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Monitoring Performance of Joints in UHPC Bridge in Buchanan County, Iowa

出版	University of Iowa, 2020
URL	http://books.google.com.hk/books?id=k5ZF0AEACAAJ&hl=&source=gbs_api

註釋To optimize the ultra-high-performance concrete (UHPC) technology, a unique UHPC technology was developed by varying length and diameter of steel fibers. In comparison with other UHPC's, the proposed UHPC material exhibited higher compressive and tensile strengths. This paper presents the construction and performance monitoring of a new UHPC bridge utilizing an innovative UHPC technology from Korea. This is the third bridge built using UHPC materials in the US. Unlike other UHPC materials, the proposed UHPC material was produced with local cement and aggregates using typical ready-mix concrete equipment. This paper discusses experiences gained from the design and construction process including mix design, batching, delivery of steel fibers to the ready-mix concrete batch unit, and post-tensioning of precast slabs. Joints of the bridge decks have been monitored using strain gauges, mounted on each side of a joint, for several years. Based on the strain measured under the heavy truck loadings over several years, the magnitude of all strain values was very small, less than 20 micro-strains. The strains measured from each side of a joint were also quite similar indicating a good load transfer between bridge decks. Finally, a comprehensive 3D FEA bridge model was developed to estimate the bridge performance. Numerical straining analysis was conducted for the girders and their results were compared with the field data from the test sections. The finite element model showed a higher straining under the same truck loads. Based on the finite element model the maximum straining occurred in the top slab. While the maximum deformation appeared in the exterior bulbs.