parts. Consequently, the main drawbacks related to overdesign increase in weight and cost will be minimized; thereby the product operational efficiency will be improved.

Open access

Paulo Araldi, Carlos Eduardo Tino Balestra and Gustavo Savaris

Abstract

The present study aimed to analyze the interference of different curing conditions on the development of the concrete compressive strength under the perspective of construction management. It is known that the conditions of humidity and temperature are the main factors related to the behavior of the concrete strength, so that modifying these parameters directly affects the material’s behavior and, consequently, construction management. Forty-two specimens of concrete were molded and each 6 specimens were submitted to different temperature and humidity conditions. The first group was oven-cured at a temperature of 100°C. The second and third groups were kept at ambient temperature of 23 + 2°C being that the latter was submerged in water and the former was exposed to the air humidity. The specimens of groups 4 and 5 were placed in a freezer at 5°C. Group 4 was submerged in water and group 5 was not. The curing of group 6 occurred under submerged condition with water at about 100°C. Group 7, on the other hand, was cured in water vapor. The group submitted to curing at room temperature and submerged condition was the one with the highest compressive strength value, while the ones with the lowest compressive strength were the groups of samples cured in the oven and those submerged at 100°C. The results were compared and tested using statistic methods, which proved that the curing conditions directly affected concrete properties.

Open access

Isabelle Portugal Serrado, João Alberto Neves dos Santos, Nylvandir Liberato Fernandes de Oliveira and Andrey Pimentel Aleluia Freitas

Abstract

Due to the economic crisis, the Brazilian construction companies faced the challenge of remaining competitive in the market, therefore they need to be restructured. Construction projects are intrinsically risky because it changes the environment both physically and socially. Given this complexity and the great exposure to risk, this research aims to evaluate the market risks in construction projects through a field research, analyzing the perception and judgment of professionals in the area. The data analysis was performed by a multivariate index based on the statistical technique Factor Analysis that can be ordered by risk factors by degree of importance. It was possible to confirm the degree of correlation between the subgroups of risk factors and to establish a ranking of the degree of their importance, and the first one considered more relevant was the risk of reducing the quality of the workforce. It was also identified the low maturity in risk management in organizations, even though in civil works a thorough risk analysis is required.

Open access

Michael Pace

Abstract

This non-experimental correlational study extends previous research investigating the relationship between project management methodology and reported project success, as well as the moderating variables of industry and project manager experience. The sample included North American project managers with five years’ experience, 25 years of age or older, and experience with multiple project management methodologies. The survey instrument consisted of 58 questions, utilizing a 5-point Likert scale to record responses. The survey contained three sections, including demographic information, questions related to a successful project, and questions related to a less-than successful (failed / challenged) project. 367 usable responses were received. The examination of the constructs included Pearson’s correlation coefficient as well as linear regression to determine the impact of moderating variables. Results indicated that project management methodology has a weak correlation with reported project success, and this correlation is not moderated by industry nor project manager experience. The results did not align with previously conducted studies, illustrating a need to continue the study of methods impacting success including investigating additional moderating variables.

Open access

Jaydeep Balakrishnan and Chun Hung Cheng

Abstract

Given the creation of different types of knowledge propositions in project and production management, we discuss what we call ‘evangelical’ propositions and what as knowledge intermediaries our role should be in its dissemination. We examine both proposition accuracy as well as the process by which the proposition was arrived at. We suggest strategies for knowledge intermediaries to adopt in order to achieve balance in evaluating these developments. Further, we support our suggestions by examining the development of the Theory of Constraints (TOC) and Critical Chain Project Management (CCPM) and the debate that has accompanied these, as a case study. The debate relates to how much of the knowledge proposition in these is really new and whether the method of developing the proposition was lacking in some sense. Knowledge intermediaries, those who are expected to play an important role in disseminating knowledge, will be better prepared to deal with similar innovations in a balanced manner, by analyzing the case of TOC/CCPM.

Open access

Chien-Ho Ko and Jiun-De Kuo

Abstract

Traditional formwork design processes entail considerable waste, increasing non-value-adding manpower costs and operational time. The purpose of this research is to use lean thinking in formwork design so as to enhance design correctness and eliminate waste through establishing a Lean Formwork Design Process. In the design process, the concurrent design concept is adopted to provide a visual communication platform for design team members using Building Information Modeling (BIM). Industry Foundation Classes (IFC) are used as a protocol for sharing design artifacts. Design correctness is established to review and correct design errors, thus allowing for the construction of an organizational learning environment. Finally, the Lean Formwork Design Process is conceptualized using stock-flow diagrams. A real case is used to validate the applicability of the proposed approach. Application results show that the proposed method can enhance design correctness and reduce manpower waste and operational time in formwork engineering. This study is one of the first to apply lean thinking to improve practices in formwork design.

Open access

Luli Hoxha and Cheryl McMahan

Abstract

The world population is aging rapidly. The United Nations listed aging as one of the main social transformations of the twenty-first century. Aging impacts project managers as well. The most prevalent form of discrimination in workplaces is age discrimination. This study evaluated how project managers’ age influences project success. The population was 108 active or former project managers working in Albania or Kosovo. By using quantitative analysis, it was demonstrated that project managers’ age did not significantly predict project success. Therefore, there is a need to increase awareness among employers, so older project managers are not discriminated based on age.

Open access

R. S. Abdulrahman, A. D. Ibrahim and P. G. Chindo

Abstract

For organizations to be successful, they should be committed in managing risk proactively and consistently throughout the project and equally important is the determination of the Risk Management Maturity (RMM) of organizations because it is the commencing point in the review of the current RM systems, practices, and culture of construction organisations. It was reported that construction organisations lack the knowledge of their capability to manage risk and as a result, JV projects continue to fail. Studies have identified, categorised and assessed risk associated with JV projects in their local and international context but no study has assessed the RMM of construction organisations in JV projects. Therefore, this study assessed the RMM of construction organisations in JV projects. The attributes and dimensions used to assess the RMM of construction organisations were identified from literature and used in the survey to collect data from respondents and subsequently analysed using the Fuzzy synthetic evaluation technique. Findings revealed that construction organisations undertaking JV projects are at the “defined maturity level” which means that these organisations only practice informal risk management and uses only qualitative risk assessment technique. The study recommends that further studies should focus on how to improve and move from the current RMM level of construction organisations to the next maturity level (managed and optimised).