Analysis of Vegetation Effects on Slope Stability of Embankment
Md. Murad Hasan,
Mehejabin Chowdhury Ankan
Issue:
Volume 8, Issue 4, July 2020
Pages:
77-86
Received:
17 December 2019
Accepted:
26 December 2019
Published:
25 August 2020
Abstract: Embankments play a significant role in protecting cities from many natural disasters. Erosion and landslides of embankments and natural slopes are common phenomena occurring every year in Bangladesh. It has become a great concern of protecting embankments and natural slopes from failure. In many cases, traditional methods for protecting embankments and natural slopes are not effective during their designed lives. In such a condition, bio-engineering has been adopted in many countries as an effective and environment friendly measure for the protection of slopes. The role played by vegetation in improving slope stability is now well recognized. Many research works have been done in many countries on many species of trees that are locally available and suitable for the climatic and soil conditions of that country. In this study, an attempt has been made to evaluate the performance of lebbek tree and royal poincianain protecting the Rajshahi City Protection embankment. In-situ direct shear test was performed on block samples to determine the in-situ shear strength of rooted soil and soil without root. A numerical analysis has been performed to compute the factor of safety and shear strength of slope soil with root and without root. Also the effect of different types of vegetation on slope stability is observed by numerical analysis. It has been found that the values of factor of safety vary between 1.781 and 1.926 in case of slope without root whereas the values of factor of safety vary between 1.997 and 2.173 in case of slope with root. In numerical analysis, the shear strength of soil varies between 40.311 kPa to 41.782kPa in case of slope without root whereas in case of slope with root this value varies between 50.929 kPa to 52.13 kPa. The average percentage of increase in shear strength for lebbek tree root is 14.35% whereas this value for royal poinciana is 24.29%. It has been also found thatthe factor of safety of soil slopes without vegetation, with uniform vegetation, cylindrical vegetation and semi-spherical vegetation are 1.605, 1.653, 1.654 and 1.616 respectively. From the results, it is understood that plants with cylindrical root architecture increase the most significantly slope stability. It also appears that lebbek tree and royal poinciana may be low-cost and environment friendly alternative solution for the protection of embankment in Bangladesh.
Abstract: Embankments play a significant role in protecting cities from many natural disasters. Erosion and landslides of embankments and natural slopes are common phenomena occurring every year in Bangladesh. It has become a great concern of protecting embankments and natural slopes from failure. In many cases, traditional methods for protecting embankments...
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Challenges Facing Local Contractors Working with Chinese Contractors in Addis Ababa Building Projects
Solomon Esaiyas,
Girmay Kahssay
Issue:
Volume 8, Issue 4, July 2020
Pages:
87-96
Received:
15 July 2020
Accepted:
30 July 2020
Published:
14 September 2020
Abstract: Building construction projects particularly represents one of the largest sectors of the construction industry. Currently, the rise in construction of high rising buildings are observed in Addis Ababa, the capital city of Ethiopia. The number and size of building construction projects that are being constructed in the city are increasing through time and most of these projects were being carried out by Chinese contractors. Local contractors are also involved in those projects via a subcontracting strategy. However, it is not easy for local contractors to succeed by working with their foreign counterparts who have massive international experience and capacity. The aim of this study was assessing and identifying the challenging factors affecting local contractors’ performance in Chinese building projects in Addis Ababa. In order to achieve the objectives of this study, both quantitative and qualitative research approach were used with primary and secondary source of data. This study employed three types of data collection techniques such as a questionnaire surveys, interviews and observations. The target population for this study are local contractors and consultants involved in building projects that are carried out by Chinese contractors. In this study the researcher used Census/Parametric method of survey. That mean all target population of this study are included in this investigation, based on the consent and willingness of the participants. The Relative Importance Index (RII) was used as an instrument for analyzing data collected through questionnaire in tabular form by using Likert’s scale of five ordinal measures. Based on the analysis, it was found that the most challenging factors affecting local contractors’ performance in Chinese building projects were financial constraints, information exchange problems, cultural differences, unfamiliarity with Chinese work methodology and project complexity with a RII value of 0.84, 0.81, 0.77, 0.73 and 0.71 respectively. This study also identified and discussed the major cause and impact of those challenges and proposed measures to minimize their effect on the local performance in the upcoming projects through interviews from respondents and analyzed by using content analysis.
Abstract: Building construction projects particularly represents one of the largest sectors of the construction industry. Currently, the rise in construction of high rising buildings are observed in Addis Ababa, the capital city of Ethiopia. The number and size of building construction projects that are being constructed in the city are increasing through ti...
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Effectiveness of Joint Venture for Local Contractors in a Mega Project Construction
Issue:
Volume 8, Issue 4, July 2020
Pages:
97-105
Received:
4 August 2020
Accepted:
25 August 2020
Published:
14 September 2020
Abstract: Mega Construction Projects are defined as a very large investment construction project, or aggregate of projects, characterized by magnified cost, extreme complexity, increased risk, lofty ideals, and high visibility, in a combination that represents a significant challenge to the stakeholders, a significant impact to the community and pushes the limit of construction experience. The main objective of this study was to assess effectiveness of joint venture for local contractor to construct a mega project construction. The specific objective of this study was to determine the effective way of formation and implementation procedure, to determine legal procedures and steps of joint venture between local contractors, to analyze different kinds of joint venture among local contractors and to analyze risk of joint venture among local contractors to construct a mega project construction. The study used both qualitative and quantitative research, and data collection method used was interview, close ended questionnaires’, different books, articles, and web sites. The study uses also purposive sampling technique. The study revealed that the most motivation factor and reason to form a Joint Venture in construction is to obtain technology transfer, the most selection criteria to select a construction JV partner is ability, experience and skills of JV partner and to succeed in JV performance a JV management should be strong. The study indicated that some of the articles form the commercial code explains about JV need an amendment. The study also indicates legal issues should be considering in Ethiopian commercial code to facilitate formation construction JV. This study also revealed the best JV type suitable for local contractors to establish domestic JV is a contractual JV type. Finally, the study shows that the most factors to create a problem in construction JV is unclear partner roles and the dominant risk factor associated with construction JV is partner parent company in financial problem. Also, the study came up with conclusion that the existing legal norm context about CJV should be revised with amendment of some of the articles from the existing commercial code of Ethiopia.
Abstract: Mega Construction Projects are defined as a very large investment construction project, or aggregate of projects, characterized by magnified cost, extreme complexity, increased risk, lofty ideals, and high visibility, in a combination that represents a significant challenge to the stakeholders, a significant impact to the community and pushes the l...
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