Structural Engineering

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Browsing Structural Engineering by Author "Abebe, Fitsum"

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    Design of Precast Pre-Stressed Concrete Girder Bridges as an Economical Solution for Congested Urban Areas & Waterways.
    (Addis Ababa University, 2016-04) Abebe, Fitsum; Adamu, Asnake (PhD)
    Ethiopia is going through in a fast development and transformation process. Among which large construction activities are undergoing in road sector as part of these development program. Consequently faster completion with high quality of these projects is required. Therefore adoption of up-to-date design and construction technologies is the only way out. However, the current bridge design and construction practice in many local contractors focuses on conventional type of bridge design & construction. This drift has affected the construction activity in such a way that by lingering the construction speeds, compromising construction quality and serviceability. The main reason is several design and construction professional believe that reinforced concrete bridges are economical and easy for construction. Likely this might be factual for limited span range. However, for long span bridges, this argument doesn’t always hold true. In another issue, bridge construction located in big cities must be safe and environmental friendly. This is to imply that the construction activity shall not affect the traffic flow and the day-to-day activities of inhabitants nearby. Since Environmental and Social impact is sensitive issue for bridge construction in urban areas, contractors and owners must use precast prestressed concrete girder bridges as a means of mitigation measure. This research has designed precast-prestressed concrete girder bridges in parallel with reinforced concrete counterparts' inorder to compare the design and construction aspects of each method. Consequently, the findings were interpreted in terms of construction cost, construction time and environmental friendliness. In view of that, the advantages of light weight Vs. long span capability of prestressed concrete girder bridges demand less number of steel reinforcements. Moreover as the precast units are repeatedly manufactured, the cost effectiveness also increases. With this regard, the research has clearly put a span range in such a way that a precast-prestressed concrete girder bridges are considered to be economical for the bridge design and construction projects.