In Ethiopia, reinforced concrete bridges that were constructed in the early and midrnof 20rnth rncentury exist in large numbers and are still in service. Due to the changingrnnature of vehicular load supported by these bridges and frequent permit trucksrnusing the bridges, assessment of bridges to obtain their load carrying capacity isrnusually desired. The legal owner of the bridges, the Ethiopian Roads Authority,rncannot provide necessary information such as as-built drawings, and properties ofrnconstruction materials. rnThe thesis demonstrates the assessment of load carrying capacity of old andrndeteriorated reinforced concrete bridges without plans (as built drawings or designrndrawings). Assessment codes give sufficient recommendations on how to load raternbridges that does not have sufficient data to be used in load rating. The safe live loadrncarrying capacity of a highway structure is known as its rating. rnA case study has been conducted on one of the bridges along the heavily loadedrnroute corridors bridges i.e. Koka River Bridge. Data obtained from historical records,rnfield inspection and measurement besides design code existing by the time ofrnconstruction of the bridge, 1953 G.C. has been used to prepare an effective FiniternElement model on Abaqus/CAE 6.13-1. A moving tire load on the bridge deck has beenrnused for the analysis, and the results obtained have been used to load rate thernbridge for a permit load and ERAâ€™s legal loads. rnThe bridge was found to have sufficient capacity to withstand Legal loads andrnselected permit load, it has 50% and 8% reserve capacity respectively. However, it isrnrecommended to maintain defects and distresses noticed on field inspection sincernthey might lead to further deterioration of the bridge.