924 research outputs found

    Evaluation, Comparison, and Design of Two Experimental Bridges in Tennessee

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    This thesis describes the design and evaluates the adequacy of the moment connection of an experimental two-span highway bridge designed by the Tennessee Department of Transportation. The Massman Drive bridge is an experimental design that unifies the construction economy of simple span bridges and the structural economy of continuous span bridges. The experimental connection, consisting of cover plates and kicker wedge plates, is used to connect the two adjoining girders over the center pier. As a result, the bridge is designed to function as a continuous bridge during the deck pour and behave compositely with the reinforced concrete deck under the live load. After completing a moment comparison analysis, it is concluded that the Massman Drive bridge indeed acts as continuous over the pier as it was designed. This thesis also compares the measured lateral wheel load distribution factors for two experimental two-span highway bridges designed by the Tennessee Department of Transportation. The measured load distribution factors were then compared to distribution factors from several methods commonly in use such as AASHTO 1996, AASHTO 2001 LRFD, and Henry’s Method. Results from American Association of State Highway and Transportation Officials (AASHTO) 1996 produced load distribution factors that were deemed to be conservative. Interior girder load distribution factors from both the DuPont Access and Massman Drive bridges compared well to the AASHTO 2001 Load and Resistance Factor Design (LRFD) specifications. Exterior girder distribution factors compared well with Henry’s Method, while the values from AASHTO were consistently high. Also, the factors were consistent between the Massman Drive and DuPont Access bridges

    X. Ductile materials under combined stress

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    Two GTPs are consumed on EF-Tu per peptide bond in poly(Phe) synthesis, in spite of switching stoichiometry of the EF-Tu·aminoacyl-tRNA complex with temperature

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    AbstractRecent observations indicate that the stoichiometry for the complex between EF-Tu · GTP and aminoacyl-tRNA (aa-tRNA) changes with temperature. At 37°C two EF-Tu · GTPs bind one aa-tRNA in an extended ternary complex, but at 0°C the complex has 1:1 stoichiometry. However, the present experiments show that there are two GTPs hydrolyzed on EF-Tu per peptide bond in poly(Phe) synthesis at 37°C as well as at 0°C. This indicates two different pathways for the enzymatic binding of aa-tRNA to the A-site on the ribosome
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