Browsing by Subject "post-tensioning"
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Item Structural Implication of Post-Tensioned Ducts in Prestressed Concrete Girders(2012) Massey, Joshua; Bayrak, OguzhanPrestressed concrete girders are used extensively to support bridge decks in highway bridges. The maximum length of a typical prestressed concrete girder is generally limited to what can be transported safely by trucks to the construction site – approximately 160 feet. With the use of post‐tensioned strands placed in ducts cast into the girders, multiple pretensioned concrete girders can be spliced together to form a continuous member along the length of a bridge, allowing greater structural continuity and more efficient use of materials. However, due to the location of the ducts in the relatively thin web regions of the girders, new failure modes can control the shear strength of the members. The structural implications of corrugated steel and plastic ducts cast in the web regions of spliced Tx‐Girders under the effects of compressive loading are studied in this report.Item Using Post-Tensioning in Large Scale Additive Parts for Load Bearing Structures(University of Texas at Austin, 2018) Chesser, Phillip C.; Lind, Randall F.; Post, Brian K.; Roschli, Alex; Love, Lonnie J.; Gaul, Katherine T.One of the perennial problems with additive manufacturing (AM) is the lack of inter-laminar bond strength between the layers, also known as z-strength. This can make the use of AM fabricated parts in load bearing applications problematic. This problem can be solved in some applications with post-tensioning. The use of post-tensioning in structures can be used to ensure that layer interfaces only see compressive stresses. This method is commonly used to strengthen concrete structures since concrete is weak in tension while strong in compression. This paper explores the successful application of post-tensioning to improve z-strength of large structures made with Big Area Additive Manufacturing (BAAM) where loads are significant. Theory and examples are presented herein.