Browsing by Author "Martha, Bimrew"

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    Performance Evaluation of Reinforced concrete Bridges without Plans: A case study on the assessment of Koka Bridge
    (Addis Ababa University, 2019-06-12) Martha, Bimrew; Abraham, Gebre (PhD)
    In Ethiopia, reinforced concrete bridges that were constructed in the early and mid of 20 th century exist in large numbers and are still in service. Due to the changing nature of vehicular load supported by these bridges and frequent permit trucks using the bridges, assessment of bridges to obtain their load carrying capacity is usually desired. The legal owner of the bridges, the Ethiopian Roads Authority, cannot provide necessary information such as as-built drawings, and properties of construction materials. The thesis demonstrates the assessment of load carrying capacity of old and deteriorated reinforced concrete bridges without plans (as built drawings or design drawings). Assessment codes give sufficient recommendations on how to load rate bridges that does not have sufficient data to be used in load rating. The safe live load carrying capacity of a highway structure is known as its rating. A case study has been conducted on one of the bridges along the heavily loaded route corridors bridges i.e. Koka River Bridge. Data obtained from historical records, field inspection and measurement besides design code existing by the time of construction of the bridge, 1953 G.C. has been used to prepare an effective Finite Element model on Abaqus/CAE 6.13-1. A moving tire load on the bridge deck has been used for the analysis, and the results obtained have been used to load rate the bridge for a permit load and ERA’s legal loads. The bridge was found to have sufficient capacity to withstand Legal loads and selected permit load, it has 50% and 8% reserve capacity respectively. However, it is recommended to maintain defects and distresses noticed on field inspection since they might lead to further deterioration of the bridge.