The Cause and Significance of Crack and Structural Defect Assessment of School Building in Dire Dawa City (Case Study on Legehare Cracked School Building in Dire Dawa City)
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2017-06
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Addis Ababa University
Abstract
This thesis focuses on investigating the cause of significant crack on a five story School Building located in Dire Dawa city. The building is constructed with reinforced concrete frame structure with infill hollow block concrete walls. Large diagonal crack is observed on many walls coupled with minor crack on some structural members. The fact that this defect is observed within three to five service years of the building brought attention for investigation.
In this paper different approaches are followed to reach to a conclusion. Diagonal crack on many walls is the first cue for a possible differential settlement problem. Hence, Soil samples were collected around the building and different laboratory tests related to settlement have been carried out. According to the tests and settlement estimation result, there is a significant differential settlement among the foundations.
In addition to the settlement analysis, conventional structural analysis and design has been conducted to verify whether the building structure satisfies the revised Ethiopian code of ES EN 1992 and ES EN 1998:2015. The result shows that most of the structural members are found to be safe with the exception of only few columns and beams were over stressed.
The building frame was further analyzed by considering the effect of foundation settlement. The total settlement obtained from the soil investigation was used as a vertical ground displacement at the corresponding foundation levels and the building was redesigned for this displaced condition. The result from the design showed that significant number of structural members (beams and columns) do not satisfy the requirement of the Ethiopian building code.
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Structures