Assessment of Potential Causes of Construction Delay in Tunnels; A Case Study at Awash-Weldiya Railway project
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Date
2017-10
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Addis Ababa University
Abstract
Extensive investments in transport are currently being carried out in Ethiopia. A substantial part
consists of railway projects with some underground/tunnel constructions.
This research deals with assessment of potential causes of construction delay in tunnels; a case
study at Awash-Weldiya railway project which is a new railway line in Ethiopia. The objectives
of the research were to: (1) assess the extent of construction delay at tunnels of Awash – Weldiya
railway project, (2) identify the key causes of delay and problems encountered during the
construction of the tunnels, and (3) to rate the impact of the causes of delay on the construction
time of the tunnels.
Questionnaire survey together with desk study was used to collect data on tunnel construction
delay. A desk study of 6 completed tunnels on the project were investigated and analyzed using
descriptive statistics. From the results it was found that 4 out of the 6 tunnels suffered delay. The
rate of delay on the delayed 4 tunnels ranges from a minimum of 12.84% to 119.41% of the
scheduled amount for each tunnel. The average delay of phase one tunnels of Awash-Weldiya
railway project was 38.8%.
From a number of causes of delay in literature, considering the opinion of professionals of the
project 47 causes were identified and prepared as a questionnaire. A total of 17 questionnaires
from professionals were collected. The findings from the questionnaire shows that Land
acquisition costs and right of way problems, Delays in payment from client, Late in approving
documents, and Project location were among the top ten causes of delay. The findings also indicate
that the main problems were right of way, flooding, quality, and health and safety problems.
Based on impact all the 47 causes were grouped in to three zones in a risk matrix: consequently,
14 causes had high impact, 31 causes with moderate impact, and 2 causes had minor impact on the
construction time of phase one tunnels of Awash – Weldiya railway project.
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Keywords
Delay, Risk sources, Tunnel