Experimental Testing and Analytical Modeling of Strip Footing in Reinforced Sandy Soil with Multi-Geogrid Layers Under Different Loading Conditions
Aram Mohammed Raheem,
Mohammed Abdulsalam Abdulkarem
Issue:
Volume 4, Issue 1, January 2016
Pages:
1-11
Received:
20 January 2016
Accepted:
30 January 2016
Published:
19 February 2016
Abstract: In this study, large-scale physical models with dimensions of (0.9m * 0.9m * 0.55m) have been designed and constructed to investigate the behavior of strip footing in reinforced sandy soil with multi-geogrid layers under inclined and eccentric loading conditions. The effect of several parameters such as geogrid layers (N), soil relative density (RD), depth of the topmost geogrid layer (U/B), load inclination angle () and load eccentricity ratio (e/B) on the bearing capacity ratio (BCR) of reinforced soil have been investigated through 120 experimental tests. As the number of the geogrid layers increased from 0 to 4, the BCR increased by 255% for 15o load inclination angle and by 470% for 0.05 load eccentricity ratio in 60% RD. When the RD of the soil increased from 60% to 80%, the average decreases in horizontal displacement and footing tilting angle were about 35% and 21% respectively. Hyperbolic analytical model was used to predict the relationships of most of the studied parameters. However, p-q analytical model was suggested to model the relationship between the BCR versus U/B. Both suggested models (hyperbolic and p-q) were in a very good agreement with the experimental results.
Abstract: In this study, large-scale physical models with dimensions of (0.9m * 0.9m * 0.55m) have been designed and constructed to investigate the behavior of strip footing in reinforced sandy soil with multi-geogrid layers under inclined and eccentric loading conditions. The effect of several parameters such as geogrid layers (N), soil relative density (RD...
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Uncertainty and Risk Factors Assessment for Cross-Country Pipelines Projects Using AHP
Hesham Abd El Khalek,
Remon Fayek Aziz,
Hamada Kamel
Issue:
Volume 4, Issue 1, January 2016
Pages:
12-23
Received:
16 January 2016
Accepted:
30 January 2016
Published:
23 February 2016
Abstract: Infrastructure cross-country pipelines projects carry out higher risk than traditional because they entail high capital outlays and intricate site conditions. The high-risk exposure associated with infrastructure cross-country pipelines projects needs special attention from contractors to analyze and manage their risks. They cannot be eliminated but can be minimized or transferred from one project stakeholder to another. Therefore, current research aims for identifying the risk factors that affect infrastructure cross-country pipelines projects based on experts experience and company’s point of view which participated in similar projects. The risk factors classified under two categories to company level risks and project level risks. The risk factors were assessed using risk assessment models that facilitate this assessment procedure, prioritize these projects based upon its risk indexes and evaluate risk contingency value. Analytical hierarchy process (AHP) used to evaluate risk factors weights (likelihood) and FUZZY LOGIC approach to evaluate risk factors impact (Risk consequences) using software aids such as EXCEL and MATLAB software, accordingly risk indexes for both company level and project level evaluated and overall project risk index determined. Five case studies in different countries were selected to determine the highest risk factors and to implement the designed models and test its results. Results show that project no 3 in Iraq conquer the highest risk index (39.75%); however, project 5 in Egypt has the lowest risk index (5.24%). Results of risk factors in other countries are (32.81%) in Emirates, (17.27%) in Saudi Arabia and (11.67%) in Libya. Therefore, the developed model can be used to sort projects based upon risk, which facilitate company’s decision of which project can be pursued.
Abstract: Infrastructure cross-country pipelines projects carry out higher risk than traditional because they entail high capital outlays and intricate site conditions. The high-risk exposure associated with infrastructure cross-country pipelines projects needs special attention from contractors to analyze and manage their risks. They cannot be eliminated bu...
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Risk and Uncertainty Assessment Model in Construction Projects Using Fuzzy Logic
Hesham Abd El Khalek,
Remon Fayek Aziz,
Hamada Mohamed Kamel
Issue:
Volume 4, Issue 1, January 2016
Pages:
24-39
Received:
12 January 2016
Accepted:
1 February 2016
Published:
29 February 2016
Abstract: In the global construction market, most construction companies are willing to undertake international projects in order to maximize their profitability by taking advantage of attractive emerging markets and minimize dependence on local market. Due to the nature of construction works, there are lots of risks and uncertainties associated with the company and project conditions. Therefore, how the profitability of the project changes with occurrence of various risk events, in other words, the sensitivity of project costs to risk events, should be estimated realistically. This paper offers a comprehensive risk assessment methodology that provides a decision support tool, which can be utilized through the bidding decisions for international construction projects introducing a risk model that facilitate this assessment procedure, prioritize these projects and evaluate risk contingency value. The risk models is developed using the analytic hierarchy process (AHP) to evaluate risk factors weights (likelihood) and FUZZY LOGIC approach to evaluate risk factors impact (Risk consequences) using software aids such as EXCEL and MATLAB software. The reliability of the developed software has been tested by applications on a real construction projects. The proposed methodology and decision support tool have been proved to be reliable for the estimation of cost overrun due to risk while giving bidding decisions in international markets. Therefore, the developed model can be used to sort projects based upon risk, which facilitate company’s decision of which project can be pursued. The developed risk model is validated, which prove its robustness in risk assessment (97%) in company level and (105%) in project level. It can also be used to sort construction projects based upon risk. The developed contingency risk model demonstrate the ability to evaluate risk contingency value by aggregating rules combining company risk index and project risk index using fuzzy logic approach and MATLAB software.
Abstract: In the global construction market, most construction companies are willing to undertake international projects in order to maximize their profitability by taking advantage of attractive emerging markets and minimize dependence on local market. Due to the nature of construction works, there are lots of risks and uncertainties associated with the com...
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