Showing 2 results for Statistical Analysis
S. S. Shahebrahimi, A. Lork, D. Sedaghat Shayegan,
Volume 12, Issue 2 (4-2022)
Abstract
In this study the challenges of managing the civil projects in oil and gas industry over recent years that failed were investigated. For this purpose, the relevant cases and their effectiveness were categorized by analyzing research data obtained from the questionnaire results. The results obtained from the research showed that there is a positive and significant relationship between the project management knowledge and reduction in the challenges. Lack of attention to the project's feasibility study before starting the project, adverse risks at the beginning and end of the projects, proper knowledge of contracts, and the project team's skill are the items that will fail the project if they are not appropriately managed. Since the team's correct design and the key persons of the project and before that feasibility and the necessity of doing it in vital projects in the country are very important and in such a way, the two components studied in this research are derived from the risk management of projects. Considering the importance of this issue as a case study, these cases were investigated in gas pipeline projects in Fars province.
B. Ganjavi, M. Bararnia,
Volume 12, Issue 3 (4-2022)
Abstract
In present study, the effects of optimization on seismic energy spectra including input energy, damping energy and yielding hysteretic energy are parametrically discussed. To this end, 12 generic steel moment-resisting frames having fundamental periods ranging from 0.3 to 3s are optimized by using uniform damage and deformation approaches subjected to a series of 40 non-pule strong ground motions. In order to obtain the optimum distribution of structural properties, an iterative optimization procedure has been adopted. In this approach, the structural properties are modified so that inefficient material is gradually shifted from strong to weak areas of a structure. This process is continued until a state of uniform damage is achieved. Then, the maximum energy demand parameters are computed for different structures designed by optimum load pattern as well as code-based pattern, and the mean energy spectra, energy-based reduction factor and the dispersion of the results are compared and discussed. Results indicate that optimum seismic load pattern can significantly affect the energy demands spectra especially in inelastic range of response. In addition, using energy-based reduction factors of optimum structures in short-period and long-period regions will result in respectively overestimation and underestimation of the required input energy demands for code-based structures, reflecting the difference dose exists in reality between the conventional forced-based methodology and energy-based seismic design approach that can more realistically incorporate the frequency content and duration of earthquake ground motions.
